I was able to work around this by requiring a focus run after the flip. I don't *need* to re-focus after a flip, but it doesn't take too long and is way better than having captures fail.

I am kind of surprised that no one is affected.


Risingcam IMX571C, but I do not think it is the camera driver (see below)
KStars 3.6.0 stable, 28 Aug build

This is a new issue for me. It could be something as simple as a setting I have overlooked, as I recently moved from astroberry to a mini-PC with Ubuntu Mate, and I keep finding settings that I need to change from their default but have not thought about in ages (once I got them set in astroberry, ages ago). For example, I shot 3 full nights before I remembered to change the temperature source for triggering a focus run from 'camera' to 'Rigelsys' (why on earth does that default to the camera, anyway??).

The symptoms: main camera image download fails / timeout immediately after the flip repositioining. I do not suspect the camera driver because capture successfully resumes when a new job starts:

I can also re-start successful captures by hitting the Stop button for the capture sequence in the Camera tab. The scheduler immediately re-starts the capture sequence and all is well. But I didn't put all that work into cable management just to still need an alarm clock set for every flip. I can work around it by carefully scheduling jobs, but I'd rather just have it work correctly :)

The log is not very informative - it simply reports the timeouts.


File Attachment:

File Name: flip-camera-failure.txt
File Size: 802 KB


[this post makes the possibly dubious assumption that I have more or less figured it out]

The IMX571 sensor features "Low-Conversion Gain" (LCG) and "High-Conversion Gain" (HCG). Some manufacturers have their camera automatically switch from LCG to HCG at a specific gain value (I think for ZWO LCG is 0 - 200, HCG kicks in automatically above 200).

The Risingcam (and, I presume, Omegon, Altair, etc that are Touptek cameras) uses gain values from 100 and up.

People on CN have performed sensor analysis on the Risingcam ATR3CMOS26000KPA, using the native driver. Those analyses consistently show that the best gains to use for maximum dynamic range are LCG/100 and HCG/100. The dynamic range is very similar between those two settings.

The INDI driver has a 'checkbox' style entry that allows you to set LCG or HCG. I decided to use LCG/100 for unfiltered OSC imaging and HCG/100 for imaging with the Antlia AlpT duoband filter. But, during one recent narrowband session I happened to notice that the LCG / HCG switch setting had reverted to LCG, even though I had looked at the start of the session to make sure it was on HCG. Some investigation led me to realize that the INDI driver uses a 'switch at a certain gain' mechanism, but the gain to switch at is adjustable. I always knew the "HCG Threshold" setting was there, but I assumed incorrectly that it was for the 'HDR' mode.

So, if you leave HCG Threshold at the default 900 and think you have manually set Dual Mode to HCG, when you tell the camera to take an image at Gain 100 it switches the mode to LCG. Going forward I will try setting the Threshold to 102, and using HCG/102 for narrowband imaging.

Does anyone know what happens if you change the HCG/LCG gain ratio setting?


Ron DeBry replied to the topic 'Meridian Flip not triggering' in the forum. 4 weeks ago

Is the "Meridian Behavior" tab in iOptron drivers new? I had the same issue appear (drove me nuts for a few nights before I noticed that tab). I recently installed 3.6.9 from scratch on an Ubuntu mini-pc, so it is possible that I had correctly set those values in my CEM25p driver nearly two years ago when I first installed astroberry on the pi, and the correct settings persisted when I switched to a CEM40 in December. But I have absolutely zero memory of ever visiting a meridian tab in the driver before.


I use "full field", bin 2x2, crank up the camera gain and increase the exposure time.

I was imaging the Wizard nebula last couple of sessions at f/9 with a 5nm duoband filter, and focusing was quick and easy.


Ron DeBry replied to the topic 'KStars crashing' in the forum. 1 month ago

The nightly seems to not crash, but when I played around with the telescope simulator it kept getting caught in some kind of loop - flickering back and forth between a couple of messages about a meridian flip failing (I had sent it to a position that should have been at least 3 hours away from a meridian flip...)

I didn't want to risk that happening when connected to my mount, so I reverted back to stable. Still crashing, but I have found what might be a workaround. I open Kstars, start Ekos - the IND panel shows up unpopulated by any settings / switches, then after a second or two Kstars crashes. If I restart Kstars and tell it to *not* close the existing INDI server, it *seems* to work correctly from then on.


Ron DeBry replied to the topic 'KStars crashing' in the forum. 1 month ago

Thanks, Ray. I'm not sure there's a particular xxxx_config.xml file involved and it does not *look* to be related to an INDI driver. Seems to be Kstars itself crashing.

I have noticed a few times on my Ubuntu Mate install that it reports the Marco window manager has crashed, and I have a couple of odd-seeming issues that could be related to the window manager (a fair number of windows within Ekos and within PHD2 appear without any 'minimize' or 'close' widgets).

I am installing the nightly, to see if that will write a new version of some KStars file that might have gotten corrupted. If worst comes to worst I might need to back all the way up and install an earlier version of Ubuntu.


Ron DeBry created a new topic ' KStars crashing' in the forum. 1 month ago

Ubuntu-mate 22.04 LTS on a mini-pc
KStars stable installed from ppa

Ran well a couple of nights, including an all-night session last night. Ekos stopped as normal at dawn, with KStars still open as normal. I tried to start a new Ekos session with the "main camera+simulators" profile to take flats (this is an existing profile I have used before), and KStars crashed.

Kstars now crashes very nearly every time I try to run it, regardless of the profile chosen. Have rebooted, power-cycled, run apt-get update, etc. no change. I unplugged every usb device and tried with only the simulators.

With the simulators profile, when KStars crashes I have hit the Run button and the INDI control panel window comes up, but there is no information in the Telescope Simulator tab (it's blank).

Ran kstars with dbg, and it says:

Thread 1 "kstars" received signal SIGSEGV, Segmentation fault.
__strlen_sse2 () at ../sysdeps/x86_64/multiarch/strlen-vec.S:126
126 ../sysdeps/x86_64/multiarch/strlen-vec.S: No such file or directory.

I did type bt, but I'm not sure how to capture the information - should I pipe it to something that will save the text to a file? (I used unix 35 years ago, but have forgotten 99.9% of what little I knew back then)

If I had to guess, given that there were no software or hardware changes in between 5:15am (dawn shutdown) and 8:00am, something on the hard drive may have gotten corrupted?

Is there a least painful way to re-install Kstars?


The other night with my CEM40 PHD2 surprised me by recalibrating after the scheduler slewed to the target, soon after calibrating near the equator (+22°, which is as close as I could get without running into a tree). This was with the stable build.

I was using my new mini-pc install for the first time, so I cannot be certain I did not miss some relevant setting, though I am pretty sure I had "reuse calibration" set correctly. The mount does report its position to PHD2, because I can see the coordinates recorded in the PHD2 log as each calibration starts. Can you look at your PHD2 log to see if yours actually knows where the mount is, also? There is nothing in the PHD2 log to explain why it recalibrated, but I won't be able to investigate further until the skies clear again - so maybe October...

Unfortunately, I do not have the corresponding KStars logs. One setting I overlooked while setting up the new computer is the checkbox for 'log to a file'.


All appears to be working with my Ubuntu 22.04 LTS install.

As for x11vnc, when I complained about slow and clunky I was still setting up and had a monitor physically plugged in to the mini-pc and another monitor for the computer that was logged in with vnc reader. Not sure if that was actually slowing things down - I also disabled the Conky system monitor that the rlancaste script installs (found it annoying), and I am now happy with the responsiveness using x11vnc.

I have both wifi adapters running, with the external adapter connecting to the home wifi and the internal putting up a hotspot. Both work well, and the range for the internal wifi hotspot is a refreshing change from the internal Pi wifi.

Decided to remove the 'tracking on/off' toggle from the tool bar - there's no confirmation dialog box (unlike when you turn tracking off in the Mount tab), and the added convenience isn't worth the risk of an accidental click. Still no minimize widget for Mount Control, and last night PHD2's 'Review calibration data' panel came up with no widgets at all. I couldn't close it or move it to the back, so I just dragged it nearly off screen and continued on.


I ended up starting all over again, with a clean install of Ubuntu Mate (available from the main Ubuntu Mate web site). This time I used Rob Lancaster's installation/setup script: github.com/rlancaste/AstroPi3/blob/master/setupUbuntuSBC.sh

There is nothing at all wrong with Damian's walkthrough (and I still needed to redirect gpsd to the correct place). But I noticed that Rob's script includes configuring network manager to put up a hotspot if none of its known networks are available, and it configures the ethernet interface for direct connection to a pc. You could set up Damian's way and then just follow along the commands in the script as well. I have not tried using the 2nd wlan adapter yet, will cross that bridge eventually.

The script installs x11vnc. It works, but is disappointingly slow and clunky. I've been spoiled by VNC Connect on the Pi, but not so spoiled that I want to pay $4/month. I may try another vnc option or just go back to NoMachine.

Mate gives me a layout I am happier with, including a Windows-style quick-switch tabs bar. I also spent a while going through every KStars option panel (I think - I probably still missed some) and learned you can add a Toggle Mount Control to the main KStars tool bar. Which is good, because I still don't have a minimize widget on Mount Control (even using the PC directly with monitor connected). I wonder if that is a recent KStars change. I also added a Toggle Mount Tracking button, for those times when I have balanced a light panel on top of the tube and don't want the mount to rotate.


Thanks for the clarification about NoMachine. That is not necessarily a deal-breaker, but it is another inconvenience. While imaging with astroberry, I tend to keep an open vnc connection on the desktop on one floor of the house and the laptop on the other, but I'm sure I could get used to having to log in again more frequently. I will keep exploring vnc options. There is something fundamental I am missing, because I get the same error message when I try to start either tigervnc or tightvnc. There is probably some precursor installation I have missed.

I don't have a lot invested in the system yet, so I'm thinking about maybe starting over from scratch with an Ubuntu server install followed by a different desktop (you noted being forced to use Gnome - that comes from choosing the Ubuntu desktop installation option).

One thing I find clunky about Gnome for KStars is actually something the Gnome developers probably think of as 'elegance'.

In this first image of an astroberry install (not mine, I stole it from a google groups post, but mine is similar) you see how the various KStars component windows each have a Windows-style tab near the top of the screen. Switching from one to another is a simple matter of clicking on that tab. If I need to adjust something in the INDI Control Panel it is a single click to bring focus back to the control panel.

In Gnome, the KStars windows are organized as dots in the main KStars icon on the left. To bring the INDI Control Panel to the front you need to click on the KStars icon, then click on the pop-up window for the component you want. (you can also see in the screenshot where I don't have a minimize widget on the Mount Control window - which is a pain given that Mount Control is persistently on top).

I don't know if there is an Ubuntu desktop flavor that is more like the Debian buster desktop, but I'm looking.