Guide Scope not settling.

Sasumba

Hi I purchased the ASIAIR pro and few weeks ago, and I have tried on a numerous occasions to do some deep sky photography, but I just cannot seem to get it to guide properly at all, keep getting error message saying timed out, waiting for guider to settle, now I know all my setting are correct ie: main camera, focal lengths etc etc, even after I have polar aligned it still will not guide properly, any ideas pls share?

Kring

In my experience and through my struggles I found a few gotcha's in my routine.

Have you set your dithering under guiding settling to 4" for 1 second? that should be your starting point... the settling in my experience is where the issue can be, you are expecting too much stability so it times out. start big and see if this resolves, then you can word down to 1" for 5s if it's stable
For any decent guiding it requires exceptional polar alignment, we're talking 00, 00' 05" total error. I've found that anything above that and you will have drifting stars that require a lot of guiding correction. the more correction you need to more radical the guiding trend lines are, which means settling takes longer
Polar alignment isn't exact in my experience... when I do it... and say I get to 05" total error and it took me like 6 minutes to dial that in. If I go back and run it again It's now 01' 15" total error... I don't think the PA routine is calculating for the duration it takes you to polar align... so in that 6 minutes of time while I fumbled with knobs the sky moved and that's not be accounted for... If you want truly accurate polar alignment I found it takes 3 or 4 runs at it, and your last run should basically start out as perfect polar alignment and you just hit finish.
for whatever reason, the polar alignment via the mount (I have CGX) is NOT the same as the AAP's PA routine.. it's off by a notable amount and I'm not certain who's is right. have you checked to see if your mount's polar alignment is close to the AAPs? a large delta here is probably a problem
Some people use a spotting scope for initial alignment, I've found that it isn't always accurate and you may be telling your mount inaccurate coordinates for initial alignment which can set things askew. use the main camera for centering stars in alignment

Just some thoughts, not sure if you have all this covered and you are dealing with a different issue. but thought I'd share since some of this I recently figured out and it got me from unable to guide, to rough nights averaging 1-2" to recent nights getting pretty stable averages around .5-.8". In my case it was 100% polar alignment as the cause.

w7ay

Kring Polar alignment isn't exact in my experience... when I do it... and say I get to 05" total error and it took me like 6 minutes to dial that in. If I go back and run it again It's now 01' 15" total error...

Check for absolute mechanical stability of your tripod and mount. Remember, we are talking about arc seconds type of accuracy. Make sure the altitude and azimuth bolts are locked down tightly between passes and not allowed to move even a couple of microns.

A simple exercise is to look at distance between your tripod legs. Lets say the spread is 0.5 meters. Now move one leg 0.5mm away from the ground. That represents 0.001 of a radian (angle is small enough that the tangent of the angle is practically the same as the angle). By doing that, you have moved the mount by more than 200 arc seconds! And that is for just a 0.5mm movement of one tripod leg. To get the polar alignment repeatability to be down to 1 arc second, that tripod leg needs to be stable to about 2.5 microns.

I get decent repeatability (better than 10 arc seconds) by restarting from the mount's (RainbowAstro RST-135) home position and reapplying the Polar Alignment process. The mount is on top of a William Optics Mortar tri-pier that sits on three concrete slabs (Casa Depot stepping stones from their Gardening department), on a flat garage roof.

The acid test is with my mount simulator, where the only mechanical error is the flexing of the 15mm "NATO rails" (used a lot in the photography world) that holds my iPad (used as a SideCar display for my Mac) and an ASI174. With that setup, I am within an arc second or two of repeatability.

There are other factors too, like atmospheric refraction changes with passing time (probably won't apply unless you are close to the equator, with the alignment stars close to horizon).

The Polar Alignment algorithm in ASIAIR is one of the (few) things that actually work properly on ASIAIR. As long as the no-60º-slew bug does not happen to your mount; but that is a mount protocol bug and not a Polar Alignment algorithm bug.

All that said, Polar Alignment error will only cause stars to rotate around your guide star, and not do harm to autoguiding. With a 500mm type focal length OTA and a 60 arc second polar alignment error, you can run 10 minute sub frames and not see any evidence of field rotation. When looking for field rotation, keep in mind that when autoguiding, the field rotates around the guide star, and not around the center of your image frame. You are more likely to see star elongations that are caused by back-focus errors than from polar alignment errors.

Chen

Sasumba

Kring thank you all so much, I am actually new to all this, and I very much appreciate all the advice that you have given me, I will follow your instructions and see how I get on.

Byrdsfan1948

@Kring I am relatively new to this hobby and all my guiding experience limited to the ASIAIR Pro. Your PA comments here are very interesting,
A few nights I was able to take 100, 3 minute subs dithering every third image. My guiding was perfect all night even after a Meridian Filp. The last two nights however, it has been a total mess. In particular the problem is almost all in DEC while the RA is virtually perfect. This is not a new issue but one that I have experienced from day one. Some nights the guiding is virtually problem free only to be a total mess the next night. This drastic difference is not due to weather or seeing conditions, and obviously since my equipment is not different night to night, not that either.
I would have discounted your comments regarding the PA if I had not recently been noticing what I think you're referring to.... Last night for example I finished my PA process with a supposed total error of 00, 00', 05". Yet my guiding was virtually impossible for more than a few subs at a time. In the past I have done a PA routine, sync to mount, then go to the home position. Then out of curiosity redid the entire PA routine. I would of course expect that the beginning PA error would be fairly close to what I had just gotten. However I have found that it was different enough that it required me to redo it.
This past week the weather has been good enough to allow me to leave my scope set up outside in exactly the same location all week. Yet each evening when I check the PA I find that it needs significant adjustment often 5-10 minutes off from where is was set the night before.
I am sure that part of this problem must be from my mount. I use an Ioptron CEM25EC. But this same mount can also result in virtually perfect guiding all night, some nights. After reading your comments I am starting to wonder just how consistently accurate the ASIAIR PRO PA process maybe? Obviously for starters it can only be as accurate as the limitations of our individual equipment allows. But beyond that I now wonder just accurate and repeatable it is itself? I'm sure there must be easy ways we can look int this question deeper.

Kring

I hav two important things to share.

First: I was able to get out last night, I ran the AAP Polar Alignment 10 times.. every time I dial it down to < 00’ 05” I hit finish then run it again and it’s off by anywhere from 02’ 00” to 00’ 40”…. So something is off, I’d be curious if others have similar erratic PA results.

Next I attempted to guide…horriible, stars running off the screen. Cleared calibration, stars moving so fast the AAP couldn’t even keep a star on screen to calibrate.

Ran 5 more PA attempts, all dodgy like the earlier ones, tried to guide.. same thing. Impossible.

I then dusted off my PC, ran SharpCap Polar Alignment and I was off by over 04’ 25” on Dec and 02’35’ on RA… used SharpCap to get it to perfect 00 00’ 01” alignment, ran that two more times and it was dead on… so this confirms my mount is perfect, and AAP PA is having some sort of issue.

Hooked AAP back up and guiding was terrible again… did a goto & sync still bad, disconnected and reconnected mount, turned tracking on/off, recycled guidecam, checked time and locations and they were all in sync. Out of a bit of frustration while watching my stars run across the screen. I went to scope settings, turned tracking of, then back on.. still streaking. Then changed it from Sidereal to lunar, solar, lunar, sideral… BAM. They stapped into rock-solid!

So there’s the big issue.. something was stuck. I recall now that a few of the previous times I had run away stars it snapped back into place and I didn’t know why.. but it wasn’t mount or polar alignment related. It just started working.

This might be pointless now, since they confirmed guiding we will be getting a big update and multi-star in next version. But for those having issues right now… try this fix of changing tracking from Sidereal to lunar, solar, lunar, sidereal… seems silly, and matbe you don’t need all 4… but when I did just 1 it didn’t work.

To finish on a positive note, last night’s frustration with this was flushed away quickly when I had the best guiding I’ve ever had… the combination of dead-on polar alignment and flushing out the AAP tracking issues here’s what I got!

Byrdsfan1948

Kring, I'll add my experience from last night to your's. First I can confirm your failure to repeat PA. According to my first attempt that took just over 9 minutes I was at 00, 00, 02" I returned to home position and redid the PA. I was far enough out so that the smile face was gone, and I needed another few adjustments to get it back to about 05" like you. At that point I went back to home and then a GO TO to the Leo Triplets. My goal last night was to just focus on guiding for a few hours so it was more a convenient target than a particularly interesting one for me last night.
Unfortunately, while different than yours I ran into just as mysterious and frustrating issues. The first problem was that now it seems my ASIAIR will often disconnect from my the mount which then will not respond. The solution is simply to cycle the ASIAIR on and off again. I know this in NOT a power or cable issue because I now power my mount totally separately from the ASIAIR using the 12 volt power brick that came with the mount and plug that into an outside 120 v power outlet. My ASIAIR now only powers the cameras. Last night this first occurred when I tried to calibrate on a guide star.......... It appeared that while pulses were being sent to the mount it was not responding. Adjustments to aggression and duration didn't help. I then recycled the ASIAIR and that solved that. However that then lead to the next problem. Instead of getting run away stars like you did, the DEC and RA lines on my guide graph just slowly moved off the graph, until they totally disappeared. Ironically even though they were gone my total guiding error showed as well under 01". The only way I could restore them was to pick a new guide star and restart guiding........... But then eventually they again would over the next few minutes drift back off the graph. Again total error showed as quite acceptable. It was as if the camera was picking a location away from the center of the box that the guide star was centered in and then guiding from there. Eventually out of frustration I gave up and shut the rig down. But not before I had to again recycle the ASIAIR to be able to return to home position. Unfortunately once I got there I didn't think to re run a PA to see what that may show at that point.......... If the skies cooperate tonight I will make sure to do that. Bottom line it sure appears to me that there is something going on with the ASIAIR that is causing all these strange issues we are seeing. While I didn't think to try cycling through the various tracking rates as you did. However as I was shutting down I gave some thought to changing the tracking percentage rate of the sidereal rate. Currently I am set at 0.5. I'll add that idea to my list for tonight if I need ideas.

What is equally baffling to me here is that it also appears that on some nights I can get perfectly acceptable, and totally trouble free guiding. I am using exactly the same equipment and being especially mindful of things like balance and level. One last observation. I noticed that last night there were very few good guide star options in the Leo Triplet area. I am using a 200mm FL 50mm guide scope with the ASI120 mini...... My camera seemed to be having a lot of trouble keeping a reasonably consistent star image to guide on. They faded in and out a lot and I had even got some lost star messages. I played with the gain as well as shot time from 1-4 seconds with no help with the problem. The seeing was crystal clear and no moon at all so that was not the problem. Just one more mystery to add to the growing list I guess :-).