WATS ALL THE NOISE ! ! ?

Hi all,

Hope you all doin well....

Ive been workin away tryin to improve my imaging and im makin progress I think...

this is my latest effort......... but there seems to be a lot of noise at the centre of the frame.....CAN ANYBODY SUGGEST A REASON FOR THIS???
(the rest of the image looks good... detail comin up if it wasnt for this problem))... (I was using scope lens cap to do "hat trick" to reduce camera shake and i noticed at the end of the night that an orange light in distance was reflecting off lens cap as i did this... could that be it?)

farm3.static.flickr.com/2282/2343292061_15f15a7e1e_b.jpg

its a BIG improvement from my last attempt anyway farm4.static.flickr.com/3097/2283825809_bd061c177b_b.jpg

THANKS ALL,,

KEEP LOOKIN UP!!!!!!!!

KEVIN

isn't this a "vignetting" problem?
I have seen this in my pictures too.
if you use a stacking program then you can add a special picture containing these vignetting data.
the program will correct the picture according to this.
as a simple sollution, take a picture with a white T-shirt over the lens.
etc.
maybe this gives you a hint

Looks like vignetting to me also, if you have photoshop, it can be used to reduce it.

The circular part of the image, center, is vignetting. This can be reduced by taking flats (if you don't want to go down the route of hardware changes).

I have the same issue with my setup and flats largely remove the effect. Post processing will help but not as much as taking flats (and flat darks as well).

The image displays what could either be coma or tracking errors or both. Coma seems evident in the uppr right corner. Tracking seems evident in the central parts of the image.

There also seems to be some vertical and horizontal banding going on in the central portion of the image - that may be down to the imager or processing or both.

There's a lot of noise in the image - longer images and dark/bias subtraction will help reduce that.

I can't quite figure out what is going on at the base of the image - that may be due to a light leak or not...

Other than that, you've certainly captured some detail in the galaxy which is no mean feat. Its a great start - work on the calibration frames (bias, dark, flats and dark-flats) and you'll progress.

HTH

Dave

Thanks all,

Im goin to give it another go tonight... ill let ye know how i get on....


thanks for help and interest!!!

kevin

Vignetting is part of the issue, but it looks to me more like moisture in the atmosphere. Some more details would be helpful - what ISO?, how long an exposure? (I'll bet you were pushing up to 1600 ISO?, and over a minutes exposure?). Try a lower ISO, or shorter exposures and stack the images, it'll help but if the air is wet you'll never get rid of it entirely.
Darks will help with a noisy image whereas Flats will clean up any dust etc in the optical train. However light reflected from moisture in the atmosphere will cause exactly what you are seeing in that pic - Lots of reflected light from the brightest parts of the image.
Good capture of the Whirlpool by the way - on a drier night you'll get a world of difference, I reckon this is all down to seeing and transparency (transparency being the killer here).
BTW - Hat tricking is not necessary if you use a remote trigger and mirror lockup (if your using an SLR), again more detail on equipment might help.