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Old 21-01-2021, 03:06 PM
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multiweb (Marc)
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Join Date: Oct 2007
Location: Sydney
Posts: 22,062
Quote:
Originally Posted by Ryderscope View Post
1. I'm still not convinced that it is tilt as the radial pattern looks fairly even in the corners to me. (Once again, I'm happy to be proved wrong on this. I'm just not seeing any convincing arguments here).

2. I wouldn't have thought that focusing with the Bath mask would be more accurate than using the auto focuser, no worries though I can give this a shot. I have one that should fit the FSQ. It does beg the question though which is that if this was an issue, what is wrong with the auto focusing? Note that I also tried 'manually' focusing by moving the stepper motor through the focus zone in small increments until the best focus was achieved.

3. I have the Feather Touch posi drive focuser on this OTA. I has a step size of 2.3 microns which equates to 26 steps per critical focus zone for this OTA.

4. We will have to disagree on the quality of the raw files. To me they are not up to the quality I would expect to the extent that I would not bother attempting to process the data.

5. There is also an issue with registering images from this OTA which have been taken pre and post meridian resulting from the elongation of the stars in the image. This will take longer to explain so I will post a separate reply on that one.

6. The Gerd Numen M68 tilt adapter is a solid unit which comes with good recommendations from others that have used them. I specifically purchased this one as the ZWO tilt adapters have a very poor reputation. The general advice is that small pixel full frame sensors are always going to show up any foibles in the image train, particularly tilt, which I why I included one in the image train.

Thanks Marc, I hope you don't mind me challenging some of your responses. I appreciate the input and am just trying to nut my way through this

Best,
Rodney
That's cool. As emailed if you want to rule out the refractor fix the CAA potential tilt, get rid of all attachments but for the camera and reshoot at different angles. If there's a problem you'll pick it up straight away. If not add components and reshoot until you figure out where the issue lies.
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