Just me or CEM60 Meridian Flip stop working with 457?

Hi - I’ve used my CEM60 for several years with SGP and never had issues with meridian flips (or at least I can’t remember the last time I did). The only thing I changed was upgrading to the new stable build this past week and now it fails every single time. Anyone else having issues? My logs report the dreaded “ASCOM Telescope: Failed to flip because starting pier side and ending pier side are the same!” All looks ok in my settings, have Ioptron commander set to flip after 5 degrees and SGP set to flip before that at 2 degrees past (8 minutes). Time’s all seem synced up in handset, commander, and on PC. The mount attempts to flip and begins a slew and then errors out.

Any tips on things I should investigate?


A log would be helpful. Not much has changed in the meridian flip code for a long while.

Thank you,

Thanks. I’ll try to post one tomorrow, was thinking there might be some other common user error type things that I should look into in the meantime.

Hoi i have the same setup version and CEM60 no issue yet seen, if needed we can compiar settings if you like, let me know


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Hi - here is my log from last night below. There are two attempted meridian flips. The first one at around 21:15 was a test and the 2nd one at around 01:14 was my actual sequence for the night. Both failed. I watched both and all appears to start as normal with the flip box coming up and a slew starts for a couple of seconds before it stops and then the failure notification pops up. Crossing my fingers that someone sees something that may be causing my issue. Thank you for any help.


Looks like I just needed to upgrade my firmware on the mount. Flips are working again.

I’m going to be looking at using meridian flips in a while. I’ve got a CEM60ec. Which firmware were you on? I don’t want to upgrade to the latest one as there were issues reported with guiding, in any case I have a manual dome. I do want to do them with my travelling setup though using my IEQ30 pro so I need to practise,

I didn’t make a note of the versions I had prior but believe it was the 2017 version(s). The versions that addressed the meridian flip bug are:

V20190221 Firmware upgrade for HC
V20190424 Firmware upgrade for main board and RA motor control board

There are two or three more after the above ones. Here is the firmware history:

I’ll add that I used the old firmware versions for a couple of years with no issues. It just cropped up this past week after I upgraded to build 457 of SGP. I don’t know why this latent bug suddenly decided to bite me.


I recently updated to the following s/w versions and in so doing have found the EC’s performance to be the best that I’ve experienced. I use PHD2 in conjunction with the mount with 4-sec exposures and a inter exposure delay of 1-sec. thus for approx 5-secs the encoders are doing their thing better than ever.

190221 HC
190716 Main, RA & Dec PCBs


I’ll have to check next time I connect the hand controller. I know that just after I bought the mount people started have oscillation issues. Mine wasn’t affected because it had the previous firmware. I didn’t know if the issue had been fixed yet and, in any case I always have a fight with the ra and Dec board updates!

I have the CEM60EC on the latest firmware and have no issues with SGP or guiding. It’s been a solid workhorse for 2 years for me other than the AC adapter needed to be replaced recently.

Thanks for posting this! I was able to update the iOptron mount firmware (Mainboard, RA, Dec, and Controller), the iOptron Commander/ASCOM software and SGP before setting up last night. I watched the meridian flip closely and it all worked without issue.

You most likely saved me the headache of having older firmware and new software.

Current Versions:
iOptron Commander/ASCOM Drivers: v5.74
CEM60 Mainboard, RA, Dec: v190716
CEM60 Hand Controller: v200113 (not connected)
SGP : v3.1.0.457
PHD2: v2.6.7

afbeelding I have these version, it work all