To HyperTune or Not - That is the question
#1
Posted 23 May 2009 - 03:22 PM
Hey gang,
I have had no end of frustration trying to get nice round stars. They always seem egg shaped.
Worse, the direction of elongation is not consistent.
My mount is an EQ-6 Pro.
On my OTA, the C11, I have re-aligned the primary, secondary and corrector plate as per Celestron specs.
I even tried using my WO80 instead of the C11 and still get eggs for stars.
Its not in a particular part of the image, it is usually every where but not always.
Now, I have done polar alignment many times, I did 3-star alignment many times and still EGGS
Now, the other night, I though I would do a PE check using PHD and PEAS. I got wonderful data but, I forgot to disable the guiding output.
Here is the PEAS output.
#5
Posted 23 May 2009 - 03:28 PM
So, given this info, and the egg shaped stars, should I hyper tune my EQ-6 Pro or, is the problem somewhere else ?
Any ideas would be help full.
Thanks,
-Jerry
#6
Posted 23 May 2009 - 09:34 PM
You can try defocusing the star a tiny bit to help with the seeing, but it may just be to a point that it ain't gonna' work.
As far as the hypertune is concerned, if you have the time and patience, see Bobby's tutorial (stargazer27). You can get some nice tips there. It'll only make your mount better.
David
#9
Posted 24 May 2009 - 05:42 PM
-Jerry
#10
Posted 24 May 2009 - 05:44 PM
Jerry
#11
Posted 24 May 2009 - 05:49 PM
Jerry
#12
Posted 24 May 2009 - 07:38 PM
Lapping the worm gear is just as it sounds. You would use a fine grit lapping compound on the worm and run the gears until they run smooth. I’ve used lapping compound for years, but if you have never lapped anything, then you should fine someone who has and ask for help. The best tip for lapping the worm gear is to keep the compound away from all bearings. It only takes a small amount of compound in a bearing and it will be junk.
Next tip- after lapping clean the gears very well. I have a sonic cleaner, but you can do a good job with brake parts cleaner from an auto store.
#13
Posted 24 May 2009 - 09:48 PM
David, what did you mean 'PA' ?
Jerry
PA=Polar align.
David
#14
Posted 24 May 2009 - 11:49 PM
Jerry
#15
Posted 25 May 2009 - 12:21 AM
Jerry3762,
thanks for info on Lapping.
I did some research on Internet and found a number of web sites that talk about it including one where a person lapped the worms of a Losmandy G11. Very good description as well as pics.
Now, since the EQ-6 Pro/Atlas mounts have fixed positions for both the worm and the worm gear, and the fact that lapping will, in essence, remove small amounts of material from both parts of the worm drive, how do you tighten, or snug up the two parts when finished ? Its not like these mounts have adjustments for these gears. They only go into one spot.
Or, am I missing something.
David,
PA is not something I have too many issues with. I have adjusted my polar scope to be sure it is aligned with the polar axis of the mount and I always perform a PA before any usage of the mount.
The star, when guiding is turned off, typically stays close to where it should be but, it's not perfect as this is not a permanent setup. Every time I use it, I have to setup everything.
Perhaps I may have to spend more time learning to drift align.
-Jerry
#16
Posted 25 May 2009 - 07:05 AM
Jerry3762,
thanks for info on Lapping.
I did some research on Internet and found a number of web sites that talk about it including one where a person lapped the worms of a Losmandy G11. Very good description as well as pics.
I doubt you will find the road to round stars involves "hypertuning" or any other futzing with the mount. The usual way to get them is by fine-tuning the PHD settings--experiment with various settings and guide exposures. Also...
Guide exposures shouldn't be longer than about two seconds nor shorter than 1 second.
Set guide rate in the HC for .5.
Are you drift aligning? If not, do so.
Be scrupulous about eliminating ANY potential flex between scope and guide scope.
I think you will find these things will work much better than attacking the worm gear.
#17
Posted 25 May 2009 - 07:17 AM
http://timsastroblog...up-for-eq6.html