Jupiter 30/10/2010

firstlight (Tony) · #1 01-11-2010, 12:14 AM

I came to set up late last night as I had committed to helping some friends with an astro-night.

The night was great early and we were treated to an Io shadow transit and Io re-emergence. When I got home I set the scope up again, and by the time I was ready to image, the high level cloud rolled in. This is the only sequence I managed to capture and there are a multitude of things wrong with the processing etc, foremost is the fact that I neglected to capture a dark frame and the one I used is from a month ago and I'm pretty sure that it is for 1 minute (avi was for 2 minutes). Not happy with the colour but it is best I can come up with, and HEAPS better than it was.

I'm still amazed that I have anything that approaches detail when I look at the raw data.

WO 110mm Magrez on NEQ6
Merlincam (SPC880 flashed to SPC900NC)
120 sec, 60 fps (7200 captured, 4445 used)
Stacked Registax 5.1
Processed Registax and PS CS2

Thanks for looking.

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mswhin63 (Malcolm) · #2 01-11-2010, 02:13 AM

Nice try difficult to get anything with clouds, Try using Colour align with Registax. "Estimate". You blue is well out. After you get it back in you may find colour improvement. Although colour looks good.

firstlight (Tony) · #3 01-11-2010, 09:13 AM

Here is the repro, however I did use colour align. The result from Registax had a purple halo around the planet, I had to use colour adjustment in PS to tone it down. I can get rid of the last of it, but Jupiter is green.

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mswhin63 (Malcolm) · #4 01-11-2010, 02:55 PM

Interesting, wondering are you using any filters?

Possibly a fringe killer filter or IR/UV filter is needed.

I have heard of an optic issue creating a purple fringe around an image but would need someone to clarify this as I use a DOB for my imaging. I also experience only a minor fringing but colour align usually gets rid of it.

firstlight (Tony) · #5 01-11-2010, 04:18 PM

I was in fact using a IR/UV cut filter. I think that the major promlem may be the fact that I did not use good data for the processing, that is to say the dark frame was not suited for the capture. I should have shot a dark frame or 2 when I was packing up, but to be honest I was pretty disappointed that the sky deteriorated so quickly and I took my ball and went home

.

I did a process without the dark frame and the image was much lighter, but the hot pixel at the bottom was very distracting. As I didn't prepare a dark frame I used one I captured last month, but it was for 60 seconds not 120 and I seem to remember that it was much cooler as well. The result from Registax was MUCH darker than I have previously got. While this seems to be causing some artifacts, it seems to have brought out some good data as well.

Probably should just shoot a more appropiate dark frame, don't you think?

mswhin63 (Malcolm) · #6 01-11-2010, 05:16 PM

Actually i have never used dark frames at all in my captures, but i think the issue might be refrator fringe, but best a refractor person tell you this.

I did a search on Fringe Killer and came up with this site. It seems specific problem relating to refractors - http://www.astromart.com/articles/ar...article_id=135

firstlight (Tony) · #7 01-11-2010, 06:01 PM

Hopefully the weather will settle in a couple of days (Skippy indicates it will) so I'll hopefully have a longer test session. It is an ED refractor, but I have a lot of glass between the objective and the camera, so it might be the optical train. I'm sure the cloud and poor transparancy was not helping either.

Thanks for you thoughts and help, Malcolm.