7 replies to this topic

[DTonucci]

Hi Everyone,

 

I tried to search the forum to see if there is an answer to this question and I couldn't find one specifically so here goes...

 

I have a Stellarvue 102T SVX with the 1x flattener and the ZWO ASI 2600MCpro that has been a joy to use.  No real complaints, just looking for advice.  I have analyzed many frames using Pixinsights and have always noticed that the stars on the corners appear like there is something going on in my image train.  I have attached example files from the image inspector, the FWHM analysis and eccentricity analysis (using the L-extreme filter on a Ioptron GEM 45 mount).  The images I get from the telescope look great, so I am just asking if I have a problem or are these image analysis results good?  Do I have tilt or is the flattener too close to the camera?  As a newbie to the field of astrophotography I do not know and cannot find a consistent answer in the forums.

 

Thanks a bunch for your help and expertise,

Dave

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Edited by DTonucci, 06 December 2024 - 05:30 PM.

[idclimber]

The SVX102 with either the reducer or flattener is sensitive to backspace. You most likely need to refine that to get the best stars in the corners. I have also found with my scope that the patterns don't follow the book on which way to go. 

 

If you can upload that sub to a shared drive I will take a closer look. I will also pull up a sub with that flattener out of my library for you to compare. I typically image with the reducer not the flattener. I also have the larger SVX152 on the mount most of the time.

 

Also note my SVX102 was just realigned by Stellarvue with the Moonlight focuser this spring. I am still trying to get the backspace and scope to perform as it did prior. 

[DTonucci]

Hi Dave

 

Thanks for your comments, I will load a sub this evening to the original post.  I didnt think I would have to play with back focus, since it is not an adjustable flattener, I know how to lengthen the back focus with spacers, but not shorten it.

 

Dave

[GrafikDihzahyn]

FWIW, I also struggled to get my stars corrected on my SVX-80T with the included flattener. 56, 55.5, 55, 54.5, 54mm, nothing was working it seemed. Stellarvue ended up replacing my flattener with the newer model after helping me sort the issue over a few months time. They were responsive with emails and I was sending through my subs for them to check. I went ahead and purchased the Stellarvue Variable Length Extension to fine tune once I received the updated flattener, rather than using the plethora of 1mm, .5mm spacers I was using before. I eventually purchased the adjustable Reducer/Flattener and haven't used the flattener only version much at all since.

 

It also looks like you may have a bit of sensor tilt. I had struggled with the tilt adjustment out in-the-field until someone here mentioned building a laser rig. Made quick work of the process during the daytime one afternoon.

[idclimber]

Here is the analysis of a sub I pulled from 2021. The target was M51 and the result is in my Astrobin account linked in my signature. This was 120" unguided on my MX+

 

 

 

This is an old sub as I do not use the flattener much.  In hindsight I am not sure the mount was performing optimally. I get lower fwhm from my AP1600 and my SVX152. 

[DTonucci]

Thanks to those that commented.

 

I will try the back spacing and reach out to Stellarvue for assistance.  The FWHM doesnt seem to be too bad and maybe it is just tilt and back spacing.  That's a good place to start.

 

Regards

[PhotonHunter1]

I’ve got a SVX-T 102 and their flattener, you just need to dial in the back focus. The stars in the corners appear to all point inwards which mean you need to increase your backspacing. Iif I had to guess I’d say just 1-2mm.

[DTonucci]

Thanks for the info Apollo, now I just need to buy some spacers