Weasner's General LXD55/75 Feedback Page

GENERAL FEEDBACK

Last updated: 25 June 2006

This page is for user comments and information of a general nature or items applicable to all LXD55 and LXD75 models. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me and I'll post them. Please use an appropriate Subject Line on your message. Thanks.

Subject:	LXD 75 Binoviewer/Barlow Use
Sent:	Sunday, June 18, 2006 09:30:03
From:	lorrie_s (lorrie_s@sbcglobal.net)
I have an LXD 75 schmidt cassegrain I use with a binoviewer.  I want to
increase the magnification of my eyepieces with a 2x barlow.  Will I
need to place the barlow on the binoviewer nosepiece, or will I need two
barlows, placed at the eyepieces to accomplish this?  Will magnification
increase or decrease if I use one method over the other?   ...Thanks,
Dennis

Mike here: The Barlow Lens is used to increase the focal length of the telescope. So, adding one before the binoviewer could work. HOWEVER, you may or may not be able to properly focus the resulting image. You could also use two of them on the eyepiece end but the same caveat could apply.

Subject:	Jerky Tracking with LXD-75
Sent:	Tuesday, June 13, 2006 08:31:22
From:	Gernot Stenz (stenzg@in.tum.de)
[Introductory story first]
last year I asked some questions regarding the PEC function of the
Autostar. By the end of January I have given up on PEC and declared it
non-functional. Doing that was easy because around that time I obtained
my first Pictor 201XT autoguider, one of the most hated accessories in
the amateur astronomers' world. Nevertheless, it worked for us and full
autoguiding for 200g and 250mA is just grand. Sadly, however, the use of
the Pictor was restricted to our GP-DX... until quite recently I could
borrow a 909 APM, upgrade my Autostar to the patched 42dd and try the
whole thing on my balcony. *It worked*. The Autostar immediately
recognized the APM (indicated by the new focuser menu entry), and after
I had adapted the calibration times the Pictor calibrated and guided. I
have some 180s frames to prove it. Of course, getting the proper values
for Alt/Dec Percent (i.e. backlash compensation) was a bit tricky.

But then my balcony limited my possibilities. No north star, no
alignment, bad fst. Last night we drove out into the countryside
(despite the full moon) to do some real testing. But then, suddenly all
went wrong again. After setting up the mount and scopes I first took a
look at Jupiter. The image, though sharp, was a bit unrestful. There
seemed to be a slight kind of vibration around the RA axis. Also, when
targeting the focusing star with 64x speed, the RA movement was a bit of
a staccato. The same happened later with the camera attached, the live
view showed pinpoint stars gently swaying back and forth for a few
arcseconds. So, after only a few seconds of exposure the stars became
eggs. Stable eggs with the help of the autoguider, but eggs nonetheless.

Now I am puzzled. The setup (mount, scopes, energy pack) was the same as
for the successful balcony session. The only thing that changed was a
new calibrate motors/train drives routine I went through. What could
have gone wrong? Something similar had happened once before last year,
when I couldn't make any exposures longer than 15 seconds, but that
effect had vanished in between. I tend to rule out the power source,
since even as the RA axis hobbled accross the skies, movement in DEC was
as smooth as ever. Could it be a faulty cable connector on the Autostar?

Thanks in advance, Gernot

-- 
    __o  Gernot Stenz  e-mail:stenzg@informatik.tu-muenchen.de        /\
   -\<,          WWW:  http://www4.in.tum.de/~stenzg               /\/--\
_(_)/(_)_Strasbourg - Paris: 3639 km______________________________/      \

Mike here: I doubt that it is a connection or Autostar problem. Sounds more like some debris or dirt on the encoders OR lubrication that has stiffened up (or needs to be redistributed). Try unlocking the axes and slowly move the telescope around on the axes in all directions, back and forth, several times.

Subject:	Re:LXD55 SN10 Counter Weight
Sent:	Friday, June 2, 2006 05:58:32
From:	Dieter.Wolf@DNSint.com (Dieter.Wolf@DNSint.com)
Hi Ed,

besides what Mike already told you will ALWAYS need three counterweights
for the 10 inch and as a rule of thumb set them one or two fingers apart
from the end of the rod.

cs,
Dieter (Munich, Germany)

Subject:	aligning an LXD
Sent:	Wednesday, May 31, 2006 21:25:37
From:	richard seymour (rseymour@wolfenet.com)
I noticed in your 31 May 2006 LXD report that you did a two-star
alignment.

May i suggest a 3 star?

It's an Autostar improvement that the LXD's can make use of,
and helps correct the "cone error" of the GEM mount
(it will use a star on each side of the "meridian flip")

have fun
--dick

Mike here: Thanks Dick. I have done 3-star alignments with the LXD55 in the past. I didn't see much difference in accuracy once I had aligned the axis with the 1-star. I will try it again with the LXD75 on the next Oracle trip.
By the way, one thing I noted but didn't comment on was that once the alignment was complete, a message appeared showing the offset from the pole. That was added in 4.2Ed and was very useful.

And:

I'd be curious to learn if the polar offset appears after a 3-star,
too (you could run a quicky indoor test to answer that).

have fun
--dick

Mike here: Well, I could except the telescope is all packed for the next trip to Oracle (tentatively planned for 24 June).

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