saturn 5-21-2011

[darbyvet]

Here are some pics I took of Saturn.I am still learning and would love some feedback. The images are fuzzy.I dont know how to make them sharper.
I used Mike Salways great tutorial as a guide to how to process these images.

Set up
Celestron c11 edge HD on cgem mount
DMK 21au camera, televue 2.5x powermate, astronomik rgb filters.

images captured with iccapture,processed with vdub,pcfe,registax6,astraimage for rgb combine

[renormalised]

Great piccies, Carl!!!:)

The piccie looks like the focus is a little soft. What you could do is try and bring your target up in your capture program and tweak the image's focus whilst it's onscreen. Another way is to take a quick snapshot and judge the focus that way. Or move to a nearby star and use a bahtinov mask to get focus then move back to the planet.

[darbyvet]

Thanks. I do use a Bahtinov mask to focus on a star close to Saturn.I can usually get to less than 1 pixel in focus (I use bahtinov frame grabber to asses how close to focus I am). I rarely get decent seeing so it is hard to know for sure I have perfect focus.Could the soft images be due to collimation problems. I thought the scope was out of collimation so I fiddled with the collimation screws without really knowing what I was doing:( and I think I may it worse.I am waiting for some Bobs knobs to arrive so I can replace the screws and try collimating again.Would love some input on collimation.

[renormalised]

What does the Airy disk look like inside and outside of focus?? Is it symmetrical or does it skew to one side or another??

If you've got good focus and it still looks soft, it maybe collimation but it's most likely the seeing you've got.

Unless we can see what your airy disks look like, it's a little hard to judge the collimation and if it needs correcting.

[darbyvet]

Thanks for the help.I have not been able to see the airy disk.I bought an artificial star to help, but even with it at the back of my yard (250feet away) I have to really move the primary mirror a long way to focus. I thought I had got it pretty well collimated, but when I looked at an actual star the collimation was way off (I think I did take a pic-If I can fijnd it I will post it). I do have pretty crappy seeing most of the time.I would say the best I get is about 6/10 on the Pickering scale.I go through vdub frame by frame to remove the blurred images (usually remove about 20% of the red and green channel and about 50-60% of the blue channel). I have an atmospheric dispersion corrector-would that help? If it ever stops raining here (upstate New York) I will take some pics of an in focus and out of focus star!
Sorry for all the questions-Dont have a local astronomy club to bug