Howard,
Celestron's built in all-star polar alignment will get you aligned within a
couple of minutes of the pole if you use the camera itself to ensure that
the alignment Star is in the exact center of the field of view at each
step. This should allow you to shoot about as long as you could ever
reasonably expect.
When I had my CGEM and my CGE I could set up at sunset and start the
alignment as soon as it was dark enough to find an alignment Star. by
imaging just a piece of the field and very short exposures I could get near
real time feedback on the laptop screen. After you do it once, you can get
it done before it's dark enough to start doing any real imaging.
The all star polar alignment is amazingly accurate , especially if you pair
it with the camera.
Mike
On Wed, Feb 1, 2017 at 3:39 PM Howard Anderson <handy13@xxxxxxxxxxxxxx>
wrote:
Hi,
I am seeing a small amount of field rotation in 40 minute images
I am taking with my remote TOA-130 on a CGE 800 (Older)
mount. Seems to be worse at high latitudes but seems to
diminish to zero when the object is near the Zenith. Does
not completely make sense to me but I have the images to
show that it is happening that way.
I believe this is because my mount is not precisely aligned.
I do not like the drift method.
Years ago I and others worked out a method for extremely precise
rapid alignment of the LX-200 scopes using a SYNC operation
which moved the coordinate system so that it would sync
with a star that was centered in the field. I believe this
sync operation essentially "rotated" the celestial sphere
coordinates.
This is the procedure I use to get near-perfect polar
alignment of the LX-200:
http://www.astroshow.com/astrotip/align.htm#iterative%20alignment%20procedure
I would like to do something similar for the CGEM mount. It has
a SYNC operation in the menu.
Does anyone know if the Meade sync operation and the
CGEM SYNC operation do essentially the same thing?
If so I can use a similar procedure to what I use with the
LX-200.
It is 270 miles to my remote telescope so I would like to think
this through in advance. I will probably go there within two
or three months...
Any suggestions not involving the drift method would be welcome
indeed...
Thanks,
Howard
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