PCL: Comet Alignment module

[NKV]

Ok,
So in this case obs-date is used just to sequence the files?
The exact time is not used because the speed is already available.

I have some tiff files.
I converted them to fits and set a dummy obs- date in each of them, taking care of the real acquisition number.
If I put the comet rate at that time ( from Skyx), it should work, right?
Thanks again,
Andrea

No ano No.
obs-date required to calculate real time between shoots.
For example. You can set comet speed 60pixel per hour. You can take one shoot per minute. So the comet must move 1pixel from shoot to shoot.
Bat, what happen if you stop shooting in middle of the night for refocusing. How to calculate time between that shoots? Who can warranty that images taken exactly one per 60.00000000000 seconds, not 60.1 ?

So obs-date must be present. You can create obs-date KeyWord in many ways. From EXIF of FileSystem(DateOfFileWritten). Anyway, obs-date should represent one of time event type (start, stop, middle, create,...). And should be stable.

[Juan Conejero]

Hi everybody,

I have just released an update with version 1.2.2.65 of the CometAlignment module for all platforms.

It is the same version Nikolay has published here with the following additions:

* New output file extension parameter (.xisf by default).

* New input and output hints parameters.

* The interface has been cleaned up and reorganized to meet PixInsight tool GUI guidelines.

Nikolay, congratulations on an excellent work!

PS: I like the icon!

[lucchett]

thanks Nikolay, I think I understand now..

Andrea

[outerspace]

Nicolay & Juan

Great. Works like a charm.
Thanks a lot!

[mikeoday]

The problem:

I have a stack of 186 sub-images of comet 252P that was moving very fast. 

The images are 6016x4016 pixels.   

In image #1 the comet is at 3140,1085  and in #186 it is at 2665,2555.

That is, the comet has moved -475 pixels in X direction and 1470 in y direction.  As such, I would have liked the resultant stacked image to be larger than the individual subs at (6016+475)x(4016x1470) with the center of the comet at (2665-475/2),(1085+1470/2).  I would then crop the center (6016x4016) of the image as necessary and re-combine it with the star aligned image.

Alas, I end up with a stacked comet image that is the same dimensions as the sub, the comet in the location of image #1 and all of those extra pixels above the comet in the later subs cropped away by the tool.

Attached is an example of one of the subs that has been re-aligned with significant loss of information.

Does anyone know how I can force the tool (or another tool) to align the subs without cropping the information in the subs (ie. by enlarging the canvas to allow the alignment to proceed whilst retaining all of the information in the subs).

[mikeoday]

Here are more image that show the problem ...

1. star alignment showing incomplete removal of comet path through the centre of the image.

2. resultant comet aligned image

3. simulation of how the final image might look with the current comet aligned image (what I don't want); and

4. simulation of where I want the comet to appear in the final image (with all the information above the comet retained (which currently is not))

Any ideas on how I can achieve it would be greatly appreciated.

Cheers
mike

[Alejandro Tombolini]

Hi Mike, if I remember well you can select the image that will determine the final position of the comet, with the blue arrow (double click in the # section). This processing example may help.
Saludos,
Alejandro.

[NKV]

Does anyone know how I can force the tool (or another tool) to align the subs without cropping the information in the subs (ie. by enlarging the canvas to allow the alignment to proceed whilst retaining all of the information in the subs).

ImageContainer + Crop 200% to create black spaces around read pixels.

[mikeoday]

Hi Mike, if I remember well you can select the image that will determine the final position of the comet, with the blue arrow (double click in the # section). This processing example may help.
Saludos,
Alejandro.

Thanks Alejandro, I did not know that.  I've tried it and it does re-align the images to centre on the selected image.  Unfortunately though it does not enlarge the canvas to accommodate  all of the subs.  That is, the problem remains that the individual comet aligned subs are all still the original dimensions with the image content shifted (and the remainder filled with black) so I still miss out on a lot of data.

Cheers
Mike

[mikeoday]

Does anyone know how I can force the tool (or another tool) to align the subs without cropping the information in the subs (ie. by enlarging the canvas to allow the alignment to proceed whilst retaining all of the information in the subs).

ImageContainer + Crop 200% to create black spaces around read pixels.

Thanks for that, yes the Crop tool worked  

In case anyone else is wondering about the details...

The Crop tool can also be used to increase the canvas size around the image.  The Image Container tool was also new to me and allows you to collect together all the images that you want before applying a tool to the whole collection as a single action.

Cheers
Mike

[lucchett]

Hi,
I have a question on the Subctract operand image functionality.

this is what I did:

-star align my images
-crop my images
-run comet align and integrate a Comet Aligned image (very good)
-run again comet align module on star aligned (and cropped) frames, subtracting comet aligned image at each step.

The resulting files are not good bacause the operation digs to much in the data and the background is lost.
I have tried to replicate the operation in pixelmath and it seems that a "rescale" option can cure the problem.

is this step already included in the processing?
I couldn't check the final integrated star only image because re-aligning the comet image to star manually is painful.


Thank you very much,
Andrea

[paolobar]

Hello.
I noted a little GUI problem in the CometAlignment process: when loading the file list with long file names, the list windows is missing the Horizontal Scroll bar and the file names are going "under" the right buttons and they also has their labels truncated (see screen shot attached).
Checking into the code I noted a comment that suggest that behavior is required.
I'm wandering why...
Any idea?