Matteo Gaetan created a new topic ' FITS Viewer Optimization' in the forum. 3 years ago

Hello,

I would like to add a request.

Right now, this is the typical behavior that I am encountering:

- I plan a sequence of n pictures with x seconds of exposure and launch it - I have dithering set to every two exposures
- The first picture finishes acquiring and it's typically downloaded and displayed in 2.5s (the estimated time to download matches that, too) - so far, so good
- The second picture finishes acquiring, the dithering starts - but then, somehow, the estimated time to download gets increased by the presence of the dithering and the new estimate is now around 6.5s - and it stays like that for the rest of the session, also for the undithered frames

Also, I tried turning on the option "compute HFR" so that I can monitor the focus and decide when it's a good time to refocus, based on computed numbers. However, this slows down the images even more and the estimate becomes 8-9s.

Given that the next image doesn't start acquiring until the previous one it's downloaded, this is actually slowing down the whole acquisition: from a nice and fast 2.5s, if I have dithering - which I pretty much have to have - it goes to 6.5s and if I add HFR it goes to 9s. Now, it may not seem much, but when I take about 50 images in one night, it adds up.

2.5*50 = 125s (a little over two minutes wasted).
9s for every picture, means 9*50 = 450s. That's 7.5 minutes just on download times, or 5 minutes longer what it could be if I didn't have dithering or HFR enabled.

Now my questions:

- would it be possible to download the image and then issue the command to dither? That way the estimate for the download time would keep to a nice and constant 2.5s and not increase to 6.5 for all frames, whether I am dithering or not. I understand this would delay the beginning of dithering by the download time, but 2.5s is better than 6.5s - I don't know if this can be optimized even further and I understand that the capture program needs a confirmation that the previous image is complete before starting the next one, and downloading it is a pretty sure way that it is indeed finished. But the download times shouldn't be increased due to dithering
- would it be possible for the HFR to be computed by the FITS Viewer after the image is downloaded and displayed, such that it doesn't slow down the download time and increase the estimate as well? I have plenty of time while the next image is being captured to wait for the HFR of the previous one to be calculated and displayed. Even if I was using very short exposures (say 15-20s), if the difference between no HFR and HFR is 6s added to the download time, there's still a lot of time left while the next image is being captured
- better yet, would it be possible to compute the HFR manually, on request, only when the user requires it? This way, the download time wouldn't be affected at all, and I could ask FITS Viewer to compute the HFR while the next image is already being captured. I don't have an automatic focuser, so I need to be by my rig anyway and I could ask for the HFR every few pictures to see if it's increasing or staying pretty constant and judge when it would be a good time for a refocus. Right now I just refocus every hour, just because, or I have to look closesly at each image until the star "seem" to become bigger. But a mathematically computed number over the whole frame is much safer than trusting my own eyes

Thanks for taking this into consideration!
Matteo

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