wimvb

What was it?

What @daz said. 🙂 Don't fiddle with parameters while guiding. It won't break anything, but you won't be able to tell anything from what you changed anyway. Let it guide for at least an hour (unless it really is all over the place). Then view the guide graph in PHD Log Viewer (link on the PHD site). This is a very handy tool for trouble shooting and guide tuning. Btw, as asked before; what mount do you use?

I believe that at about 11:30 minutes he starts to remove the DEC bearings. You shouldn't need to do this, but any cover rings may come loose while you pull the assembly out, this is no problem. The most improtant thing is that you put any screws and bolts somewhere where they can't get lost. And remember in which order you do things. I always have my cellphone handy so I can take pictures while I do this kind of stuff.

Yes, but only the DEC belt. After you've removed the cover, if you look closely just behind the larger DEC belt wheel, you see a grub screw pressing against the DEC motor. This is the belt tension screw. You don't need to touch that. You may be able to remove the belt without loosening anything, but if it won't come off easily, just loosen the three motor bolts, jus like in the video. No, only DEC. When you've removed the gray cover, you'll see a small printed circuit board (pcb, probably green) with one white connector. You have to take the connector off. Do this gently, because one half of the connector is surface mounted to the pcb. Hold this part down while you gently pull the other half out. It's a tight fit, so you probably have to wiggle it a bit. This shouldn't be a problem if you're gentle with it. BUT REMEMBER WHICH WAY IT WAS INSERTED, SO YOU KNOW HOW TO REINSERT IT LATER. The encoder ring is shiny and has fine lines on it. Don't scratch this part, and don't get grease on it. Other than that, there is nothing critical here. When you pull out the DEC with the CW bar, anything that may be lodged inside may fall out. If something falls out while you pull the DEC assembly out, then you probably don't have to remove the assembly completely. Yes, just reversed order. You'll be allright. SkyWatcher mounts can take a beating and most parts handle hard contact with a floor better than the floor itself (personal experience with a metal part and a wooden floor). Good luck.

@AstroKeith and @MikeP have sound suggestions. Try those first. If that doesn't work, use yor endoscope to look around in the DEC housing while trying to move the DEC axis. Look for any loose part or anything that may have caught where it shouldn't. If you have checked all this, and still haven't found anything, you probably have to remove the DEC assembly. For that you need to remove the DEC encoder cover (gray) and the CW shaft lock and DEC clutch. Follow the steps in the video below until 11 minutes in. You shouldn't need to remove any bearings. Only DEC disassembly is necessary. Be careful with the DEC encoder ring; it is a delicate part. You will need a few allen keys and a phillips screw driver. I don't think you will need to remove both the timing belts only the DEC. (Not relevant to this problem, but near the chuck on the motor side, there is a hidden grub screw to adjust the timing belt tension. It is hidden, because you first need to remove another grub screw from the outside to reach it.)

Definitely. And replaced them if they needed too much wiggling.

Here's how the DEC clutch works on the AZ-EQ6. I took the polar scope cap off to show the inside.

Does the DEC setting circle move freely when you unlock it? It looks to me as if there is something blocking free movement in DEC, just as Tomatobro suggested.

That is normal. I checked earlier this evening. Clutch and cw bar rotatw with DEC

That is very unexpected. The "knock" you descibe suggests a mechanical obstruction and not just binding (binding is more gradual, like tightening a nut). So you need to find out where that obstruction is. Worst case you may need to take out the DEC axis. But start with loosening one item at a time. Is there a sound in the DEC housing when you rotate the mount in RA? An item in the housing would probably move, and you might hear that. It's difficult to analyse and suggest things to look for without being with the mount.

Then temperature swings can be ruled out. But do remove the polar camera and have a look inside the housing.

I watched the video again, and you do have an iPolar or similar device. Is there a chance a part of this has come loose and dropped into the hole in the CW bar?

@Tomatobro Excellent idea and easy to check.

From here on there are two possible ways to go. 1 is to release bolts and screws in the DEC mechanism. 2 is to warm everything up with a heat blanket (a car seat heating cover runs off 12 V and could keep your mount warm). If moisture has come into the mechanism and has frozen, then heating and drying is needed. With the weather we have had lately, with fog and temperatures slightly above freezing alternated with really cold weather, moisture is definitely a possibility. Although I don't know how it could get deep enough inside the mount. The thing I would is nr 1. Try is to release the four bolts that hold the worm housing just a little (a quarter turn). Are they tightened more than when you adjusted backlash? Does the DEC axis move more freely. If not, release both backlash grub screws a little (not more than a quarter turn should be necessary). By now the DEC axis should be loose. Move the DEC axis to verify that it can swing freely. Once the axis is loose, tighten the grub screws to the point where they both push equally against the worm mechanism. Then tighten the four bolts that fix the housing. Don't use too much force. This procedure should have released any tension that had possibly built up in cold weather.

I've been speed reading this thread. As others have suggested, cold may have to do with it. Since the axis is stuck mechanically, I wouldn't try to force anything with the motors, so leave the power turned off until you know more. Second, take everything off the mount while testing. It will be easier to tinker, and you don't want to release bolts with an expensive scope hanging off the mount.

Maybe time to load that mount with a longer fl and make it work for a living. 😄 Galaxy season is coming soon.

Enjoy it while it lasts. 🙂 I've had numbers this low, but it's very dependent on where I point my scope and how sky conditions are. I always get the best guiding when clouds are about to move in. Most likely the decreasing transparency also quiets down the seeing.

Correct, but it will be easier to see if anything unusual is happening. With my AZ-EQ6 I usually set the Y-scale to 2" so I can se any residual error. It turns out that despite using PPEC guiding, I have a residual periodic error of 0.1 - 0.125" in my guiding.

Guiding RMS is in my experience usually better at high altitude, because there is less air mass to interfere with the light, so generally a smaller effect of seeing.

You are guiding all right. What I meant was that since there were no tracking deviations larger than MinMo, there were also no correction pulses being sent to the mount in the time frame you showed. In that time frame, you would have had the same tracking results even without guiding. This isn't bad. In the end it's the quality of your images that matters.

Looks good, but here are a few observations. You have a guiding rms error less than 0.1 pixel (which I think is as good as you can hope for), but the smallest movement that PHD will react to (MinMo) is 0.19 pixels. (Your graph confirms this with just 3 small correcting pulses being sent in 100 possible.) PHD isn't sending any guide pulses. So in effect you're not guiding at all. Also, you have a Y-scale of +/- 8 arc seconds. You can safely set the Y-scale to +/- 2 arc seconds. Finally, there are no DEC pulses at all. Your polar alignment must be spot on.

Would that mean that you connect the focuser to an RPi4, and all else to a Windows machine? Then run everything on ASCOM except the focuser? (Remember, the OP wants to run NINA which is Windows). It seems a lot less hassle and cheaper to get a ZWO eaf and forget the Bullseye. I wrote arduino firmware for my own diy focusmotor, using the MoonLite protocol, and used that with the MoonLite INDI driver. I would assume that the ASCOM MoonLite driver must use the same protocol, and that it is easier to rewrite the Bullseye firmware to follow the MoonLite protocol. Not all MoonLite commands need to be implemented.

You are correct about calibrating old lights with old flats and new lights with new flats. But as far as stacking is concerned, you should, if possible, stack old and new calibrated lights in the same session, and not combine two stacked images as layers in PS. If you have two stacks with approximately equal numbers of lights, then stacking each seperately and combining afterwards is ok. But if the stacks consist of a different number of subs, then snr of the final image will be close to the snr of the stack with the smaller number of subs.

Converting an INDI driver into ASCOM isn't an easy task, as INDI and ASCOM are completely different. In this case it is probably easier to convert the Bullseye firmware to accept another focuser protocol. If you eg rewrite the Bullseye Arduino code to use the MoonLite protocol (MoonLite commands), you could then use the MoonLite ASCOM driver to control the focuser. The MoonLite command set is available on the internet, and not too difficult to implement. Maybe someone already has done that.

Since you used NINA as well as astroberry, you clearly used different hardware as well. I've seen similar artefacts a long time ago. At that time they were caused by electrical interference, ie a hardware/cabling problem. Here the cause may be something else of course, but if I were you, I would at least check usb and power cables, and how they are routed. Even grounding issues can affect data transfer.