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sunka

WO 71mm Star f/4.9 fringing?

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Hi,

I am new to refractors and have a problem with my WO 71mm Star f/4.9. If bright star is in FOV I get this horrible halos/fringing. Isn't that supposed to happen only in doublets? uncalibrated example of problem is in attachment, left star is the worst  (taken with Sony A7r, 120s exposures)

Thanks!

image.jpeg

Edited by sunka

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Hi,

I think there have been a few of these scopes had to be returned for re-aligning, think there has been a slight issue with them, did you buy from FLO, if so drop them an email and they will probably explain more.

sorry, but hope that helps a bit

Bill

Edited by RuralBill

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Sorry just noticed you are not in the UK, so not sure on who to contact, but maybe FLO will still shed some light on the issue

Bill

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Yes Sorry, that scope has a serious problem which you are not going to be able to resolve yourself. You need to return it for repair/replacement.

ChrisH

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9 minutes ago, RuralBill said:

Hi,

I think there have been a few of these scopes had to be returned for re-aligning, think there has been a slight issue with them, did you buy from FLO, if so drop them an email and they will probably explain more.

sorry, but hope that helps a bit

Bill

Sorry did not mean to post this again, just edited spelling mistakes.... :)

Edited by RuralBill

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7 minutes ago, ChrisLX200 said:

Yes Sorry, that scope has a serious problem which you are not going to be able to resolve yourself. You need to return it for repair/replacement.

ChrisH

Is that why they have discontinued them ?.

Bill

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20 minutes ago, RuralBill said:

Is that why they have discontinued them ?.

Bill

No, I don't think so. They are a popular/capable scope and the issue affected only very few examples - I guess you're unlucky in that respect. I'm not sure why they were discontinued - perhaps too expensive to manufacture for the asking price so there was little profit to be had? Good examples are treasured by their owners so I hope you can get yours fixed and performing as it should.

ChrisH

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Well thats what I dreaded, I hope its something else... :(

I bought it second hand. So far I imaged with ASI174mm and there have only been slight halos. But ASI174MM is not full frame of course. A few images with it:

http://www.astronom.si/galerija/file.php?n=5634&w=o

http://www.astronom.si/galerija/file.php?n=5649&w=o

http://www.astronom.si/galerija/file.php?n=5658&w=o

The only thing I can think of is severe vignetting due to adapters -> I used T-2 to Sony alpha which narrows optical train down and than I attached it to scope with T2 to M48 adapter... I also attached M27 and M57 short exposures just before I started NGC7000.

EDIT: I also wrote to FLO guys now

_DSC0029.jpg

_DSC0031.jpg

 

EDIT 2: its not vignetting... this is with canon eos 50D and m48 adapter

 

Untitled.png

Edited by sunka
additional info

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Scope is back from collimation, first test look good (beside slight tilt). Tested with ASI174MM.

Vega:

center:

image (1).png

top center:

image (2).png

top right:

image (3).png

middle right:

image (4).png

bottom right:

image (5).png

bottom center:

image (6).png

bottom left:

image (7).png

middle left:

image (8).png

top left:

image (9).png

Andromeda luminance:

IMG_8455.JPG

I still have to test it with APS-C and full frame.

Edited by sunka

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Certainly appears better then the original post and image. Is the tilt in that focuser, camera and spacer assembly ?

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As of today I'm not sure about the tilt - Vega shots seem to indicate it, but yesterday's Andromeda session doesn't show it (check attachment). Setup only differs in 2mm T2  spacer ring. I must test the scope with bigger sensor next to see what's what.

 

 

image.jpeg

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