Joe

I drilled holes as close to the center of the mounting plate as the
ribbing would permit and now the balance is much much better. I
still need a few pounds at the front to balance things but this is
much better than the 30 I had before.

Thanks for your help.

Regards
Gavin

--- In ap-gto@..., "Joseph Zeglinski" <J.Zeglinski@...>
wrote:

Gavin,

An after thought.

Rather than drilling the two rearward holes for the back ring,

right away,

can you get one or two Vice Grips or C-Clamps to fix the rear OTA

ring to the

plate temporarily, and see if it helps the balancing act. That way

you aren't

committed to more holes and making Swiss cheese out of the plate.

The front

ring will still provide solid support as you test the "optimum

position" of

the temporarily sliding rear OTA ring position.

Too bad you can't find a nice clearing "between the ribs" of

the plate,

for all the screws, of an alternate displaced DEC axle hole

pattern.

Best of luck,

Joe


----- Original Message -----
From: "Gavin Bray" <gavbray@...>
To: <ap-gto@...>
Sent: Tuesday, July 03, 2007 6:06 PM
Subject: [ap-gto] Re: Balancing the declination axis

Joe

Actually you're right - I misread what you said. Sorry about that
and thanks for persisting.

What I will do is drill some more holes for the back ring as

close

to the plate's attachments holes as possible. This will allow me

to

overhang the front of the OTA and hopefully go a long way to

solving

the balancing issue. I'll do this this weekend and will let the
group know.

I'm afraid your second suggestion about drilling new plate
attachment holes isn't feasible due to the plate's ribbing.

Also, someone suggested using the AP 15" ribbed mounting plate
rather than the 24" as the 15"'s attachment holes are apparently

off

center. I'll look into this too.

What would be really nice is if AP made a 24" plate that's off
center. :-}

Thanks
Gavin

--- In ap-gto@..., "Joseph Zeglinski" <J.Zeglinski@>
wrote:

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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