More Questions Relating to Live Stack Saving

[garyhawkins]

As I mentioned in my previous email. I've started to use SharpCap for photometry image capture. To avoid saturation for bright stars, I need to use both low gains and short exposures. This increases scintillation errors as you're not benefiting from integrating the target over a longer period of time.

Thus, I decided to use the Advanced Live Stack feature 'Save and Reset every'. A typical run might be 2sec exposure, Gain=50, save and rest every 1 min. Thus, 30 images are stacked and averaged greatly improving SNR and reducing scintillation errors.

I've observed the following:

Both 16bit and 32bit images are saved with the Save and Reset every' feature. I believe the 32bit images are incorrect as described in the bug thread I posted yesterday. For my camera, ZWO ASI533MC, the unbinned image is 3008x3008. The saved 16bit and 32bit FITS files are 53MB and 106MB, compared to 17MB for a 16bit FITS image saved directly during image capture. Why is there such a difference in the directly saved and live stack 16bit FIT image size? This latter file size results in serious storage issues on long imaging runs, made even worse because both 16bit and 32bit images are saved in Live stack? Would be in possible to remove the 32bit image storage, or make it user selectable? Finally, each set of images goes into a separate folder. Would it be possible to have all live stack saved images go in the same folder, or again make this user-selectable as then the science images are all in one place?

Version 4 seems pretty stable - loving the recent upgrades.

Best regards,

Gary

[admin]

Hi Gary,

the files are larger because they store full colour data (3 channels) rather than being RAW data with the colour still encoded in the individual pixel brightnesses. Live stacking has to work in full colour, otherwise alignment would be limited to offsets of +/- even number of pixels in each direction with no rotation capability.

You should be able to set up the filenames to do exactly what you want using the option of setting filename templates manually - see https://docs.sharpcap.co.uk/3.2/#Filenames%20Tab .

cheers,

Robin

[Jean-Francois]

Hello,

I do in the past nights some imaging with the Live Stack.
It works very good ... Yesterday, my neighbors have a look at the "live" Orion nebula (+ other objects) ... they were all very satisfied.

But yesterday I had some problem with the automatic image saving (in the last version 4).
It is not really easy to understand what SharpCap does at which moment.
The only way is to try and to have a quick look in the directory (visible several seconds in the message line).

Yesterday, after 15 minutes of Live stacking (but without active saving), my computer/SharpCap mentions a problem ... that maybe the plate was full.
I was very surprised ... I saved nothing, the plate was a day before with ~150 GB free place.
I search in different directories and I found that SharpCap was saving each individual raw frame.

Also, is it possible to improve the selection ... maybe with check boxes ?

Regards,
Jean-Francois

[admin]

Hi,

I guess you are referring to the drop down box where you choose if/when to save individual frames - Putting in 4 radiobuttons for the 4 choices would be an option, but it then requires 4x more space, which would either mean moving it to a different tab or moving something else that's important to a different tab. It's tricky trying to keep all the key options in view on the first tab...

cheers,

Robin

[Jean-Francois]

Hello Robin,

Is it not possible to add the selection capability direct on the drop list (in the Live Stack window) ?

I need to use the Live Stack more times (without 6 months between 2 uses).

The point of my question was ... yesterday, the computer disc was full after some minutes, but I start no saving before that (or I wanted only one actual image ... but not all the intermediate images).

Regards,
Jean-Francois

[admin]

I'm afraid I'm confused now...

I thought we were talking about this option :

Capture.JPG (23.87 KiB) Viewed 991 times

I'm not sure what would need to be added to the list here – it seems to cover all the possibilities.

cheers,

Robin

[Jean-Francois]

Hello Robin,

No, I mean in the "Actions" the "Save" drop down menu.

It was not really clear. In the past nights, the Live Stacking tool saved a "Stack_16bits_..." and a "Stack_32bits_.." images and with a "processed" directory. I try to open the "32bits" images with Prism software, but it is not possible. With which software can you open the "32bits" images ?

I see now on my (too much directories), that one night I have both (16 and 32) and other night only 16bits images. Maybe that one night click somewhere one time more.

The idea was to have a list (of all possibility) to select (individually) and then the possibility to save it automatically or only on-demand.

Regards,
Jean-Francois

[admin]

Hi,

Right, I understand now. I will have to think about that – it does make sense, but I do worry sometimes about hiding away options like which formats to save in on another part of the UI that might not get easily found by the user.

Pixinsight supports 32-bit fits files – I'm sure other processing applications must as well, but I haven't got any personal experience with that as I tend not to use the 32 bit files myself (the addition of them was an end user request)

Cheers, Robin

[Jean-Francois]

Hello Robin,

Here a small exemple what could be ...

Live_Stack_Save_settings.png (125.29 KiB) Viewed 968 times

Regards,
Jean-Francois

[admin]

Hi,

I'm quite reluctant to add any extra height to the live stacking control area – using up more pixels there means that the image itself becomes correspondingly smaller (and that's what we are all trying to see after all...) Things are made worse by the fact that most people now have wide aspect ratio screens, which means vertical space is at a premium. It's all a balancing act between trying to keep the actual controls from getting too big while at the same time making them both functional and understandable. Sometimes it's the hardest part of developing the program!

Cheers, Robin