One day, Two Astronomy Sessions

Monday, well actually Sunday, I decided that mornings were substantially better for trying to see anything in the “night” sky. Maybe that would be better said, when the sun in below the horizon enough to make it seem like it's night. That would be because Monday morning started about 5 AM with the idea from Sunday to get up early, hopefully before the clouds returned, and see what could be seen in the sky. With the haze, VERY high humidity, and the possibility that my eyes weren't completely open, the only real target was the moon. Fortunately, that's what I had planned for on Sunday.

The list of lunar objects is being drawn from the Astronomical League's “Lunar List”. These images are from the list and were close to the terminator (division between day and night), which is where I like to photograph them. As with my carvings, a low angle of light makes the relief stand out better.

Manilius and Rima Hyginus

This image shows off two of the targets, as will the next image, in one photo. The prominent crater just above the center is target #1, Manilius. The thumbnail sketch is that it's about 24 miles in diameter, has a central mountain, and is about 9400 feet deep. I find it's interesting that to the right of the crater, the terrain is rough, while to the left, the terrain is very smooth. I wonder why? Target #2 is at the lower left. It's a valley with a small crater more or less in the center of the valley. It looks somewhat like a bird in flight, with a small body and very long, thin wings. This is Rima Hyginus. “Rima” translates to “groove” and it's believed that this groove was once a lava tube that has collapsed. Its about 133 miles long and about 2 miles wide. The crater in the center is Hyginus, and is a sight of Transient Lunar Phenomena (TLP), according to Virtual Moon Atlas. The Phenomena? “smokes according to Sacco.” What?? Well, Hyginus is a crater believed to be formed by a volcano, rather than an impact crater. The moon, as I understand it, is supposed to be volcanically Inactive, but, who knows? Five minutes of research on the net does show some references to TLP activity in this area of the moon! Who knew? I might image this one more often.

This is another two in one image, this time two crater groups in the southern part of the moon. The craters, marked as you can see are Maurolycus and Gemma Frisius. Maurolycus is about 69 miles in diameter and that apparently is big enough to have small craters on the floor of this crater. For me, one of the interesting things to see is that the shadow covering the floor of the crater is larger than some of the surrounding craters. That most likely indicates how deep the crater is relative to some of the surrounding craters. Gemma Frisius is about 53 miles in diameter. Other than that, I don't know much more about these two craters.

Mars F10

Mars F 30

Yep, that's Saturn

The other two targets for the day are rather obvious when you look at them. They are, of course, Mars and Saturn. I might keep track of Mars as often as I can, because it looks like there might be a storm a-brewing. I want to see if the dark area that looks like a funny looking “X” changes over time. Of course, that means the clouds have to part, so good luck with that, I guess. The reason for two images of Mars that look slightly different, is because I wanted to experiment with changing focal length of the scope and observing it's impact on the resulting image. One result was expected, one not. The expected result: the F30 images looks a little darker. Why? (Thank you for asking.) The same amount of light is spread out over a larger field of view (FOV). Same light, larger surface area = dimmer image. The unexpected result: just how similar in detail the images are. I was expecting a little more detail in the F30 image, but it's not there. That very likely is because the seeing (steadiness mostly, in this case) was poor. Think of taking a picture of a runner. If the shutter is open too long, you get a blurred picture. Basically, that's what is happening here.

Until next time.