Annotation script

[Herbert_W]

Hi Andres!

Answer to #231

Is it possible to get the converted catalogs (in the format, which is nessecary for your script)
for download? My Lap hasnt always a connection to the net.

It would not be easy because some catalogs are huge (>10GB) and JavaScript is not very fast. I would have to program indexes and a search mechanism. This is a lot of work and I have currently other priorities.

I will think about it but I can't promise anything.

Ok - its a pity, but thanks for your reply and again: thank you for this great tool!!

Best regards.
Herbert, Austria

[Andres.Pozo]

Hi Andres!

Answer to #231

Is it possible to get the converted catalogs (in the format, which is nessecary for your script)
for download? My Lap hasnt always a connection to the net.

It would not be easy because some catalogs are huge (>10GB) and JavaScript is not very fast. I would have to program indexes and a search mechanism. This is a lot of work and I have currently other priorities.

I will think about it but I can't promise anything.

Ok - its a pity, but thanks for your reply and again: thank you for this great tool!!

Best regards.
Herbert, Austria

Herbert,
have you tried to use custom catalogs? Please read http://pixinsight.com/forum/index.php?topic=3966.msg28257#msg28257
You can download the catalogs that you want from Vizier, process them using Excel or similar and save them in the format used by AnnotateImage.

[georg.viehoever]

I know its probably a toy only for "real" astrophotographers : Would it be possible to optionally draw the constellations (Orion, Ursus Major, ... connecting lines only) with the Annotation script? Would be nice, mostly for wide fields.
Georg

[Andres.Pozo]

I know its probably a toy only for "real" astrophotographers : Would it be possible to optionally draw the constellations (Orion, Ursus Major, ... connecting lines only) with the Annotation script? Would be nice, mostly for wide fields.
Georg

I have not done it yet because currently ImageSolver can not solve wide field images reliably. However, the next version of ImageSolver will be able to solve them. Drawing the constellations would be a reasonable next step.

[Andres.Pozo]

Rüdiger has lend me an image taken with a Canon  EF 1,2/50mm L @ f2,8. I have solved it with ImageSolver 2.0 using 5th degree polynomials.

This image is an animated GIF with a comparison between the old algorithm and the new one:


The second image is a representation of the distortions that the algorithm detects on the image. The red lines exaggerate 10 times the distortion.

[mschuster]

Well done! But a nit: Higher degree polys tend to "ring" or "oscillate". It looks to me like there is a circular zone of no distortion in your map. Is this correct?
Mike

[Andres.Pozo]

Well done! But a nit: Higher degree polys tend to "ring" or "oscillate". It looks to me like there is a circular zone of no distortion in your map. Is this correct?
Mike

I don't understand what do you mean. The distortion image shows an oscillation. If you draw a graph or a radial cross section, the distortion goes up and down. The degree of the polynomials can be selected by the user, and for many images a lineal polynomial is still good enough.

The polynomials are calculated using a least squares linear multiple regression algorithm. If the center of the image shows no distortion is because the best solution is to consider that the center has no distortion.

The attached image is the distortion of a 105mm objective. The minimum distortion is not at the center.

[mschuster]

Thanks Andres, Just wondering:

About 80% out toward the edge, there is a ring of little distortion. Is this real? Maybe it would help to see an animation of the entire image and a matching map.

IMO solutions that are best in the least squares sense can still oscillate - the residual error of the model oscillates across the data. Just wondering if this is the case or not.

Is it possible to generate a map of residuals? Also, in the map arrows would help visualization (which direction is the local distortion offset?).

Mike

[Andres.Pozo]

The script generates two debug images: the distortion map that you have already seen and a residuals image. In the residuals image the script draws a green cross at the predicted position of the star and a red line from the predicted position to the real position. When the residuals are zero, the red line degenerates to a point. The residuals image for Rudiger's image is this (click on it to open at full size):


In the distortion map, the red lines start always at the center of each cell. I prefer not to add an arrow because they would obfuscate the image in the areas with little distortion.

[Andres.Pozo]

I have just finished a new version of AnnotateImage. This version has two new layers:

• Constellation lines: The layer draws on the image the asterisms of the constellations.
• Constellation borders: The layer draws on the image the borders between constellations.

These layers are useful for wide field images together the catalog layers "Named stars" and "Bright stars".

A few examples (click on the images for full size):

[georg.viehoever]

That is simply fantastic!

[Josh Lake]

 

This script was already invaluable for my astronomy classes. Now, even more so! Thank you.

[georg.viehoever]

I have just finished a new version of AnnotateImage. This version has two new layers:

• Constellation lines: The layer draws on the image the asterisms of the constellations.
• Constellation borders: The layer draws on the image the borders between constellations.

Will Juan distribute it via the update mechanism?
Georg

[Juan Conejero]

Will Juan distribute it via the update mechanism?

Sure thing. Can I proceed with the zip file you have posted here, Andrés?

[Andres.Pozo]

Will Juan distribute it via the update mechanism?

Sure thing. Can I proceed with the zip file you have posted here, Andrés?

Ok.