Re: Need help with issue in RA guiding and Synchronous Pulseguide


Glad to hear the good news.
Which three gears are you referring? Worm, big worm wheel and spur gear?
--- In ap-gto@..., "photonphisher" <parijat_singh@...>

Progress at last!

I took the 3 gears out from the RA gearbox, cleaned thoroughly and
placed them back. Did not see any noticeable dirt in there but cleaned
all of them re-greased anyway.

And just completed running several hours of tests in PEMPro, imaging
and guiding. So far, the issue has not come back. So either there was
something in the gear teeth (which I could not see) or old grease, or
the act of taking the gears out and assembling back with the pinions.
Not sure but the issue seems to be gone now! :)

Thanks to all who responded with ideas and suggestions...
I think the gears might need more maintenance perhaps than just lube,
maybe cleaning once in a while.


--- In ap-gto@..., "photonphisher" parijat_singh@ wrote:

Hi Marj,

The moon is up, so I am not in a big hurry right now....and have
time to do some more tests.


--- In ap-gto@..., Marj <marj@> wrote:


Roland and I will be back in the office tomorrow and will review
your information at that time. We have been on the road since NEAF.

Marjorie Christen

On May 3, 2012, at 4:28 PM, "photonphisher"
<parijat_singh@<mailto:parijat_singh@>> wrote:

Hi Marj,
In the tracking curve I had uploaded, you can see PEM was always
disabled (red button on the left). So I had ruled that out initially.\;

I think the gears are something I have not cleaned in a year (only
lubricated). They look clean but it I understand from some of the posts
here, it is suspect as it does not take much to cause a 5" irregularity.

Thanks again.

--- In ap-gto@...<>,
"marjchristen" <marj@> wrote:

I suggest that you disable the PEM first and evaluate the
performance. The rest of the steps you mention may not be needed if the
problem is dur to an erroneous PEM curve.

Marj Christen

--- In ap-gto@...<>,
"photonphisher" <parijat_singh@> wrote:

Hi Marj and All,

Thanks a lot for your valuable suggestions. I now have a good
list of things to check and ponder on.

I am planning to remove the 3 gears and carefully clean them
well, and apply fresh grease.
Then double check the worm binding, backlash etc.
And disable PEM before checking the tracking.

Some homework to do :)

Thanks again, very much appreciate the help.


--- In
ap-gto@...<>, "marjchristen"
<marj@> wrote:

Dear Parijat,

Here is another idea. Do you have PEM set to yes? If you do,
set it to "no" and see what happens. Sometimes, people create a bad
periodic error correction model and then when the correction is
activated, it causes strange movement.


--- In
ap-gto@...<>, "photonphisher"
<parijat_singh@> wrote:

Hi Floyd
Yes it happens once per worm cycle. I monitored it for 5
cycles and showed up exactly at the same location each time. I can only
think of the worm/block/assembly but I don't know the internals.

Last night I was seeing dumbells in 30 sec exposures if
they fell in the right (or wrong) window. :(


--- In
"bakersfieldbiker" <fblue@> wrote:

Oh, I agree, it was probably not the situation, just was
This only happens one time per worm cycle?

--- In
ap-gto@...<>, "photonphisher"
<parijat_singh@> wrote:

Hi Floyd,
I moved it 360degrees and it move smoothly with
fingers. The mesh is optimum that there is little or no backlash. Also
the screw on the spur gear is very tight.
That is the only gear in phase with the worm period
and I felt nothing wrong with it physically and moving it full circle.
No binding whatsoever. I would think binding would cause an issue much
more prominent than 5arcsec.


--- In
"bakersfieldbiker" <fblue@> wrote:

Hi Parijat,
Did you actually move the spur gear on the worm and
this is where you say it moves smoothly? Just curious, because of an
earlier thread where I described a binding in the worm gear bearing that
I found on the AP-900.
Probably not related, but am wondering.

--- In
ap-gto@...<>, "photonphisher"
<parijat_singh@> wrote:

Hi David,
Thanks for your reply.
I have checked the gears for binding, etc. but
they are all smoothly moving. Hence running out of ideas.


--- In
ap-gto@...<>, David Holko
<dholko@> wrote:


About a year ago I had a issue with my AP1200 RA
motor. Howard got on
the phone with me and walked me thru a few
checks. I am sure that once
the staff returns from NEAF you will be able to
contact Howard and he
will do the same. It is not difficult to remove
the top of the RA
housing and see and feel the gears and how the
move with your fingers.
To see if there are binding.
I ended up sending the control box, RA housing
and cables back to AP and
it all got sorted out. No issues since.


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