Why did my long exposure (star trails) photo come up with all of this noise?

I took this star trails photo: (go ahead and enlarge it) and it came up with a bunch of red and green noise. I've never had any problems like this before, just on my new Canon t4i. I've shot star trails for this long (long exposure, about 2-3 hours, ISO 100, large aperture) on my old Nikon D5100 and never got any sort of noise. I shoot regularly on this camera and even do other long exposures for shorter amounts of time but never get and noise.No, there was no big light behind me or anything, all light was natural. I've shot in the middle of the woods and had the same problem. Any suggestions?

Added (1). Correction: never get any noise*

One has to wonder why you bought a different brand camera?

The sensor of your old D5100 out performs the Canon T4i/650D by a large margin when shooting in low light and it has a long exposure NR (Noise Reduction) feature

http://www.dxomark.com/...nd3)/Nikon

I'm surprised that your camera did not shut off after less than half an hour. Usually that is about the limit for a CMOS sensor because they overheat and shut off the camera to prevent damage to the sensor

Upgrading to the Nikon D5200 might have been a better plan based upon the subjects you enjoy shooging.

I can't see a red/green light in the pic. The red area is due to the mountain and green is the tee. It just that there was some extra source of light and not pitch dark hence the result

To avoid noise issue you should try a different approach for your star trails photography, instead of doing one huge long exposure you should try doing multiple long exposure.

-Make sure the battery is fully loaded, if you have a battery grip use it.

-Turn off the noise reduction. (it's very important otherwise it will create blank spot in your star trails)

-Set the camera to 100 iso.

-Set the camera to continuous shooting.

-Set the camera to JPEG high quality and watch the camera from time to time because not all camera have the buffer to handle it.

-Use between 20s - 30s exposure.

-Press the shutter on your remote control and lock it.

-Unlock the shutter and stop when you're done.

-Do not move the camera, put the cap lens on and take a dark frame, same shutter speed as the others frames, this dark frame will be use for noise reduction.

-Do not move the camera, the last frame will be for the foreground. Adjust the shutter speed in order to get good details in your foreground or if you have a powerful flashlight you can use it to paint light your subject etc.

This part is done.

Now download this little program called Star trails http://www.startrails.de/html/software.html

You will need any photoshop or gimp for later.

In star trails go to file -> open images and select all your frame except the dark frame and the one for the foreground.

Then go to file -> open dark frames and select your dark frame.

Then click build -> star trails. Wait until its done.

Save as a tiff file then open the Tiff file in photoshop or gimp.

- Now drag the foreground frame and paste it as a new layer on top of your tiff file.

- Create a black mask on the foreground layer and paint over it with white paint to show the foreground.

-You can apply other adjustments, noise reduction, sharpness, curves etc. To your like.

Hope it help.