I have blogged previously that I’ve set a goal for myself of figuring out how to work my iPhone to take pics through the telescope, and I’ve had earlier success for the moon. But to be honest? The moon is dead simple. If I set an ISO between 24 and 50, and play with my duration to be between 1/100th of a second to 1/300th of a second, and it’s relatively in focus, I can get “something”. The more moon there is showing, the brighter it is, and it’s easy to get washed out without a filter, but any of the setup problems virtually disappear when it’s the moon.
On Saturday, August 10th, I stuck my head out of my back door, saw the moon and went ahead and set up. As always, I’m setting up a Celestron NexStar 8SE, stock alt-azimuth mount, and an iPhone XS Max phone running Night Cap software. The only “variables” that were up for the night were the new Phone Skope phone adapter that allows you to mount the phone over the eyepiece and my choice of eyepiece, which tonight was a 25mm Celestron Plossl that comes with the 8SE scope. My night was divided into three “target zones” — the moon (below), planets (next blog post) and stars (the blog post after that).
With stock f/1.8 settings, I used ISO 24 and 1/300s to get me this:
That is a straight single frame, no tweaking or adjustment of anything other than flipping it horizontally to correct for my diagonal giving me the mirror image by default. Like I said above, the moon is dead easy.
I tried stacking in Nebulosity, and I have little experience using it on the moon. I made it worse, stacking all the images:
I thought it was my choice of stacking technique, so I went a little more complicated to remove the possibility of rotational errors, and, well, it was even WORSE:
I really don’t need to stack it, the single frames are more than sufficient for now. Post-processing will come, but it’s farther down my priority list.
At the top of the big image, I zoomed in a bit to see the top ridge above Mare Imbrium. It is called Montes Jura, and the little alcove below it is Sinus Iridum. The closer photo is below:
The big crater is Copernicus and the little mountain area above it a bit to the left is Montes Carpalus. A third of the way from the bottom of the picture to Copernicus is the landing sites of Apollo 12 (Nov 19, 1969) and Apollo 14 (Feb 5, 1971).
Zoomed in even further on Copernicus, starting to have some issues with focus:
The crater is about 93km across, and about 3.8 km deep (from the top of the rim). The little mountains in the centre are 800m tall, the result of rock “rebounding” upwards after the impact crater was formed by a meteor hitting it.
I then decided to go to the bottom of the moon, and see what I could get of the rocky/bumpy portion. About one-third of the way from the left side, and one-third from the bottom, just below the darker area, there is a prominent crater with a dot in the centre. The crater itself is my favourite, Tycho, and I have no real idea why. Maybe I just like the name of it, but mostly I think it is because it is one of the first ones I ever imaged and subsequently learned its name. Tycho is near the size of Copernicus, 85 km across, but a smidge deeper (at 4 km, or 4.7 km if you go to the top of the ridge). The central mountain is 2 km tall.
The two craters are quite different in age though — Copernicus is about 800 million years old, while Tycho is a young buck, only 100 million years ago. Or, as the joke goes, 800 million and 100 million, plus two days, as I took the photo two days ago.