Saturn 28/1/09 - second post

[Screwdriverone]

Hi All,

Not much time to get out lately so I had another look at the captures I took on the first light night with R2 the Flexdob. This one seems a little darker than before although it was one of the first I took.

Its also a little different in as much as I rotated the view to line her up horizontally.

Hope you like it, comments are welcome, as are criticisms...

Details:

Scope: 305cm Skywatcher Flex Dob, FL = 1500mm
Camera: Philips Toucam Pro II @ Prime Focus
Magnification: 2.5x APO GSO Barlow
Frames: best 177 stacked in Registax from 30 secs captured at 30 fps
Time: 13:38 UTC (12:38am AEST)
Processing: LR deconvolution and Wavelets applied in Astra Image Pro

Thanks for looking,

Cheers

Chris

[peter_4059]

That's a good image Chris. Plenty of detail in there.

[Screwdriverone]

Thanks Peter,

After looking at this again I just realised what I forgot to do was set the black point on the space around the disc, which is why it looks a bit orangey. DOH! :doh:

Still, not bad though!

Cheers

Chris

[Quark]

Hi Chris,

Another very nice effort, don't think there is anything wrong with the colour. Although the image is dim there is some nice detail within it.

I think 30 sec's at 30 fps is the problem contributing to how dim it appears.
Don't be afraid to really push the gain, that will make it brighter, and try extending the capture out to 2 min's. At 30 fps that will give you 3600 frames, depending on the quality of the seeing, try for a stack of the best 1000 frames. This will give you a lot more signal.

You also may have to try a slightly slower exposure rate.

Looking at the quality of the two images you have posted, there is nothing wrong with your collimation or focus, you just need to experiment with;

1) longer captures, with the colour chip that you have you should be able to capture for 2 min's and still resolve any storm activity or cloud structure and any moons present will still be well resolved.

2) Try either more gain, you can go close to max gain, if you capture over 3000 frames and use the best 1000 the extra noise from using high gain will be smoothed out. Not sure if your capture software allows you to view a histogram, if it does use it to determine the correct gain and exposure, try and extend the histogram to about 2/3 of the distance across the graph.

3) If your image is still not bright enough then reduce the exposure, this will obviously mean less frames captured but the image will be brighter.

I think your Saturn images are progressing nicely and look forward to seeing more of them, just try for my signal.

Regards
Trevor

[RB]

Nice shooting Chris.

:thumbsup:

[Screwdriverone]

Thanks Trevor and Andrew!

I appreciate the wishes, and the tips Trevor, next time out I will push up the gain as described, I think I try for too much "realistic" view on the PC screen during capture and therefore it looks dim as it is underexposed.

Also, from memory, Saturn was a bit low so during this capture so I think some of the dimness was due to the extra atmosphere and looking at the original capture AVI some heat haze off the nearby house. Next capture will hopefully be from dark sky site without this issue.

I have the histogram in K3CCD tools and use it too infrequently, I will apply these tips and see how it goes.

I really appreciate the help, the only way is up hey?

Cheers for now,

Chris

[Matty P]

Nice capture Chris. Apart from it being slighty dim there is lots of detail showing.

Well done. :thumbsup:

[Paul Haese]

Not a bad effort, but to get the image well illuminated will do two things, remove the slight onion ringing you have there and make your image really shine. To do this use the histogram rather than go for frames. Frames are necessary but illumination is much more important for a nice planetary image.