PEC evaluation and correction.

First try of PEC, done with a brilliant star in Andromeda.

Very accurate polar align with the king method in astrosnap.

My idea is to take 120 images of 10s , this covers 1200s , ie two worm drive turns.

The un-aligned adding (20 minutes of imaging ) of images gives :

With IRIS 3.57 software, i used the TRACK name number command to generate dx.dat ( for me DEC ) and dy.dat ( for me RA ).

Method is

0 Import images into the working directorie of IRIS

1 Add all images of your serie, to and select a rectangle which contains a "blurred" star.

2 Use Track name number, and IRIS tracks the star in the rectangles and generates two files which contains the dx or dy data versus the time.

Graphic is pixel versus the time in seconds.

One pixel is 1.3", this gives +/- 6 arcsecond, obtanied from vesta with focal distance of the scope of approx 887mm ie C8at4.4.

Oustanding for the price, but care must be taken, the measuring is not scientific, i need more information about this..

I think this a good PEC plot since it repeats nicely, ( note timing is not accurate, because the time is needed for acquisition ).

RA shows nice periodical shape, and DEC shows a drift.

Next time i will try another set of graphs, to see if it is repeatable, if yes, i dive into PEC !!!

Now , please see http://xmcvs.free.fr/ep/index.htm for further research in the periodical error domain