Scope balancing question


paul_schroeder@...
 

Quick question. I have tried to be very careful in balancing my one month old
600 prior to each use, but I might be doing something wrong.

The challenge I'm having is that the instrument I'm using is fairly light (an AP
Traveler) and the bearings on both axes of the 600 are really quite stiff (much,
much more so than on my Great Polaris). Even with the clutches fully
disengaged, it takes a fair amount of force to rotate the mount on either axis.
I had my ten year old son try to rotate the dec axis by simply turning the
counterweight shaft and he had to try pretty hard to do it with only one hand.

Given that there's a lot of resistance to rotation, I'm not sure I've gotten an
exact balance. I can move the 9 lb counterweight an inch or so up or down the
shaft with no real noticeable difference in the balance point, mainly due to the
stiffness of the bearings.

Is this level of "stiffness" in the bearings typical? Should plus or minus one
inch on counterweight position be considered sufficiently precise? I'm also
having problems with the clutches slipping (I don't want to over-tighten them),
and I'm wondering if this is due to poor balancing.

Any suggestions would be appreciated!

Best regards,

Paul Schroeder


Larry Denmark <kldenmark@...>
 

Hi Paul,

The Traveler is light weight and there is a certain amount of inherent stiffness
in the 600E... more so than was in my AP400 mount. But I am not certain if you
are not experiencing a problem because I do not understand the following:

I'm not clear which axis your son had trouble turning. Did he try and rotate
the DEC axis by turning the counterweight as though it was a steering wheel (so
as to revolve the telescope in a circle around the DEC axis, as you stated) or
did he grasp the counterweight and pull or push on the counterweight shaft (so
as to move the mount about the RA axis)? And was the traveler seated on the
mount at the time (I assume so... but do not know for sure).

If he had difficulty turning it about the DEC axis, you probably do not have a
problem. If he had trouble revolving around the RA axis, especially if the
Traveler was seated opposite the weights, the clutch plates are too tight. They
are easy to adjust... let us know if that is the case.

Larry

E-mail . . . kldenmark@att.net
Web site . . http://home.att.net/~kldenmark/

----- Original Message -----
From: <Paul_Schroeder@datacard.com>
To: <ap-gto@egroups.com>
Sent: Saturday, April 29, 2000 1:30 PM
Subject: [ap-gto] Scope balancing question




Quick question. I have tried to be very careful in balancing my one month old
600 prior to each use, but I might be doing something wrong.

The challenge I'm having is that the instrument I'm using is fairly light (an
AP
Traveler) and the bearings on both axes of the 600 are really quite stiff
(much,
much more so than on my Great Polaris). Even with the clutches fully
disengaged, it takes a fair amount of force to rotate the mount on either
axis.
I had my ten year old son try to rotate the dec axis boy simply turning the
counterweight shaft and he had to try pretty hard to do it with only one hand.

Given that there's a lot of resistance to rotation, I'm not sure I've gotten
an
exact balance. I can move the 9 lb counterweight an inch or so up or down the
shaft with no real noticeable difference in the balance point, mainly due to
the
stiffness of the bearings.

Is this level of "stiffness" in the bearings typical? Should plus or minus
one
inch on counterweight position be considered sufficiently precise? I'm also
having problems with the clutches slipping (I don't want to over-tighten
them),
and I'm wondering if this is due to poor balancing.

Any suggestions would be appreciated!

Best regards,

Paul Schroeder


Larry Denmark <kldenmark@...>
 

Wow,

Many to many "not"s in my last message <g>.

Since you stated that you can move the 9 lb. counterweight an inch or so before
noticing a difference, it implies that moving it 3 or 4 inches will make a
noticeable difference... and that's OK.

A-P makes great mounts... not sensitive beam-balances <g>.

Larry

----- Original Message -----
From: "Larry Denmark" <kldenmark@worldnet.att.net>
To: <ap-gto@egroups.com>
Sent: Saturday, April 29, 2000 2:40 PM
Subject: Re: [ap-gto] Scope balancing question


Hi Paul,

The Traveler is light weight and there is a certain amount of inherent
stiffness
in the 600E... more so than was in my AP400 mount. But I am not certain if
you
are not experiencing a problem because I do not understand the following:

I'm not clear which axis your son had trouble turning. Did he try and rotate
the DEC axis by turning the counterweight as though it was a steering wheel
(so
as to revolve the telescope in a circle around the DEC axis, as you stated) or
did he grasp the counterweight and pull or push on the counterweight shaft (so
as to move the mount about the RA axis)? And was the traveler seated on the
mount at the time (I assume so... but do not know for sure).

If he had difficulty turning it about the DEC axis, you probably do not have a
problem. If he had trouble revolving around the RA axis, especially if the
Traveler was seated opposite the weights, the clutch plates are too tight.
They
are easy to adjust... let us know if that is the case.

Larry

E-mail . . . kldenmark@att.net
Web site . . http://home.att.net/~kldenmark/