What’s Up This Second Week of July in the Morning Skies

Before the rainy weekend gets you too down, the rest of this week’s forecast looks rather promising for clear nights. The temperatures will be in the 70s during the hour or two following sunset. Make sure you pack bug spray when going stargazing – the mosquitoes are making themselves known this time of year. During the upcoming clear nights, be on the lookout for the third quarter moon, a moon-Jupiter meetup, the early-morning Pleiades, and distorted distant galaxies.

The third quarter moon is often visible in the morning after sunrise.

Sunday, July 9th, will mark the third quarter moon of July. When the moon is in this phase it usually rises quite late, around 1 AM. So, the best time to see it without losing sleep is early morning or during the middle of the day. It can be a fun scavenger hunt to find the moon hidden within the bright blue daytime sky.

On Tuesday, July 11th, look at the eastern skies shortly before sunrise to be greeted by a celestial meetup of the waning crescent moon and Jupiter. Both objects are very bright, so they will be hard to miss. A set of binoculars will do both of these objects justice. You will be able to see the craters on the moon as well as four of the largest moons orbiting Jupiter.

Jupiter peeks up in the morning near the moon.

If you see this event a day later, the moon will be on the opposite side of Jupiter. The people on the other side of the world will get to see Jupiter reach its closest apparent distance to the moon of about 3°. Sometimes the moon’s path overlaps with that of another planet leading to occultation, or the “eclipsing” of a background planet, like Jupiter, by the moon.

Anytime this week between 2:30 AM and 6 AM look in the eastern skies for a twinkling reminder of the winter skies – the Pleiades cluster. Since we are on the opposite side of the sun for the summer months, all the winter night-sky objects are just hidden by the sun’s glow and a bright blue daytime sky. The early morning hours, when the sun is still hidden, is an ideal time to try spying on some fall and winter celestial objects. Although, winter will be here before we know it and so will all those deep-sky objects.

Technically Spring is the ideal “galaxy season”, however, we are surrounded by distant galaxies at all times. Unfortunately, galaxies (apart from the Andromeda Galaxy and Triangulum Galaxy) are incredibly far away and consequently are very faint and appear very small. Viewing them requires dark skies and a long focal-length telescope (> 800mm). We can only see the luminous matter in these galaxies and galaxy clusters (i.e. stars, nebulae, etc.) which account for only a small percent of the total galaxy/cluster mass. The rest of the mass is found in dark matter which, as far as we know, only interacts through gravity. These massive collections of luminous matter and dark matter can actually stretch space enough to make a gravitational lens. This lensing can only be seen with very powerful telescopes, but NASA has a very informative page with pictures and videos on the strange effects of gravitational lensing - https://www.nasa.gov/content/discoveries-highlights-shining-a-light-on-dark-matter [IMAGE: https://www.nasa.gov/mission_pages/hubble/multimedia/ero/ero_abell370.html – This image was taken by the Hubble Space Telescope of galaxy cluster Abell 370. The weird, stretched shapes are caused by intense gravitational lensing by the massive foreground galaxies.]

Make sure to get all your stargazing equipment ready this weekend for the very clear week ahead. Lean back and gaze up into a sky filled with planets, stars, nebulae, galaxies, and more. I always find it incredible to think about how the light coming from these distant objects makes it all the way through millions of miles or light years of space only to get absorbed by my eye. Try having your eyes absorb the light from the moon, Jupiter, the Pleiades, and distant galaxies this week.

Clear Skies!

Jared May: What's Up July 8 - 14, 2023