6 replies to this topic

[katie_panda]

Since clear skies have been so rare recently, I decided to brave the 4 degree F weather the other night when there were no clouds in sight. This was taken with my 8" SCT and an ASI178MC. It's the first time I've been able to resolve detail on Mars! It's small but I'm pretty excited about it. It was high in the sky at the time, and although the jetstream was passing overhead seeing was decent. Jupiter was low over a neighbor's roof so it came out pretty mushy.

 

This was stacked out of a relatively short capture (probably a few hundred frames) using the default settings on ASI's planetary stacking tool. Once I get the time I'm interested to experiment with other tools, but this was an exciting result for such low effort.

 

[wizbang396]

Still looks good

[jtomney]

That looks pretty darn good given the planet's size (and I can totally relate to your comments about the weather - when it is clear the seeing is usually a 2/10 in our area of the country). It looks to me like you have albedo features M. Erythraeum, Aurorae Sinus, and Nilacus Lacus there with S. Meridiani just setting. Are you using a Barlow in your imaging train? If not, something like a 2x Barlow ought to help (with my 1500mm FL Newtonian I use the same ZWO camera with a 2.5x Barlow and a small ROI to get a reasonably sized image). Keep up the good work!

 

Jim Tomney

Asst Coordinator
ALPO Online Section

[katie_panda]

That looks pretty darn good given the planet's size (and I can totally relate to your comments about the weather - when it is clear the seeing is usually a 2/10 in our area of the country). It looks to me like you have albedo features M. Erythraeum, Aurorae Sinus, and Nilacus Lacus there with S. Meridiani just setting. Are you using a Barlow in your imaging train? If not, something like a 2x Barlow ought to help (with my 1500mm FL Newtonian I use the same ZWO camera with a 2.5x Barlow and a small ROI to get a reasonably sized image). Keep up the good work!

 

Jim Tomney

Asst Coordinator
ALPO Online Section

Thanks! I'm starting to get this equipment figured out. I tried looking at a Mars map to work out what I was seeing but hadn't worked it out for sure yet.

 

I started out the night with a 2x Barlow but realized that it wasn't doing anything useful when I started with Jupiter. And due to an issue with the altitude axis on this mount it's really frustrating to center a target on that tiny sensor with a Barlow in the train. By the time I took this shot of Mars the scope had probably cooled down enough to try putting it back in, but I didn't try it. My fingers were probably pretty numb by then anyways...

 

Since we've got clouds for a while I'm going to take some time to take apart the mount and see if I can improve it for next time.

[Kiwi Paul]

That’s a very good effort. Well done. You can increase your capture time to 6 minutes with Mars to capture many more frames. Also, if you centre the target on the chip and then really carefully align your finder scope you have a fighting chance to get the image on the chip if the target is high overhead. It would be a good idea to put the Barlow back into the optical train. Make sure you take account of the 5 x rule. So 5 x the size of the camera pixels in microns gives you the ideal f/ ratio you should get close to.
Cheers Paul

[katie_panda]

That’s a very good effort. Well done. You can increase your capture time to 6 minutes with Mars to capture many more frames. Also, if you centre the target on the chip and then really carefully align your finder scope you have a fighting chance to get the image on the chip if the target is high overhead. It would be a good idea to put the Barlow back into the optical train. Make sure you take account of the 5 x rule. So 5 x the size of the camera pixels in microns gives you the ideal f/ ratio you should get close to.
Cheers Paul

Thanks!

 

Hmm... that would actually give f/12 for my camera, and my scope is f/10 which is pretty close. Although I guess the Barlow would mean I'm oversampling, which is better than undersampling.

 

My biggest problem with long captures was disk space. Non-upgradeable 128GB SSD and only one USB port on my laptop limits things. I had to keep transferring stuff to cloud storage then deleting throughout the night. But I pulled out an older laptop with a bigger drive (and the ability to be upgraded) and got it set up for next time.

Edited by katie_panda, 06 February 2023 - 05:37 PM.

[Kiwi Paul]

F/12 is close enough.
You can limit file size by using as small an ROI ( region of interest) as you can.
The old laptop will probably be fine. You could get yourself a 1, 2 or more Terrabite SSD and save directly to that.
Cheers Paul