You may want to do

sudo apt-get update

and

sudo apt-get dist-upgrade

and then try the

sudo apt-get install

command again.

I believe that's the exact command I've used a few times now, and it's worked for me. However, this solution isn't functional for me yet -- I need t run these Mini PCs headless, but can't seem to get VNC to run at startup. I can only VNC in after I login with a physical monitor, keyboard and mouse.  FYI in case that's your ultimate goal.

install Tiger Vnc

create a systemd service file example ""
also set permissions correctly
example contents ( change both username / home dir / and monitor geometry )

---

---

then enable service

Or .... make sure that your user logs in automatically and make sure that VNC is an application that gets started automatically when your user logs in. For both you can search online how to do that. It depends on the login manager and the desktop that you are using.

Indeed, that is the ultimate goal. I've heard that NoMachine is a good solution.

You can search for all of this on internet yourself, right?

linuxhint.com/enable-automatic-login-on-ubuntu-20-04/

Unlike the R Pi, it's easiest to get most mini PCs to create a virtual screen by fooling the hardware into thinking there's a monitor attached. This is done with a cheap "dummy HDMI" plug you can get for $4 to $8 online. Here's a link to a good one on Amazon .

Wouter's link to the "auto-login" feature on ubuntu is perfect. You can also set that up during ubuntu install.

Hang in there! All this confusion and thrashing about are a one-time setup thing. Once you get it working, it will "just work" from now on.

Good luck!
Scott
 

Just a suggestion…For those who are not already well-versed in Linux, this platform can be mind-numbingly confusing.  I just wrote about 2 pages of examples for you, but I’ll boil it down this way instead: most people who ask questions here have already burned up Google and they’re exhausted (from their day jobs, this hobby, and now learning a very alien operating system).  They just need a helpful point in the right direction.Cheers and clear skies! 

Yes it is confusing. But the link I posted literally is the first hit I get when I search on Google. Have you tried that at least?

Also, with RPi it is really easy to set up a virtual frame buffer with the correct dimensions. With any other device, like the mini PC you're using, it is exceedingly hard. You'll need to set up Xorg to use a frame buffer and then an .xinitrc again with a frame buffer to get this working. I have been using a mini PC for about two years and in the end I gave up because a Raspberry Pi 4 with 4 Gb just performs better. Even with the virtual frame buffer and using a wired network, there were a lot of hick ups in the virtual display and things like plate solving just didn't perform very well. I had to wait for over a minute for a solution to come and with an RPi it is about 2 seconds. Not kidding!!!

My advice: use the mini PC for something else and get you a Raspberry Pi 4. That works and it works really well. There are scripts that can help you to install Ubuntu and KStars and they work. If you don't know Linux very well then a mini PC is just too hard. I have been using Linux for over 20 years and found it hard to configure my mini PC. Just my $0.02

For me, the RPi4 is out because of my full-frame cameras. Jasem and I troubleshooted it, and Kstars just isn’t able to use > 2gb RAM [EDIT: I was referring to KStars on Stellarmate OS]. I get a few frames into my session and those ASI6200 images cause Kstars to crash unless I turn off all kinds of features that I need. The Pi is also laggy even on LAN, which is a big irritation of mine.

Agreed - My 2600MC beats up on the SM and the WiFi 2.4 versus USB3 is irritating.  Have a 16G mini now.

I use an ASI6200MM with a Raspberry Pi 4 with 4 Gb and if I switch off the FITS viewer, KStars runs all night without crashing. If KStars doesn't run on an RPi then why would it run on a mini PC? Also, why isn't KStars able to use more than 2 Gb of memory? Are you running a 64 bit Ubuntu on the RPi? Finally, yes the Pi is laggy for me to but not nearly as much as on the mini PC.