First autoguided images - M13 and M51

I've been lurking on this forum for about a year gaining a lot of insight into deep sky imaging. A week or so ago I finally finished acquiring all the equipment I needed for autoguiding and wanted to share the results.

These images were taken through a C8 at about f/4 with an Atik 16IC-Color. Guiding was with a SV Nighthawk using a DSI. I used five minute subs with a total time of 30 minutes on M13 and 50 minutes on M51. I wanted to go much longer on M51 but the clouds had other plans.

Guiding went well on the Dec axis but I had motion of a couple of pixels on the RA. I'll need to take some time to figure out how to tune that out.

Thanks for looking and suggestions are appreciated!

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and M51

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Nice images for sure Eric.
The ideal polar alignment should have very little if any DEC error. You'll find that a mount will track much better with a well tuned polar alignment and thus will have to make less corrections.

Well done Eric, and welcome aboard! 8)
Looking forward to your next shots...

Nice work Eric )

Hi Eric,

I agree that the RA errors could come from the polar alignment and this should be checked. If you have a cross hair function on your software turn it on and rotate your camera so the movements on your mount will parallel the lines (orthogonal). Put a star on the line that corresponds to the RA access and turn "OFF" the motor. Take a 2 minute image and see if the star becomes a line that follows the cross hair line.

The other most common cause I am aware of is your mount needs a little weight on the side that the RA motor is driving into. Some mounts will float near the ecliptic or just bounce if the motor is not "LOADED". It is an easy fix. When you balance your mount in RA make it a little heavier on the east side.

Very nice, congratulations! It is a big breakthrough to conquer autoguiding. Yeah the 2 primary things with autoguiding (given a good mount the actual basic thing) are good balance (it can vary on some scope setups at different angles too) and drift aligned polar alignment. So, brush up on drift alignment as it is a basic skill needed for autoguiding.


Greg.

Eric,
Nice images and congrats on the Autoguiding. It is a simple principle in concept but can be a challenge to achieve in a practical sense.

I will throw in my thought here on things to check. I see you use a separate guidescope. I am curious as to how the two OTAs are mounted. My bigest challenge with autoguiding accuracy has been differential flexure of the two OTAs. That's what can also cause different guiding behaviors at differnt parts of the sky. The symptom is a long term drift (on the imager) while the guider is dead nuts. The drift acan be in any direction though - not just RA.

If the RA motion of a couple of pixels is evident in the guiding trace, and is back and fourth, it is not flexure. I note you have a G11. They can be kind of jumpy and want a higher correction rate. What is your correction rate?

Also, I think you have the "East side heavy" OK if you are taking a 21 lb counterweight 1/2 inch off balance on a G11.