Analyzing of vignetting of my lenses and telescopes

[Astrofriend]

Hi,

I spend a day here to analyze my master flats and what vignetting I have on my lenses and telescopes. It's very simple done but still interesting to set figures on it.

 

It's done on a full frame camera and I use the values from the center and the corner of the sensor. The corner is 22 mm of from the center on a full frame sensor. I never liked to have strong vignetting in my optics, and in the future I want to go for bigger size than full frame.

 

I have put together a page over the vignetting I got:

http://www.astrofriend.eu/astronomy/projects/project-different-lenses-vignetting/01-different-lenses-vignetting.html

 

Maybe interesting for some of you to have a look at.

 

My telescope shall handle a medium format sensor of the size 48 x 36 mm with the setup I have now. My medium format optics already do it. Just missing the medium format camera.

 

/Lars

[TimBrandt]

Hi Lars, I know this was posted some time ago but very interesting. but thanks for sharing.  It has been a big help in reassuring me on some vignetting I'm experiencing with a Williams Optics GT81 and a ZWO ASI2600 APS-C camera. 

 Kind regards

Tim

[Astrofriend]

Hi Tim,

Strange that you have disturbing vignetting from a high quality telescope like that. It even has a 2.5" focuser. Telescope with that big focusers normally have an over sized back lens system to hold down the vignetting. Have you added a reducer to the system ? But still the camera isn't a full frame, it's a APS-C. Can yoy put some figures on the relation in signal at the corners relative the center ? Bias must be subtracted first. At the homepage there were no information of how big sensor the telescope is designed for.

/Lars