First Quarter Moon and a Star Gazing Night: September 2017

Thank you to Craig Austin for this Star Gazing post. Craig is often present during Moose Hill’s Star Gazing Nights, along with a few members of the Astronomical Society of Southern New England, and other local amateur astronomers. Moose Hill is grateful to everyone who volunteers their time to share their scopes and knowledge with anyone who is interested in learning more and seeing the night sky from our open field.

It was a busy Friday night at the end of September at Moose Hill.  A dozen or so observers were setup and about fifty people came out to the field to see through the telescopes and ask questions on what they were seeing.

As a warm up to the event, those who arrived early enough were able to glimpse Saturn before it went behind the trees. However, the prime feature of the night was the moon, since…well…it was the biggest and brightest object out there!

First Quarter Moon

The moon was a few days past the half-moon phase (also called 1st Quarter Moon).  When the  moon is this bright it’s harder to see faint objects like galaxies and nebula. Some of the observers with larger scopes managed to show double stars like Gamma Cygni (a blue and gold pair) and globular clusters (one is in Hercules).  I briefly had the fuzzy oval of the Andromeda Galaxy before I lost it again.

Andromeda Galaxy, ultraviolet image by NASA

But, I did get to see the Pleiades, a tight group of stars that looks like a really small dipper.

I fielded several questions about the moon.  One that came up several times was about why different regions of the moon were ‘light’ colored and ‘dark’ colored.

Generally, the light colored regions typically have the mountains and craters, and the dark colored regions are plains that are often referred to as ‘mares’ or seas – there is no water on the moon so these aren’t actually seas. So what are these regions made out of?

If you answered:  Cheese/Green Cheese – Sorry – there aren’t enough space cows that could make enough milk to make enough cheese to create the moon.

The better answer is that each region is made of a different kind of rock.

moon map

The light areas are mostly made of a silicon (sand-like) material called regolith. It is a loose material similar to a dry riverbed with different sized bits from particles of dust to small boulders.

The darker regions are made of cooled lava flows called basalt. At one time, the moon was a lot warmer in its interior and was bombarded constantly by meteorites. Some impacts caused the liquid mantle inside to come out, much like when you bleed when you are cut.

Thanks for reading!  Now if you could pass the cheese… please!

The next Star Gazing Night is Saturday, November 18 from 7-9pm. Check before you come – if there are clouds or rain, we will cancel – by calling 781-784-5691, x8103 after 6pm to see if the program is running!

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