Venus near Orion "club-top" stars

Event Date: August 7th
Time: 5:04(.37) AM


Brief

   Orion's club--held in his right hand--has two stars marking the top of it: Chi1 and Chi2 Orionis.  Yesterday, Venus passed close to Chi1, about 0.7º apart from it.  Today is a little interesting: although not passing as close to Chi1 as yesterday, it is exactly the same separation from both Chi stars at the time above, at 1º 15' 14".  The first image shows a zoom-out with Orion's stick-figure included.
Using that, try viewing Orion a little earlier with a darker sky, and see if Venus' placement helps you find these stars with the eye alone.  Venus, unlabeled yet bright enough, is seen between the star labels.

Detailed

 If you look at them through a wide-field telescope or powerful binoculars, you can probably notice this.  Looking with the eye alone at this time is much more challenging: the sky is already getting brighter and the stars are 4th magnitude, with Chi1 slightly brighter.  It can also be difficult to see the star for two other reasons: there is a 71% waning gibbous Moon high in the sky, still washing it out somewhat, while this section of Orion's constellation is where the Milky Way passes through.  Although this arm, the Orion Arm, isn't as dense and thick-looking as the center where we see Sagittarius' Teapot somewhat dimly, it is still enough stars far in the "background" to make the Chi stars a bit more challenging to see.
   This second image is a 5º zoom-in, showing waxing-crescent Venus with the two stars.  This is a powerful binocular view, although a low f-ratio telescope can provide a large enough field of about 3º, to fit all three as well.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Another Summer Triangle??

Event Date: August 6th
Time: 6:00 AM


Brief
 
  At the end of yesterday's Summer Triangle entry, while talking about light refraction through our atmosphere for some stars, I mentioned Sirius, in comparison with some-what dimmer Vega.  While the latter sets in the west-northwest at this hour, Sirius is about 180º apart azimuth-wise, rising in the east-southeast.  The "dog star" follows Orion, which I featured back in July and now getting higher in the twilight sky.  Seeing Orion (no stick-figure this time) rising reminds us that we are entering our later months of the year, since it is a winter-riser in the evening.  Also, as seen in the image of both, look at Venus and Jupiter high above them.  What do you notice with them and Sirius on the rise?

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

Throughout June and July, we have seen Venus pull away from Jupiter gradually, and faster now since it is much closer to us and moves faster in prograde.  The two are now separated by 18º, after being less than 5º in late June.  However, look at Sirius, and remember how it is rising about four minutes earlier each morning.  Therefore, along with the movement of Venus and having the Summer Triangle in the west, do we have another easy-to-see triangle in the sky??  It seems that way, as it become more defined throughout the month.  In a couple of weeks, it is a fun target, which will be above the horizon while the Vega/Deneb/Altair trio still is, seen from our latitude.  How many evenings can you see both??  Also, when Mars isn't having one of its closest oppositions, Jupiter is brighter than it.  Sirius at magnitude -1.5, Venus being ranging -3.8 and -4.9 and Jupiter (range -1.8 to -2.9) are--on average--the three brightest targets in the sky after the Sun and Moon.
   Keep watching Sirius while Venus pulls away from Jupiter.  By September, we have a very attractive isosceles triangle.  Can you predict the exact date of that?  The "other" triangle will cover a huge amount of sky, and moreso than the standard triangle of the aforementioned dimmer stars.

Summer Triangle low in morning

Event Date: August 5th
Time: 5:30 AM


Brief
 
   The Summer Triangle dominated the sky all night long during July, albeit only dark enough to see it easily for about 11 hours at our latitude; some of that being during nautical twilight time.  Now that the sky is staying darker longer, and the Triangle is setting about four minutes later each morning, Vega and Altair become a little tougher to see through atmospheric pollution during morning twilight.  Deneb is still far enough north and east to see for awhile longer.
After showing the Triangle transiting a few times this season, I will show it low in the west-northwest this morning, seen below.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   As the Sun starts setting about a minute later each day starting late this month, Altair will be seen setting before Vega, being a little less than 30º closer to the celestial equator.  Vega is far enough north that it gradually sinks towards the horizon.  I have shown this before when placing the celestial grid in, and you can remind yourself of that HERE (include link).  Deneb is a little further north than Vega and east enough of it that as seen from our latitude, it sets about three hours after Vega.  Watch these two stars as they reach atmospheric pollution: Vega refracts enough light that it gives off a "rainbow-y" appearance, while dimmer Deneb has a green hue to it.  Other stars that resemble Vega are those a little brighter or just about as bright: Sirius is one of them, although we have to wait a few weeks until we see it rise further from our star's glare.  I will talk more on Sirius tomorrow looking east-southeast.

Mars, Saturn & Spica within 8º field

Event Date: August 4th
Time: 9:00 PM


Brief
 
   Mars continues to appear closer to Saturn with each passing day, and has been speeding up in prograde motion as we continue to pull away from it in orbit.  Saturn has started to move a little further east itself, yet much more slowly than Mars.  Near both of them is Spica.  With tonight's configuration, Mars is close to becoming the apex of an isosceles triangle with the other two. 
   The first image shows all three zoomed out labeled, while the second is a binocular field of 8º.  As Mars squeezes a little closer to forming a near equilateral triangle, shortly after Saturn and Spica's peek of encounter (2 days from now), I will show the trio again in a smaller field.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   Now within binocular view with Saturn, a little over 6º apart, Mars is slightly closer with Spica, while Saturn and Spica are slightly under 4.5º apart.  This is almost as close as these two will be for the next 28 years; Saturn will need to come all the way around the sky again for its next revolution and meet the star then.  Until that time, Saturn will pass by many other 1st and second magnitude stars, with varying numbers for separation.  When in prograde and retrograde, as we have reviewed earlier in the year, a planet can pass a star at one separation, and then be either closer or further the next time it passes it.  This is a result of being in a different part of our own orbit, being tilted from other planets slightly, and seeing it from different perspectives.  We notice this with Saturn's ring tilt.

Mercury joins Venus and Jupiter in east

Event Date: August 3rd
Time: 6:00 AM


Brief

   Shortly before Mercury reached inferior conjunction in late July, it reached perihelion.  Unfortunately, its retrograde motion had brought it too close to the Sun to see.  Even if it was far enough from the Sun to try to view, it would have been very dim, and the geometry of the western evening sky was becoming worse each day.  Now, as we start August looking towards the east in the morning, the geometry is improving at that azimuth.  Here is the elusive planet shown in orbit for this morning.  Notice that we are looking far from edge-on to the plane, north of it.  Therefore, Mercury's ecliptic latitude of (-)4.3º south, coupled with moving a bit further from the Sun towards aphelion over the next month, will slightly slow down its rate of brightening.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   Mercury's current retrograde motion is pulling it quickly from the Sun, and will gradually brighten, to become more visible.  By the middle and end of August, we will have Mercury at its best apparition since that bright greatest-elongation sighting in March.  At that time, it was far enough north of the Sun looking west.  Approximately half a year later, as hinted above, the geometry quality reverses for the time of day.  As a result, Mercury will become more and more north of the Sun, until it speeds up enough in prograde motion to fall back into the glare of the Sun.  Since our star is now rising later, faster, than it was during mid-June and July, that will give us a darker sky each week while Mercury brightens.
   Mercury is only magnitude +3.3 this morning and not visible with the Sun rising shortly after.  In about three weeks, after greatest elongation, Mercury improves in apparition for one more week before the declination gap between it and the Sun starts to shrink.  By then, it will be an easy target to view, below (unlabeled) Venus and Jupiter higher in the southeast.  Because the greatest elongation will be less than 19º, as opposed to 28º at best for some times of the year, the maximum gap between Sunrises will only reach 90 minutes.  Still, this will be enough time to easily see Mercury...especially as it brightens after that.  Look forward to a good pairing with the waning crescent Moon by mid-August, and I will talk more about that when we reach those dates.

Jupiter and Venus further separated: rise in dark

Event Date: August 2nd
Time: 4:00 AM


Brief

   Yesterday, when showing Orion with Sirius just beginning to rise, I intentionally left off the labeling of Jupiter and Venus, so as not to distract from my topic of discussion.  This morning, with Venus quickly approaching greatest western elongation, I will show it with a few number updates.  Jupiter rises well before Venus now, and far separated from it, compared to a month ago when the two were only about 5º apart.  Since then, Venus has waxed in phase, become a little brighter, and has moved further away from us in orbit.  Although we don't really notice these features with the eye alone, a telescope magnifying it at minimum 60x can show the phase. 
Here they are, with Venus' orbit showing, as well as the celestial equator and ecliptic.  Notice how Venus is still on the thick (closer) section, yet moving to the thinner (further) part.  The second image shows the planet zoomed in at a magnification of about 200x.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

While Venus is still two weeks from greatest elongation, it spends about a week before and after at nearly the same elongation: 45.7º.  During that time, with the geometry improving in the morning for the eastern sky, its rise-gap with the Sun continues to grow quickly.  The Sun continues to move closer to the celestial equator from our perspective, while Venus follows it further north.  This morning for example, Venus rises at 2:58 while the Sun does at 6:13: 3 hours 15 minutes different.  This gap grows slightly close to the time of greatest elongation and after it.  I will mention the date when the difference is the largest.  As for Jupiter, 15.4º away from Venus this morning, it now rises at 1:45 AM local daylight time, and well placed during morning twilight before the Sun's light makes it harder to see.  Remember, this happens shortly after Sunrise.  If you follow Jupiter during the time that twilight's later stages happen, it can be easier to continue tracking it with the eye alone, albeit a short time.

dog days, and the rising star to represent

Event Date: August 1st
Time: 6:12 AM


Brief

  Over the last several years, my astro-blog colleagues would introduce the month of August by talking about the "dog days".  Why?  Although too close to the glare of the Sun to see easily, the first week of the month is when the "dog star" Sirius crosses the horizon just minutes before the Sun.  As the brightest star of Canis Major, Orion's larger companion of two dogs, hence the wording dog days.  The star is seen low in the image below, just below Orion's stick figure, while Canis Major's stick figure shows the star as the dog's nose.
NOTE: as always the case of my images, most Sun-glare and atmospheric pollution being absent will make the star seem much brighter than originally seen at this altitude.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

  Other people may use the term dog-days in ways having little or no link to astronomy: being the middle of summer in the northern hemisphere, many locations deal with very warm or sweltering heat, that can bring out the "dog" in people mood-wise: whether that of aggressive dogs fighting, or people involved in "heated" arguments, either can be considered.
   Getting back to Sirius marking Canis Major's nose, some jokingly consider him as "Rudolph the white nosed doggie" of the heavens!  Okay, so I just thought of that off of the top of my head, yet maybe I am not the first!  As August progresses, and we see Sirius higher at this time of morning each day, it will become easy to see quickly.  The Sun continues to have a rise-time gap increase by more seconds each day, making it darker at this time of morning each week between now and the end of daylight savings time in early November.

Pisces' stars labeled, dim deep sky

Event Date: July 31st
Time: 4:00 AM


Brief

If the image below of Pisces--featured yesterday--looks complex and makes you dizzy, that is intentional: it is too reflect some of what I talked about yesterday about the dim constellation, of two fish tied, with a star further away representing the knot of the rope (or string?).  To learn more about the ancient constellation, click here.
   I also talked about deep sky sighting within constellation boundaries, although such are very far away and few to easily see with a telescope.  Since Pisces is viewed nearly perpendicular to the galactic plane, the way Virgo is seen 180º away, it contains several galaxies, visible in telescopes.  However, none of them get much attention when we look in deep-sky wonder books and magazines.  To help somewhat, I labeled where some of those galaxies are.  Being perpendicular to our own galaxy, very few nebulae and star clusters are near Pisces; M2 being an exception, shown in Aquarius a few entries back.
Here is the image, including some of the labeled deep-sky.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   I labeled several stars in Pisces, yet most of them are between 3rd and 5th magnitude, making the constellation hard to see in light polluted skies.  Wait until it is near transit, as seen above, with no big Moon in the sky for nights that such is the case.
   Besides the galaxies marked (little green circles), I also included the celestial meridian and ecliptic.  As mentioned yesterday, this is a part of the sky where the Sun gains northern declination quickly.  If you remember my first entry about the March equinox on the 19th of that month, I showed the Sun passing through Pisces in the daytime, obviously not highlighting the constellation then being light.
   Finally, despite most galaxies being dim, I kept the Andromeda Galaxy (M31) labeled and highlighted in the top left corner.  If you forget where to find the eastern fish of Pisces, it is not far from the galaxy, marked by the star Tau Piscium.  For some odd reason, that fish is only marked by that star, while the western one is highlighted by the circlet asterism made up of 7 stars.

Pisces on the rise, following Aquarius

Event Date: July 30th
Time: 1:00 AM/4:00 AM


Brief

   Today, the clock is forwarded only two hours past yesterday's date, to look a little further east along the ecliptic.  That is, Aquarius' zodiacal neighbor to the east, being Pisces.  I have shown the former over the last two days, and at the hour above, the latter clears the horizon, as seen from our global coordinates of 38ºN and 122ºW.  Pisces however, has no bright stars seen easily through atmospheric pollution, so waiting for it to get much higher helps see the shape that its stick figure gives us.  Let's first take a look at it as it clears the horizon, and then when higher up for those who need to wait that long--light pollution levels pending.  For the first, I kept Aquarius' figure visible to show that the two rise only a short time relative to each other.  More on that shortly in the detailed section.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

Although I do not include the ecliptic for image one, looking at the altitudes of both constellations reminds us that this the section of the Sun's path where it starts to rapidly gain northern declination when moving along it in February and March.  If I did have the ecliptic showing, it would form a low angle with the horizon.  Besides earlier Sunrises and later Sunsets as a result of declination change northbound, this is also in this part of the sky where we see the Moon rise only about 26-30 minutes earlier each day, with the time depending on the phase: (near) full Moons rise in the evening, while old, waning crescent Moons rise only a short time before Sunrise and seen low.  This isn't too important to remember, unless you want to try to predict Moonrise times without the help of online almanacs!  Minus the Sun for now, for every zodiacal constellation that rises up to the time of twilight, we are looking further north towards our axis.  Gemini, which I showed a few days ago, is the most northern of the constellations with Taurus close to the same in declination.  The Sun visited those constellations during June, and we see them both now low in the sky during [morning] nautical and astronomical twilight respectively.
For a final note on Pisces, getting back on topic, it is almost perpendicular to the galactic plane, so nearly void of any deep sky, Messier-type of targets.  More on that tomorrow.

More on Aquarius' position and stars

Event Date: July 29th
Time: 11:00 PM


Brief

Yestersday, I showed Aquarius with its stick figure. Although most of its stars are too dim to see easily, they trace out the Water Bearer quite well for if we look carefully at it.  First, the image I will include is the same as yesterday's first one...sortof...minus labeling and the stick figure!  The azimuth is identical to yesterday's looking east-southeast.  If you see the "arrow" of Capricornus to its southwest (right), Aquarius' extended legs extended, his torso, and then a lopsided "loop" showing his "water bowl". 
**This is one of the rare times that I will ever show an image with no labeling or stick figures, yet it should help you recognize this part of the sky when dark enough to see low.**

Detailed

   The second image is a near-duplicate of yesterday's of Aquarius and M2, including the figure and star names.  Did you easily identify the Aquarius stars without the aid of the stick figure?? 

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

   I normally do not duplicate images so soon for journals on consecutive dates, with the exception of showing how our revolution around the Sun shows a slightly change in altitude; that can be noticed today also if we look closely.  This time, I also labeled a few more stars that could help identify it if you looked for those before anything else.  Good luck seeing it in the night sky, where there are no stick figures, hence putting in image one, once again. 
Use the images of Aquarius' stick figure and labels when outside viewing, or one of today's popular "apps" on mobile devices if you point it towards Aquarius: such can help enhance viewing dim astronomy constellations and as a reminder of where they are.  However, try to also get to know your sky well by studying it aid-free.  When you go back later to your software or app, see how easily you can identify dim stars as well as brighter ones!  Many of the labeled above are 3rd or 4th magnitude.  If you don't see the most eastern ones at first, wait until the entire constellation gets higher out of atmospheric pollution.

Aquarius and M2 rise late-evening

Event Date: July 28th
Time: 11:00 PM

Brief

During late evening hours, a cluster that receives little attention by most beginning astronomers, rises in the east-southeast: a globular cluster labeled M2.  If you remember earlier this month when I talked about the Crab Nebula, the comet-lookalike that inspired Charles (M)essier to create his deep-sky catalog, I mentioned this one labeled as M1.  M3, I talked about earlier in the year as a fine globular cluster which gets high in the sky. 
   Let us look to see where M2 is in relation to a +2.9 magnitude star in Aquarius-- its parent constellation. 4.8º away from the cluster, is the star Sadal Suud.  At almost the same magnitude, Sadal Melik, another star not from M2, is extremely close to the celestial equator (1/4º away).  M2 itself, is only 3/4º away from the equator, which is about the same separation of Polaris from the north axis.

Detailed

M2 is slightly dimmer than 3, yet looks about the same.  One reason for this perhaps, is that 2 and 3 are estimated to be almost the same distance away, at 37,000 and 35,000 light years respectively. 
As for what else is worth knowing about M2, it is magnitude 7.5, 23 arc-minutes in in size (about 3/4 that of a full Moon at perigee), 100,000 stars and possibly visible to the unaided eye with a dark enough sky.  This last part is worth remembering, because--like Aquarius itself--M2 is far from the galactic plane, and there is no interference of a Milky Way band behind it.  If you remember my showings of constellations of Gemini and Sagittarius, they are backed by the billions of stars that make up our Milky Way.  These stars can easily distract the eye from deep sky objects visible to the eye alone.
   Compare the two with their images following the detailed section, for a close up of both M2 and M3 in 1º fields.  M3 is low in the west-northwest during this hour in July, and we will slowly lose it to the horizon as the months get us into the fall. 
   Which cluster of the two do you like better...one over the other?  When viewing, remember to use an eyepiece that magnifies it enough, yet not small enough in focal length that contrast degrades; one leading to the cluster losing its brightness against the background sky.  M3 is larger in angular size, at 48 arc-minutes, although it takes a dark sky to see lots of the stars far from the core.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Gemini on the rise, before the Sun

Event Date: July 27th
Time: 5:30 AM


Brief

   A little earlier this month, I showed Orion rising as a morning constellation shortly before Sunrise, reminding us that we are nearing Summer's mid-point.  We are a little close to that now, happening in about a week.  Along with Orion, which I include the stick-figure for today shown a little higher in the sky before Sunrise, we have another constellation rising in the east-northeast, which we haven't seen much of since May evenings: Gemini!  The twin stars of Castor and Pollux are the only ones to see easily with atmospheric pollution washing out the other dimmer ones.  Here they are below, with Orion seen to the right.  Venus and Jupiter continue to separate above them further west, with Aldebaran not far away.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

 Castor rises a little less than two hours before the Sun, while Pollux rises about 30 minutes after Castor.  Since these stars are far enough north, a little moreso than the Sun at the June solstice, it didn't take long since that day for them to be visible.  As the Sun continues to move a little more south each day and the stars rise about four minutes earlier each day, we will clearly see them low above the horizon in a couple of weeks.  With Sunset also happening a little later each day as a result of moving further from the east-northeast azimuth, it will also give more dark time to see these two 1st-magnitude stars.
   With constellations such as Orion and Gemini visible rising west of the Sun, it gives us a preview of our late-fall/early-winter evening sky.  Granted, the Sun will be on the other side of the sky when that comes and we will see the constellations for several hours in long darkness.  Enjoy them now for the short time that they can be seen this morning, and a few minutes longer each day.

northern constellations seen high and low

Event Date: July 26th
Time: 12:33(.38) AM


Brief

   Yesterday, I showed the Summer Triangle at transit, as we approach the transit time getting closer to midnight.  This morning, I will slide the sky down more towards the horizon, while keeping the horizon visible.  On the rise already, are four constellations which I haven't talked about in over a month: Pegasus the [flying] horse, and [chained] Princess Andromeda, [vain] Queen Cassiopeia, and Andromeda's [boyfriend] hero Perseus.  Here they are shown below, with the Summer Triangle still visible higher up.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

Although I didn't choose to put the celestial grid into today as I did yesterday with an overlap, I kept the celestial equator in; I did this to show that all of these constellations are northern hemisphere ones.  Of course, this means that viewers in the mid-southern latitudes have little or no viewing of these constellations during most days and hours of the year.  The further south the viewers are, the less they see of the stars that make them up.  Cassiopeia is far north, so one of the hardest to see even at low-value southern latitudes, near the equator.  Perseus is a little further east of the others yet far enough north that once it clears the horizon, some of its stars spend almost an entire 24 hours that way.  A few of them are even circumpolar as seen from our latitude, although spending a few hours just above the horizon and atmospheric pollution washing them out, makes us forget about them until more easily visible again in the northeast.

Summer Triangle: high near midnight

Event Date: July 25th
Time: 12:37(.33) AM


Brief

   The Summer Triangle's transit time is nearing midnight for our longitude.  It will transit closest to the exact minute August 2nd and 3rd, about two minutes later and earlier respectively.  Of course, for a few hours before and after transit during the night, we can still enjoy seeing the three stars very high up.  During the two hours sandwiching transit, Vega and Deneb don't seem to change altitude, since they are far enough north on our celestial dome.  Take a look at the alt/az and celestial grid (grey) overlap with the Triangle in the image below, to see what I are referring to.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

Vega (upper right), which transits a little over an hour before the center of the triangle transits.  I talked about the center and how to find it earlier in the season; review here if you forget.  For now, look at Vega's position with the celestial gridline just below it (red-south): the space between the meridian and where Vega is shows that there is very little change in altitude.  As seen from our mid-northern latitude, Vega only changes in altitude by 12º between transit and the time above.  This may not seem like a small amount for an hour elapsed, yet remember that Vega transits less than a degree from zenith, and has several hours to set after transit.  The rate of altitude change varies as it circles the north axis.  Deneb, which transits a little north of zenith and further from it than Vega, spends an even longer time setting after transit.  Altair spends the least time above the horizon, although still a decent amount of time, being about 9º in northen declination.

waxing crescent Moon south of Sun: terminator

Event Date: July 24th
Time: 8:24(.01) PM

Brief

   The Moon may be already a little over 1/3rd illuminated and separated far enough from the Sun to be visible for much of the evening.  Because of a declination difference of about 19º however with our star, the Moon sets only about 3 hours later.  Despite slowly gaining ecliptic latitude back towards ascending node, the Moon is moving further south each day for the next few.  During this time of year, evening western skies show us some of that azimuth's worst geometry of the year-- concerning apparition for the Moon and any planets if they were to be visible.  We saw this with Mercury during its last swing east of the Sun, as it faded and sank quickly.
   Here is the Moon and Sun at our star's official set time.

Detailed

   Despite only having a few good evening hours to see the Moon, don't forget to look for it also during the afternoon, when it rises shortly after 12 today.  That gives us 8+ hours to see it before Sundown, including its terminator.  The terminator is not the Arnold Schwarzenegger movie character; astronomically speaking, it marks the dark part of the Moon's disc where the Sun either rises or sets, for waxing and waning Moons respectively.  If an individual [astronaut] was able to walk quickly enough to stay on the terminator on the Moon one minute after another, he or she would constantly see the Sun rising or setting. 
   Here is another zoom in of the fat, crescent Moon for this evening, with a field of view of 1º.  Even if the software cannot provide the real image, it does well, providing a sample of the terminator for each phase.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Jupiter near the Hyades; further from Venus

Event Date: July 23rd
Time: 4:30 AM


Brief

Venus (-4.8) and Jupiter (-2.1) are 9.8º apart this morning, and only visible together in binoculars with a large enough field.  They are almost just as fun to view with the unaided eye, now that they rise well before the Sun, which is starting to move south a little faster each day.  It is still well north of the celestial equator however, by almost 20º, a little over a degree south of Jupiter.  For an update on positioning, more than anything else, here they are shown below, with the sky almost completely dark during astronomical twilight.  This gives us a chance to see the Pleiades star cluster clearly above them (unlabeled), and even the Hyades, once it comes high enough above the horizon.

Detailed
Jupiter is already getting close to its maximum declination for where it is in orbit; close to where the Sun is in late-May/early June.  Venus is slightly south of the Sun, yet moving slowly enough in prograde that it is separating quickly from the Sun and nearing greatest eastern elongation.  Rising at 3:08 AM, about three hours before the Sun, we see Venus for over an hour above the horizon before it starts to dim with the Sun's light brightening the sky.  Jupiter rises 50 minutes before Venus this morning, giving us a chance to see it clearly during dawn, higher in the sky than Venus.
   In this second image below, we see Jupiter moving closer to star Epsilon Tauri in the Hyades.  Just as Venus had some close encounters with some of the easier-to-see stars in the cluster earlier this season, Jupiter passes near some of them as well.  This morning, they can be seen with binoculars or a wide-field telescope 1.8º apart.  The Hyades stick-figure is drawn out, and the field is 7º.  With this large a field, the entire "V" shape of the Hyades can fit, for those wanting to see it that way with Jupiter fitting as well.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Mars closing-in on Saturn & Spica

Event Date: July 22nd
Time: 9:00 PM


Brief

Mars continues to gain on Saturn, and now less than 13º apart.  As Saturn moves much more slowly in prograde motion, it is gradually closing in on Spica for their last close encounter of this revolution for Saturn.  I will mention more of that in the detailed in about three or four weeks prior to their closest conjunction.  For now, I will show the planets and Spica with the Moon west of them, setting and waxing as a 17% crescent at the time above.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

 For months now, as a result of prograde and retrograde motion and the difference in ecliptic latitudes, Spica and Saturn have had a variety of separations.  Since late fall, it has ranged from just under 5º to 7º, so always binocular-friendly during that time.  In a little over 2 weeks, after one more separation of under 5º, the separations increase each year for about the next 14; about half a revolution for Saturn.  Only its retrogrades will bring it a little closer each time to Spica, while its prograde motions move it further east until opposite the star on the celestial dome.
   Look at the image one more time: what is that bright star above Mars similar in color?  The answer is tomorrow, and why it is important to keep track of it setting in the west during these later summer weeks until season's end.

Orion zoomed and his "illustration"

Event Date: July 21st
Time: 5:30 AM


Brief

   I will stick with Orion for this entry, following yesterday's morning intro for him, and show another zoom-in of the constellation's stick figure with two more dimmer stars labeled. In my previous entry, I featured Betelgeuse, a red-giant, and Rigel a very hot younger star.  The other two that are shown, as seen below with the constellation and dimmer stars making out the rest of his figure, are Bellatrix (Gamma Orionis) and Saiph (Kappa Orionis).

Detailed

  Bellatrix and Saiph mark Orion's left shoulder and right knee respectively. Betelgeuse marks his right shoulder and Rigel, his left foot.  As the following image shows with the illustration, we see how this is determined.  I placed it over the stick figure, and took away the star labels.

click on imags to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Despite a recognizable stick figure resembling a person, the illustration is much more detailed: it shows his putting his shield up to Taurus the bull, charging towards him.  While more stars make up a club in his right hand, these "weapon" stars are 3rd and 4th magnitude.  They are much dimmer--and perhaps ignored--by most people viewing Orion in dark skies.  The belt is easy to see from almost anywhere without a Moon in the way, while Betelgeuse and Rigel and both brighter than those.

Orion: now rising before the Sun

Event Date: July 20th
Time: 5:30 AM


Brief

   Orion is starting to make a return in the eastern sky, giving us our first chance to see some of its stars since mid-spring.  The belt's stars rise vertically as seen from mid-northern latitudes, with further-north Betelgeuse slightly earlier, and southern Rigel, later.  When we saw Orion setting during the spring evenings, Rigel was the first to go, followed by Betelgeuse.  This is similar to how we will see Altair setting before Vega and Deneb for the Summer Triangle later this season, although it is the last to rise.  As shown below in the first image, I will put the celestial grid in to further show the declinations of the stars. 

Detailed

   The furthest west star, Mintaka, is less 1/2º from the celestial equator.  When we start seeing this star all night long in the fall, it will nearly trace out the equator with its local path.  In the zoom-in shown below, I label it and the other belt stars as well.  Mintaka was the first to rise, and the celestial equator shows slightly north of it.  The zoom in is 4x.
   Looking at the belt's stars relative to the equator, it is often mentioned that it is the asterism that "splits the sky".  When viewing the constellation of Orion from the same latitude south, as I did from an Australian location during the spring two times, not only would Orion appear upside down; he would rise at a different angle.  Instead of from his side, he would rise feet first, and the head would be seen later.  Staying with our hemisphere and latitude, here are the stars shown below.  I will label more stars when Orion is easier and higher to see in this part of the sky at the end of the month.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Pluto transits before midnight

Event Date: July 19th
Time: 11:47(.42) PM


Brief

   At this time of year for the next few decades, Pluto is at, or near transit in the late evening hours.  With a revolution period of about 248 years, as a result of being a mean distance of over 3 billion miles of the Sun and Earth, summer evenings for the northern hemisphere are the time to try to find the dwarf planet, at magnitude 14.
   First, is a zoom-out showing Pluto not far from the galactic center in northern Sagittarius.  Its interesting orbit, inclined 17º from the ecliptic is shown as well, reminding us of a main reason of Pluto's demotion back in 2006.  The celestial equator and ecliptic are presented to show that Pluto is still far south and low for viewing from our latitude, despite a good ecliptic latitude of 3.8º.

Detailed

  A telescope of 12" or larger is recommended to see Pluto any bigger than just a pinpoint, helping gather enough light to still magnify up to 5-600x.  A telescope too small, such as 8" may still help find it, although it will be very difficult to differentiate from stars of the same magnitude. 
   The light reflected from Pluto to our eyes takes a little less than 5 hours to reach our eyes.  Thinking that the light from our Moon takes only a little over a second, that makes it even more interesting that Pluto (being smaller than Moon) can still reflect enough light for us to see from here, granted that optical aid is required.
The second image shows a zoom-in of about 500x as mentioned above, to further show that only the most powerful of telescopes easily pick up detail of Pluto's surface, which is all but featureless.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Venus apparition improves--still near Jupiter

Event Date: July 18th
Time: 5:30 AM


Brief

   We are only a few weeks away from Venus' greatest western elongation (g.w.e).  It seems as if we acknowledged that not long ago when it happened east of the Sun in late March; one of the first Venus highlights of my blog when starting it about a week before that. 

   Here is Venus with its orbit showing, as we see it approaching g.w.e.  Since it started rising before the Sun the morning of June 6th, Venus has separated from the Sun by almost 42º and rising 2 hours, 46 minutes earlier.  It continues to slightly change configuration with (unlabeled) Jupiter and Aldebaran, above and upper right respectively.  Notice the difference in brightness for these three.

Detailed

  Since that last greatest elongation, Venus have encountered best apparent magnitude, greatest brilliancy, the last transit of most of our lifetimes across the Sun and recently, best magnitude and greatest brilliancy again.  Since I spent alot of time on that when east of the Sun, I will hold off on the calculations on finding when greatest brilliancy is.  Refer back here for when it reached greatest brilliancy then.  Also, there has been so much to talk about with Venus and Jupiter near the star clusters and each other, that took some entry date-space this month and I didn't want to ignore those attractive sightings.
   As the geometry of the eastern morning sky improves and Venus continues to reach g.w.e., the time-gap between it and the Sun rising will increase quickly.  Even after g.w.e., Venus will remain separated enough from the Sun that the gap continues to increase for several more days.  When observing Venus in a telescope, it has shrunk from nearly 1 arc-minute in angular diameter to about half that at 34 arc-seconds.  The percent illuminated is 32, putting it very close to greatest brilliancy.  Take a look at the phase and size here, with a field of 1/2º.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Crab Nebula (M1) before Sunrise

Event Date: July 17th
Time: 5:00/5:43(.34) AM



Brief

   Yesterday, I ended the entry with a mention of a "smudge" in the first image shown there; today I will identify it.  As seen in small telescopes, the Crab Nebula doesn't look colorful, although large telescopes help give it a slightly pink-purple hue; stacked photos can reveal this also.  Overall however, just viewing the nebula, it looks grey.  The nebula is 1.1º from star Zeta Tauri mentioned yesterday while being occulted by the Moon.  The first image below uses a 2º field showing both the star and "Crab".  The time for this entry is 30 minutes earlier than yesterday, to show a darker sky for seeing the Nebula.  As mornings pass, with later Sunrises and the nebula higher before Sunrise each day, it will be further out of atmospheric pollution and look much more clear.  As seen in the first image below. It is 7.5º high at the time above.

Detailed

   This next image is a more impressive view of the Crab, showing more color.  The field of view is 1/2º, which is of magnification of about 120x, To obtain such a view, a telescope of at least 10" minimum is recommended, to gather enough light and not sacrifice contrast in the meantime; finding the happy medium helps seeing the Nebula very well, and especially when it reaches high altitudes.
   Now, how long has this nebula been viewable?  It is the remnants of a star which exploded as a supernova nearly 1,000 years ago (1054).  At 9th magnitude, it is not visible to the eye alone under even the darkest of skies.  At 11 arc-minutes, it is 1/3º the angular size of a full Moon at perigee.  Find out more about the nebula here, also numbered by Messier as the 1st in his catalog.  If you recall from my M3 entry during the spring however, that globular cluster was the first he discovered, not numbered.
According to the info about the Crab provided by the software, "he observed this nebula when he was searching for Halley's Comet in 1758, inspiring him to develop a list of celestial objects that may be mistaken for comets".  Hence, the Crab being the 1st,

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

 

moon "visits" [star] Zeta Tauri

Event Date: July 16th
Time: 5:00/5:43(.34) AM


Brief

  Let's continue following the Moon, after its fun grouping with Venus, Jupiter and Aldebaran.  This morning, we even get to see our satellite occult a 3.0 magnitude star: Zeta Tauri, the southern horn of Taurus.  El Nath, which I have shown and talked about a few times, is the northern star.  The first image shows a 5º high-power binocular view of the star and Moon, about 43 minutes before the start of occulatation.  The Moon's light makes the star very difficult to see the star with the eye alone, so I am refraining to show them zoomed out. 

Detailed

   As we see the Moon rise, its lit portion moves closer to Zeta Tauri, and starts covering it up at the second time listed above.  This second image shows a magnification of the star (centered) a second before the Moon covers it.  The Moon's orbit doesn't always let it occult this star, as a result of the precession of the nodes, talked about here several times.  Unfortunately, the sky is too light to see the star by the time that the occultation finishes at 6:48(.11).  As a result of Zeta Tauri disappearing behind the lit portion of the Moon, it may be very difficult to see during the last few minutes before occultation begins. Viewers in Hawaii and any islands a little further east of there, get a good view of the end of the occultation, although the pair is low in the sky.
Finally, Also with this first zoom in, notice the "smudge" at the Moon's upper left about 1º away.  What is that??  Find out tomorrow.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

moon, planets and Aldebaran: tight grouping!

Event Date: July 15th
Time: 5:00 AM


Brief

   This morning has been one well worth looking forward to: we have three solar system bodies within a 7º circle, being Venus, Jupiter and now, the waning crescent Moon!  Besides that, Aldebaran is close to all of them, as the Moon and planets have given this star alot of company...from our vantage point anyway!  The first image shows the planets, Moon and star as a quartet, with the Pleiades star cluster seen above them.  Nothing is labeled, so to give a clearer imitation of what we see.  It doesn't get too much more interesting than this, when it comes to deep sky and solar system body groupings!  Don't forget of course, about the Hyades cluster, which is visible as well.

Detailed
 
   Aldebaran is 65 light years away, in comparison to the Moon less than a quarter-million miles away; Venus is about 43 million away, although moving further from us each day; Jupiter less than 500 million miles away, coming a little closer between now and opposition this fall. 
   Although the closest separation of Venus and Jupiter is past us, they will remain within binocular view together for about one more week.  Venus is starting to pick up in prograde quickly while much slower Jupiter is losing speed in that direction.  While Jupiter will stay near Aldebaran for awhile longer, including the time of its back and forth with retrograde and pro-grade resuming, Venus will be far from it from then.
   As we look at this second image, it does not show the tightest binocular field of Aldebaran, planets, and the Moon.  Instead, I include the stars of the Hyades along with them, increasing the field by a couple of degrees.  Since the magnification is not much different between a field of 7 and 9º, this makes it more interesting, I think.  I put in the Hyades stick figure to more clearly identify the stars that make it up.  Even though the stick figure extends to Aldebaran, once again, it is not part of the cluster.  Why the software makers decided to extend the line to it, I can only guess that at one time long ago, the star was mistakingly thought to be part of the Hyades.  Once light year distances of the Hyades stars were found to be much further from us than Aldebaran, along with the red giant being much cooler and larger than them, it makes sense to think of it as separate.  Aldebaran is also a much older star than the cluster's, hence the red color as opposed to yellow or white.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Moon approaches Jupiter and Venus...again!

Event Date: July 14th
Time: 5:00 AM


Brief

   Last month, I did a 3-part series of Venus, Jupiter and the Moon when the latter was approaching the planets.  The three had an attractive grouping June 17th in a binocular field, talked about here (show link).  Over the next 24 hours, we can enjoy watching the Moon approach Venus, Jupiter and the Hyades cluster again.  The good part about watching them all this time, is that the Sun is further out of the way; Venus and Jupiter have risen 4 minutes earlier each day while the Sun has risen several seconds later on average each day.  As a result of this, as mentioned yesterday, we get to see the grouping at a better altitude during twilight, and even better, in dark skies earlier than that, albeit low in the sky.
   The image here is similar to yesterday's first one, showing how the Moon has waned a little more and now closer to the planets.  This time also, I included the Moon's orbit.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

Look where Jupiter is in relation to the Moon's orbit: in the way, so to speak!  As seen on the other side of the world, which is where the Moon will be seen when the it reaches Jupiter's spot in the sky, there will be an occultation.  This will be the case for the next few times that the Moon meets with Jupiter, until our satellite's orbit moves it north or south of the giant planet; that, and/or it changes enough in ecliptic latitude.  For us in North America, we will miss the occultation as the two will be below the horizon.  When they rise, the Moon will have already moved further east of Jupiter.  However, we are in for another fun grouping of the two with Venus and the Hyades!  See tomorrow's entry for more on a very neat grouping.

Moon, bright planets, bright open star clusters

Event Date: July 13th
Time: 5:00 AM


Brief

   *I revert back to double-section writing today with the detailed [section] to follow.*  There is alot to talk about with Venus and Jupiter still seen well together within most pairs of binoculars.  At 6.3º apart, the angle is still small enough to enjoy and higher in the sky now by the time that the Sun rises.  Since having our earliest Sunset of about 5:46 last month, our star now rises less towards the north and about 11 minutes later than it did that day.  That may not seem like much difference, yet it will become later faster as the Sun starts to lose declination faster late this month and into August.  Before we get ahead of ourselves too much with that in mind, let's look at the altitude of the two bright planets close the the Hyades star cluster, with the Pleiades northwest of them and the waning crescent Moon even further west.  Venus is 17º high and Jupiter 24º high, which is high enough to see above most hills and trees.

Detailed

Looking closer at Venus and the Hyades, let's zoom in and include the stick figure for the asterism: it appears that Venus--along with [star] Aldebaran--acts as an extension of the Hyades eastern limb of the "V" shape. 

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

As mentioned several times this season, Aldebaran is not part of the cluster, and of course we know that Venus isn't.  As for Jupiter, its prograde motion means that it is moving further from the Pleiades and closer to the Hyades.  The rate of pro-grade for Jupiter has been about the same as Venus' over the last couple of weeks, hence the close separation over that time.  Venus was in retrograde, went stationary after a fast "deceleration", and will accelerate in pro-grade throughout the rest of the time that it is on this west side of the Sun.  When it reaches superior conjunction in about 7 1/2 months, it will naturally be moving faster in pro-grade than the Sun, eventually on the east side of it again and an evening target again.

more on Uranus and Neptune at same altitude

Event Date: July 12th
Time: 3:48(.38) AM


NOTE: no double-section today, as the topic is very similar to yesterday's

  This is part two of the Uranus/Neptune same-altitude series I am featuring, ending with this one; it is not the most interesting topic perhaps, so a no-brainer to keep it limited, compared to a Venus-Jupter-Moon grouping, shown last month!  In any case, the two planets' positions on the celestial dome only change by a hair, figuratively speaking.  Therefore, the only thing to really notice is the time above, which is about 3 minutes, 56 seconds earlier than yesterday.  Considering the difference, this makes it more clear why I even bother mention the slight movement of the planets: our stars, particularly those along the celestial equator and ecliptic rise this much earlier each evening, +/- a second depending on the exact declination and where viewed from on Earth.
   Shown below is an image very similar to yesterday's second one with the zoom in.  This time, look at the difference in time and notice that the spacing of the planets between the altitude gridlines are still the same.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Uranus and Neptune: same altitude before dawn

Event Date: July 11th
Time: 3:52(.34) AM

Brief

   Uranus and Neptune are now well placed shortly before the start of astronomical twilight.  Since Neptune is barely visible through most small telescopes at just slightly brighter than 8th magnitude, this is important to remember when trying to use a star field to find it.  Once we start to get too far into morning twilight, it is no longer visible, and Uranus (+5.8) disappears from our telescopes shortly after.  Even for nights that we have a dark enough sky to barely see Uranus with the unaided eye (unlike this morning with the Moon in the way), it is only a few arc-seconds in size, so difficult to see.  For this morning, I will show them at the same altitude at just under 41º, which I have done before.  The first image is a zoom-out of the two, while the second is a zoom-in (2x).  Both show the alt/az grid.  By looking at the second, we see that the two planets are precisely the same space between two of the gridlines.  Also, the image azimuth is close to  centered between them at azimuth 150º.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   Since the planets have moved a little further in prograde since I last showed this not long ago, the altitude value is slightly different.  Since then, Neptune has started retrograde, while Uranus is about to approach stationary a little later this week.  As a result of the timing and different movement of the two for some dates, there will be more slight variances in altitude over the next several months.  Also, Uranus is in a part of the sky for which it changes faster in declination; it is where the Sun is in early spring, when our days grow longer faster as a result of declination change for the Sun; that is a result of our tilt.  Each year this decade, as Uranus also increases faster in declination than Neptune, it also separates further from it.  Because of that, as the years continue to pass, there will be years for when Uranus is rising when Neptune is about to set.  They will not have another closest encounter with each other during our lifetime, as it will be the year 2165 when that happens!  Any humans still existing by then--if any at all--will see them at a spectacular 0.8º apart January of that year!  The last time that they were at their closest was not too long ago in comparison: late October of 1993.  Doing the math, given that Uranus has to catch up with Neptune with every revolution, that is almost 172 years between conjunctions, or a little more than twice the time it takes Uranus to revolve around the Sun.  Neptune's revolution is a little under 164 years, while Uranus' is short of 84 years.

Mars and Saturn's orbits pre-conjunction

Event Date: July 10th
Time: 9:00 PM


Brief

   Although I have shown Mars and Saturn a few times as they become less separated, I haven't talked much about their orbits.  Looking below, as I show them along with the celestial equator and the ecliptic.  By doing this, we see Mars close to passing descending node (two weeks from today) and sinking fast below the ecliptic for weeks after that.  Let's take a look to clarify, with Mars now only 19º  separated from Saturn.  In about a month, the two planets will be at their closest for this time.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   In the meantime, not only is Saturn much slower moving in the same direction; its orbit keeps it north of the ecliptic for another 7 years.  By the time Saturn reaches the point of the sky that Mars will be in just seven months, the Red planet will have caught up with it twice...almost three times.  Of course, since Saturn moves almost through 1/4 of the sky during that 7-year period, it means that Mars has to catch up with it, every time it revolves around the Sun.  Mars revolves every 687 days (just over 98 weeks).
Saturn revolves roughly 1/15th the rate of Mars, meaning that Mars has to move about 1/15th further than one full revolution to catch up with Saturn for a conjunction with each revolution.