CCD Noise

[Kenza]

Hi! Last night I had my first imaging session with an Atik 4000 Mono. Because I live in a light polluted area I used an H-alpha filter and tried my luck on a small region in NGC 7000. Here is one of two 10 minute frames which I have just stretched without further processing. Is the amount of noise in the image normal for a CCD or am I doing something wrong? The sensor T was -10 degrees. I have also included the original FITS file for anyone who would like to process it, and I will gladly post the other 10 minute frame for stacking.NA Nebula.tiff

CCD Image 44.fit

[lensman57]

Hi! Last night I had my first imaging session with an Atik 4000 Mono. Because I live in a light polluted area I used an H-alpha filter and tried my luck on a small region in NGC 7000. Here is one of two 10 minute frames which I have just stretched without further processing. Is the amount of noise in the image normal for a CCD or am I doing something wrong? The sensor T was -10 degrees. I have also included the original FITS file for anyone who would like to process it, and I will gladly post the other 10 minute frame for stacking.NA Nebula.tiff

Looks normal to me, to subdue the noise you'd need a lot more than 2 frames, at about 8 the reduction starts to become visibly effective at 16 it is near ideal, at 32 and beyond the law of diminishing returns sets in, so I guess anything above 10 subs is good, also cool the CCD as far as the peltier allows it, I am not sure if the use of Dark frames is necessary with Kodak sensors but it would not hurt to experiment with it.

A.G

[Uranium235]

One look at that image tells everything.

Your focus is way off (blobby stars give it away), and if the telescope is not in focus then any data you capture will appear noisy, regardless of the sub length. That deals with noise within the target data, but what about the rest of the image? Well, another type of noise that may present itself with a Kodak chipped camera is hot pixels. -10c isnt low enough for that chip, go as low as you can, my stock temp is -20, and lower during the winter (8300 chip).

Your chip has a few hot pixels, and as the previous post stated you can eliminate those by collecting about 16 subs then using a sigma clipping routine when stacking (DSS does it). Though, with the appropriate software (ie: Maxim DL) you can filter out the hot pixels with a couple of mouseclicks (kernel filter) if you dont have enough for sigma clipping.

[Kenza]

Ok, i think this is better. This is a stacked image of 11 x 5min and 1 x 10 min Lights. Also I took 4 Darks. But It still looks a bit out of focus. I focused with MaximDL but I couldn't get FHWM below 6. I guess it's just practice. I can upload the stacked FITS file if anyone wants to play with it, I am not that good at post-processing. As for cooling, when i connected the camera in Maxim the sensor temp. read 24.5 degrees so I cooled it down to -15.

Pelican 5.tif

[Kenza]

I reduced the noise using Imagenomic noiseware plug-in.

Pelican Imagenomic 2.tif