Announcements and News
Cloudy Nights Announcements
Discussion of CN Articles, Reviews, and Reports
General Observing and Astronomy
ATM, Optics and DIY Forum
Cats & Casses
Video and Electronically Assisted Astronomy
Astrophotography and Sketching
Beginning and Intermediate Imaging
DSLR & Digital Camera Astro Imaging & Processing
CCD Imaging & Processing
Solar System Imaging & Processing
Astro Imaging/Sketching Contest
Solar System Observing
Deep Sky Observing
Double Star Observing
Solar Observing and Imaging
Variable Star Observing and Radio Astronomy
Telescope Specific Forums
Celestron NexStar, NexStar GPS, CPC
Astronomy Shows & Conferences
Astro Art, Websites & Other Media
Astronomy Clubs and Star Parties
Astronomy Software & Computers
Books, Star Charts & Stellar Media
Science! Astronomy & Space Exploration, and Others
The Off Topic Observatory
Off Topic Observatory Games
Cloudy Days & Microscopes
Cameras & Photography
Swap and Shop
S&S Misc Astro
S&S Information for New Members
CN Feedback and Vendor Announcements
Vendor and Group Announcements
International Year of Astronomy 2009 - Forums are now closed.
IYA Archive Info
Articles and Columns
/ G11 tracking speed/polar align
G11 tracking speed/polar align
February 3, 2011 7:36 PM
I have finally had my mount setup on top of a permanent pier and for some time have been struggling hard to polar align.
I am trying to align following the declination drift alignment. I go through the all drill, from south to east and back. I take my time on each side (S/E) and adjust Az/Al accordingly.
The thing is my G11 is not tracking the way it should... the star keeps drifting East along the reticle. No matter which star I pick: North, South...
I have been told it can be a motor issue, I mean, the RA motor is "speeding up".
Has anyone in here had this kind if issue?
I am really cornered around here and very frustrated I cannot polar align properly.
Thanks for your help.
________________________________ C11 FS-102NSV LS60THaCPT/B1200 G-11 Gemini ST2000XM + CFW10 AO8 DMK21AF04.AS (icx618ALA) DMK41AU02.AS
February 3, 2011 11:40 PM
I'm not familier with the gemini system but I know there are settings for the motor encoder which determines the speed. You may want to double check all of the setup parameters.
By the way, assuming that north is up in youar drawing, and you are using a diagonal, then your East - West designations are incorrect. With the EP ained north when using a diagonal, the left right orientations are reversed.
February 4, 2011 12:36 AM
RA drift that remains after Dec is aligned is due to drive speed, or periodic error, or both. You can address RA drift with a custom drive speed (if the drive has that feature), or by enabling PEC, or by guiding out the error manually, or with an autoguider. But the ALT/AZ adjustments won't help with RA drift, if the Dec alignment is good.
Mis-alignment in Dec will cause field rotation, which can't be guided out. So that's the axis you need to nail when you're drift aligning.
February 4, 2011 8:49 AM
Are you using Gemini's "Polar Axis Correction" function? If not, you need to give it a try. With one careful iteration, I can guide for 8 minutes (can't go any longer...sky fog!) with no problem. With a couple of iterations, you'd be REALLY close.
What I do is first align on 4 stars in the West, then 4 stars in the East. Find a star that's barely west of the meridian and as close to the Celestial Equator as possible. Goto that star and center it. Now, goto Polar Axis Correction. One tip; before enabling it, look through your scope or finder so that when you enable it, you can see which way the star moved. Enabling PAC, the mount slews to where the star would be if you were polar aligned.
Now, using the mechanical adjustments, center the star. Once centered, redo your pointing model and you'll be good to go!
Money can't buy happiness, but it sure makes living with misery a lot easier!
/ G11 tracking speed/polar align
Back To Top
Like This Topic
Remove This Ad
CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.
I don't want no stinking ads, but I want to help Cloudy Nights!!!!