On Friday night last with intermittent cloud decided to do a complete check of collimation and alignment.
First check, collimation. Out of focus centred star image see below. Collimation near perfect! Note this is factory set collimation as I have not touched it.
I then spent some time over Friday night taking a series of exposures at stepped focus intervals while dodging clouds. I did not touch the alignment in the dark and in a hurry.
In the clear light of day yesterday (Saturday) carefully analysed these images and worked out 'exactly' what adjustments were needed. These adjustments were for the Camera Frame position. The size of these adjustments are less than 0.5mm in lateral and vertical camera frame position. Typically about 0.2 to 0.3 mm.
I made these adjustments and waited for dark. The first image told me I was closer than I had ever been. I must have done something dumb in past attempts such as adjusting the WRONG way! It is easy to get confused with inverted real images when viewing images the correct way up!
Here is the first test image. Carina Nebula 14x4 min for each of RGB. 7MB
http://d1355990.i49.quadrahosting.com.au/2014_01/CAR_N.jpg
It still needs a slight tweak so I will repeat the process tonight.
By the way the tweak needed is about or less than 0.1 mm to the right and the same up.
Bert
