Succesful CEM60 meridian flip


I want to report that tonight I succesfully could make an automated meridian flip with SGP and my iOptron CEM60 mount. I had this planned months ago, but between work and clouds, I had never tried it. The firmware and ASCOM driver are the latest for the mount. Also the SGP and PHD2 are latest versions to date.

Attached there are the pre-flip image (frame 2) and post-flip image (frame 3). Each one is 180 seconds at ISO 1600. The selected options were:

  • Degrees past the meridian: 1
  • Wait For Meridian
  • Auto Center After Meridian Flip
  • And also on the Telescope tab, 30 seconds for Mount Settling Time

I have installed on my laptop and is the default Solver. My setup is a C925 EdgeHD with hyperstar, microtouch focuser and a modified Canon T1i DSLR, and a Starshoot Autoguider on a Stellarvue F60M3 guide scope.

It is amazing to see how at the beginning of the session SGP centered precisely on the target, focused, plate solved and began to image as expected. When the second frame finalized, a message appeared, indicating that the time to the flip (around two minutes) was less than the next frame duration (three minutes). SGP paused the sequence and once the two minutes elapsed it stopped the guider, made the flip, took and image, plate solved it, placed the scope right on target again, re started the autoguider and continued with the third frame of the sequence.

You can see in the images that the pre and post flip images are very precisely framed around Marfik, which was my selected target.

Thanks to all the users and developers who worked to make this feature work as intended.

Best regards,

Bogotá, Colombia


Thanks for posting on your successful “meridian flip” with your CEM60. I also have a CEM60 that I will be using with SGP if the weather will ever clear in Indiana. We have been nearly two months without a decent night to observe.

Fred K.

Tell me about it Fred.

This year there hasn’t been too rainy but it has been the most clouded of the past years here at Bogotá.



Well done, Alfredo.

I tried two nights of automatic meridian flip with CEM60EC, but failed. While the selected options I did were:
. Degrees past the meridian: 0.5
.Wait For Meridian
.Auto Center After Meridian Flip
.And also on the Telescope tab, 65 seconds for Mount Settling Time
It worked as like a recovery mode after flip when I settled degrees with 0.2 and 0.5, it’s obviously not a standard procedure of meridian flip as expected. Could you post your degrees of meridian flip in CEM60 command. I will try your settings on Saturday night when possible.

Best regards.

Chaos Jing

Hey Chaos

I suggest you use 1 degree past the meridian and 30 seconds for mount settling time.

On the CEM60 hand control I have:

  • Set Position Limit: 15 degrees past the meridian (I’m at 4.8 degrees north in the northern hemisphere and the maximum is different for southern hemisphere)
  • Set Behavior: Flip when reaches the 15 degrees past the meridian.

Thus, if SGP wouldn’t be controlling the mount, the mount itself would wait until reaching 15 degrees past the meridian, which is like an hour, before doing the flip. Now, in SGP I have 1 degree past the meridian (4 min) which is 56 min before the mount orders the filp. Since SGP invokes the flip 56 min before, there is no conflict.

My guess is that your mount must have still the default option of 0 degrees and since you are using 0.5 degrees past the meridian in SGP, a conflict may arise there (it is a guess, I may be wrong).

Let me know if my settings work for you.



Hey Alfredo
Thank you very much,pal. Perhaps my understanding of meridian flip controlling btw SGP and the telescope is wrong. I’m completely confused with it. I’ll try your settings ASAP. Wish it work perfect soon.

Best regards.

Chaos Jing


Keep us posted here about your results.

Dear Alfredo
Thanks for your suggestion, I finally had Auto meridian flip done smoothly. The Settings are familiar to yours as follow.

The selected options in SGP were:
Degrees past the meridian: 1
Wait For Meridian
Auto Center After Meridian Flip
And also on the Telescope tab, 75 seconds for Mount Settling Time (while 30s was too fast to wait for the flip done, and SGP started centering and plate-solve during slewing)

In CEM60EC command center I take:
Set Position Limit: 5 degrees past the meridian ;
Set Behavior: Flip when reaches the 5 degrees past the meridian.

With settings above, I have SGP flipped several times successfully.

Thanks for your post and suggestion.

Best regards,

Good to know it worked also for you.

SGP is a very good automation software