LX200 - best solution to "perfect" tracking

My 10" LX200 Classic has great optics, but not-so-good tracking
(despite many, many hours of tuning, balancing and PEC training). I had
intended to fix the tracking problem by upgrading to a 14" LX200 GPS,
but have decided not to do this now.

Briefly, the reason is that having seen what I can achieve with a CCD
and an 80mm ED (piggy-backed on the SCT), I believe there is loads of
mileage in the 10" optics that is only compromised (at the moment) by
the tracking problems. Also, my average seeing leaves VERY few nights
where I could take advantage of the extra aperture, so it would just be
lots of $ for little improvement in practice.

So, hopefully at a lower cost, I intend to improve the tracking only
(scope is pier mounted on a wedge in an observatory). What are my best
options? I see gear upgrade kits are available, and many alternative
mounts too. Not sure which way to go...

Given a budget up to (say) =A32K - how can I get my LX200 Classic
pointing at a deep sky object for hours? Currently, I'm lucky to get a
minute before lumps and bumps in the gears (or other tracking problems)
spoil the images.

Suggestions and (best of all) first hand experiences solicited.
Cheers
Beats

On 28 Jan 2005 00:30:28 -0800, "justbeats"
wrote:

My 10" LX200 Classic has great optics, but not-so-good tracking
(despite many, many hours of tuning, balancing and PEC training). I had
intended to fix the tracking problem by upgrading to a 14" LX200 GPS,
but have decided not to do this now.

Briefly, the reason is that having seen what I can achieve with a CCD
and an 80mm ED (piggy-backed on the SCT), I believe there is loads of
mileage in the 10" optics that is only compromised (at the moment) by
the tracking problems. Also, my average seeing leaves VERY few nights
where I could take advantage of the extra aperture, so it would just be
lots of $ for little improvement in practice.

So, hopefully at a lower cost, I intend to improve the tracking only
(scope is pier mounted on a wedge in an observatory). What are my best
options? I see gear upgrade kits are available, and many alternative
mounts too. Not sure which way to go...

Given a budget up to (say) £2K - how can I get my LX200 Classic
pointing at a deep sky object for hours? Currently, I'm lucky to get a
minute before lumps and bumps in the gears (or other tracking problems)
spoil the images.

Get a custom set of gears made for it. The electronics should be
fine.
-Rich

I'm lucky to get a
minute before lumps and bumps in the gears (or other tracking problems)

Lumps and bumps in the gear train are problems discussed in the Losmandy
google discussion group. Basically the gears are lapped into matching sets
with the use of diamond dust suspended in greese. This sounds complicated but
it isn't. By the way, precision sets of gears are always lapped prior to
installation.

On 28 Jan 2005 00:30:28 -0800, "justbeats"
wrote:

Given a budget up to (say) £2K - how can I get my LX200 Classic
pointing at a deep sky object for hours? Currently, I'm lucky to get a
minute before lumps and bumps in the gears (or other tracking problems)
spoil the images.

There is only one way to get close to perfect tracking on a budget, and
that is to take the mount out of the equation. You do that by correcting
the tracking in the optical train. Right now the only way to do that is
with an AO7. If your CCD is a dual-sensor SBIG, you can add the AO7 and
stay well inside your budget. If not, maybe you can do so by trading in
your current camera.

Otherwise, you options are to tune up the mount- lap or replace the
gears, and definitely replace the bearings if your LX200 was made while
Meade was still using plastic sleeve bearings (which was most of the
life of the Classic models), or to replace the mount altogether. Here in
the U.S. your budget would easily allow you to buy a G-11 + Gemini
controller. Maybe not outside the U.S., though.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

"justbeats" wrote in message
oups.com...
My 10" LX200 Classic has great optics, but not-so-good tracking
(despite many, many hours of tuning, balancing and PEC training). I had
intended to fix the tracking problem by upgrading to a 14" LX200 GPS,
but have decided not to do this now.
You don't mention what camera you have, but the ultimate 'fix', is the
AO7. With this, the errors in the mount can be corrected better than any
mechanical fix.

Briefly, the reason is that having seen what I can achieve with a CCD
and an 80mm ED (piggy-backed on the SCT), I believe there is loads of
mileage in the 10" optics that is only compromised (at the moment) by
the tracking problems. Also, my average seeing leaves VERY few nights
where I could take advantage of the extra aperture, so it would just be
lots of $ for little improvement in practice.

So, hopefully at a lower cost, I intend to improve the tracking only
(scope is pier mounted on a wedge in an observatory). What are my best
options? I see gear upgrade kits are available, and many alternative
mounts too. Not sure which way to go...

Given a budget up to (say) £2K - how can I get my LX200 Classic
pointing at a deep sky object for hours? Currently, I'm lucky to get a
minute before lumps and bumps in the gears (or other tracking problems)
spoil the images.

Suggestions and (best of all) first hand experiences solicited.
Cheers
Beats
I spent a lot of time and effort trying to get a LX200 to track well. I
honed the gears, replaced parts of the gearset, re-aligned the system to
get good orthogonality, etc. etc.. the biggest single improvement on the
tracking, was a mirror lock (it is suprising just how much the image does
shift as the mirror rolls round the baffle tube). At the end, the unit was
useable, but not great. Putting the OTA, on a Losmandy G11, went further,
but even this would not track for long without guider intervention. An
AP900, finally got the tracking as I wanted it...
That having all been said, an AO7, fitted to an identical LX200, provided
there is a suitable guidestar, gives results that are as good, or better.

Best Wishes

Useful feedback so far - thanks folks. Looks like a little extra
information will help...

I have a rudimentary "mirror lock" using a contraption through the
shipping bolt hole. Works quite well to stop mirror flop. Not had much
problem with that.

My camera is SXV-H9 + guide head. I had intended to do guided exposures
using the Orion 80ED as guide scope, but this can't react fast enough
to the small errors in the drive system (which can't be PEC trained out
entirely either). One minute (unguided) track and stack with multiple
exposures is OK on the 80ED, because of the more forgiving image scale,
but not satisfactory on the LX200, even with focal reducer (I usually
get a tail on stars on 50% of images due to the aforementioned lumps
and bumps in the drive train).

I've seen the AO-7, it's not compatible with SXV (which I'm very
pleased with), so I think I'd rather fix the mount.

From what you say Chris, a Losmandy G11 *with* guider might be the
ticket...? Bearing in mind I was prepared to spend =A36K+ on a 14"
LX200, I could stretch the budget if it would really work...
Cheers again
Beats

"justbeats" wrote in message
oups.com...
Useful feedback so far - thanks folks. Looks like a little extra
information will help...

I have a rudimentary "mirror lock" using a contraption through the
shipping bolt hole. Works quite well to stop mirror flop. Not had much
problem with that.

My camera is SXV-H9 + guide head. I had intended to do guided exposures
using the Orion 80ED as guide scope, but this can't react fast enough
to the small errors in the drive system (which can't be PEC trained out
entirely either). One minute (unguided) track and stack with multiple
exposures is OK on the 80ED, because of the more forgiving image scale,
but not satisfactory on the LX200, even with focal reducer (I usually
get a tail on stars on 50% of images due to the aforementioned lumps
and bumps in the drive train).
OK. The problem here is not that the guider can't respond quickly enough,
but that the scope can't. You are accelerating/decelerating a heavy lump
of metal, and this limits how qickly the guide corrections can be made.

I've seen the AO-7, it's not compatible with SXV (which I'm very
pleased with), so I think I'd rather fix the mount.
Wait a while.
Starlight, are launching their own AO system. It is short (much shorter
than the AO7, which adds a lot to the light path), and produces an
'absolute' movement (so can be used with a seperate guide scope, or with a
small OAG - they are offering a tiny OAG, to fit between the AO unit and
the camera. Terry Platt has had a prototype running for some time, and is
meant to be showing it at AstroFest in the UK next week. It might be worth
waiting, and seeing if they announce a 'release date' at this show. :-)

From what you say Chris, a Losmandy G11 *with* guider might be the
ticket...? Bearing in mind I was prepared to spend £6K+ on a 14"
LX200, I could stretch the budget if it would really work...
Cheers again
Beats
Your existing guider will work with the G11.
The G11, does move much smoother than the LX200 ever manages. With the
Gemini controller, it is possible to get very good movement, which is
repeatable, and accurate. It also responds better to guide corrections,
without the problems of the gearbox becoming unloaded on the LX200 (I
presume you have got some extra weight on the East fork arm?). However, ou
really must 'try' the handcontroller, before considering this controller.
It is very much an 'acquired taste'. The lack of buttons means there is a
complex menu structure, which on the latter software releases works well,
but it is not necessarily to everybodies liking.

Best Wishes

Yowza! I "Googled" to find out more about the prospective Starlight AO
system you mention - and didn't find anything at all. Have I instigated
a leaked "product announcement" here?!?!

It isn't just inertia stopping guiding corrections - it's the time to
expose/download the guide image too. I've got some very brief
transients screwing things up. Too quick to correct, but slow enough to
add tails to the brighter stars.

An abilty to AO-adapt to images off a piggy-backed scope is new (to
me), and really cool. This sounds right up my street (guide scope can
point "elsewhere" for a bright guide star, while the AO system can
quickly adapt the image hitting the CCD on the main scope)..

Thanks for the tip. I'll wait! Wonder if Terry needs a beta tester...?

justbeats wrote:
My 10" LX200 Classic has great optics, but not-so-good tracking
(despite many, many hours of tuning, balancing and PEC training). I had
intended to fix the tracking problem by upgrading to a 14" LX200 GPS,
but have decided not to do this now.

Briefly, the reason is that having seen what I can achieve with a CCD
and an 80mm ED (piggy-backed on the SCT), I believe there is loads of
mileage in the 10" optics that is only compromised (at the moment) by
the tracking problems. Also, my average seeing leaves VERY few nights
where I could take advantage of the extra aperture, so it would just be
lots of $ for little improvement in practice.

So, hopefully at a lower cost, I intend to improve the tracking only
(scope is pier mounted on a wedge in an observatory). What are my best
options? I see gear upgrade kits are available, and many alternative
mounts too. Not sure which way to go...

Given a budget up to (say) £2K - how can I get my LX200 Classic
pointing at a deep sky object for hours? Currently, I'm lucky to get a
minute before lumps and bumps in the gears (or other tracking problems)
spoil the images.

Suggestions and (best of all) first hand experiences solicited.
Cheers
Beats


Lock the mirror and use a auto-guider. That will help, but will not
make it perfect. There are no gears or motors that are perfect.
Even dust on gear can cause a tracking error.

Steve

"justbeats" wrote in message
oups.com...
Yowza! I "Googled" to find out more about the prospective Starlight AO
system you mention - and didn't find anything at all. Have I instigated
a leaked "product announcement" here?!?!
No, it has been discussed on the Starlight Express Yahoo group, for
months, and there has even been a picture posted of it.
It probably just hasn't had the 'keywords' right, to have hit Google yet.

It isn't just inertia stopping guiding corrections - it's the time to
expose/download the guide image too. I've got some very brief
transients screwing things up. Too quick to correct, but slow enough to
add tails to the brighter stars.
Seriously, with your USB camera, you should be able to take guide images
of brighter stars, very quickly (actual magnitude depends on the scope
used, but I have managed over 5fps, at F/6.1, on a C11, at Mag 9.5). The
download time for the guide frame, is tiny. If you really have tiny 'fast'
transients, that are quicker than perhaps 0.5 pixel/second, then these may
well just be dust on your gears (or even metal filings). There were a
number of cases of lumps of swarf in the main RA gear of the LX200 at
various times. Cleaning, might help a lot. :-)

An abilty to AO-adapt to images off a piggy-backed scope is new (to
me), and really cool. This sounds right up my street (guide scope can
point "elsewhere" for a bright guide star, while the AO system can
quickly adapt the image hitting the CCD on the main scope)..

Thanks for the tip. I'll wait! Wonder if Terry needs a beta tester...?

Best Wishes