This is the tool we would use to align and save the registered images

When we open up the Star Alignment process the panel below is displayed

I will not be annotating every Item as some are self evident

To start with I will explain how to use the tool as displayed below as it works great 99% of the time with the default setting

A) Displayed is your selected reference image to which all Target images will be registered too

B) There are various working modes and here we are going to leave it at the default Register / match images which is used to register normal astronomical Images ------ Other modes particularly mosaic mode deserve a guide on its own

C)Target Image selection / sorting

D) select here whether you want to use a view ( Open image on screen ) or a file after doing so select the small blue triangle next to it for a list of images/files

E) displays a list of target files, As far as I know there is no limit on the amount I have done 200 Plus

F) Select your output directory for the newly created files to be saved to

G) you can alter the output file extension if desired, I tend to leave as default

H) Sample format can also be altered if required again I tend to leave as default

For Normal use to register a selection images I would do the following

1) leave all settings at default

2) Add files or views to the target list using the C buttons

3) select a reference image using D

4) select a output directory at F

5) Then apply the process using the global Apply

For 99% of the time that's it Pi will register your images and save them in your chosen output directory

Just check in the processing consol for the results of star alignment

For the other 1% and difficult images we need to look at the options in the Lower 2 panels

When I say 1% I meant 0.01% I have only had to alter the hot pixel removal once !

I) Detection scales--------- This decides what's size stars are used for alignment increase to include larger stars

J) Noise scales--------------sets the size of which noise is ignored increase to reject more noise but to large a setting may ignore small stars

k) Hot pixel removal--------Will remove hot pixels by the use of a median filter may need to increase if you have large hot pixels i.e. binned images

L) Log sensitivity-----------sets the sensitivity of star detection lower to increase sensitivity ( fainter stars ) and increase to increase sensitivity ( brighter stars)

M) Peak response --------Relates to star Peaks ( sharpness ) lowering will inc more peaked stars and increasing will make it more tolerant of flat not so sharp images

O) Maximum Distortion --This is the amount of non round stars that will be detected , lower settings will allow for more distortion i.e. oval stars

P) Matcher Tolerance --- The amount of distortion that is allowed with star matching , increasing will aid in finding more star matching but could result in false matches, Setting would only normally need altering if your image has strong distortions e.g. very curved fields

Q) RANSAC iterations---If you can not find any star matches increasing this may aid , but is already adaptive

R )Maximum Stars---------The default settings are very good and do not require altering for std use , on rare occasions may need to be altered when using in mosaic mode , alter up or down as required

S) Triangles per star ----Minimum number of triangles per star for star matching , more can find more matches but will be a lot slower

T) Scale Tolerance------The amount of scale difference between triangles and therefore image scale , the current version is not really suitable for aligning images with large scale differences, use dynamic star alignment for this