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I want more detail!

Woody

By Woody
in Imaging - Planetary

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Woody

Woody

Posted
Posted

Hello all. This is from Saturday night.

180 Mak, 2x Barlow and SPC 900

barlow15_10_201123_01_56.png

[Philips SPC 900NC PC Camera]

Resolution=640x480

Frame Rate (fps)=5.00

Colour Space / Compression=YUY2

Exposure=-4

Brightness=68

Contrast=27

Saturation=15

Gamma=0

ColorEnable=255

BacklightCompensation=0

Gain=5

I like it but I want to do better! I think I need to experiment with the capture settings a lot more.

Also if I go any further with the wavelets in Registax I start to get the onion ring effects.

I would appreciate any advice please so I can do a better job.

Thanks for looking

Jeremy

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Bizibilder

Bizibilder

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That's about as good as I could get on Saturday (from mid-Norfolk) with my 180Mak, SPC900 and barlow - the atmosphere is the limiting factor and it was a bit "wobbly" on Saturday!

Without the barlow I managed some quite respectable "little" Jupiters with quite good detail: http://stargazerslounge.com/attachments/imaging-planetary/70905d1318790948-jupiter-sequence-sort-first-me-15-october-2011-jupiter-sequence.jpg

May I suggest keeping the gain above 50 if you can and drop the brightness to compensate - it should help to reduce the "onion ring" effect that you can get at low gain. Hope this helps.

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Space Cowboy

Space Cowboy

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Yep as Biz says your Gain needs to be above 50% else onion rings will spoil your image. That is very close to being a great shot! Personally I would use 10fps only try 5fps if seeing is very good else you wont have enough quality frames to really get the best out of your setup.

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michael.h.f.wilkinson

michael.h.f.wilkinson

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I tend to adjust gain and the other settings whilst watching the histograms. Each band (RGB) needs to occupy as much of the range from 0 to 255 as possible, without clipping (i.e, the minimum signal must be just above 0 and the maximum just below 255). This minimizes the error introduced by the analog to digital converter, which is what tends to cause onion ringing.

Have you tried applying more severe wavelet processing? Initially I was very conservative with wavelet enhancement, until one day I just tried a very large value just to see the effect. My jaw dropped at the result, the sharpening effect was so profound. I find saved settings in Registax rarely work the next time, and I have to fiddle around with wavelet settings a lot to get an optimal result.

Still a nice result

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Woody

Woody

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Thanks very much for all your input, gives me lots to try at the next opportunity:icon_salut:

I tend to adjust gain and the other settings whilst watching the histograms. Each band (RGB) needs to occupy as much of the range from 0 to 255 as possible, without clipping (i.e, the minimum signal must be just above 0 and the maximum just below 255). This minimizes the error introduced by the analog to digital converter, which is what tends to cause onion ringing.

This a great advice, thanks Michael. Can this be done in Sharpcap?

Cheers

Jeremy

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Clayton

Clayton

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That's a great result. With room to improve Jeremy.

It's hard to advise without all the info (eg. I expect that the image is a crop? But would it be possible to increase the capture scale a bit?)

Also I suggest that you try increasing the frame rate to at least 10fps (experiment with all the settings) and capture for 3-4 mins. You may get away with longer at that aperture but you should be in the ball park with those figures.

If the seeing is average you may not do much better, but under very good seeing you should be able to resolve more detail, so spend a bit of time with the focus (lot's of practise) and it will pay off when conditions are good. BTW a Motor Focus is a great investment for Planetary Imaging if you have the $$

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Woody

Woody

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Gday Clayton, thanks for those tips. Do you know what is the maximum capture time for Jupiter before you get the rotation errors?

A Focus Motor eh? And here I am supposed to be saving money for the move back home next month:rolleyes:

Cheers

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Clayton

Clayton

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Gday Clayton, thanks for those tips. Do you know what is the maximum capture time for Jupiter before you get the rotation errors?

A Focus Motor eh? And here I am supposed to be saving money for the move back home next month:rolleyes:

Cheers

Yes those motor focusers can cost a bundle. They are not essential, but I wouldn't like to be without one now.

As to the maximum time to capture Jupiter??:)

I have no idea:D:D

This image, captured with a setup similar to yours

http://stargazerslounge.com/imaging-planetary/117965-25th-oct-jupiter.html

was 210sec @ 10fps but I guess it's ruined by rotational smearing :):confused:

I don't claim to be an expert or even a skilled imager but my advice to you is don't be bound by mantra's. It costs nothing to try different things, and you will learn a lot :evil6:

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michael.h.f.wilkinson

michael.h.f.wilkinson

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What makes you so sure about that Franck? How can you distinguish between bad seeing, bad focusing and bad collimation in that shot? If it were a stellar image, maybe, by I for one cannot estimate the point spread function of the optics from that one shot.

You are of course right that collimation is a key part of a good capture, and it has not been raised yet as a potential source of the problem. I had understood that the Skymax 180 was very good at holding collimation. That does not mean it cannot be off, of course.

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  • 2 weeks later...
brucen

brucen

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I see that you all seem to suggest setting gain to around 50. When I do this Jupiter just shows as a bright white blob on screen no matter what I set the brightness at. I have been reducing gain to 0 to see any detail - although I inadvertantly set the capture to 90 frames at 10fps rather than 90 seconds at 10fps so the results are not that good anyway! If I take the frames with gain at 50 will the software enable me to compensate later?

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Clayton

Clayton

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I see that you all seem to suggest setting gain to around 50. When I do this Jupiter just shows as a bright white blob on screen no matter what I set the brightness at. I have been reducing gain to 0 to see any detail - although I inadvertantly set the capture to 90 frames at 10fps rather than 90 seconds at 10fps so the results are not that good anyway! If I take the frames with gain at 50 will the software enable me to compensate later?

If it is over exposed then you can't recover the data later:(

Try a faster shutter speed and increase the capture time.

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