Canon 1000d & vignetting

[greenkat]

Hi all

Normaly I use a Meade DSI and dont usualy get vignetting unsless using a focal reducer.

Bought a Canon 1000d and just had a bit of a test run on M92

Is this amount of vignetting normal with the 1000d ? Is it due to the bigger chip size?

Image was taken through a 6" f5 s/w refractor with 2" T adapter.

How do I get rid ? Do I need to start learning the art of flats ?

Cheers in advance

Greenkat

[Demonperformer]

From my (admittedly limited) experience with a 1000d, I have never have vignetting anything like that on either the 102SLT (f6.5) or the 6SE (f10). Would suggest you try another test on another object, and see if it produces the same result?

[philj]

Yep thats about normal for a SW and Canon chip. I started DSLR imaging with a SW ST120 and a Canon 300d and had it worse than that.

You will need to learn the dark art of taking flats now Im afraid. What you do is take a series of short expsoures of a totally flat field, easiest way is to drape a white T shirt over the objectve of the scope and point the scope at the twilight sky. Then take a series of exposures set using your cameras metering. Then combine the flats to form a master flat frame, this will be a greyish image with the vignetting evident.

Then subtract this master flat from your image which will get rid of the vignetting. Sounds difficult but once youve doe it a couple of times its easy.

I now use a light panel for making flats, some folks use light boxes.

Philj

[adamsp123]

looks normal to me, you need flats to fix it and darks will help you to during stacking.

[Glider]

Yep, par for the course.

I take my flats next day, just make sure you don't move anything like the camera or focus by accident overnight.

[Demonperformer]

said my experience was limited (enhanced by having the monitor set too dim, so it looks a lot worse)