first jupiter with only 20 sec ser file

[iwols]

well heres my 1st jupiter with great help and advise from you guys ,i know its a long way off some of these images but for a poor night and a 20 second ser file im quite pleased

02_35_57_lapl6_ap23 second attemptcropped.tif

 

[vlaiv]

Hope you don't mind, I took liberty to process a bit more your image:

I applied a bit more sharpening, RGB align, white balance and I resampled image to size that is appropriate to captured detail (it looks less blurry that way).

[iwols]

Thanks, appreciated looks a lot better I know the detail is missing would this come with more imaging time like I say I was just happy with any capture

[iwols]

And without your help I wouldnt have got this thanks

[iwols]

what would the average capture length be to get better quality? thanks

[vlaiv]

2 minutes ago, iwols said:

what would the average capture length be to get better quality? thanks

With Jupiter, you are limited by planetary rotation speed. Capture time depends on resolution you are working with (larger scopes mean less time). Video can be derotated but that is special type of processing.

I'd say limit video length to about 4-5 minutes with 8" scope if you are using AutoStakkert!3 (it can handle a bit of rotation without issues - otherwise, 2-3 minutes on 8" scope).

Try to get at least 20000 frames captured (say you capture at 100fps - that would be 200s or just over 3 minutes - but greater FPS is better of course, with 5ms exposure you can capture up to 200fps if your camera and computer can handle it).

[iwols]

thanks vlaiv

[iwols]

I know 5ms is recommended, but is there much to gain at say 3 or 4 ms

[vlaiv]

14 minutes ago, iwols said:

I know 5ms is recommended, but is there much to gain at say 3 or 4 ms

Single exposure in lucky imaging is fine balance and in principle - if you can, you should go with longer exposures.

On one hand - you want longer single exposure as that improves SNR both for that single frame and for whole stack. Software will more easily recognize good frame from poor one if there is not much noise - it will align it better. Total SNR will let you sharpen more before noise and artifacts become apparent.

Problem with longer exposure is something called coherence time. Atmosphere is in motion and most of the blurring we see at telescope is actually motion blur of atmosphere. Point of lucky imaging is to minimize that motion blur among other things. In order to do so - you need to use very short exposures. You need to expose for just enough time for atmosphere to be stable. You'll still have distortion of the image - but that distortion won't turn into heavier blur if you don't let it by freezing it in "an instant" instead of letting it change and create motion blur on top of distortion (it's like blending two or more different distortions on top of each other).

Given the above - correct approach would be - expose for short enough time to freeze the seeing (for coherence time for you site and telescope size) but not shorter than that.

In answer to your question - yes, you can gain quite a bit if your coherence time is less then 5ms and you expose for shorter period of time, but if your coherence time is longer than 5ms - you gain nothing and actually loose a bit because each sub will have more noise and be harder to stack properly and resulting stack will have lower noise.

People with very good observing sites on good nights can even expose for 10ms or even more - but that combination of things is rate. In most cases you need to limit yourself to about 5-6ms for 8" aperture.

[iwols]

thanks for the detailed explanation Vlaiv  👍

[Pete Presland]

Very nice image, all my captures this year with the asi224 have been around 6-7 ms.  I limit the captures to 180secs, which produces around 18500 SER frames.