Polar Alignment and Meade LX200GPS

Did you notice that the LX200GPS manual forgot to mention Polar Home, and barely talks about Polar mode at all? Well, here I will attempt to fill in the crucial info, using the information gathered from lx200gps Yahoogroup:

Here is an excellent description from Todd:


Polar home is forks level, handles down [for a 8 or 10" scope] (ra lock
pointing down midway between hard stops), scope pointing paralell to forks
(Dec Circle=90 degrees).  You need to center Polaris with the wedge and
sync Arcturus with slew keys.   Use one star align and wait for it to tell
you to set polar home (described above), then it will go into the 45 degree
mode you described which should have the finder on top, then use the mount
to center polaris and press enter, then it should slew to Arcturus for a
sync with the keypad.  This may get you close but to get closer you need to
iterate between the sync star (or another star) and polaris.  You sync the
star then goto polaris and move the mount half way to polaris, then goto
and the chosen star and sync... and so on until you are happy with the goto
to polaris...  You can search on the web for "iterative polar aligning" or
such and that should bring up some info...

Here is from Buck:

scope will be upside down.. Forks point north . Panel faces north.  Dec set
to 90* when it asks you to center Polaris use the wedge  controls only....if
you cannot do this then move the tri-pod .. the tube should be pointing a
Polaris then follow the instructions sounds like you are tiring to use both
and Polar and Alt/ AZ alignment at the same time you cannot do this..
Try here it will help

http://groups.yahoo.com/group/LX200GPS/files/Polar Alignment Information.doc
make sure you copy in the whole short cut
Buck

From Dick:

Photos exist at:
http://rseymour.home.wolfenet.com/polar.html

The celestial pole is to the right ->
(hemisphere agnostic)
(southern readers insert "Sig Oct" for "Polaris" below)

Yes, "Polar Home" (just before aligning) is "barrel inverted".
Or, simply reached by lifting the barrel to Dec=90 from the
 power-up position.  I use a bubble level to guarantee that
  the forks are equidistant from the ground, thus insuring that
   the "underside" of the barrel is lined up precisely with
    "straight up" (or Hour Angle = 0 , as the scrolling text says).

Then it will slew in RA to Polaris's value, and drop the DEC
the 40 arcmin needed... and ask you to center it via the wedge.

*Where* (what RA/Azimuth) that Polaris position is will vary
as Polaris rotates around the Pole.

After centering Polaris, tapping [enter] will give you the
Align Star list to choose from.

See if those two positions (power-up and Polar Home) help.

good luck\
--dick

From Buck:

Turgut
another thing that will help is to first set up your Wedge Mech.. set the
Lat. adjustment to your lat. using the wedge scale or a Protractor (
Protractor is closer than Meade Scale) as you can place it right on the
forks, then center your Long bolts in there slots, if you have a Meade . or
make sure you have and equal amount of adjustment on both sides .. this will
prevent you from having to move the tri-pod legs..during set up.. and if you
are going to observe from the same site mark the tri-pod  spots were the
tips are to help you set up next time  . or if you use vibe pads leave them
out side  weather will not hurt them and they make great markers.. I used a
magic marker to do this job even with the GPS it cuts time ..
Buck
From Daniel:
Turgut,

The 45 degree turn you described is the scope offsetting the OTA from
Polaris. If the OTA and forks are orthagonal and the OTA is pointed
right at Polaris the scope will be quite a bit out of polar alignment
(since Polaris isn't precisely at the north celestial pole).
Offsetting the OTA's position and then having you adjust the
*wedge's* controls to center Polaris gets you closer to polar
alignment the first time around (compared to pointing right at
Polaris with no offset). That's the idea behind it, anyway.

That probably made no sense but I hope it helped a little bit.

A little recap: place scope on wedge, point telescope toward Polaris
with forks pointing toward Polaris. Rotate the forks so the handles
are down and the finder is on the ground side of the OTA (rather than
the sky side). Center Polaris using only the wedge's manual controls.
When slewing to the alignment star (usually in the south part of the
sky near the meridian) use only the Autostar buttons to slew and
center the star. That's it. That's good enough for a rough alignment
that will let you enjoy a full night of viewing and some decent
imaging. Now, if imaging is your goal, you'll need to refine the
alignment (via drift, iterative, Kochab, etc.) and, even with the
best alignment, the lack of PEC will still result in tracking errors.

Regards,
Daniel

PS: If you haven't yet, join LX200GPS@YAHOOGROUPS.COM by visiting http://groups.yahoo.com