G11 slewing past meridian pointing to the ground...

Steve Lang

Hey Tyler.

I experienced something very very very similar to Bob's problem from the
message with the subject "Slew Errors #EXOS2 #ExploreStars" but with my
PMC-8 G11 a few nights ago.

- I have Lat/Long set right, been using the current setup for over a
year now (I am in Southern Hemisphere)
- Haven't yet tried an automated meridian flip, but slewing to targets
either side of the meridian has been working fine so far
- I use NINA (1.10, with hot fix #1), PHD2, Ascom 6.4SP1, latest release
Ascom driver and latest mount firmware
- PA was good enough - G11 on tripod but in observatory so haven't had
to revisit that in a long time

I was locating Cat's Paw Neb (RA 17:20:50.89, -36d 06'54.0", which at
that time was very high (Az/Alt: +288d 44'53.9" /+87d 48'36.7"). Used
NINA to platesolve, sync, move etc. Usual stuff that has been working
well for me, and the same as what I used to do with APT (which Bob used).

What seemed to happen is that the mount didn't get close enough first
time (not surprising, I had re-balanced and loosened clutches etc.),
platesolved, sync'd with mount driver, then tried to make a slight
adjustment then slew to a better place.

It seems that the scope was originally on the wrong side of the
meridian, and needed to re-slew was across the meridian. It started this
process by rotating the scope around DEC towards the ground! Luckily I
was in the obs, and hit the panic (power) switch before the cables were
tangled around the mount. It was a close thing, quite disconcerting.
Very much so, has dented my trust.

The reason I mention the link to Bob's message ("Slew Errors #EXOS2
#ExploreStars") as it seems very similar. Close to meridian (in my case
zenith), platesove (which would normally send a sync to the mount), then
an instruction to move to a new place. In both our cases, it seems like
the mount rotated (DEC)

Now I haven't yet managed to get any debug logs from ascom or NINA that
relate to this (not sure I can...) and I'm not keen to repeat the
exercise. Unlike in Bob's case, I'm sure all my software settings are
fine, but the solve/sync near zenith, followed by a move to a new
absolute co-ordinate seems to have been problematic at this time.

I've had no problems like this in the past at all that I can remember.

Any idea what might have gone wrong? Could it be a bug/condition that I
triggered (because I'm in southern hemisphere)?

Cheers -


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*Mounts:* ES PMC-8 G11, Orion Atlas
*Scopes:* ES FCD100-80, GSO RC8, Orion XT10i
*Cameras:* QHY 8L, QHY163m, QHY5L-II, Polemaster
*Misc:* QHY FW, OAG
*Software:* NINA, PixInsight

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