Balancing the declination axis


Gavin Bray
 

Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin


Kent Kirkley
 

In a message dated 6/8/07 5:35:20 AM, gavbray@gmail.com writes:


Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin
Gavin:

Depends on how unbalanced it is.
The 1200 will tolerate some imbalance.
More than likely yours is tail heavy, anyway you can add weight to the front
should balance it.

A lot of us adjustable saddles (like the Cassady Tip-In) for this very
reason.

Kent Kirkley


**************************************
See what's free at
http://www.aol.com.


Roland Christen
 

In a message dated 6/8/2007 5:35:29 AM Central Daylight Time,
gavbray@gmail.com writes:


There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?
If it is a lot out of balance you may need to add a counterweight to the
tube. A small amount ~ 3 - 4 lb is not going to cause any problem for the mount.

Roland Christen


**************************************
See what's free at
http://www.aol.com.


Kent Kirkley
 

In a message dated 6/8/07 12:07:39 PM, marj@astro-physics.com writes:


Or the AP plate that is the original tip-inĀ  - the DOVELM16..........
http://www.astro-physics.com/products/accessories/mounting_plates/mounting_pl
ates.htm
Right Marj.......sorry I left that one out.

Kent Kirkley


**************************************
See what's free at
http://www.aol.com.


Jeff Young <jey@...>
 

Gavin --

I've got a similar setup (16" LX200GPS OTA in Parallax rings on
1200GTO), but with a 4" refractor on top. The refractor is front-heavy
enough that if I mount it reasonably far forward it balances things out.

I use a short, flexible, felt-lined ABS dew shield. I imagine a
full-length aluminium one would weigh considerably more, and help to
balance things (as well as controlling dew and ambient light). Do you
have a dew shield, or is your location dry enough not to need one?

Barring that, then yes, you'd need to attach some sort of counterweight
to the front. Losmandy has some weights on threaded rods that normally
attach to dovetail blocks, but you could probably drill and tap the
front of your 1200RP plate to attach it.

I'm going to guess based on your name and your post regarding the
southern hemisphere that you're in Australia. Do they use lead flashing
on roofs down there? If so, you could poke a couple of holes in a strip
of lead and use the larger screws around the front cell (the ones
normally used to attach a dovetail) to attach it to the underside of the
cell.

-- Jeff.



________________________________

From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] On
Behalf Of Gavin Bray
Sent: Friday, June 08, 2007 11:31 AM
To: ap-gto@yahoogroups.com
Subject: [ap-gto] Balancing the declination axis



Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting
plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance
it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin


michael mcdermott <classicstone9474@...>
 

Hi Garvin, As Jeff has stated I have a aluminium dew shield that I hack-sawed down the length due to dome clearance problem (in a Sirius Home model). I have a 14" sct wth Orion 80 ed guide scope. The dew shield helps balance the scope on my AP1200GTO. I also customed design my own Declination weights from 2" hex bar stock. I tapped threaded the ends of the bar stock and bolted it thru the holes that are already in the AP ribbed Plate. I also drilled a hole thru the face of the hex stock, this is how I can add additional weights to the front of the scope if I need to attach my Dream Machine camera on the rear. - Mike

Gavin Bray <gavbray@gmail.com> wrote: Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin


Joe Zeglinski
 

Hi Gavin,
Just another OTA balancing approach.

In case you go for an OTA counterweight - I have a Questar-7 which came
with a "cumber bun" looking OTA counterweight. It is just one of those soft
lead sheets covered on both surfaces in thick Mylar, with Velcro end flaps to
secure it when it is wrapped around the 9 inch OTA. It is a standard Questar
product for the Q7. The nice thing is that it doesn't need screws for
attachment, and can be positioned around the OTA, at any point of it's length,
for counter balancing. In the old days of drafting tables, they used to sell
large drafting table weighted "cover sheets" made of similar material - to
keep the thin drafting sheets from sliding to the floor overnight. If you
could find an architectural supply store, perhaps they still have them - then
cut up a strip to suit your OTA and weight needed.

Otherwise, you could purchase or two of these belts from Questar and join
the Velcro tabs end to end to fit your OTA diameter. At 3 lbs, maybe one might
suffice, and you could make up the missing length with a span of Velcro -
sewing supply stores would have them in very wide widths.

The Questar-7 lead OTA weight "cumber bun" measures 26"L x 6"W x 1/8"
thick, and weighs 3 lbs.

Joe

----- Original Message -----
From: "Gavin Bray" <gavbray@gmail.com>
To: <ap-gto@yahoogroups.com>
Sent: Friday, June 08, 2007 6:30 AM
Subject: [ap-gto] Balancing the declination axis


Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin



To UNSUBSCRIBE, or for general information on the ap-gto list
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Another similar option is to join a few ankle weights that wrap around the ankle and attach with velcro (great stuff). You can probably find them in sporting goods departments.


Marj Christen
Astro-Physics, Inc
11250 Forest Hills Road
Machesney Park, IL 61115
Phone: 815-282-1513
Fax: 815-282-9847
www.astro-physics.com
Please include this e-mail with your response.

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]On Behalf Of Joseph Zeglinski
Sent: Friday, June 08, 2007 10:11 AM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] Balancing the declination axis



Hi Gavin,
Just another OTA balancing approach.

In case you go for an OTA counterweight - I have a Questar-7 which came
with a "cumber bun" looking OTA counterweight. It is just one of those soft
lead sheets covered on both surfaces in thick Mylar, with Velcro end flaps to
secure it when it is wrapped around the 9 inch OTA. It is a standard Questar
product for the Q7. The nice thing is that it doesn't need screws for
attachment, and can be positioned around the OTA, at any point of it's length,
for counter balancing. In the old days of drafting tables, they used to sell
large drafting table weighted "cover sheets" made of similar material - to
keep the thin drafting sheets from sliding to the floor overnight. If you
could find an architectural supply store, perhaps they still have them - then
cut up a strip to suit your OTA and weight needed.

Otherwise, you could purchase or two of these belts from Questar and join
the Velcro tabs end to end to fit your OTA diameter. At 3 lbs, maybe one might
suffice, and you could make up the missing length with a span of Velcro -
sewing supply stores would have them in very wide widths.

The Questar-7 lead OTA weight "cumber bun" measures 26"L x 6"W x 1/8"
thick, and weighs 3 lbs.

Joe

----- Original Message -----
From: "Gavin Bray" < gavbray@gmail. <mailto:gavbray%40gmail.com> com>
To: < ap-gto@yahoogroups. <mailto:ap-gto%40yahoogroups.com> com>
Sent: Friday, June 08, 2007 6:30 AM
Subject: [ap-gto] Balancing the declination axis

Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin



To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups. <http://groups.yahoo.com/group/ap-gto> yahoo.com/group/ap-gto
Yahoo! Groups Links




 

Or the AP plate that is the original tip-in - the DOVELM16..........
http://www.astro-physics.com/products/accessories/mounting_plates/mounting_plates.htm


Marj Christen
Astro-Physics, Inc
11250 Forest Hills Road
Machesney Park, IL 61115
Phone: 815-282-1513
Fax: 815-282-9847
www.astro-physics.com
Please include this e-mail with your response.

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]On Behalf Of kgkirkley@aol.com
Sent: Friday, June 08, 2007 11:56 AM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] Balancing the declination axis




In a message dated 6/8/07 5:35:20 AM, gavbray@gmail. <mailto:gavbray%40gmail.com> com writes:

Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin
Gavin:

Depends on how unbalanced it is.
The 1200 will tolerate some imbalance.
More than likely yours is tail heavy, anyway you can add weight to the front
should balance it.

A lot of us adjustable saddles (like the Cassady Tip-In) for this very
reason.

Kent Kirkley

**************************************
See what's free at
http://www.aol. <http://www.aol.com.> com.


ayiomamitis
 

Gavin,

I have a similar problem with my AP160 with CCD camera attached. Since
I have a Losmandy plate on top of the rings for a piggyback scope, I
have used two pairs of Losmandy rings as pseudo-weights to balance
everything.

Not the most elegant solution but it works nicely. Prior to selling my
Pronto, I always had it piggyback and used that for properly balancing
everything.

Anthony.

--- In ap-gto@yahoogroups.com, "Gavin Bray" <gavbray@...> wrote:

Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin


Jeff Young <jey@...>
 

Which reminds me... I still have the two radius blocks mounted to the
front of my OTA from when I had upper and lower dovetail plates attached
(before moving to rings). They add a bit of weight to the front, and
give a nice surface to seat the dewshield against.

Had forgotten about that until Anthony's comment about the extra
rings....

-- Jeff.



________________________________

From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] On
Behalf Of ayiomamitis
Sent: Friday, June 08, 2007 8:33 PM
To: ap-gto@yahoogroups.com
Subject: [ap-gto] Re: Balancing the declination axis



Gavin,

I have a similar problem with my AP160 with CCD camera attached.
Since
I have a Losmandy plate on top of the rings for a piggyback
scope, I
have used two pairs of Losmandy rings as pseudo-weights to
balance
everything.

Not the most elegant solution but it works nicely. Prior to
selling my
Pronto, I always had it piggyback and used that for properly
balancing
everything.

Anthony.

--- In ap-gto@yahoogroups.com <mailto:ap-gto%40yahoogroups.com>
, "Gavin Bray" <gavbray@...> wrote:
>
> Hello
>
> I have a 14" LX200R mounted on a AP1200 with the 1200RP
mounting plate
> and Parallax Instruments rings.
>
> There's not enough adjustment of the OTA in the rings to
balance it in
> the declination axis.
>
> Does this mean I need to purchase a tube counterweight?
>
> If so, any recommendations?
>
> Is there some alternative??
>
> Thanks
> Gavin
>


Jeff <jlc@...>
 

Lots of good ideas so far.

I have the same problem w/ a 12" LX200 OTA on an AP1200. I use the cassady
saddle, but I cant push the OTA far enough forward to balance.

I have run it in "out of balance" mode for a little while now, but the dec
motor seems to labor occasionally which was a cause for concern.
(And, btw, it does not seem to be that much out of balance. I suspect the
motor was laboring either due to cold, low battery power, or a dirty battery
plug connection.)

Recently I put a Losmandy three-axis camera dovetail mount on the bottom OTA
dovetail plate near the front of the OTA, and put my Pentax 67 on the camera
mount.
That balanced it very well.

So I'm going to get a couple Losmandy DA (dovetail adapter blocks) and mount
some lead weights on them.
I did this with my dob a long time ago -- I used a plastic electronics box
from radio shack to hold the weights - it looks rather stylish. B^)
(Losmandy sells a counterweight system, but it is $80 for 5 lbs.)



_____

From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] On Behalf Of
Gavin Bray
Sent: Friday, June 08, 2007 3:31 AM
To: ap-gto@yahoogroups.com
Subject: [ap-gto] Balancing the declination axis



Hello

I have a 14" LX200R mounted on a AP1200 with the 1200RP mounting plate
and Parallax Instruments rings.

There's not enough adjustment of the OTA in the rings to balance it in
the declination axis.

Does this mean I need to purchase a tube counterweight?

If so, any recommendations?

Is there some alternative??

Thanks
Gavin


Gavin Bray
 

Thanks for all the suggestions.

I think I might have something fabricated, possibly in stainless
steel, so as not to distract from the mount's good looks. :-)

Regards
Gavin


Gavin Bray
 

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


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





To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups.yahoo.com/group/ap-gto
Yahoo! Groups Links




Gavin Bray
 

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

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

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@...>
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





To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups.yahoo.com/group/ap-gto
Yahoo! Groups Links




Mal Speer <mal@...>
 

I have a C-14 on a 1200 mount. I use a Losmandy plate and the 16" AP
saddle. The balance point is at the saddle plate and saddle flush in
the rear with a Kendrick dew shield attached. I purchased one of
those Losmandy weight sets, but I was not able to use it because I
only have a saddle plate on the bottom. When I put the weight on the
setup was not dynamically balanced. You probably need two of those
weight sets one on the top and one on the bottom.
Mal



--- In ap-gto@yahoogroups.com, "Gavin Bray" <gavbray@...> wrote:

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

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

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@>
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





To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups.yahoo.com/group/ap-gto
Yahoo! Groups Links




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@gmail.com>
To: <ap-gto@yahoogroups.com>
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


Gavin Bray
 

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@yahoogroups.com, "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@yahoogroups.com>
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


Joe Zeglinski
 

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@gmail.com>
To: <ap-gto@yahoogroups.com>
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@yahoogroups.com, "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@yahoogroups.com>
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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