Re: Balancing the declination axis


Joe Zeglinski
 

Hi Gavin,

I'm not sure if you got what I meant by "moving the OTA rings closer
together".
(1)
The idea is that by reducing the spacing "between" the rings, you might be
able to slide the OTA more forward (since the back end ring is then closer to
the front one). That could give you a few more inches of leverage, as the OTA
now overhangs the front of the plate more.

(2)
The other approach - can you drill plate attachment holes in it, "shifted
off centre of the plate", closer to the rear of the plate? In essence, you are
now moving the entire OTA and rings forward as well.
This was AP's approach in their recent DOVELM2 dovetail attachment to the
AP900 DEC axle head. Actually, they shifted their pattern "forward of centre",
since they wanted to accommodate refractors with heavy lenses, so the entire
dovetail block ended up being shifted downward. You want the reverse of this,
I believe.

Actually, I found it necessary to drill my own DOVELM2 pattern as a mirror
of the AP pattern position, since my Questar-7 balance and attachment
procedure required it. If it had been a Losmandy G11 saddle, I would not have
to do that, but the AP saddle is grooved on just one side, so rotating my
DOVELM2 to shift the hole pattern in the opposite direction, would not have
worked properly.

Perhaps a combination of (1) and (2) above might be necessary, if the
imbalance is really bad - hopefully not.

Joe

----- Original Message -----
From: "Gavin Bray" <gavbray@...>
To: <ap-gto@...>
Sent: Tuesday, July 03, 2007 3:24 AM
Subject: [ap-gto] Re: Balancing the declination axis


Hi Joe

Yes, I've drilled new holes and have the rings and tube as far
forward as possible without the tube overhanging the mounting plate
too much.

I think I need something where the backend of the tube is a lot
closer to the dec axis.

Regards
Gavin

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