Black edges? cause?

[Karlax]

 Hi,

Could someone please tell me what is causing these black strips are at the edge of my final integrated image?

The image is comprised of a stack of 90 images and the first and last images are exactly the same so the strips are not edge artifacts caused by stacking.

Skywatcher ED100-PRO with field flattener on EQ6-R PRO mount. Imaged with Nikon D7200

Thanks in advance for any advice.

i'm guessing this is vignetting but i'm a little confused as the ED100-PRO with field flattener is advertised as having no vignetting unless using a full size sensor which i am not.

[bulrichl]

The image is highly stretched by STF Auto Stretch, but this is considered an optimal stretch. So in order to get the most out of your imaging, you indeed have to use flat field calibration with this telescope even using a smaller sized sensor.

Bernd

[msmythers]

Another reason to use flats in your calibration is dust/reflections. I've taken your jpg, flattened it as much as I could and then used curves to apply a high contrast and also remove the color from the image. All of the round dark spots are dust/reflections. The only way to reasonably deal with them is by collecting flats. The edge issue would most likely be taken care of also with flats.


Mike

[Karlax]

Thanks guys, you can ignore the round sports though, i realised there was a few light spots of rain when a rogue cloud passed by during the imaging run whilst i was indoors.

[pfile]

thats not rain, the size of the spots indicates that they are dust particles on the sensor.

as others have said, you need flats no matter what optics you are using.