Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Differential Photometry of Multiple Stars in FITS Files at the same time

Software
  • Please log in to reply
21 replies to this topic

#1 arushi

arushi

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 12 Feb 2023

Posted 06 November 2023 - 09:41 PM

Hello,

 

There are several software (AstroImageJ, Muniwin Siril...) which allow undertaking Differential Photometry of a single star in an image using comparison stars.

 

Has anyone come across a software or algorithms which allow differential photometry of multiple stars (of similar sizes) in the same FITS files at the same time?

 

 

Thank you, in advance.

 

Arushi

 

---

Founder

www.MonitorMyPlanet.com

 

 

 



#2 pvdv

pvdv

    Vostok 1

  • -----
  • Posts: 187
  • Joined: 06 Mar 2022

Posted 07 November 2023 - 05:56 AM

Maybe the "Prose" python package?

https://github.com/lgrcia/prose

with a bit of glue code you can base your program on

https://prose.readth...es/transit.html

and iterate, eventually in parallel, the sources that interest you.

Version 2 was a bit buggy and, imho, and I thought it would be orphaned as soon as it had fulfilled its role of providing a couple of papers and citations (as it is often the case for programs/libraries supporting academic achievment), but it seems to have survived and improved.


  • arushi likes this

#3 PeterSurma

PeterSurma

    Mariner 2

  • -----
  • Posts: 269
  • Joined: 24 Aug 2006
  • Loc: Heidelberg, Germany

Posted 07 November 2023 - 06:03 AM

Hi,

 

I guess that DAOPHOT (author: stetson) allows to this. However this pro software and probably rather complex to use. Google for daophot photometry...

 

Kind regards,

Peter


Edited by PeterSurma, 07 November 2023 - 06:05 AM.

  • arushi likes this

#4 Tapio

Tapio

    Voyager 1

  • -----
  • Posts: 10,253
  • Joined: 24 Sep 2006
  • Loc: Tampere, Finland

Posted 07 November 2023 - 06:13 AM

I just learned a month ago that Fotodiff can do that.
  • arushi likes this

#5 pvdv

pvdv

    Vostok 1

  • -----
  • Posts: 187
  • Joined: 06 Mar 2022

Posted 07 November 2023 - 06:26 AM

Hi,

 

I guess that DAOPHOT (author: stetson) allows to this. However this pro software and probably rather complex to use. Google for daophot photometry...

 

Kind regards,

Peter

I don't think "pro" and "complex" scares Arushi. ;)

Hint: check her website.


  • arushi likes this

#6 arushi

arushi

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 12 Feb 2023

Posted 07 November 2023 - 10:18 PM

Thank you everyone for the very helpful tips. I now have newer ideas to proceed ahead!


  • happylimpet likes this

#7 topcode

topcode

    Explorer 1

  • -----
  • Posts: 94
  • Joined: 02 Jul 2023

Posted 08 November 2023 - 12:55 AM

Hello,

 

There are several software (AstroImageJ, Muniwin Siril...) which allow undertaking Differential Photometry of a single star in an image using comparison stars.

 

Has anyone come across a software or algorithms which allow differential photometry of multiple stars (of similar sizes) in the same FITS files at the same time?

 

I may be mistaken, but im pretty sure AstroImageJ lets you do that aswell, unless i am misunderstanding what you want, astro image j lets you select multiple target stars for multi object photometry, in addition to the calibration stars.


  • Matthew Paul and arushi like this

#8 pbealo

pbealo

    Apollo

  • *****
  • Posts: 1,409
  • Joined: 12 Oct 2006
  • Loc: New Hampshire

Posted 08 November 2023 - 01:42 PM

Become an AAVSO member and use their VPhot application from our website. It allows multiple target stars in a single field. When I image BU TAU in the Pleiades I actually measure ~20 other variables as well and report them all.

 

Peter


  • PrestonE, PartlyCloudy and arushi like this

#9 arushi

arushi

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 12 Feb 2023

Posted 08 November 2023 - 08:25 PM

Thank you everyone for sharing these tips and your experiences with doing multi stars photometry. It will help me in expanding my Python algorithms that were focused on asteroid photometry and offsets (and measuring the success of NASA DART Deflection mission) to exoplanetary/variable stars photometry.

 

More details about ,my asteroid photometry project are available at: https://www.monitorm....com/posts/1393

 

Best regards,

Arushi


  • SeymoreStars, PartlyCloudy, Xilman and 1 other like this

#10 han.k

han.k

    ASTAP Software

  • *****
  • Vendors
  • Posts: 1,184
  • Joined: 09 Mar 2015
  • Loc: the Netherlands

Posted 09 November 2023 - 04:25 AM


Has anyone come across a software or algorithms which allow differential photometry of multiple stars (of similar sizes) in the same FITS files at the same time?

In the ASTAP program  with one click (1) you can get a report with the measured magnitudes off all detectable stars in the image. It is currently just a manual tool for the user. I assume your more interested in building automatic processing where the input is a series of images and as an output a database report of stars which show variability. An other possibility is using the ASTAP command line option and extract for all detectable object the X, Y position and flux (2).

 

You could do the same with the astrometric solver nova.astrometry.net which will report besides the astrometric solution the X,Y positions of detected objects and measured flux in a separate .axy file (3). I'm not sure if the flux measurement is accurate but you could also use an other SourceExtractor called SExtractor (4).

 

The problem with option (2), (3), (4) is the limited accuracy. The full star flux is measured, not the bright center only with something like 0.8 *FWHM aperture diameter. But maybe that can be finalized with Photutils

 

Han

 

Example ASTAP output:

Limiting magnitude is 18.1   (18.1< m <18.1, SNR=7, aperture ⌀1.5)
Passband filter used: CV
Passband database=BP

fitsX fitsY HFD α[°] δ[°] ADU SNR Magn_measured | Gaia-V Gaia-B Gaia-R Gaia-SG Gaia-SR Gaia-SI Gaia-G Gaia-BP Gaia-RP
3755.45 2692.99 3.604 23.747631 30.448624 31952 118 14.797 | 14.620 15.480 14.134 15.003 14.347 14.103 14.380 14.828 13.766
3826.88 2702.46 3.386 23.778321 30.445076 6398 30 16.544 | 16.377 17.496 15.773 16.887 16.008 15.663 16.035 16.618 15.321
3803.23 2709.42 3.958 23.768154 30.442512 27335 110 14.967 | 14.793 15.309 14.473 14.987 14.662 14.548 14.668 14.949 14.225
3787.76 2712.94 3.378 23.761501 30.441217 8257 34 16.267 | 16.232 16.877 15.846 16.502 16.045 15.881 16.065 16.407 15.549
...

...

 

 

Example .axy output file of the Astrometry.net program (FITS file containing a table) :

X Y FLUX BACKGROUND
pix pix unknown unknown
1.123544E+3 8.713094E+2 6.500356E+4 5.314375E+2
1.499517E+3 8.148891E+2 6.294556E+4 3.233750E+2
9.518344E+2 1.210799E+3 6.291008E+4 3.636250E+2
2.758500E+2 1.599166E+3 5.722616E+4 2.857852E+2
2.207960E+3 6.560481E+1 5.679797E+4 1.856523E+2
1.569948E+3 9.320018E+1 5.378906E+4 2.603789E+2
8.052805E+2 8.783582E+1 5.033514E+4 3.156016E+2


Edited by han.k, 09 November 2023 - 07:00 AM.

  • arushi likes this

#11 Ed Wiley

Ed Wiley

    Vanguard

  • *****
  • Posts: 2,460
  • Joined: 18 May 2005
  • Loc: Texas, USA

Posted 09 November 2023 - 06:12 PM

First, for those of you who might not know, Arushi gave one of the best presentations I heard at the AAVSO Annual meeting. Congratulations Aurshi!

 

Arushi: Try Tycho Tracker by Daniel Parrot. It costs a bit, but not too expensive. It is specifically designed for asteroid discovery and photometry and Daniel is a great programmer. You can try a Demo version.  

 

Clear Skies.

Ed Wiley

AAVSO WEY

Instructor, AAVSO CCD1+2


  • PrestonE, PartlyCloudy, pvdv and 1 other like this

#12 jfgout

jfgout

    Mariner 2

  • *****
  • Posts: 231
  • Joined: 24 Dec 2009
  • Loc: Starkville, MS

Posted 09 November 2023 - 11:15 PM

Plenty of great advice in this thread. Tycho is definitely on my list of software to try. VPHOT, the online analysis software from AAVSO is well worth the cost of membership. Extremely easy to use.

 

I'll add one option to the list, this photometry pipeline written in Python: https://github.com/m...tometrypipeline

 

I don't know if it is still maintained, but if you like to write your own code, it is nice to have an open source software that you can modify at will.

 

Best,

 

jf


  • arushi likes this

#13 arushi

arushi

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 12 Feb 2023

Posted 10 November 2023 - 11:40 AM

Thank you for these resources and examples. Will check them out.



#14 han.k

han.k

    ASTAP Software

  • *****
  • Vendors
  • Posts: 1,184
  • Joined: 09 Mar 2015
  • Loc: the Netherlands

Posted 11 November 2023 - 02:33 AM

I found an other Python based photometry pipeline called AUTOPHOT.  This seems an active project. It can utilize both  aperture photometry and PSF photometry . Differential photometry (instrumental magnitudes)  is extended to absolute photometry using reference catalogs for calibration.  So similar as some pipelines/programs mentioned before. The link is interesting to read since it describes in detail the process and challenges.

 

The development of previous mentioned PHOTOMETRYPIPELINE (PP) pipeline package seems stalled but a good read about it can be found here

 

So both photometry programs and pipelines are available.

 

 



#15 StupendousMan

StupendousMan

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 21 Aug 2005

Posted 11 November 2023 - 07:38 PM

I wrote a package to perform inhomogeneous ensemble photometry on stars in a set of images.   I suggest you use your favorite tool to perform photometry on all the stars in a set of N images, one image at a time, to create a set of N datafiles containing the instrumental magnitudes of the stars in each image.  You can then use the software in 

 

      http://spiff.rit.edu/ensemble/

 

to perform the ensemble solution.  The outputs will be

 

       a) a list of the offsets in zeropoint for each of the N images, relative to one chosen as the reference

       b) a list of the average differential magnitude of each star in the set, relative to the brightest star

       c) for each star, a list of the differential magnitudes in each of the images in which it appears

 

Read the documentation at the URL above to determine if this would meet your needs.  If so, you'll need to compile the code on your own machine; it's written in C.

 

Good luck!



#16 gordtulloch

gordtulloch

    Apollo

  • *****
  • Posts: 1,247
  • Joined: 10 Feb 2005
  • Loc: Winnipeg Canada

Posted 06 December 2023 - 07:45 PM

Plenty of great advice in this thread. Tycho is definitely on my list of software to try. VPHOT, the online analysis software from AAVSO is well worth the cost of membership. Extremely easy to use.

 

I'll add one option to the list, this photometry pipeline written in Python: https://github.com/m...tometrypipeline

 

I don't know if it is still maintained, but if you like to write your own code, it is nice to have an open source software that you can modify at will.

 

Best,

 

jf

That code doesn't run, it seems to have an old version of some of the objects that are missing attributes. I've had an issue in the queue since 2020 with no response so I'd say it's abandonware.



#17 descott12

descott12

    Soyuz

  • *****
  • Posts: 3,933
  • Joined: 28 Sep 2018
  • Loc: Charlotte, NC

Posted 06 December 2023 - 08:22 PM

Thank you everyone for sharing these tips and your experiences with doing multi stars photometry. It will help me in expanding my Python algorithms that were focused on asteroid photometry and offsets (and measuring the success of NASA DART Deflection mission) to exoplanetary/variable stars photometry.

 

More details about ,my asteroid photometry project are available at: https://www.monitorm....com/posts/1393

 

Best regards,

Arushi

VERY IMPRESSIVE!!!!!



#18 erff88

erff88

    Vostok 1

  • -----
  • Posts: 121
  • Joined: 31 Jul 2015
  • Loc: Chicago-area

Posted 15 December 2023 - 01:12 AM

lol.



#19 Xilman

Xilman

    Messenger

  • -----
  • Posts: 413
  • Joined: 26 Feb 2018
  • Loc: Cambridge UK & La Palma (MPC J22)

Posted 31 January 2024 - 05:29 AM

Hello,

 

There are several software (AstroImageJ, Muniwin Siril...) which allow undertaking Differential Photometry of a single star in an image using comparison stars.

 

Has anyone come across a software or algorithms which allow differential photometry of multiple stars (of similar sizes) in the same FITS files at the same time?

 

 

Thank you, in advance.

 

Arushi

 

---

Founder

www.MonitorMyPlanet.com

I use Russ Laher's Aperture Photometry Tool (APT, https://aperturephotometry.org/ ) on uncrowded fields. It implements elliptical apertures as well as circular, which is valuable for photometry of galaxies and (slightly) trailed asteroid images.

 

APT is under active development and Russ is very amenable to implementing enhancements and, especially, fixing bugs. I've contributed to each of these topics. A start has been made on PSF photometry.  It is usable but needs more work before it is really ready for prime time, IMO.

 

Good old fashioned DAOPHOT (I drive it under IRAF) is much better for crowded fields where PSF photometry is essential to deal with blended images. Unlike APT, this centroids images, has a variety of computed PSFs to be used, can generate PSFs from the image itself, and permits PSFs which vary over the image plane. Unfortunately, this package is not entirely user-friendly.

 

Each of the above runs on all major OS, AFAIK. I run them under Ubuntu Linux.

 

Paul

 

APT is under active development and Russ is very amenable to implementing enhancements and, especially, fixing bugs. I've contributed to each of these topics. An



#20 Xilman

Xilman

    Messenger

  • -----
  • Posts: 413
  • Joined: 26 Feb 2018
  • Loc: Cambridge UK & La Palma (MPC J22)

Posted 31 January 2024 - 05:35 AM

More details about ,my asteroid photometry project are available at: https://www.monitorm....com/posts/1393

Impressive results!

 

The BAA ARPS (Asteroids and Remote Planets) section has a very productive team doing asteroidal photometry, concentrating primarily on measuring rotational light curves. They also have an exo-planetary transit effort. Now the moon is out of the way and the sky is dust free again, I will be observing them again.

 

If you haven't heard of them and may be interested in collaborating, drop me a line and I provide more info.

 

ATB,

 

Paul



#21 arushi

arushi

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 12 Feb 2023

Posted 02 February 2024 - 08:59 PM

Hello Paul,

 

Thank you so much for sharing about Russ Laher's Aperture Photometry Tool.

 

I have looked at it, and it seems to meet my needs nicely.

 

I will make sure to download the software and test it out on my images soon!

 

Thanks for suggesting I join the BAA group. I am already a member and am in contact with them.

 

On another note, would you be aware of any list of all binary asteroids and their mutual orbital period apart from the Johnston's Archive.

 

Thank you.

 

Best regards,

Arushi



#22 Xilman

Xilman

    Messenger

  • -----
  • Posts: 413
  • Joined: 26 Feb 2018
  • Loc: Cambridge UK & La Palma (MPC J22)

Posted 03 February 2024 - 06:18 AM

On another note, would you be aware of any list of all binary asteroids and their mutual orbital period apart from the Johnston's Archive.

Can't help with that one, sorry. I suggest that you ask on the ARPS mailing list.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: Software



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics