Over the last few weeks I've been exploring the feasibility of using KStars/Ekos in Raspberry Pi to control my Fujifilm GFX 50SII for imaging sessions.
It has involved a lot of trial and error, and given indications of frustrations from other's exploring this topic, I thought that it would be worth documenting some of my findings.
Camera setup - prior to connecting the camera to my RPi, I set the following:
a. Turn off all power saver options – otherwise exposures longer than 60 sec won’t download;
b. Set viewfinder to EVF only + eye – turns off all display unless you put your eye to the viewfinder, reducing camera battery load;
c. Set Connection mode to USB Tether Shooting Auto;
d. Set the shutter to EFC, the dial wheel to manual, and exposure length to ‘Bulb’;
e. Connect the camera to the RPi and turn it on followed by a powerup of the Pi.
Once the RPi is powered up and I've connected to it via the browser on my desktop, I fire up KStars, then Ekos and initiate the camera connection using the Fuji camera driver. Configuring this was quite a hassle, in particular getting the camera to take 16-bit rather than 8-bit images - taking a FITS format file shifted it into 16-bit mode, and that setting is now saved in my configuration and gets applied to raw format files as well.
Other INDI settings that seem to work are as follows:
a. Option set to FORCE BULB = ON - enables longer exposure lengths that sit between Fuji's rather large exposure steps, i.e., other than 1/2/4/8/15 and 30 minutes - the exposure is reported as the closest of these in Lightroom, but checking the EXIF in RawDigger, the actual shutter open length is accurately recorded;
b. I've not found a way to save images to the camera SD card, and reading between the lines in the camera manual, I don't think that it’s possible with the camera in this connection mode - as a consequence I set the SD image parameter in the INDI image tab to 'DELETE';
On the EKOS camera control tab I do the following:
a. Manually set any exposure length and number of exposures as normal;
b. Set file format to RAW and Native;
c. Under file settings I select Save = Locally and explicitly select the destination folder - if I don't manually navigate to the desired folder on the RPi where I want the files stored, it is sometimes unable to locate the default directory shown at startup;
d. Leave the delay set to 0;
e. Unless I want to inspect each file, I disable the option 'Use FITS viewer' under the FITS viewer tab of the EKOS options dialogue (bottom right of the EKOS camera dialogue) - if I don't do this, the reported file download times sometimes approach 30 seconds per file - from what I can work out, this is not the amount of time taken for the file to download, but the combined time taken to download the file and to reformat the 50MB raw file to allow display in the FITS viewer. When I have the viewer disabled, average download times are around 2.5 seconds. I find I can turn the FITS viewer on and off in between images if I want to check progress.
This overall setup was initially quite unstable, but whenever I fixed a problem, I saved my configuration in the Options tab of the INDI control panel, and now reload that configuration each time I start up a new session.
I was concerned that the setup might become unstable during a session, but have just successfully run a trial session taking 150 minutes of exposures (inside) in a mix of exposure lengths from 11 to 450 seconds, with all images saved onto the RPi, and subsequently downloaded to my desktop with FileZilla where I imported and checked them in LR and with RawDigger. This exhausted the camera battery, but the 10,000 mAhr momax powerbank I was using to power the RPi was only half discharged.
I would be interested to know if anyone else is playing in this space and whether you've found a way to save to the SD card.