Safely installing a heavy OTA onto an AP900

Joe Zeglinski


I recently received my AP900 and had a look at the DOVEM2 dovetail plate
for my existing Losmandy DSUB adapter on a 25 lb. Questar-7 OTA.

The AP dovetail doesn't quite mate the same way. The Losmandy has two
closely fitted V-grooves, into which the OTA's DSUB just slides down, and is
locked in place with one knob. The AP900 DOVEM2 has only one V-groove, and a
much wider, by about 3/16" channel, with a straight, non-grooved wall on the
other side - the two lock knobs act as both the other "channel" and the locks,
for the DSUB plate.

My "queasiness" is handling the heavy MAK OTA to get it locked safely into
the groove. I guess I would have felt safer if the plate was initially mated
"in both notched channels" as on the Losmandy mount. However, the DOVEM2 is
very well designed for a variety of OTA plates, and even balance point

So, how do you owners of C9 and similar OTA's used with Losmandy mounts,
do the attachment now on your AP mounts?

Assuming, of course, the mount is positioned and locked in the CWD (counter
weights down) position:

1.. Do you preset the DOVEM2 knobs so they are very close to the width of
the DSUB, and similarly slide the OTA down the channel vertically (as on a
G11, for example), before lock in? Or ...

2.. Do you set the DOVEM2 knobs wide open, and "clip in" the OTA with DSUB
sideways, then tighten the knobs?

Which approach is safer, while precariously standing on snow?

The latter approach seems a bit more hazardous than doing the longitudinal
vertical OTA slide. It's just that using the two DOVEM2 bolt tips as a
substitute V-groove slide, seems prone to jamming the DSUB plate on the way

It sure would be nice if at least, some of the AP documentation showed
"hefty OTA's" actually being installed, on portable mounts, instead of the
lighter refractors, or the large OTA's already pictured in observatories.
But I suppose those are AP refractors. Perhaps AP could show some shots of how
to "handle" their AP MAK in this situation - that would be instructive for us
who already have an investment in good SCT's and MAK's, and just want to
safely use our AP mounts, while perhaps avoiding wrenching our backs in the

Opinions please.

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