wimvb

If you mean the RA lock nut, then this shouldn't be very tight. If it is to tight, it will make balancing more difficult, and the mount won't go very smooth with the clutch off. The three grub screws that hold the lock nut in place should pinch the RA shaft thread so the nut won't come loose.

The way I interprete ZWO’s statement, they can either opt to program the pe into the mount, or provide a paper copy of the pe with the mount as a certificate. The former seems quite useless if pe depends on load, position and/or balance. The other is useless either way. ( now Russell Crowe’s lesser of two weavels comes to mind)

I thought that I too was accurate, and never really bothered about the little image rotation that I had. Untill I started imaging ngc2276, qhich is only 4 degrees from the NCP, and rotation was much worse. I will check my cone error as well, and then do a new polar alignment.

Polar misalignment is also a possibility, I'd think. The mount doesn't rotate 180 about the polar axis, but about the RA axis. After the flip, there is a mismatch in pointing, and this is compensated during plate solve by moving in RA (adjusting the 180 degree rotation) and DEC (basically a shift), until the center of the fov is aligned with the pre-flip view. The pre- and post flip angle depends on the DEC angle where you are pointing. Obviously it is worst near the Pole. So, essentially Vlaiv's answer in the linked thread.

Unfortunately it isn’t. I suspect that it’s from edge reflections from my unmounted filters. DBE couldn’t clean this up, but it’s so weak that I decided to leave it.

I found that image too. As you say, impossible to compete with a 32” telescope on a mountain top in Arizona.

Ngc 2276 is an asymmetric spiral galaxy in Cepheus, located at a distance of approximately 120 millino lightyears. The asymmetry in its structure is most likely caused by gravitational interactions with its close neighbour, elliptical galaxy ngc 2300. Ngc 2276 is only about half the size of ngc 2300. Data for this image was collected during two clear nights of the first week of this year with my SkyWatcher 190MN and ASI294MM, and consists of 9 hours of RGB data and 5 hours and 40 minutes of luminance. Processing was done in PixInsight. To get more detail in the structure of ngc 2276, I drizzled a small crop of the L data and used deconvolution and Multiscale Median Transform before inserting it back in the undrizzled larger view. After this I did normal LRGB processing. There is the slightest hint of IFN in this image, just left of this galaxy pair, but I didn't push it in processing.

Very nice. It looks like this object demands a very long integration time.

Guiding was consistently below 0.5”, and seeing was good but not exceptional if my star hfr value during focusing is anything to rely on. But being this close to Polaris, I found out that good polar alignment is absolutely critical. I think I am about 5 arc minutes or less out, and I got severe field rotation between pre and post flip subs. I had to crop quite a lot.

Very nice image. I've been targeting the same galaxy and can only add that to do this pair justice you will need a lot more data. At more than 15 hours (I believe), I've so far managed to show ngc 2300 to its full size compared to ngc 2276 (it's 2 times larger) and reveal the slightest hints of ifn. I'll post my attempt later.

Still, this means that PHD will "have its hands full" with such a mount. And then one could ask, why do several of these mounts pop up now?

Ever since I checked Sharpstar’s and ZWO’s mounts I get ads from aliexpress trying to sell me harmonic drive motors. Usually for £ 120 - 200.

@dannybgoode, just out of curiosity, what type of computer do you use with NINA?

SharpCap gives you an accurate PA allright, but where do you set up? Before I put my rig on a pier, I had to avoid setting up on a wooden deck or putting the tripod directly on grass, because me moving around would move the mount enough to change PA. To help with alignment I pressed fence post anchors into the ground for the tripod legs to sit on (the kind with L shaped top, with the vertical part removed). This also helped with polar alignment.

I had a look at the guide log. The calibration looks very good; orthogonality is ok, and step sizes in DEC and RA are the same. No apparent sign of backlash (the guiding assistant confirms this: only 665 ms, which you don't need to improve.) I think that a guiding aggression of 0.9 is a bit high, but this is not the cause of your problems. The guiding assistant shows that DEC wanders off quite fast, meaning that your polar alignment was way off. The numbers shown at the end of the GA run again confirm this; 21 arc-minutes is not good. The reason that RA wanders off during the GA run is a combination of polar misalignment and periodic error. Next time you run GA, let it run for at least 10 minutes to get a better understanding of how large periodic error your mount has. If you create a new PHD profile, you shouldn't need to take new darks, afaIk. Otoh, unless you have a permanent setup on a pier, you need to recalibrate PHD at the beginning of each session, even if you don't take the guidescope/camera off the main telescope. Regarding the conflicting cameras, this is a possibility. When ZWO cameras were still relatively new, there were several reports of camera conflicts, but I think that software developers both at ZWO and in the astrophotography community have solved most of these issues. Many people run ZWO cameras for imaging and guiding (the ASIAIR is based on the premise that this will never be an issue). But I think that very few people run basically the same camera model for imaging and guiding. I don't know how to do this in Windows, but you might want to check the camera identity by looking at the respective COM port information. (e.g, when I check what is connected to the USB ports of my Raspberry Pi, I get the identity 03c3:294e for my ZWO ASI294MM PRO imaging camera, and 03c3:290f for my ZWO ASI290M-mini guide camera. 03c3 is the vendor ID, and the rest is the camera ID.) If these identities are different, the cameras shouldn't interfere, but if they are the same, you can have a problem.

You don't have to do anything in EQMOD, as long as you don't use the encoders. The encoders are mainly used in SkyWatcher's Freedom Find function, where you can release the clutches to move the mount by hand, and the mount knows how far it moved. EQMOD doesn't use this functionality afaIk. But you need of course adjust any backlash setting if you use that in EQMOD. (PHD recommends against setting dec backlash in EQMOD.) And of course, don't forget to turn off any sprinklers next time you set up. (At least now we can laugh about it.)

You can't see it in the image. There are very fine straight, dark lines radially. They are so narrow, you will need a magnifying glass to see the individual lines. When the axis rotates, these lines will pass a small sensor on the encoder pcb. This sensor consists of an led and a small light sensor. If a dark line passes the light sensor, no light is reflected back, whereas if a polished bright section between dark lines passes the sensor, light is reflected back into the sensor. The motor board software just keeps track of how many lines pass. Depending on the direction of rotation, a counter simply counts up or down. When you dis-/reassemble the mount, you have to make sure you keep this disc or ring clean and free of grease, otherwise the reflection is messed up.

I noticed I was a bit sloppy in my previous image of the encoder disc/ring. Your image shows it better. Btw, did you swap the washer and bearing? It was a while since I regreased my mount, but I'm pretty sure that the bearing should be sandwiched between the two washers. For future reference, here's en excellent write up by Scott Cunnington that I had almost forgotten. http://reset.cbm8bit.com/uploads/files/magazines/59ae571fe9ecb_AZEQ6 Stripdown guide final.pdf

Glad you got it sorted.

Depending on seeing and where you point it, that mount should give you <0.5" guiding for extended periods.

The encoder ring/disc is on the bottom side of the DEC head, as shown in this image. It is fixed to the DEC head and most likely made from glass, ceramic, or a highly polished metal.

This is just a washer (as you've probably figured out already). I'll post an image of the encoder in a minute. (Was away from keyboard for a while)

Btw, I also suspect that this is not the entire story. Corrosion can cause binding, but in your case there was a full stop. When you reassemble the DEC, before you put the clutch back, test if the DEC axis runs smoothly for one complete rotation. Then check again for each item you put back on.

The bearing between the washers, yes. As per this old post (the second image shows the sandwich configuration of the washers and bearings. All bearings sit between two hardmetal washers, not directly against aluminium. Chemistry 101: two different metals in contact are more sensitive to corrosion. And aluminium is too soft and will eventually wear.