Planet/disk stabilization for ASI 183MM Pro?

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A.Cidadão
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Joined: Thu Feb 21, 2019 12:11 pm

Planet/disk stabilization for ASI 183MM Pro?

#1

Post by A.Cidadão »

Hello from Portugal,

I use an ASI 183MM Pro camera with a 14" SCT to obtain lunar images but mostly multispectral planetary data.

The ASI 183MM Pro is a large array camera that I often use with a FOV of 640x480 for planets. FPS usually range from 150 (Venus, IR1000) to 2 (Jupiter, CH4). All filters are used with specific master flat frames (full array) and frames are real-time corrected when obtaining SER files. It works very well, and flat correction is applied to the specific FOV I choose.

I use SharpCap Pro (v4.0.7824), and I would like to profit from the "planet/disk stabilization" ability the software has to immobilize the planet for focusing but also to allow long periods of unattended imaging (hours-long time-lapse image sequences) without any need of guiding (my scope is permanently mounted, little corrections would be needed, and I have not installed "st4" guiding for my LX200).

I know that the "planet/disk stabilization" ability works in this version, since my webcam image promptly responds when I activate the feature and I move in front of the camera. What happens is that "planet/disk stabilization" does not work (button is grey) when I activate my 183MM Pro.

Is this camera supported? Is the sensor too large? The stabilization routine does not work with real-time flat-corrected frames?

Thanks in advence!

António
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Re: Planet/disk stabilization for ASI 183MM Pro?

#2

Post by admin »

Hi,

there isn't any good reason why the Planet/Disk stabilization control should be disabled - as far as I can see there isn't any code that would disable that in any circumstances.
Capture.JPG
Capture.JPG (19.15 KiB) Viewed 1343 times
Just switch the control from Off to On. The only way I can see that would be disabled is if all the other controls were disabled too?

cheers,

Robin
A.Cidadão
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Re: Planet/disk stabilization for ASI 183MM Pro?

#3

Post by A.Cidadão »

Thank you very much for your prompt reply Robin.

I tried the "planet/disk stabilization" feature with two Lumenera cameras (twain), a webcam, and four different ASI models I use (290MM, 178MM, 462MC and 183MM Pro). It works with all of them except with the 183MM Pro (which is a refrigerated model but that I use for lunar and planetary imaging). With this specific camera, the "on/off" switch for "planet/disk stabilization" is disabled (light grey; it is inactive in the off position). Other commands work. I attach an image. Situation is also present in today's version.

Thanks!

António
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Re: Planet/disk stabilization for ASI 183MM Pro?

#4

Post by admin »

Hi,

sorry, my mistake - I didn't spot the key piece of code that does disable the stabilization :(

The requirements for stabilization are :

* Camera must be in live view

and

* Camera must be in an 8 bit mode (RAW8/MONO8/RGB32/RGB24)

I suspect your camera is in 16 bit mode.

cheers,

Robin
A.Cidadão
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Re: Planet/disk stabilization for ASI 183MM Pro?

#5

Post by A.Cidadão »

Hi Robin, Thanks! Makes perfect sense and in fact it now works at 8 bits.

This translates into a great solution for the focusing job (planet stabilized while focusing).

Now, can it be used in 16 bit mode even at a cost of a lower FPS rate?

I'm asking this because methane imaging uses fairly long integrations, needs 16bit imaging to better sample the low flux, and it would allow unattended long time-lapse animations of fast-rotating planets like Jupiter.

Anyway, stabilizing planets for focusing will be great!

Thanks!

António
A.Cidadão
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Joined: Thu Feb 21, 2019 12:11 pm

Re: Planet/disk stabilization for ASI 183MM Pro?

#6

Post by A.Cidadão »

Hi Robin, please do not consider the possibility I suggested in my last message. For that specific use, filling the FOV periphery with "black" while keeping the planet centered would not work. If mount errors were high enough the planet would eventually exit the FOV. For this to work it would be necessary a true "complete FOV" X-Y shift while keeping the planet centered. Large arrays would allow this but the procedure would have to be different.

It is great as it is now for focusing!

Thanks!

António
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Re: Planet/disk stabilization for ASI 183MM Pro?

#7

Post by admin »

Hi,

glad that is sorted - in theory it would be possible to write the code to deal with 16 bit depths, but it did not seem worthwile as high speed imaging is almost always performed at 8 bit (as soon as you set a high gain to bring up the brightness from a low photon arrival rate, the noise level goes well above 1 ADU, which means there is no point in having higher bit depths - all you would be doing is sampling the noise in more detail).

cheers,

Robin
A.Cidadão
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Re: Planet/disk stabilization for ASI 183MM Pro?

#8

Post by A.Cidadão »

Thank you!

But please be aware that the frame periphery with stabilization on is white (or gray) and not black.

I just confirmed this when imaging Venus in daylight with an IR1000nm filter.

By the way, in this situation I put gain to zero and 8 bit is not enough.

Thanks again!

António
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Re: Planet/disk stabilization for ASI 183MM Pro?

#9

Post by admin »

Hi,

yes, the border added is deliberately grey rather than black - the intention is to make it obvious that the border area is not real camera data. If it was set to black then it might be difficult to spot the difference between the border and the image background.

thanks,

Robin
Maurizio
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Re: Planet/disk stabilization for ASI 183MM Pro?

#10

Post by Maurizio »

Un saluto a tutti , sono nuovo del forum e utilizzo SharpCap da poco.
Chiedo se è possibile avere l 'opzione di stabilizzazione Pianeta/disco anche a 16 bit.
camera Player One Saturn sqr mono

Vi ringrazio

Maurizio

Hi everyone, I’ve just joined the community. I started using SharpCad recently. I would like to ask if it’s possible to get the option to stabilize the planet/disco at 16 bit too. Camera player One Saturn sqr mono
Last edited by Maurizio on Wed Jan 04, 2023 12:26 am, edited 1 time in total.
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