Atik Cameras

Author Topic: EFW2 extent of vignetting on f/4 system?  (Read 762 times)

DaveAus

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EFW2 extent of vignetting on f/4 system?
« on: November 05, 2016, 02:39:59 AM »
I have a perfectly good Quantum filter wheel which I'm probably going to have to ditch because of failure of ASCOM to recognise it following upgrade to Win10. So I'm considering the EFW2 9 position 1.25” as a possible replacement.

I use an Atik 383L+ mono camera and I've seen the following promotional text :

“Of special interest to Atik 383L+ users is the short distance from the filters to the CCD. This means that popular 1.25″ filters can be used with this sensor down to f/5, without any relevant vignetting.”

My 'scope is f/4. Has anyone had experience of using the EFW2 1.25” with a f/4 system? If so, can you say how bad, if at all, vignetting is. Is it worse that I was getting with the Quantum filter wheel as shown in the attached image? Any advice would be most welcome.

Thanks for reading.

vince

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Re: EFW2 extent of vignetting on f/4 system?
« Reply #1 on: November 07, 2016, 02:04:36 PM »
Hi Dave,

The EFW2 will move the filters closer to the camera by a millimetre or two so the image should be slightly better but you are always going to have vignetting with this setup.

Best regards
Vince

DaveAus

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Re: EFW2 extent of vignetting on f/4 system?
« Reply #2 on: November 08, 2016, 04:10:14 AM »
Thanks Vince.

If possible, it would be good to get someone's feedback based on actual use.

Ajay_Narayanan

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Re: EFW2 extent of vignetting on f/4 system?
« Reply #3 on: December 24, 2016, 06:07:01 AM »
I moved to 36 mm filters to reduce vignetting. I image at f/6. There is some vignetting, but if you are more than a casual imager you should use flats. For me flats take care of the residual vignetting.

Ajay

Chris

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Re: EFW2 extent of vignetting on f/4 system?
« Reply #4 on: December 25, 2016, 11:38:51 AM »
I have a perfectly good Quantum filter wheel which I'm probably going to have to ditch because of failure of ASCOM to recognise it following upgrade to Win10.
I got a Quantum wheel going on W10 by using an updated Nautilus filter wheel driver. Try contacting the driver author Júlio Silva julio.silva@j2ssystems.com

I've a Quantum wheel and a 383L+ and flats cope with vignetting with no problems.  Try looking at the actual change in signal level on your flats, it may not be s much as it appears.

Chris

DaveAus

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Re: EFW2 extent of vignetting on f/4 system?
« Reply #5 on: January 12, 2017, 02:05:27 AM »
Chris

Please accept my apologies for not responding sooner to your posting. I only found it yesterday.

At your suggestion I did contact Julio and he very quickly sent me a link to the updated zipped installation files. These worked a treat and now, at long last, I have the filter wheel back under control again. So thank you very much for your suggestion and know that could not have resumed imaging without it. Now if only the clouds will clear!

Regards

David