If you're suffering from stiction, you'll know it. It's the words "sticky"
and "friction" combined, and refers to the situation when you have to apply
a great amount of force to "break" an axis' initial resistance to moving.
The problem is that you will then excessively accelerate the axis,
frequently overshooting your target. The axis moves smoothly once it's
moving, but you can often get into a frustrating back-and-forth dilemma
where you can never get the scope aimed accurately. It's not good.

Paul Sterngold

--- Brian Kennedy <draco61@...> wrote:

Excuse me if I missed this earlier. What exactly is "stiction"? I
just received my GM8 and am wondering if this is a real concern and
something I should worry about.

Thanks,
Brian

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Excuse me if I missed this earlier. What exactly is "stiction"? I
just received my GM8 and am wondering if this is a real concern and
something I should worry about.

Thanks,
Brian

Hello Paul!
I think you are right.
Scott is sending me a new worm bearing block that will allow more movement.
This will help to correct problem #1, but I am afraid that the major issue
is #2.
Do you have any suggestion to solve such a problem? I understand from the
list that the fix is not so easy.
So, I am thinking of asking my dealer (as soon as he is back from his
vacation) for replacing the whole dec assembly (the mount is only a few
weeks old). Maybe this will take some time, but at the moment I don't see
any other solution. What do you think?

Regards,
Girolamo

--- In Losmandy_users@..., "Steve Nightingale" <
snightingale40@h...> wrote:

Hi everyone,

I'm confused as to where we stand on the undersized shaft issue. In
summary:

1. Is it beneficial to insert a third bearing in the RA axis up

near

the pressure plate?

2. Is it relatively easy to insert?

3. Will Scott sell us an additional bearing, and if so, at what

cost?

Thanks,

Steve

Ditto everything Steve has said, except I need to fix lower dec axis,
RA seems fine.

Bill

I have a question about the vernier scale on my G-11. All the
verviers that I have used have one scale up against another so that a
choce can be made which two lines are aligned. In my G-11 there is a
gap of about 1/32 in making it difficult to use the vernier. Do I
have a problem or is this the way it is. Thanks for any response.

This is about my fifth attempt at posting. I hope this works

In a message dated 8/21/00 8:28:55 AM EST, havriliak@... writes:

Do I
have a problem or is this the way it is. Thanks for any response.

Nope, just the way it is....

Actually, no problem for me, my close range eyesight forces
me to use head mounted magnifiers to see the setting circles.
Well enough to use them VERY accurately I might say !!
And yes, with a good polar alignment, they will put an object
in the eyepiece FOV every time.
Maintains accuracy after a meridian flip.

Something to be aware of. When you are slewing with the hand
controller, both the DEC, and RA circles will move. No real problem
with RA, but with DEC, periodic realigning is necessary if you
use the faster slew speeds a lot.

Still during my first Messier Marathon this year, I was able to go
through the Virgo galaxies easily, as the vernier scales were accurate
enough to put every galaxy in the FOV right off.

VERY nice indeed...

开云体育

To those that might be in the know:

One of the applications I hope to achieve with the goto system would be
'remote' imaging (remote in the sense of 30' to 100' away in a nice warm
room.) One of the issues that I need to contend with is centering up or
otherwise framing objects in the CCD's field of view. Since it probably
won't be likely that the pointing accuracy will be such that the object
will be exactly centered (or not, depending on what you're after), it
requires the ability to move the scope in small increments at a
reasonable rate of speed (like around 4X or so.) It seems that there
will at least be a slewing speed (~800+X) available through planetarium
programs (I have Guide 7.0) and a guiding speed (~.2 - .8X) available
through the CCD camera control (as in MaxIm). Question I have is will
there be a centering speed available remotely (i.e. one around 4X) or
will I be limited to the 2 speeds above? Also, is there any way possible
for the information stored in the controller box to be sent to a
separate program on a remote computer such that you would have access to
all the functions on the controller? Or is this something planned for
future software upgrades?

Thanks in advance for any info you might have.

--
Jim Girard

I just wanted to say hi and thank Ian for starting this group. I just
purchasd a GM8 any will no doubt have many questions. In reading the
previous posts, I see we are well represented by many knowledgeable
people.

Brian

From: "James A. Thibert" <thibertj@...>
Reply-To: sct-user@...
To: sct-user@...
CC: losmandy-user@...
Subject: [sct-user] Backlash is my friend
Date: Sun, 20 Aug 2000 08:14:34 GMT

Hi Folks.
just got in from an intensive night of running guiding tests getting ready
for next weeks shooting with no moon.
As many of you are aware,my saga of the g-11 has been
ongoing however,ongoing has met relentless!

I have now improved my g-11 substantially.It's gone from an horrendous 25 to
40 arcsecs to better than 10.
I got a roll of test shots back the other day showing various length star
shots from 30 minutes to 120 minutes and all show nice round stars even
under 8 power magnification.

Everything done was recorded so I could give feedback to SBIG's Alan Holmes
who was helping on the st-4 side.

All in all there were a couple interesting nites when I took the g-11
completley apart in the dark and swapped gears between dec and ra and
also,tore down the st-4 in the dark to clear condensate and rejuvinate the
dessicant.

The st-4 ccdtrack program has a number of graphs including an x and y axis
histogram that has gone from looking like the shadow of an elephant to
looking like the empire state building.
Some things that made a difference...3'rd bearing on each axis,200 mag polar
alignment that stays for 15 minutes east and west,relieve the torque on the
ra gears.Accept some backlash in favour of smoother drive.(plus lapping)
Some things that didn't work or made it worse...tight worm gear,isolating
clutch bearings,isolating the motors,
swapping gears.
Swearing,yelling and karate chops were fun but fall into the latter category
now that we have sct-users as support.
Thanks to all who helped me out.
Good seeing.....Jimmy
________________________________________________________________________
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Hi everyone,

I'm confused as to where we stand on the undersized shaft issue. In
summary:

1. Is it beneficial to insert a third bearing in the RA axis up near
the pressure plate?

2. Is it relatively easy to insert?

3. Will Scott sell us an additional bearing, and if so, at what cost?

Thanks,

Steve

Paul,

Others have told of putting a thin piece of rubber between the motor

assemblies and the mount.<<<<

That sounds promising. Similar to putting the rubber pads under the feet
of the tripods I assume.

Take care,
Gregory david Stempel
FIREFRAME

pjward@... wrote:

Having tried the GOTO mount in the S.H. for a time, I can say it
works very well when polar aligned. The non-aligned mode still has
some bugs. When used with T-Point it is remarkably accurate.

Hi Peter

What would you say the pointing accuracy is w/ and w/o T-Point? And did you
use it with the existing digital circles? If so, how effective were they?
Inquiring minds want to know <g>.... (I have one on order from Anacortes,
already; just want to know what I'm in for. )



--
Jim Girard

I encountered the same problem with my 4" apo and didn't think about lack
of weight atop the mount. Good suggestion!

I did find that backing off the worm from the worm wheel a small amount
greatly reduced the amount of vibration.

Others have told of putting a thin piece of rubber between the motor
assemblies and the mount.

Paul Sterngold

--- Gregory David Stempel <fyrframe@...> wrote:

Adam,

I have just been looking at Jupiter and Saturn for the first time

through my TV101/G11 combination. At medium power (x100) a vibration of
the image was obvious. The vibration frequency seemed to be close to
that of the ticking from the RA motor <<<<<

Could it be, the TV is just to light for the system. I am wondering if
there is not enough weight on the G11 to "hold" things in place. I have
a GM8 with an 8in SCT and do not get the vibration you speak of.

Also, what is the mount sitting on, solid ground?? Try some rubber under
the feet of the mount.

No offense, but disassembling the mount head should not be the first
step to controlling a problem. Look for the simple solutions first.

Take care,
Gregory david Stempel
FIREFRAME

__________________________________________________
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Send instant messages & get email alerts with Yahoo! Messenger.

Hello Group,

The mount in the GOTO pictures is mine. The spacer is not required,
just an optional extra that gives you a bit more rotation in RA. They
are standard on the "Z" version of Losmandy's mounts that go to Japan.

The hand paddle is just like the current one. It looks no different,
but there are a couple of internal mods to get around a RF
problem. The deluxe hand paddle, as far as I know, has not been made
yet, hence no piccys.

Having tried the GOTO mount in the S.H. for a time, I can say it
works very well when polar aligned. The non-aligned mode still has
some bugs. When used with T-Point it is remarkably accurate.

Regards
Peter Ward

In a message dated 8/18/00 2:24:43 PM EST, fpark@... writes:

What is the Best grease to use on the G-11 Worm Gear?
Fred

Well this is what I've done;




Allan

I am wondering.....

The Sky allows alignment on two or more stars with virtually any set of
encoders and mount. You then have "the sky" as a database for targeting
rather than the limited library provided by such computer interfaces as
the NGC Sky Vector. You would then just point and click your way to
discovery and observations. Adding a CCD would add accuracy in targeting
the harder to find DSO's.

So, if this is the case it would seem a much better idea to bypass the
NGC Sky Vector all together (sell it on Astromart or give it ot Michael)
and go directly from the encoders to the The Sky software. All one would
need is to interface the encoders with computer and The Sky. A simple
serial cable of some kind could do this. Couldn't it?

Has anyone attempted this?? Would there be a point to this change, or is
this a case of fixing something that isn't broken?


Thanks and of course, take care.
Gregory david Stempel
FIREFRAME

Adam,

I have just been looking at Jupiter and Saturn for the first time through my TV101/G11 combination. At medium power (x100) a vibration of the image was obvious. The vibration frequency seemed to be close to that of the ticking from the RA motor <<<<<

Could it be, the TV is just to light for the system. I am wondering if
there is not enough weight on the G11 to "hold" things in place. I have
a GM8 with an 8in SCT and do not get the vibration you speak of.

Also, what is the mount sitting on, solid ground?? Try some rubber under
the feet of the mount.

No offense, but disassembling the mount head should not be the first
step to controlling a problem. Look for the simple solutions first.

Take care,
Gregory david Stempel
FIREFRAME

Could be Donald, I was just having another look and thinking that the dec
encoder unit would be hitting the RA motor housing if it weren't for the
spacer. Could jus tbe the perspective in the picture though.

I also noticed there is no picture of the hand controller on the page. I'd
like to see it.

Regards

Eddie Trimarchi
~~~~~~~~~~~~~~~