I'm using a DSLR with EKOS on a Raspberry Pi. Now, it is a Raspberry Pi 2, so maybe that is the route of all my issues, but it seems to work fine so far, the only issue being sequence image download time.
I have so far been using an intervalometer to do my image capture. Due to sky conditions and mount performance I usually image in the 30-120 second range. With the intervalometer I will do a 1 second hold between images.
Using the sequences in EKOS, a 30 second capture has a 25 second download, after each capture. If I was doing 2-3 minute sequences ok but at 30 seconds that is knocking down my imaging time by nearly 50%. The flat sequence is much worse, at 1/800th of a second to capture and 25 seconds to download. Normally I can be down a 30 flat sequence in less then 60 seconds.
Would it be possible to have an option in EKOS for DSLRs that allows it to just run the sequence without downloading any images? The images would be stored on the camera storage. All other captures outside of a sequence with this option would still download and display the images.
Yes. The Gphoto INDI driver offers two options. Ram and SDcard. If set to Ram, images are downloaded and deleted from memory. However if set to SDcard, images will end up saved to both the card and downloaded to the raspberry pi.
Looking at the CLI options for what is supported it should be possible to trigger a capture and keep the image without downloading.
I did discover the fast exposure option, and so that does solve 50% of the problem. For 30 second exposures with fast exposure on I have a delay of around 3 seconds between exposures, some of which is mirror actions. All in all that is totally fine for delay.
It however does not work for things like flats. The fast exposure requires that download times take less then the exposure time. For me that means anything less then 25 seconds will error. I think for flats we still need something like a don't download option. That will just take the N flats and leave them on the SD card.
I do have some additional questions about fast exposures. Is there a reason for there being a fast exposure amount that is different from the sequence length? If I try and take a 10 count with 10 fast exposures kstars will crash. If I set it to more fast exposures then sequence length it works. I also can set the fast exposure count from the app, but I am unable to put it in the preset in the app. I do see the option to autoset that via the sequence when using VNC.
I also need to disable the fast exposure when doing preview captures, as otherwise it throws an error if the download time is longer then the exposure, even if it does seem to take the image.
It might be due to the FITS Viewer on low end systems not having enough time to process the first image when the next comes. That's my theory anyway. This shouldn't lead to a crash, but I can see how it can.