SCT 8", 4x powermate, Toucam and Saturn

[firstlight (Tony)]

Well I got up this morning and captured some Ringed Planet. I tried with the 4X powermate and 15 fps. I had to use more gain than I was comfortable... processed in Registax, but have no idea what I am doing.

I'm getting this banding (interlacing?) and the band detail on the planet is not defined (you can almost see some storm action if you squint and use averted imagination). I think I am not capturing with the right settings.

All help gratefully accepted.

[Shiraz (Ray)]

Hi Tony. That is pretty darn good optically - good fine detail. The CCD is operating right down in the weeds though - the SNR is very low in all channels and the colour balance seems to have suffered.
You asked, so a few things you might consider are (in combination maybe): - try using flats and/or darks to reduce the fixed pattern noise (I once had the same problem with a QHY5C and flats helped a lot) - try longer exposure times to get more signal in each frame and make sure to record the video for at least 6 minutes to get the best possible SNR on stacking - maybe try a bit shorter focal length to increase the photon density on the chip (8m+ is possibly asking a bit too much of an 8inch/webcam combo on a dim object like Saturn).
Hopefully someone with Toucam experience will chip in here re settings, compression etc. All the best, Ray

[coldlegs (Stephen)]

Tony
I get that when the gain is turned up too high. It's electrical signal noise in the toucam. The only things I can do are drop the gain and turn up the gamma a little and have the brightness near max. Using darks at the same gain and exposure length helps also.
Stephen

[firstlight (Tony)]

Originally Posted by Shiraz

Hi Tony. That is pretty darn good optically - good fine detail. The CCD is operating right down in the weeds though - the SNR is very low in all channels and the colour balance seems to have suffered.
You asked, so a few things you might consider are (in combination maybe): - try using flats and/or darks to reduce the fixed pattern noise (I once had the same problem with a QHY5C and flats helped a lot) - try longer exposure times to get more signal in each frame and make sure to record the video for at least 6 minutes to get the best possible SNR on stacking - maybe try a bit shorter focal length to increase the photon density on the chip (8m+ is possibly asking a bit too much of an 8inch/webcam combo on a dim object like Saturn).
Hopefully someone with Toucam experience will chip in here re settings, compression etc. All the best, Ray

Thanks Ray. I will try a few of those things you mentioned the next time I have a chance to do some imaging. I realise that I'm pushing the setup I have but only one thought comes to me at this time: Need... More... Aperture... Need... More... (insert drool here).

Originally Posted by coldlegs

Tony
I get that when the gain is turned up too high. It's electrical signal noise in the toucam. The only things I can do are drop the gain and turn up the gamma a little and have the brightness near max. Using darks at the same gain and exposure length helps also.
Stephen

Thanks Stephen, I was using more gain than I was comfortable with, so I will try dropping the frame rate some more, and boost the others as you suggested. I took some darks, but when I processed the avi on the laptop, I was not impressed with the result, but this may have more to the do with the laptop display than anything else... Must remember to try again.

[firstlight (Tony)]

Did another restacking on one of the sequences from the other morning and changed a few settings in Registax. This time all the frames were used so there was a bit more info in the result. Played a bit with Registax to process it, then finished off with PS CS2. I will redo it again with a dark frame and see what I get .

Obvious heavy handed processing, but happier with this one so far.

[firstlight (Tony)]

OK, I repro'ed the previous sequences with a dark frame and stacked 3 of the in PS. This spans approximately 10 minutes of video... not the best I guess but I have a result that starts to show some storm action.

[Shiraz (Ray)]

Serious improvement there Tony - congrats. Naaah you don't need more aperture - it's great fun trying to push a smallish scope to it's limits. Regards Ray

[asimov (John)]

Hi Tony, not a bad image. I've used an 8" SCT (+ 900NC) on Saturn a few times and realistically speaking, 3X (F30) will be your maximum. I used to quite frequently run maxed out gain, & while most times you would see these lines in the live feed, if you have enough frames to stack, they would be averaged out in the final image. It's also linked with frame rate. No more than 10FPS is highly recommended.

Remember also that you can shoot Saturn for a max. time of 6 mins. In 5/10 + seeing, you should receive enough good frames for a nice stack.

Keep practicing & good luck

[John Hothersall]

Thats a good reprocess and can see storm starting to show. I would iterate getting the image brighter. VirtualDub has many filter features for improving avi's like deinterlace and denoise filters that may be worth a try.

John.

[firstlight (Tony)]

Originally Posted by John Hothersall

Thats a good reprocess and can see storm starting to show. I would iterate getting the image brighter. VirtualDub has many filter features for improving avi's like deinterlace and denoise filters that may be worth a try.

John.

What do you mean by iterate, John?

I may have to look at using something like VirtualDub... I was just happy I didn't have to do something else before I started.

[firstlight (Tony)]

Hi John I took your advice to mean that I should click the "realign with processed" button in Registax. I think I am seeing some good results, but I still may have over cooked it. There seems to be the redness in the ring system, but the bands and the storms seems to have been enhanced.