PixInsight Error Combining Two Sets of Data

[dugstruble]

I am getting an error trying to register two sets of Ha data in PixInsight; Star Alignment between a set of Ha data taken with my Stellarvue 70mm from 2017 and a set of Ha data I just finished with my Stellarvue 102mm. I have done this several times before and it worked. I had a custom process icon set tweaking the Star Detection and Star Matching settings, but lost my process icon set and am starting over. I found a forum thread that I original used on altering these settings, but doesn't seem to be working this time:

https://pixinsight.com/forum/index.php?topic=12437.0
 
The scale of the 70mm is 2.33"/px and the scale of the 102mm is 1.10"/px. When running Star Alignment, I keep getting this error message:

"unable to find an initial set of putative stars"
 
Both data sets are very good. I am rather stumped. There has to be a way to make these two data sets register together. Like I said, I have done it many times before.
 
Any ideas?

[wvanreeven]

Is dithering involved in any (or both) of the images? That would make a difference of a factor 2 which should be taken into account.


HTH, Wouter

[dugstruble]

Yes dithering was used with both sets of data.

[John_Gill]

Hi,

I have had similar problems, so try the following:
StarAlignment ---> Star Matching ---> RANSAC - increase tolerance to 6 or 7

and/or
StarAlignment ---> Star Detection --- Detection Scales -3 and/or Log Sensitivity - 1.0 and/or increase Noise Scales

I try a combination of these settings.  Mostly the RANSAC and Log Sensitivity setting fix my problem.

space is not black
John


 

[Juan Conejero]

Can you please upload your data, or at least a minimal set (as a few calibrated frames acquired with both instruments) where we can investigate the problem. There should be no need to change advanced parameters to register these images.

Without looking at the actual data, we cannot help *at all* in these cases. I have written this hundreds of times on this forum.

[dugstruble]

Can you please upload your data, or at least a minimal set (as a few calibrated frames acquired with both instruments) where we can investigate the problem. There should be no need to change advanced parameters to register these images.

Without looking at the actual data, we cannot help *at all* in these cases. I have written this hundreds of times on this forum.

I sure will. I'll take care of that tonight. Many thanks!!!

[dugstruble]

Can you please upload your data, or at least a minimal set (as a few calibrated frames acquired with both instruments) where we can investigate the problem. There should be no need to change advanced parameters to register these images.

Without looking at the actual data, we cannot help *at all* in these cases. I have written this hundreds of times on this forum.

Here is a link to download the data. These are 10 calibrates Ha subs from each telescope. I didn't want to send you over too much to download. Let me know if you need anything else please. Many thanks for taking the time to look at this. Like I said, I have combined data between these two scopes before without issue. I am not sure what is going on now:

http://www.futureworldmedia.net/personal/sh2-115.zip

Thanks!
Douglas

[dugstruble]

Can you please upload your data, or at least a minimal set (as a few calibrated frames acquired with both instruments) where we can investigate the problem. There should be no need to change advanced parameters to register these images.

Without looking at the actual data, we cannot help *at all* in these cases. I have written this hundreds of times on this forum.

Did you get a chance to download the data?

[Juan Conejero]

Did you get a chance to download the data?

Hi, yes, thank you for uploading them. These images can be registered without problems by just setting the maximum stars parameter (Star Matching section) to a very large number, such as 8000 for example. Since the difference in scale between both telescopes is quite large, StarAlignment needs to use all stars available in both images. You don't need to change any other SA parameter.

Normally SA should try with all stars automatically, but the automatic probing procedure does not work with these images for some reason that I have to investigate.

[dugstruble]

Did you get a chance to download the data?

Hi, yes, thank you for uploading them. These images can be registered without problems by just setting the maximum stars parameter (Star Matching section) to a very large number, such as 8000 for example. Since the difference in scale between both telescopes is quite large, StarAlignment needs to use all stars available in both images. You don't need to change any other SA parameter.

Normally SA should try with all stars automatically, but the automatic probing procedure does not work with these images for some reason that I have to investigate.

Juan,

Thank you so much for taking the time to look at my data. Seems to be working, however I should note it only worked using one of the subs from the smaller pixel scale as a reference image. Also, It still dropped 11 subs, so I bumped the Maximum Stars up to 10,000. Of course I have a lot more subs than what I sent you. Only 5 subs dropped after setting it to 10,000. I can live with that.

For some reason, though, I am getting a lot of subs dropping with my OIII subs now. See attached screen grab. Anything else you can think of?

Thanks,
Douglas

[dugstruble]

Did you get a chance to download the data?

Hi, yes, thank you for uploading them. These images can be registered without problems by just setting the maximum stars parameter (Star Matching section) to a very large number, such as 8000 for example. Since the difference in scale between both telescopes is quite large, StarAlignment needs to use all stars available in both images. You don't need to change any other SA parameter.

Normally SA should try with all stars automatically, but the automatic probing procedure does not work with these images for some reason that I have to investigate.

Juan,

Did you see my last comment?

Thanks
Douglas