Venus approaching Virgo stars

Event Date: November 5th

Time: 5:30 PM

Brief

   A couple of days ago, I revisted Venus, nearing the double star Porrima.  Today and tomorrow, we see them nicely paired together, with a separation of 1.3º this morning, low in the east-southeast.  Tomorrow, they are a little closer together, and separate quickly after that as Venus continues to move quickly in pro-grade motion.

   The first image shows the two zoomed out while the second shows them zoomed in with a 2º field.  The first also includes Spica, which Venus will pass next in a little less than 2 weeks, a little further than from Porrima.

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

Detailed

   At the current separation, Venus is easy enough to see with the eye alone provided that the sky is dark enough.  If they are too close, as we saw in the case of Venus and Regulus about 5 weeks ago, the brightness of Venus gives a "multi-starpoint" effect, glaring in the way of most stars of magnitude +1.0 and dimmer.  While a little further apart, that glare doesn't get in the way.

   As also seen in image two, is a 6.9 magnitude [HIP-catelog] star that Venus passed by, with a peak close to 0.2º when the two were below the horizon.  Now, we see Venus slightly further from that star.  Although I didn't label it, I bring this to readers' attention, since Venus may still have some fine telescopic close-encounters with background stars before we lose it to the glare of the Sun.  If you know which stars after Spica are close the the ecliptic, can you figure out which ones that it will pass and how closely?  Keep in mind the change in ecliptic latitude for Venus and see how many you are right with when predicting!

Mars apparition improving

Event Date: November 4th

Time: 5:30 PM (standard time)

Brief

Let's review the position of Mars, now that it is gradually appearing higher each evening when first visible.  Since the Red Planet is staying nearly the same magnitude this month, the slowly-improving geometry of the west-southwestern sky makes it easy to pick up low in nautical twilight with the eye.  With a telescope, try finding it during civil twilight, as shown in this image.  As noted above, remember that we are now back to standard time, and the Sun sets an extra hour earlier.

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

 

Detailed

   Mars sets two hours, 6 minutes after the Sun this evening, and that gap stays the same for about a month.  Although the geometry of the sky improves between now and February in this part of the sky, let us not forget that Mars eventually has the Sun catch up with it, from our point of view.  Therefore, we eventually lose it in the Sun's glare, not seeing it again easily until the middle of next year as a morning target.  Until that time, still put a telescope on Mars, and try to pick up a little bit of color from its rust.  Remember that we continue to pull further from Mars daily and as a result, we see it slightly smaller as a disc between now and when we lose it to our eye.  At 4.5 arc-seconds, Mars is holding steady at +1.2 in magnitude.  As it approaches perihelion early next year, that will help keep it in the low +1 range, despite still moving further away from us towards conjunction [with the Sun].

   

  

Venus near Porrima

Event Date: November 3rd

Time: 7:00 AM

Brief

   This is the final morning before daylight savings ends.  As a result, it is the last post-7:00 Sunrise until early winter, when our days are short enough that it takes a little after the top of the hour to see our star clearing the horizon.  While we still have enough darkness at 7 this morning, take a look at Venus still high above the horizon and not far from a neat double star: Porrima [Gamma Virginis].  Venus will not get extremely close to this 3rd magnitude star, yet close enough that we see the two as a fine pair a few days from now.  Before talking more about Porrima, here it is near Venus: 3.2º separated, zoomed out a little south of east.

Detailed

   At 13 arc-seconds and waxing to 81% this morning, Venus' angular size is less than 1/4 of what it was during inferior conjunction: about 1 arc-minute then.  As for Porrima, it has a companion that moves enough that moves quickly around it.  Find out more about that here, logged last year by the Urban Astronomer (a fellow Blogspotter).  As mentioned there, the 170 year-period that the two stars revolve around each other means that at times, we cannot see the companion easily unless a powerful telescope is used.  Other times, we see the companion through a small telescope, when separated enough.  Take a look at the star, and find out what type of telescope you need.  Remember that increasing the magnification with a small telescope when they are very close doesn't guarantee improving seeing the separation.  Instead, a telescope with more light gathering capability has better resolution, gives that opportunity to zoom and easily see the separation.

   This second link shows a photo of the two together, which the software will not let me do.  What the software does let me do, is show a binocular view of Porrima and Venus within a 5º field.  

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

This will not be enough to see the phase of Venus, yet when using real binoculars, we may barely detect the gibbous phase, with low magnification.

Mercury pass greatest elongation, near Antares

Event Date: November 1st

Time: 6:30 PM

Brief

   With Mercury past greatest elongation, it now starts to dim faster (mag +0.1) as it quickly approaches inferior conjunction.  Once it begins retrograde motion early next week, it will seem to "plunge" towards the Sun.  That is, it is moving east to west, while the Sun moves west to east.  Given the poor apparition of Mercury already, this means that the time to see it will be very brief to eventually not at all, over a period of days.  Here is Mercury in orbit, along with the celestial guidelines.  Once dark enough, red-giant star Antares is seen not far from it, to Mercury's east-southeast.

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

Detailed

By mid-month, we lose it for a little over a week, and it re-emerges from the glare of our star by month's end in the morning sky.  Once again, as mentioned a few entries ago, that apparition of Mercury will be much better than this one.  Also, as Mercury approaches conjunction this month, it also approaches perigee.  As we approach our aphelion with the Sun, that is another reason why can look forward to Mercury in late-November/early December: it will be a little brighter when high enough.  Look forward to then, yet in the meantime, try to still find it as an evening "star" while it is still barely bright enough to see through atmospheric pollution.  Remember to try viewing at a high elevation with little or no obstruction along the horizon, for better results.

Sun transiting lower during autumn

Event Date: November 1st

Time: 12:52(.20) PM

Brief

Now that we are past Halloween, we are are quickly approaching the halfway point of the autumn season for the northern hemisphere.  As a result of this, the Sun has already sunk quickly south of the celestial equator by several degrees, and doesn't have much further to go.  Not only is this a reminder of daylight savings ending in 3 days where it happens in the world; it is also a reminder that the official start of winter is only about 7 1/2 weeks away.  

Let's look at the Sun's position, on the ecliptic, relative to the celestial equator, when at transit.

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

Detailed

At 14º 45' south of the ecliptic, the Sun has less than 9º to go before reaching its furthest southern point.  As a result of it sinking, our length of today at out latitude, (Sunup to Sundown) is only 10 hours, 34 minutes.  Compared to what it was on the September equinox, of aprroximately 12 hours, that is a fast change over just 5 1/2 weeks.  Of course, latitudes further north of us have even less daytime and north of the arctic circle, the Sun is already below the horizon all "day" long.

   As we progress through the rest of autumn, the Sun starts to lose declination more slowly; by early December, the change is even slower and the last week of autumn has it hardly change at all.  The reverse of this holds true through the winter season, and we will monitor the Sun's position then.  Until that time, get ready for some darkness early in the evening because starting November 4th, that will be the case.  The good news??  An earlier Sunrise in the morning, albeit only for awhile.  With the Sun still sinking fast and the point of transit happening slightly later each day now, dark mornings come back and stay for awhile.

Pleiades high near midnight

Event Date: October 31st

Time: 2:16 AM

Brief

   Happy Halloween!  Let's take a look at the Pleiades star cluster on this date at transit, for an important reason.  

We'll get into this link later, regarding the cluster on a celestial dome level.  For now, keep in mind that the declination of the Pleiades--being just a little more than that of a June-solstice Sun--gives us a chance to see it high.  The image here shows it at transit time, with a big, waning gibbous Moon a small number of degrees away.

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

Detailed

By bending the sky above, we are able to show the Pleiades about 76º above the horizon.  At a latitude precisely 13.6º south of us, about that of Hawaii and many heavily-populated Mexican cities, the cluster reaches exact-zenith at transit.  Getting back to the link in the brief section, it is worth noting that the time above for the image is that of daylight savings.  Of course, centuries ago without daylight savings, the time of transit would be a little closer to just-after midnight, depending where one is in a time zone also.  Regardless of being exact, what is important to note is that on this date, the Pleiades is high enough in the sky, that it appears about the same altitude for a couple of hours.   

To find out more why a high Pleiades is significant, read more of the text for the link above...quite fascinating, for those who think about it.  In the meantime, put high-powered binoculars, or a wide-field telescope on the cluster (~25-30x) to get an excellent view of many more dim stars.  How many can you see--or even count--on a clear night, once it is high enough?

Big Dipper: at, and below horizon

Event Date: October 30th

Time: 10:51(.07) PM

Brief

The Big Dipper transits high as seen from our latitude, and about 12 hours later, crosses the meridian again.  As seen from 38º N., only one of the stars is below the horizon, being Alkaid.  Despite that, the others can be hard to see also, since they are close to the horizon and atmospheric pollution gets in the way.  Also, unless from a high point looking at miles of clear horizon, obstruction from trees and structures can easily get in the way.  In the case of the image below, I will "cheat" by taking away the horizon-landscape, showing the entire stick figure of the Dipper.  Take a look here, as its center-point crosses the meridian.

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

Detailed

   For a U.S. viewer near the western Canadian border, (northern Washington, Montana, North Dakota and Minnesota), the entire Dipper can be seen above the horizon, with Alkaid being a few degrees above it.  I have had this experience, seeing it slightly further north in very southern Canada (about 50 or 51º N).  As a result, seeing it on an early August night around 1 or 2 AM, is was decently high above the horizon.  The further north a viewer is, the higher it is at this point, and makes circles around zenith at near-pole latitudes.  Of course, it is impossible to see the entire Dipper viewed from many southern latitudes, and near the equator, it can only be seen for a limited number of hours for certain months.  I suppose that we should feel fortunate to beable to view this asterism not only from a good latitude (for those of us living north), and that it is easy to identify with what (seems like) a household object.

"northern" Moon: rising and transiting

Event Date: October 29th

Time: 6:30 PM/12:27(.17) AM

Brief

   The full Moon rises early now at this time of year, with earlier Sunsets.  Called the "Hunter's Moon", this one provided good light for the hunters during their season of attacking animals that would provide them food during cold winters, if not beyond.  Also, similar to the Harvest Moon last month, this one transits high in the sky, as seen from mid-northern latitudes.  As we get closer to the winter solstice for this time of year, we see full Moons where the Sun is 6 months before and after this date.  Therefore, if we convert to the Sun's position of April 29th, we can imagine it in the middle of spring transiting near zenith at lower northern latitudes; those at mid-northern latitudes see it a little lower, while those at far north latitudes see it in the sky almost 24/7, never below the horizon if far enough north.

   Here is the Moon rising in the first image, low in the east-northeast.  Being further north on the celestial dome, the Moon makes a slow "curve".  The celestial grid displayed, marks this, as I have shown in the past. The ecliptic is as well.

Detailed

   As the Moon became high in the sky earlier this morning, still nearly at the crest of fullness, we can see using the altitude/azimuth grid, how high we see it.  Take a look here.

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

Using the altitude markers along the meridian, we see that the Moon transits at 65º.  The maximum that we see a Moon transit at this part of the sky [at this celestial longitude] is about 3 1/2º further north, when the precession of the nodes puts the orbit as many as 5 1/2º north of the ecliptic; it is just under 2º this year, yet either way, we see the Moon very well placed for any hunters out there needing a night's-worth of extra light.  Enjoy the next few full Moons as they transit, as they do so higher than others during the year.  For example, when they transit near the northern hemisphere's first day of summer, they are low in the sky, where the Sun is seen near the first day(s) of winter.

Saturn in Sun's glare, Venus still high

Event Date: October 28th

Time: 7:30 AM

Brief

   Although Saturn is just starting to emerge from the Sun as a morning "star", it is worth mentioning the ringed wonder anyway, for what is to come.  Venus, which has been west of the Sun since immediately following its June transit, is gradually coming back towards the Sun, approaching superior conjunction early next year.  Saturn, rising about four minutes earlier each day, will quickly approach Venus for an impressive conjunction late next month.  Until then, the impressive geometry of the morning, eastern sky means that Saturn will become north of the Sun quickly for the next several weeks.

Here are the two planets, as Saturn is still in the Sun's glare yet labeled.  The orbits and ecliptic show as well.

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

Detailed

   Currently, Saturn and the Sun are about a little over 32º separated, and that will change by a little over a degree on average, between now and the planets' closest encounter.  Between now and then, we can anticipate Saturn becoming visible to the eye in about 2 weeks.  Since the Sun is rising later by a little less than a minute a day during the next few weeks, that means that we will see Saturn an extra 4-5 minutes before it each day once visible enough to see; the exact timing depending on what time of late October/November we are talking about, since the earliest Sunset is currently only about 6 weeks away.  As the Sun continues to move further south, it also means that we have more dark minutes overall to see stars in the sky, and a longer time to see Venus.  It is a result of this, as Venus slowly moves towards the Sun in separation, that for Sunrise over the next few weeks, we see Venus at about the same altitude each day.  As Sunrises start to rise earlier again gradually in mid-January, coupled with a much poorer geometry of the eastern sky, Venus will be seen much lower.  Until then, admire it at about magnitude -4, between now and early February, easily visible.

   

(long) Hydra, and (small) Crater

Event Date: October 27th

Time: 7:00 AM

Brief

There is a very "long" constellation, which as a result, takes about 8 hours to clear the horizon in its entirety: Hydra.  Considering that this constellation represents a sea serpent, this makes sense.  It is south of the celestial equator and consists of dim stars which can easily get buried in atmospheric pollution.  Alphard, at a magnitude just a little better than 2nd, is the brightest to see of Hydra at this hour of this day.  The others are 3rd and 4th magnitude.  Near the serpent, is the cup Crater, also consisting of dim stars.  To learn more about the myths and findings of these two constellations, read this: 

As for their appearance before looking at those, here they are with stick figures, rising in the east.  During spring months, these two are evening constellations,

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

Detailed

   I often wonder how some constellations such as Hydra are imagined, taking into account how much sky that it crosses.  To compare, Crater only takes a small amount of sky, as shown above.  Some other constellations take even less space, while others may stretch as much Hydra (i.e. Eridanus, the River),  Whether a lot of space or very little, we can be blessed to have a sky with enough space for 88 constellations for us to appreciate at all times!  Can you name them all?  Even if I studied them, I would probably struggle to do so.  Once you find a book or website to learn them all, try looking at the sky without the aid of stick figures (mobile app, for example).  "Purists". so to speak, enjoy trying to reform their own images of star patterns, yet that is a story for another day.  Long, short, big or small, enjoy the constellations, and any patterns that you can form in your head.

Jupiter accompanying Winter Circle stars

Event Date: October 26th

Time: 7:00 AM

Brief

   The Winter Circle, of which we see most of the stars now rising in the mid-evening, has many of its stars get very high when they transit, and then taking 6-8 extra hours to set-- depending on which star we are talking about.  Sirius is the furthest south, with Rigel next.  Procyon and Betelgeuse are a little further north, being that of the celestial equator.  Capella, Castor and Pollux are far north of the equator, with the former nearly halfway between the equator and north celestial pole.  Here they are, setting and become less visible with the Sun rising shortly after.

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

Detailed

   This circle (or "G"-shape) of stars takes up a huge chunk of sky as a "sortof-asterism".  What I mean by that, is that it is not categorized as one.  The shape that the stars make up is quite abstract, and taken from several constellations; that being, compared to most asterisms taken from one, two, or in the case of the Summer Triangle, three.  In this case, Orion, Auriga, Gemini, Taurus, Canis Major and Canis Minor are the five constellations featured for Betelgeuse/Rigel, Capella, Castor/Pollux, Betelgeuse, Sirius and Procyon respectively.  Whether you want to use Castor or Pollux alone or not, is fine; it is commonplace picking one, compared to using both.  Labeling both twins somewhat throws off the flow of the curves.  Either way, enjoy the triangle for what it is: rising one after another in the east. transiting high, and setting into the brightening Sun.

   Finally, remember that among the stars this year and next, is a much brighter one being Jupiter, at magnitude     -2.7.  As mentioned a few days ago, Jupiter moves back and forth in prograde and retrograde, with the latter movement when reaching oppositiion the Sun.

Mercury nearing greatest elongation/dichotomy

Event Date: October 25th

Time: 6:30 PM

Brief

   Mercury is almost at greatest elongation, setting a maximum 57 minutes after the Sun for the next few days.  It is still a decent apparition for being so far along in this swing east of the Sun, at -0.1.  To put this in perspective, the star Vega is just slightly dimmer, at magnitude 0.0.  Of course, Vega is high and far out of the glare of the Sun right now, making it easier to see first before Mercury.  Also, Mercury is buried in atmospheric pollution once finally visible with the eye alone.  At a separation of 24º, Mercury is just short of 7º in altitude at the time above, being the middle of civil twilight.

   The image shows Mercury and its orbit, along with the celestial guidelines, looking west-southwest.

Detailed

   Although Mercury is still south of the ecliptic and seen low, it will very slightly improve in apparition over the next few days.  The geometry of the western evening sky also has improved since late August.  Unfortunately, we lose Mercury to the glare of the Sun and then inferior conjunction, yet will have it for a much better apparition during the last month of the season.  Until then, the Sun continues to move south and therefore, darkness comes quickly with a shorter twilight time than we have on average at about the time of the equinoxes.

   This second image shows the elusive planet at more than half-illuminated (dichotomy), yet nearing it, which is often the case before time of greatest elongation.  The planet will wane faster between dichotomy and old-crescent fast, although through a powerful enough telescope with a small field, we will see the angular size of the planet grow.   Although low to the horizon, I will magnify the planet to about 200x.  The current percentage illuminated is 64%.  Look very closely, and even if looking small (6.5 arc-seconds), you may notice that slight gibbous curve.

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

Jupiter rising, zoomed with Moons

Event Date: October 24th

Time: 9:00 PM

Brief

   I have shown Jupiter transiting several times since it emerged from the Sun post-conjunction about 5 months ago.  This time, I will show it rising, along with the celestial guidelines and its orbit.  Although currently slightly south of the ecliptic, Jupiter's declination is far enough north that we see it almost as long each night as a first-day-of-Summer Sun (in the daytime), transiting the late-night sky, and still above the horizon by the time daylight washes it out in the west-northwest.  

   The first image is a zoom-out showing the lines, along with the unlabeled Pleiades and Hyades Star Clusters not far from the planet.  The second image is a zoom-in showing the Galilean Moons visible as well.  The magnification of that image is about 200x.  

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

Detailed

   When looking at image two, notice the different positions of the Moons since I last showed Jupiter about a week ago at transit.  They change from day to day, with different orbit sizes, although seeing Jupiter over the course of several hours near the time of opposition lets us see smaller-orbit ones move gradually: Io, in particular.

  Since conjunction, Jupiter has risen about an hour earlier every 15 days, mainly as a result of our revolution yet also its own.  That is, when Jupiter has moved at its fastest in prograde, as the case for days surrounding conjunction, is moved at its fastest west to east against the sky and therefore, the rises times are closer to the 3 minute mark instead of 4.  Now in retrograde, with opposition in early December, it is currently rising at intervals a little bigger than the sidereal 3 minute, 56 seconds.  For example, 4 minutes, 14 seconds tomorrow, and 4:15 the next day.  By the time of opposition, the interval increases to well over four minutes earlier.  I will remind viewers of that on opposition day.

   When magnifying Jupiter when low, a stable atmosphere and very light winds are a must, to see its features somewhat clearly.  Since atmospheric pollution is an issue while rising it is better to wait until it is high enough to see out of most of the pollution.  Remember to try to keep it in your telescope at and shortly after Sunrise, as it is bright enough (-2.7, near its peak for the year).

transiting Moon: appearing tilted at times?

Event Date: October 23rd

Time: 8:42(.54) PM

Brief

   There are times that when we see a transiting Moon, whether a fat crescent or medium-sized gibbous, it seems as if it is "leaning to one side"; making it appear as if it is still rising slightly before transit or setting after it.  To further show why this is, I included the ecliptic along with the Moon's orbit.  As shown, the Moon is close to its maximum ecliptic latitude.  That, coupled with the constantly changing "arc" of the ecliptic with the horizon, we have an angled Moon.

   While the first image is a zoom-out, showing the orbit and ecliptic, the second is a 1º zoom-in.  Can you notice the difference, between these Moons and one for it appeared perpendicular to the horizon?

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

Detailed

   As we have examined several times over the last several months, there are "points" along the not-shown celestial equator, where the ecliptic  cuts through it: the equinoxes.  If the Moon's orbit puts our satellite near ascending or descending node while at transit, we see the Moon at an even more extreme angle at transit.  There are also times for when the Moon transits (a) furthest from the nodes and (b) near/at the longitudes along the ecliptic where the Sun is at the solstices.  If the latter happens, we see very little tilt of the Moon.  Take a look at the Moon with every transit when visible enough [in phase] and not too close to full.  If you time the transit just right, do you notice a tilt...or none at all?  If you have trouble seeing at first, look at the terminator. and notice it that way.  important: try this with the eye alone and not a telescope, unless your 'scope is very level with the ground.

Mars celestial path: 3 months long

Event Date: October 22nd

Time: 6:45 PM

Brief

Yesterday, I showed Venus' celestial path as it has moved through zodical constellations rising during the late hours of the night, and wee hours of the morning: Gemini, Cancer and Leo.  This evening I will show Mars' celestial path, as it also has moved quickly in prograde over the last few months.  I will start the path on July 1st, and notice where the increment markers are, related to each other.

I hid the horizon, so to show the entire path.  The Sun has of course, moved through the part of the sky where Mars was between July 1st through now, and taking the horizon away helps see the change in gaps between increment markers.

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

Detailed

Even without the horizon, we can see from Mars' path, the angle that the ecliptic makes with it not far from parallel.  The geometry of this part of the horizon during the evening is not favorable to planets not far east of the Sun.  However, as we watch Mars over the next couple of months, that will change.  Not only does the planet stay about the same magnitude, but it eventually becomes more north of the Sun by December.  We will continue to have Mars with us throughout the fall somewhat easily visible, yet still in atmospheric pollution, not easy to see for long.  Using optical aid, try to find the planet.  There is also a very gradual change in phase for Mars, as it goes to the Sun's far side: we have seen it as a waning gibbous since opposition, yet now, it is waxing, seen from our angle.  The waxing is hard to notice however.  At 94%, we will see Mars wax nearly to full, before it falls out of view during the mid winter months, into twilight and the Sun's glare.  It is magnitude +1.2, and holds steady as it approaches perigee near the time of conjunction.

Venus' celestial path, west of Sun

Event Date: October 21st

Time: 6:00 AM

Brief

   During the weeks sandwiching inferior conjunction, Venus moves from prograde to retrograde as a disappearing evening planet, and did the opposite when rising west of the Sun in the morning.  Since resuming prograde, the planet has increased in this direction rapidly, moving through Gemini, Cancer and Leo.  Shown below, is the celestial path of Venus, as it passed through these constellations, and now in eastern Leo.  I bent the sky  downward to show enough sky to show the entire path over the last two months.  Although it is not easily obvious to view, the 10-day interval markers are slightly further apart as the path moves west to east.

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

Detailed

Back on October 3rd, Venus had a brilliant passing with Regulus.  When I viewed them before Sunup, I couldn't even see Regulus with the eye alone, because of Venus' brightness.  The planet resembled a star with lots of "points", because of its "sparkle (er, glare).  With a telescope, seeing them about 1/4 degree apart, seeing Regulus is much easier of course.  The separation between them was about half that of a Moon's diameter.

   Also, although I haven't put in the ecliptic, we can see how the path of Venus somewhat traces out our Sun's path.  Of course, since inferior conjunction, presenting Venus transiting the Sun for the final time this century, it has decreased in ecliptic latitude, reached ascending node, and now increasing in ecliptic latitude.  It is a result of that, along with the good geometry of the eastern morning sky, that Venus is high and easily viewable with less atmospheric pollution, for the next few weeks.

   If you want to get an idea of how quickly Venus is now moving past the stars, mark its position relative to Regulus, and notice over the course of the next few weeks how much that gap increases.

Mercury separating further, yet low

Event Date: October 20th

Time: 6:45 PM

Brief

   Mercury is getting close to greatest elongation.  As a result of poor geometry during the first month of fall for the western evening sky, coupled with our perspective of Mercury's plane from our point of view, it has maintained a declination that has been further south of the Sun.  That, since we first started seeing it finally emerge far enough from the Sun.  Looking west-southwest, we see it separated from the Sun by about 23º, which is less than a degree from greatest elongation.  At magnitude -0.1, it is just slightly brighter than Arcturus to its upper right.

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

Detailed

   Although just slightly brighter than Arcturus now, that will change by month's end, when Mercury starts to dim faster, reaching inferior conjunction not long after.  On average, the change in magnitude of Mercury can decrease quickly between emerging from the Sun after superior conjunction and greatest elongation, and then speeds up even more to the days just before inferior conjunction.  This time however, Mercury started approaching the Sun a little over a week ago.  As it came closer the Sun and therefore us, it means that we have seen the planet increasing in angular size at a rate fast enough to almost override its rate of waning.  Simply put, there is enough light still reflecting back to our eyes.  As Mercury approaches inferior conjunction, it will further approach perihelion with the Sun and therefore, will not be quite as close to us at that point.  That is why we will start to see a big drop in magnitude.  Overall for the best Mercury apparent magnitudes, it is best to see it just after superior conjunction just short of perihelion, while Earth is also near perihelion with the Sun; the latter happening in early January, when that is also a good time to see Mercury in the evening with a good apparition.  Look forward to that, then!

Arcturus: morning and evening viewing

Event Date: October 19th

Time: 7:00 AM/PM

Brief

   About a month ago, I showed Arcturus setting, and mentioned its meaning as the "ghost" of the Sun.  Now, the Sun has moved much further south of where Arcturus is in declination and therefore, the earlier Sunsets have made it seem as if Arcturus becomes visible at about the same altitude daily.  

This first image shows the celestial grid to show both Arcturus' declination of 19º N, and that of where the Sun is relative to the celestial equator.  Arcuturus is still 17º above the horizon at this time, and sets a little more than 1 1/2 hours later.

Detailed

   Although Arcturus sets a little less than 4 minutes earlier each evening, it becomes visible about a minute and a half earlier with each passing evening.  This latter scenario is a result of the evening daylight shortening; the western half of the sky becomes darker faster as the Sun dives below the horizon.  

   What is interesting is that although we see Arcturus set earlier, it is north enough that at this latitude, we can also see it before Sunrise, as the second image shows further down.  Backing up 12 hours to 7 AM, with the sky still dark enough, the star is easily visibile.  I kept the celestial grid in, to remind that the local path of Arcturus and other stars can be traced by looking at the celestial grid closest to them.  When magnifying, sometimes I can get extra gridlines very close to stars to show the local path a little more accurately, in that manner.

   Not long after the times shown for the images, there is a second for when they are precisely the same altitudes for a split second.  Can you find out when that is, or at least guess, when seeing them in the morning and evening?  In between seeing it rise and set, we have about 10 1/2 hours for when only a powerful telescope with clear enough skies can find the star...when the Sun lightens the sky!

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

Mars, Antares, Moon triangle

Event Date: October 18th

Time: 7:00 PM

Brief

   Let's close out the Moon/Antares/Mars combo series, by showing the Moon in a position that lets us see all three within a binocular field.  Through an 8º, or more easily 9º field of view as image two shows, we can fit all three.  As the waxing, crescent moon has moved past both, it creates a triangle with the three.  As it moves further east each day now, that triangle disappears, while Mars continues to creep up on similar-looking Antares.  

Here are the images, with the zoom-out followed by the zoom-in.

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

Detailed

   Despite both having a pale red appearance, remember that as a planet in our solar system, Mars is only about 187 million miles from us this evening, at just over 2 a.u.'s.  Antares, with a solar radii of about 2,700 as a huge, huge star, only appears as a small light, at a distance of 604 light years.  With a luminosity of over 387,000 "Suns", it is no surprise that at that distance, we still see it as well as we do.  Mars has crept up a little on its "twin", as it is now a little less than 4º apart.  As mentioned earlier in the week, different ecliptic latitudes will lead Mars a little further north of the star.  They are still a good pair to view with the eyes along, if you wait to view them long enough after dark.  Give the Sun a chance to get far enough below the horizon, and remember that twilight is slightly shorter each evening.  After Mars passes Antares, it will continue to move through the southern constellations.  However, since the Sun is gaining on it in declination, it also means that we see Mars very slightly higher in the sky each day as soon as we can see it.

Antares joins Solar System bodies--temporarily!

Event Date: October 17th
Time: 7:00 PM


Brief

   This evening, I will forward the clock ahead by 15 minutes from yesterday's entry.  Mercury is about to set and slightly visible from high elevations to avoid obstruction.  Of course, atmospheric polluiton gets in the way as well.  Besides that though, we have a trio seen in the southwest: the Moon, Mars, and red-giant star Antares.  Looking at the first image, we see the two together with the Moon.  As a result of the twilight sky, that sometimes helps notice the red color of each better with the eye alone.  With Mars, it may seem much more faint however.  The planet's orbit is displayed as well.

Detailed

   As a result of Antartes' ecliptic latitude being a little over 4º south of the ecliptic and Mars being ecliptic latitude of only about 1º south, they will only get as close as about 3 1/2º.  Many people confuse Antares for Mars, especially when the two are similar magnitudes, as they are now; Mars is far enough away from us to only be at magnitude +1.3, while Antares is about 1.1º.  Over the next several evenings, they will be close enough to be seen close enough with binoculars.  Watch Mars pass north of Antares as it continues to move slightly faster movement in prograde motion.  Also, remember that with this "acceleration" (from our perspective) and the slowly-improving geometry of the west-southestern sky, we will start to see Mars a little higher in the sky at Sunset each week, between now and December.
   The second image shows Antartes and Mars 4.2º separated, in a 7º binocular field.

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

Moon closes in on Mercury: Saturn low

Event Date: October 16th
Time: 6:45 PM


Brief

   Let's show something fun.  What, you ask??  The Moon creeping up on Mercury (-0.1), which is getting closer to greatest elongation.  The planet has been very gradually separating from the Sun, and now enough so that we can see it for a brief time once the Sun gets low enough.
   Before getting to the "creep", the first image shows the Moon and Mercury just under 1º separated.  As seen from locations such as Hawaii, viewers can see the Moon moved a little more east towards Mercury, and the pair closer together. Also, being a latitude closer to the equator, it is a little easier to see Mercury above the horizon.  Mercury's orbit shows as well.

Detailed

   As I showed two days ago, the Moon was a very old, waning crescent.  Although it is just past new now and not easily visible until it is dark enough, we will see it better tomorrow.  The geometry of the southwest, evening sky is only slowly improving this month, meaning that the Moon is low to the horizon; the Sun's glare gets in the way as well.  
   The second image is a fun one, for if you have a telescope and/or the right optics to give a wide field: center on the Moon, and watch as Mercury slips into the field.  Granted, time is short, as the Moon sets only 51 minutes after the Sun.  Note that the orbits of the two--although not displayed--means no occulation, although we see that every so often if the nodes for their orbits meet at that right place.

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

Jupiter and its Galilean Moons, near Hyades

Event Date: October 15th
Time: 10:00 PM/4:31(.27)AM


Brief

   Jupiter is still about a month and a half from opposition, yet is a strong presence in the late evening sky now.  It rises shortly after 9, and visible for the rest of the night, until the week of opposition for the latter scenario.  While high enough to view during the morning hours during dawn and just after Sunset with the unaided eye, it gives us a good opportunity to see its belts and zones (dark and light bands respectively), as well as the Great Red Spot if viewed during a small window of hours.
Seen in Taurus near the Hyades star cluster, where we saw it this summer, Jupiter has retrograded back to the Hyades, where I display it in image one.  For image two, I will show a zoom-in of the planet at transit during predawn hours.   The magnification for that, for which you can use too if weather conditions are ideal, is 200x.

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

Detailed

   As shown in image two, all four Galilean moons are present, labeled as well.  Since we are not viewing Jupiter at its equator, it means that the Moons don't all seem in line with each other.  However, the plane of the orbits are similar to that of Jupiter and the ecliptic.  Therefore, they often look to be almost in line, even if not all viewed by us either in front of or behind Jupiter.  As for the belts and zones, they are crystalizing ammonia, or simply "clouds".  The lighter zones are a result of upwelling, meaning that the ammonia is cooling as it rises.  The darker belts are downwelling, and representing a darker color being warmer.  If looking closely at Jupiter with very good seeing conditions, there seems to be a slight overlap when looking at the equatorial belts and zones-- those nearest to the equator.
As for the Great Red Spot, it is a huge storm on Jupiter, measured to be about 3 Earth-Diameters wide, and more than 1 up/down.  With a rotational period of a little less than 10 hours, we can see the Red spot transit on consecutive mornings or evenings when dark enough.  Depending how long you are viewing for during the night, and the length on the night depending on the season, that can factor into the weekly frequency of seeing the spot.  There are tables that can be found online for Red Spot transit time tables (list one).  It can be best using a blue or green filter when viewing the spot, to bring out better contrast of the red against the zones and belts.  Good luck trying to see it, and try using a magnification no less than that shown above, so the spot is visible; 3-400x in magnification is even better.  Remember, that ideal seeing conditions--being minimal humidity and wind--help see it better, as well as the belt/zone separation.