v1.8.1 guiding & auto-center issues

Improve101

For 2 nights now guiding has been a show stopper. The RA is good for about 30 seconds, then goes way off the graph. I even stopped guiding altogether and toggled the mount tracking off then on and it also made no difference, which it should. Taking a 3 second image at 800mm focal length was just streaks of stars. Mount is eq6r pro and is normally rock solid. I tried clearing the calibration several times, flipping it, changing guide camera gain, and all made no difference. Nothing is new other than the Android 1.8.1 firmware.

Also the Auto-Centering seems to be worse than ever. Takes many attempts & then just fails. Tried changing the Centre Exposure time, and that made no difference. Something is off there, also with 1.8.1, as this has been working fine in previous versions (albeit with greater centre point tolerance).

What can i do? There's no way to be able to revert software versions and it seems more regression testing is needed between releases. This is a massive problem for me as my time setting up, attempting to image, tearing down, and the rare clear night, are all sadly wasted. 😔

w7ay

Improve101 Mount is eq6r pro

Are you using the SynScan protocol ,or are you using an EQMOD connection to control the motors directly?

If you are using SynScan, be sure to read the initial SynScan specific instructions on the Guide window. I.e., the window that you get when you initially tap the small guide graph.

ASIAIR has a long standing bug (comes and goes with version since they do not perform regression testing); so much so that they apparently gave up on fixing the bug, but instead give the workaround when you first open the Guide window (before calibrating, etc).

Basically, the ASIAIR sends guide correction pulses the same way it sends slew commands. Except that guide pulses are usually done with 0.5x sidereal rate, and slew commands are between 1x to 2000x sidereal rate (depending on mount).

To do guiding, you first set the mount to 0.5x sidereal, and slew the mount for N milliseconds (these are the "steps" that are referred to in the Guide setup). N is usually in the 50ms to 0.5 second region. At 0.5x sidereal rate, it will only move the mount by a small amount.

However, if someone (inside ASIAIR) happens to send the mount to 16x sidereal rate, it will slew the mount by a huge amount. If it was set to 512x, it would run away even faster.

ZWO apparently has not found the culprit, and instead gives a workaround to set the slew slider in the GOTO panel to 1x sidereal.

So, if this is the bug that is affecting your mount, follow the instruction in the initial guide window. After setting the slew rate in the GOTO window to 1x, go back to the guide window and redo the calibration.

Most people have given up waiting for ZWO to fix the bug, and bought themselves an EQMOD adapter (usually a virtual FTDI serial chip in a USB cable).

Chen

Improve101

w7ay Hi Chen, appreciate the response.
I connect my mount directly via its USB port to the ASIAir with a regular USB cable, as I have always done, and select 'EQMod Mount' within the ASIAir app. Does this change things in terms of your recommendation there?

w7ay

Improve101 Does this change things in terms of your recommendation there?

Ah, it looks like you have the mount model that supports EQMOD from the USB Type B connector. Did you try to set the slew rate to 1x just in case the bug also exists? (My impression is the problem is only with the Celestron and SynScan protocols, not EQMOD. But it may be more widespread.)

Chen

Improve101

w7ay Sidereal was set to 0.5x and i tried 0.9x but that didn't help, so reverted back to 0.5x which is the recommended for my mount. Slew rate, i changed as needed, from about 600x to 128x and back again, but are you suggesting that i try changing that to 1x and basically don't use manual slewing arrows as itll take eons to move anywhere at 1x slew rate, as a potential workaround? I'll try it anyway.. can't hurt, but I'm not hopeful of it fixing my issue. I guess other people are ok using Android asiair v1.8.1 although I can't really confirm.

w7ay

Improve101 at 1x slew rate, as a potential workaround?

That is what the initial Guide window suggests. Read paragraph under "Tips."

Appears to imply SynScan protocol, instead of EQMOD protocol, though. But try it anyway.

Chen

Improve101

w7ay Ok Chen, i'll give it a go and cross my fingers. What software do you yourself use for imaging?

w7ay

Improve101 What software do you yourself use for imaging?

I use a Mac Pro and a M1 Mac Mini, so I use Astro Pixel Processor for the processing images.

To capture images, I use anything from ASIAIR to INDIGO (no N.I.N.A. because I try to avoid Windows). I have a semi permanent tri-pier (both tri-pier and mount are outdoors all the time), so I don't do polar alignment that often. When I do, I use ASIAIR to polar align nowadays, when I periodically have to. Before that, I had used SharpCap (a pain because I have to drag out a Windows laptop, which I rarely use -- my laptop nowadays is an M1 MacBookPro; and the SharpCap subscription model nowadays has also made it a non-starter for me).

PHD2 used to guide much better than ASIAIR, but since the introduction of multi-centroid guiding and more rapid guiding updates (up to 2 FPS now with 2x binning) ASIAIR autoguiding has caught up, and auto-guiding is finally working fine. Plate solving is not ideal (like for long focal length planetary), but for most of my other needs, it is OK.

Polar alignment has been working since ASIAIR v1.3 for my mount. It was a fiasco before that because they were blindly implementing the RainbowAstro protocol without having a physical mount on site -- the Koreans finally loaned ZWO an RST-150h to do development on. I suspect it is the same with your mount -- ZWO is simply too cheap to buy a copy (or even just to get a loaner from Celestron/SkyWatcher).

I don't use "auto" anything with ASIAIR (they are the weakest points of the ZWO software). I don't auto center after a GOTO, I do my own Meridian Flips,etc. I have never used Plan mode. As they say, "the Journey Is the Reward" -- and IMHO, those who automate the journey are missing out on the true joys of astronomy.

I am simply using ASIAIR as a manual tool. ASIAIR auto focus is terrible when compared with using a Bahtinov mask, so unless I am very lazy or not actually capturing images but doing other experiments, I still use a diffraction mask, like the Bahtinov (IMHO, the Bahtinov is the best hobby astronomy innovation since I started on the hobby almost 60 years ago).

After AstroPixelProcessor to stack, combine and apply star color correction, I do final touch ups of images with Affinity Photo (or macos Preview).

Chen

Improve101

w7ay All very interesting, thanks for the insight Chen.

wvreeven

Improve101 Contrary to w7ay I do everything auto, apart from focusing which I do using a Bahtinov-mask. Auto center, auto meridian flip, auto guide. All work very well, even when using small band filters.

Improve101

Tried the same ASIAir on a smaller rig and all worked beautifully.

Will try the main rig again soon and update if the problem persists, something hardware specific, or if it was just having an off night.