Small differences

With my small scope, I can capture the span and colors of the Orion nebula with a 45-second exposure on my digital camera: 

However, tracking is rarely good with my small setup, so the photo above has noticeable elongation of the stars. 

This second photo is made from three shorter duration photos, which reduced the elongation of the stars. The small improvement in image quality is a result of computer processing. 

My methods for combining photos are still crude. I omitted a blank image to use for compensating for my camera's noise, and I could have combined more short photos.

Here's one of the 15-second shorter photos I used:

Apparently, all the information to get the 2nd photo is in three of these shorter ones, but less error from tracking.

jg