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New photometry script in Pixinsight- brief tutorial


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#1 astrodoc71

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Posted 29 March 2013 - 10:50 AM

Hi folks,

For those of you who do use Pixinsight, there is apparently a new photometry/astrometry tool in the latest installment 1.8 RC 5. I tried this last night and it works quite well! Perhaps one day I will know what to do with all the information! However I wanted to post this brief tutorial of its basic usage. Even if you are not doing photometry or astrometry, you might discover 'something' in one of your images and wonder if it's real or not. If you are already using PI for your processing it's actually quite easy to check your image right there instead of hunting the web for comparison star charts, etc.

 

Anyway here is how it works:

1) Open your image

2) In PI version 1.8 RC5 go to "script" > "image analysis" > "aperture photometry"

3) You will pull up the aperture photometry window. It looks like this

AP1.jpg

Make sure to start off you have the "images" tab open, active image button is on (for the image you have opened) and the 2 boxes at the bottom are checked

4) Next click on "configure solver" (arrow above). You should see this:

AP2.jpg

 

You should not have to enter anything under image parameters as this should be read automatically from your image by PI. Under model parameters, leave the defaults EXCEPT for "limit magnitude" which is too low (bright). Should be at least 15.

Then click OK

 

5) Next click on the stars tab and you should see this:

AP3.jpg

Make sure the reference image button is on and your image is shown in the drop down. Defaults are fine but check that magnitude is the same as that entered in the model parameters from before

 

6) Next go to the output tab here:

AP4.jpg

Click on the box "generate image with detected stars". Make sure you choose an output directory!

Click on OK and the script should start running! Make sure to check the process console for any errors

 

7) If the script runs successfully you should see your image show up something like this, with a bunch of green squares around the solution stars.

AP5.jpg

If you check your output directory you will find an excel file with all the data in it. There is a detailed documentation file in this script which explains all the information contained in the data file

 

8) Now how do we know which of these green stars or objects go with which stars in the database?! Glad you asked!

Go to "script" > "render" >"annotate image". You will then see this:

AP6.jpg

Don't worry about all the layers and stuff! All you need to do is realize that the catalog we used for the solution "PPMXL" which is their default that you see in the image and stars tab, is not listed there! So all we need to do to get that catalog is to click on the "add layer" plus sign shown with the arrow. This pulls up a catalog list which looks like this:

 

AP7.jpg

 

9) Select PPMXL as shown above and click OK

 

10) And Voila! Your image is shown with the stars labeled from the database in your very own output directory!

AP8.jpg

 

 

Have fun!

Regards,

Dave


daveandtelescope.wordpress.com


#2 Neil

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Posted 29 March 2013 - 11:58 AM

Wow... I was staying clear of PixInsight 1.8 until it settled down a bit more, however, I'm going over there right now to download it to start resolving some images!

 

Great step by step tutorial Dave, even I can follow it.  ;)

 

Fantastic work by the people at PI, it just keeps getting better and better. :)

 

Clear Skies

 

 

Neil.



#3 Ioannis Komianos

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Posted 29 March 2013 - 12:20 PM

Thanks for the tutorial Dave !


  • Neil likes this

My equipment:
iOptron IEQ45, Skywatcher HEQ5
TSAPO 65 Quad, Altair Astro RC8"

QHY9 mono, QHY5m
Starlight SXFW, Baader 2" (LRGBHaOiiiSii)
Pixinsight 1.8, Sequence Generator Pro, Astroplanner, Phd guiding.


#4 gasman

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Posted 02 April 2013 - 06:22 PM

Excellent tutorial Dave,I really must try PI again and give it a bit more time. I downloaded the trial version recently and uninstalled it after a couple of days as it seemed too much of a steep learning curve for me at the moment. It certainly seems an app worthy of time spending on it!

Steve



#5 gasman

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Posted 06 September 2013 - 08:16 PM

Hi Dave

I`m currently trialing Pixinsight and with the recent Nova Del I thought I`d try this photometry tool but when I load an image and click on aperture photometry and then 'configer solver' nothing happens any ideas please?

thanks

Steve



#6 nCognito

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Posted 09 September 2013 - 10:38 AM

Hi Dave

I`m currently trialing Pixinsight and with the recent Nova Del I thought I`d try this photometry tool but when I load an image and click on aperture photometry and then 'configer solver' nothing happens any ideas please?

thanks

Steve

Click on search and change to the Harvard catalogue



#7 gasman

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Posted 09 September 2013 - 03:18 PM

Thanks for the info. Tried all the available catalogues but still nothing when clicking on `configure solver`. I just get this message on screen when clicking `ok`.

Reading image:

F:/020913/Nova Del/NovaDel_L.fit

Reading FITS: 16-bit integers, 1 channel(s), 1391x1039 pixels: done

*** Error [222]: C:/PixInsight/src/scripts/AdP/WCSmetadata.jsh, line 287: TypeError: DMSangle.FromString(...) is null

Regards

Steve



#8 astrodoc71

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Posted 09 September 2013 - 07:48 PM

Hi Steve,
It's been awhile since I played around with it. You might want to post the error message to the PI forum. There is a link to it from inside the program
Regards
Dave

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#9 gasman

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Posted 21 September 2013 - 09:08 PM

Been on the Pi forum and it turns out the header in my image denote the Ra and Dec coords like this Ra 20:14:40 Dec 15:23:34 when The Pi script expects it as Ra 20 14 40 Dec 15 23 34 so replace the colon with a 'space' and it's fine!. These are not the cords for Nova Del BTW.
Steve




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