Vignette when making flat frames

rafaelss

Hi everyone, tried to shoot my first flat frame using ASIAIR plus (auto exposure) and ASI2600 OSC, using a all white ipad screen on top of my Fsq-85 dew shield. But notice that all images were showing vignetting. Tried to put a white t-shirt between the dew shield and the ipad, but still had the same issue.

Is this the expected results? Or am I doing something wrong?

Regards,

Rafael

Eriktim82

Are they showing on the flats or calibrated images.

rafaelss

Eriktim82 , only on flat frames

Eriktim82 , on flats, straight from the camera

ckoos

Yes, that's expected. You have a round optical train shining light on a square or rectangle camera sensor. So, the corners will be darker than the center. It one of the reasons you take flats, so the stacking software knows how much brighter the center is compared to the corners so it can correct for it.

-chuck-

rafaelss

ckoos , ok, thank you!