RE: [APML] Refractor recommendation

["Greg Hartke" <ghartke@earthlink.net>]

BTW, Dave, did you read Dave Novoselsky's review of the 76 ED on
cloudynights (http://www.cloudynights.com/reviews/borg76ed.htm)? He's a very
experienced visual observer and always worth a read. I'm very optimistic
about the performance I can expect from mine. Besides, it's always a *lot*
easier to do AP through a refractor than through an SCT. It'll provide a
pleasant contrast.

When assessing costs, don't forget things like mounting plates, etc. The
Borg rings can use a Losmandy universal dovetail which runs something like
$75, not to mention the blocks you'll need to mount to the LX-200. (Check
with Scott Losmandy directly if you're uncertain what you'll need.) You'll
also want a finder of some sort. (I ordered a unit power reflex sight from
Orion for mine.) Also keep in mind that you'll need a counterweight set to
piggyback any scope on your LX-200. Like most, I recommend the Losmandy 2-D
CW set that you can mount under the OTA of the LX-200. I have that and it's
excellent, though I don't use it anymore since I switched to an MI-250
mount.

Hmm. This didn't occur to me before but the Borg mounting rings will be
useless for your purposes. (I bought the rings because I'll have the scope
on a side-by-side mounting plate with a guidescope occupying the other
dovetail.) In your case, you'd actually need something like a set of
Losmandy guidescope rings mounted on a dovetail atop the OTA because you'll
want to adjust the pointing of the Borg relative to the SCT pointing. If it
were me, I'm not sure I'd want to mar the finish of an expensive OTA with
the three-point Delrin tipped adjustment screws of the rings. Others do it,
though, and it may not bother you.

Another issue to consider is how well it will work to piggyback a refractor
of this focal length on your SCT. The flexure in the optical train of the
SCT could potentially lead to problems. I've shot at 200 mm piggybacked on
my LX-200 with no trouble (make sure you secure the primary through the
shipping bolt hole!) but the 76 ED will be closer to 500 mm focal length and
I'm not positive you can expect nice round star images from a long exposure
with this set up. It's worth thinking about this potential problem.

BTW, the Meade SuperWedge works excellently with about $30 in parts and a
little sweat equity used to add bearings to the adjustors and to replace the
azimuth dog (which engages the tang on the field tripod to do the azimuth
adjustment) with a more rigid home made unit. These minor mods result in
virtually zero backlash and extremely easy (two finger!) adjustment. The
only remaining backlash comes from some flexure in the tang on the tripod
(it's very minor) and there's not much you can do about that. Polar
alignment becomes a joy after you've made these mods.

The LX-200 is a very capable system for beginning and intermediate AP if you
know how to keep the drives working properly. If you don't know about the
Meade Advanced Product Users Group, you should check out their web site
(www.mapug.com) for advice on (for example) combating and removing backlash
and retrograde motion. If you keep things tweaked and train your PEC well,
the LX-200 system works quite well.

Good luck!

Regards,

Greg


-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
Behalf Of Dave Dockery
Sent: Saturday, December 14, 2002 12:03 AM
To: astro-photo@seds.org
Subject: RE: [APML] Refractor recommendation


Hi Greg,
I was wondering about the Borg.  Sounds like another great option since I'm
shooting 35mm and I've seen some of Dave's work.
Sorry about the weather but you know it's only because you bought the new
scope.
Thanks for the help,
Dave


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