Moonlite NiteCrawler rotator and SGP

Hello All,

I’ve recently installed and set up a NiteCrawler focuser/rotator on my 4" refractor, and so far the autofocus routine seems to working great, however my first attempt at getting SGP to auto rotate to a plate-solved previous sub frame has been unsuccessful. I’ve read through some other posts here and on Cloudy Nights, but I’m not sure it’s helping me.

After installing my NiteCrawler, I attempted to go back to a previously imaged target and get the centering and rotation correct. As usual, the centering worked just fine, and without making any attempts at correcting the angle, I could tell I was off by only a few degrees, plus 180 because of a meridian flip. The plate-solved results showed an angle of ~270 degrees, which made sense because my camera is at 90/270 degrees, or ‘landscape’ when I’m in the home position. I stored that plate-solved result for my target.

I made numerous attempts to auto-rotate by right clicking on my target in the list and choosing the rotate option. Every time, the camera would rotate to what it thought was zero degrees, going the wrong way, with the error increasing in each iteration. I noticed that the angle shown by SGP was initially in sync with the rotator, at 0 degrees, but then would change drastically after each plate solve, even though the camera had not even moved yet. From reading some other threads, I believe this is related to SGP changing from a ‘rotator angle’ to a ‘sky angle’ as soon as plate-solving starts, and that the two angles won’t necessarily agree, but I’m not 100% clear on how/why this change happens.

So when I used my plate-solved image to define my target, I noticed that the angle of ~270 degrees didn’t make into the field for “Rotate camera to:”, and it was still at 0 degrees. So I did not check that box, thinking it was an optional manual rotation setting. Should I have checked the box and entered in the value from the plate-solved result? Was SGP trying to rotate to 0 degrees even though the plate-solved image was at ~90/270?

Also, my camera is about 90 degrees / 270 degrees to east of north, depending on which side of the pier, so is it OK to just enter ‘90 degrees’ in the Equipment Profile in the Camera tab?

Any help would be greatly appreciated.

Thank you,

I had problems with the latest version of the NC driver and more recent versions of SGP 3+. It would rotate past the disired setting until it went all the way around. Wierd stuff.

I can confirm in the latest beta, that rotation works correctly. (my ascom driver settings are -190 to 190 with reverse rotator direction set to yes)

Hi Homer,

Thanks for the input. So I was able to get it to work tonight by the following steps:

  1. Click box for ‘Reverse rotation direction’ in Nitecrawler Setup.
  2. Plate solve a previous sub and record the angle from the result (~272 degrees or so).
  3. Assign the plate-solved result to my target, then manually enter the angle into the “Rotate camera to:” field for that target.
  4. Rough slew to target, then ‘Solve and Sync’. The rotator angle now displayed 268 degrees or so, instead of 0 degrees. (Assuming SGP has switched to Sky Angle now.)
  5. Slew to target, then Center on target.
  6. Finally Rotate to target. It hit the angle within 1 iteration to 0.1 degrees. Although I didn’t examine it closely, the sub frame appeared to match the angle of the reference sub frame.

Although I’m very glad this worked, it seems a bit cumbersome. Shouldn’t the angle be automatically populated into the target ‘Rotate camera to:’ field when I choose to update a target with the plate solved result?

Does anybody out there do this differently, or am I missing something?


1 Like

Keep reverse checked for all time
Solve and sync (does not matter where)
Center and rotate. Done
I always use my initial downloaded image
Works everytime over multiple sessions

The keep reverse on applies to only the Ascom interface and not the SGPro option I assume ?

I’ll have to test with more recent ascom drivers on my NiteCrawler. Everything has been working fine for mine. We have made some changes to the initial sync which should work better for rotation (this should actually prevent an un-needed rotation at sequence start).


Hi Jared,

I was wondering, is there a way the angle can be automatically populated into the target’s ‘Rotate camera to:’ field when I choose to update a target with the plate solved result? I would basically like to go back to previous subs on targets that I took before I had the NiteCrawler, and now plate-solve them to provide the NiteCrawler rotator with the correct angle to use moving forward.

Also, am I correct in assuming that the rotator angle shown in SGP is initially the position reported from the NiteCrawler converted into degrees, but then switches to the ‘sky angle’ after the first ‘Solve and Sync’? I’m just not sure how to know that SGP and the NiteCrawler agree with each other at any point in time as to the position of the rotator. With focus, the position is always reported and shown and agrees with the display on the NiteCrawler.


Hi All,

I ended up figuring out that if my target is created with the ‘Rotate camera to:’ field populated with ‘0’ and checked, the subsequent plate-solved result can be assigned to that target with the Sky Angle populating the field automatically. However, if the ‘Rotate camera to.’ option is not checked, it will not be updated with the Sky Angle from plate-solving. So now my advice to others for setting the Nitecrawler up with SGP would be as follows:

  1. Click box for ‘Reverse rotation direction’ in Nitecrawler Setup.
  2. Create a target in the Sequencer with the ‘Rotate camera to:’ field enabled and arbitrarily set (to 0 for example).
  3. Plate solve a previous sub and assign the plate-solved result to the target.
  4. Rough slew to target, then ‘Solve and Sync’. SGP appears to show the current Sky Angle at this point. The Nitecrawler angle is somewhat irrelevant from this point forward.
  5. Slew to target, then Center on target.
  6. Finally Rotate to target.

When I create targets using the Framing and Mosaic Wizard, the coordinates AND Sky Angle get assigned, and that seems to be the easiest approach for going to a brand new target, not based on a prior sub frame.