Quote:
Originally Posted by Kirkus
I'm still asking beginners questions, and I'm sure this one will seem extremely basic, but I just want to make sure I have this right. 
On an equatorial mount, my LXD75 for instance, if I have perfect polar alignment and my scope is tracking an object in the sky, the only axis that should move is the R.A., right? |
Hi,
Keep in mind that there is no such thing as a
perfect polar alignment, not
even from a theoretical viewpoint. At best there is an optimal polar alignment for
the part of the sky you happen to be imaging in at any one instant in time. The
effects of atmospheric refraction mean that, from a practical viewpoint, it
is better to align the polar axis of the scope with the refracted pole rather than the
true pole.
For extended imaging, the effects of refraction combined with the geometric,
eccentric bearing and gravitational flexure errors within the mount mean that
you will also need to be making tiny corrections in Dec as well, which your
autoguider should provide.
You might like to consider posting a sample image and a brief description.
Some of the more experienced astrophotographers on the forum, such as
Monte, might be able to offer a diagnosis and suitable prescription.
Good luck!
Best Regards
Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au