Time: 6:00 AM
Brief
Our most outer planets are starting to emerge from the Sun, as they move about a degree further from it each day. The Sun is moving quickly north along the horizon as it rises, meaning slightly extra twilight time and starting a little earlier each morning. With Uranus at magnitude 5.8, that is about the dimmest that we can see a star or planet under the darkest of skies with the naked eye. Even under such sky conditions, the glare of twilight means that it will not be until about the time of the Summer solstice that Uranus falls under the following sky-postition characteristics: (1) high enough out of atmospheric pollution, and (2) separated enough from the Sun to see with the eye. For either, sky conditions would need to be perfectly clear, of even haze. Before Summer however, enjoy finding it with optical aid. This morning, two other solar system bodies help us find it and Neptune: Mercury (magnitude +0.5) is 6º away from Uranus, seen to the right of it. Since Mercury is moving in prograde motion again, it will catch up quickly with Uranus and be 2º from it in a week.
An even brighter object is near Neptune: the Moon, at 5º away to Neptune's upper left. In this first image, locations are shown for the Moon and three mentioned planets.
Detailed
Once finding the Moon in a telescope, it and Neptune are precisely at right-ascension conjunction; they are the same celestial longitude, which makes it easy to slew from to it from the Moon if using an equatorial telescope; unlike an altitude/azimuth scope, an equatorial can be adjusted to a location's latitude, moving on one axis to measure right ascension, and one to measure declination. Even with a small field of view, such as 3/4º which can still fit the Moon easily, they will still be close enough to conjunction to both fit in the same field, with the Moon centered in the field.
We will see Uranus all night along during the early fall during its next opposition. Neptune is not visible to the unaided eye, and does not transit as high as Uranus for the next several years. However, even as seen from a mid-northern latitude, its declination of 11º south means that when we see it transit under dark skies later this season, we will see it doing so at slightly over 40º -- nearly halfway between the horizon and zenith. Over the next 56 years, Neptune will increase in declination moving more north. The advantage of this, although still requiring optical aid, means that a powerful enough telescope will view it far enough out of atmospheric pollution to see its blue methane color more easily.
In this second image, we see the celestial equator and ecliptic shown. The former two remind us of each planet's declination.
Once finding the Moon in a telescope, it and Neptune are precisely at right-ascension conjunction; they are the same celestial longitude, which makes it easy to slew from to it from the Moon if using an equatorial telescope; unlike an altitude/azimuth scope, an equatorial can be adjusted to a location's latitude, moving on one axis to measure right ascension, and one to measure declination. Even with a small field of view, such as 3/4º which can still fit the Moon easily, they will still be close enough to conjunction to both fit in the same field, with the Moon centered in the field.
We will see Uranus all night along during the early fall during its next opposition. Neptune is not visible to the unaided eye, and does not transit as high as Uranus for the next several years. However, even as seen from a mid-northern latitude, its declination of 11º south means that when we see it transit under dark skies later this season, we will see it doing so at slightly over 40º -- nearly halfway between the horizon and zenith. Over the next 56 years, Neptune will increase in declination moving more north. The advantage of this, although still requiring optical aid, means that a powerful enough telescope will view it far enough out of atmospheric pollution to see its blue methane color more easily.
In this second image, we see the celestial equator and ecliptic shown. The former two remind us of each planet's declination.
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| *click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp. |
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