Re: Balancing the declination axis


Joe Zeglinski
 

Hi Gavin,

I can't picture how the ribbed plate looks like underneath - is there room
to drill an extra set of holes in the plate further towards the back of the
OTA? That would be the same as sliding the OTA forward. If it were a flat
plate, then you could drill the extra DEC attachment holes anywhere, but the
ribs you mention, may interfere in this case, unless the new bolt holes can be
drilled between the plate support ribs. Anyway, worth considering a shifted
plate attachment pattern, if at all possible.

Is there any room left on the plate to move both rings forward? If not,
then perhaps, just the back ring could be moved closer to the front one, by
drilling extra holes in the plate. Then slide the OTA forward in the "narrower
spaced" rings. Moving the centre point of the ring support, might give you the
extra bit of forward OTA overhang to equal the moment produced by that extra
weight you have tried to add to the OTA.

Joe

----- Original Message -----
From: "Gavin Bray" <gavbray@gmail.com>
To: <ap-gto@yahoogroups.com>
Sent: Monday, July 02, 2007 7:40 PM
Subject: [ap-gto] Re: Balancing the declination axis


Hello

Just to recap, I have a 14" LX200R and AP1200 connected using the AP
24" ribbed mounting plate and Parallax Instruments rings.

The problem with this setup is that it's very back heavy, there's no
way to move the OTA forward, and I've had to add about 30 lbs to the
front of the mounting plate in order to balance the tube. BTW, there's
nothing heavy hanging off the tube.

This isn't a very satisfactory setup and I'm looking for something
better and that will serve me for when I get into imaging.

Specifically, I want to avoid or minimize the need for counterweights
at the front of the tube and I like the idea of rings to avoid tube
flexure.

I assume the best approach is to somehow move the tube forward so it
balances without the need for tube counterweights.

Does anyone have any suggestions as to how to achieve this?

Is something like the AP 16" dovetail the best approach?

If so, would I be able to mount the rings to the sliding bar?

Is there a better approach? I don't necessarily need to use the
existing mounting plate or rings.

Thanks
Gavin





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