# \#photometry **URL:** https://www.rubin.community/tag/photometry/65.md [Latest](https://www.rubin.community/latest.md) · [Categories](https://www.rubin.community/categories.md) · [Tags](https://www.rubin.community/tags.md) --- ## [Clarification question on DP1 Object schema for aperture photometry](https://www.rubin.community/t/clarification-question-on-dp1-object-schema-for-aperture-photometry/11938)
**Author:** [@talister](https://www.rubin.community/u/talister)\ **Replies:** 1\ **Last updated:** [May 4, 2026, 5:38pm UTC](https://www.rubin.community/t/clarification-question-on-dp1-object-schema-for-aperture-photometry/11938 "2026-05-04T17:38:05Z")
Hopefully quick question: In the DP1 Object Schema there are a series of columns of the form {ugrizy}\_apXXFlux where XX is 03, 06, 12 etc e.g. g\_ap03Flux which have the description "Flux within 3.0-pixel aperture. Forced… --- ## [Problem with Getting started tutorial part 6 "forced photometry"](https://www.rubin.community/t/problem-with-getting-started-tutorial-part-6-forced-photometry/11031)
**Author:** [@Liuhy](https://www.rubin.community/u/Liuhy)\ **Replies:** 3\ **Last updated:** [November 5, 2025, 12:04am UTC](https://www.rubin.community/t/problem-with-getting-started-tutorial-part-6-forced-photometry/11031 "2025-11-05T00:04:32Z")
Hi, I’m just beginning to learn LSST scipipe and currently I’m trying to follow the Getting started part 6: measuring sources, and I meet some problems in section “Running forced photometry on coadds”. Everything was OK … --- ## [Color conversion between LSST and SDSS broad band filters](https://www.rubin.community/t/color-conversion-between-lsst-and-sdss-broad-band-filters/8668)
**Author:** [@Vibhore](https://www.rubin.community/u/Vibhore)\ **Replies:** 1\ **Last updated:** [June 5, 2024, 5:28pm UTC](https://www.rubin.community/t/color-conversion-between-lsst-and-sdss-broad-band-filters/8668 "2024-06-05T17:28:54Z")
Hi, I am looking for any direct conversion between LSST filters to SDSS filters or vice versa, (simple transformation linear relations between m\_sdss and m\_lsst). Do any such relations exist ? Regards, Vibhore --- ## [Doubts on uncertainties estimation for very faint objects](https://www.rubin.community/t/doubts-on-uncertainties-estimation-for-very-faint-objects/8052)
**Author:** [@FabioRagosta](https://www.rubin.community/u/FabioRagosta)\ **Replies:** 1\ **Last updated:** [November 8, 2023, 9:46am UTC](https://www.rubin.community/t/doubts-on-uncertainties-estimation-for-very-faint-objects/8052 "2023-11-08T09:46:31Z")
Hi all, I am wandering if any discussion on how to estimate very faint objects’ magnitude error has been done. I have performed an exercise to retrieve a light curve of faint injected afterglow. However when using the f… --- ## [Aperture photometry with non detected sources](https://www.rubin.community/t/aperture-photometry-with-non-detected-sources/6454)
**Author:** [@Paula](https://www.rubin.community/u/Paula)\ **Replies:** 8\ **Last updated:** [October 13, 2022, 2:14pm UTC](https://www.rubin.community/t/aperture-photometry-with-non-detected-sources/6454 "2022-10-13T14:14:50Z")
Hi everyone :slight\_smile: I’m attempting to do aperture photometry on some Difference Images that I processed using the pipeline. I’ve seen some references, and it seems that the way to go is to calculate the flux from… --- ## [PhotoCalib has replaced Calib: welcoming our nanojansky overlords](https://www.rubin.community/t/photocalib-has-replaced-calib-welcoming-our-nanojansky-overlords/3648)
**Author:** [@parejkoj](https://www.rubin.community/u/parejkoj)\ **Replies:** 4\ **Last updated:** [September 30, 2022, 5:36pm UTC](https://www.rubin.community/t/photocalib-has-replaced-calib-welcoming-our-nanojansky-overlords/3648 "2022-09-30T17:36:24Z")
With the merger of DM-17029 and DM-10156, the LSST Science Pipelines now provides calibrated fluxes in units of nanojansky (nJy), internally uses reference catalogs in nJy, and uses afw.image.PhotoCalib to manage the pho… --- ## [PhotCal outside of the PS footprint](https://www.rubin.community/t/photcal-outside-of-the-ps-footprint/6923)
**Author:** [@tdboer](https://www.rubin.community/u/tdboer)\ **Replies:** 3\ **Last updated:** [September 22, 2022, 1:59am UTC](https://www.rubin.community/t/photcal-outside-of-the-ps-footprint/6923 "2022-09-22T01:59:24Z")
I have obtained some deep HSC data for a target that turns out to be partly outside of the footprint of the ps1\_pv3\_3pi\_20170110 ref\_cat (Sgr dwarf), and this is obviously leading to problems in single visit processing … --- ## [Producing LSST mags from partial SED](https://www.rubin.community/t/producing-lsst-mags-from-partial-sed/6918)
**Author:** [@RShA](https://www.rubin.community/u/RShA)\ **Replies:** 6\ **Last updated:** [August 1, 2022, 10:54am UTC](https://www.rubin.community/t/producing-lsst-mags-from-partial-sed/6918 "2022-08-01T10:54:55Z")
Hi, I’ve been trying to use rubin\_sim.photUtils.Sed.calcMag on real-life spectra and I discovered behaviour that seems strange to me. If I try to calculate mags on a SED that does not completely overlap in wavelengths w… --- ## [How to predict magnitudes from spectra](https://www.rubin.community/t/how-to-predict-magnitudes-from-spectra/6561)
**Author:** [@jgizis](https://www.rubin.community/u/jgizis)\ **Replies:** 1\ **Last updated:** [May 17, 2022, 3:46am UTC](https://www.rubin.community/t/how-to-predict-magnitudes-from-spectra/6561 "2022-05-17T03:46:45Z")
I was wondering if there is an official (preferably Python) tool to compute synthetic LSST photometry given a spectrum. --- ## [Questions about jointcal photometry patterns](https://www.rubin.community/t/questions-about-jointcal-photometry-patterns/4960)
**Author:** [@sfu](https://www.rubin.community/u/sfu)\ **Replies:** 11\ **Last updated:** [May 24, 2021, 10:59pm UTC](https://www.rubin.community/t/questions-about-jointcal-photometry-patterns/4960 "2021-05-24T22:59:36Z")
Dear all, we are using DM v19 to process some DECam data from raw, and compare the photometry (PSF mag) with DES. We use SkyMapper or PS1 (stars) as the photometric reference catalog, and Gaia as the astrometric referenc… --- ## [Incorrect reference magnitude errors from PhotoCalTask](https://www.rubin.community/t/incorrect-reference-magnitude-errors-from-photocaltask/3581)
**Author:** [@parejkoj](https://www.rubin.community/u/parejkoj)\ **Replies:** 1\ **Last updated:** [February 7, 2019, 2:02pm UTC](https://www.rubin.community/t/incorrect-reference-magnitude-errors-from-photocaltask/3581 "2019-02-07T14:02:33Z")
In DM-13054, I refactored PhotoCalTask to make Colorterms more useable by other code. This necessitated pulling the code that extracted the flux and fluxErr from the cross-matched reference catalog and computed the color… --- ## [PhotoCalib is now defined in terms of nanojansky](https://www.rubin.community/t/photocalib-is-now-defined-in-terms-of-nanojansky/3508)
**Author:** [@parejkoj](https://www.rubin.community/u/parejkoj)\ **Replies:** 0\ **Last updated:** [December 27, 2018, 8:59pm UTC](https://www.rubin.community/t/photocalib-is-now-defined-in-terms-of-nanojansky/3508 "2018-12-27T20:59:05Z")
I just merged DM-16650, which has redefined PhotoCalib to be a conversion from counts-\>nanojansky. For several reasons, this necessitated breaking backwards compatibility with old persisted PhotoCalibs objects, so if you… --- ## [Jointcal available for beta testing](https://www.rubin.community/t/jointcal-available-for-beta-testing/1685)
**Author:** [@parejkoj](https://www.rubin.community/u/parejkoj)\ **Replies:** 12\ **Last updated:** [March 3, 2017, 10:22pm UTC](https://www.rubin.community/t/jointcal-available-for-beta-testing/1685 "2017-03-03T22:22:08Z")
Jointcal is now available for beta testing. Jointcal is a package for performing simultaneous astrometric and photometric fitting of multiple visits of the same field to determine the optical distortions and photometri… --- ## [How do I do forced-photometry on a set of RA, Dec](https://www.rubin.community/t/how-do-i-do-forced-photometry-on-a-set-of-ra-dec/1074)
**Author:** [@mwv](https://www.rubin.community/u/mwv)\ **Replies:** 13\ **Last updated:** [March 3, 2017, 6:02pm UTC](https://www.rubin.community/t/how-do-i-do-forced-photometry-on-a-set-of-ra-dec/1074 "2017-03-03T18:02:40Z")
If I have a set of RA, Dec (e.g., a 2-column text file with RA, Dec in decimal degrees), what are good ways to perform forced-photometry at those RA, Dec positions on an image that has been astrometrically and photometri… --- ## [Notes from jointcal photometry discussion](https://www.rubin.community/t/notes-from-jointcal-photometry-discussion/1505)
**Author:** [@parejkoj](https://www.rubin.community/u/parejkoj)\ **Replies:** 2\ **Last updated:** [January 3, 2017, 10:28pm UTC](https://www.rubin.community/t/notes-from-jointcal-photometry-discussion/1505 "2017-01-03T22:28:31Z")
Notes a discussion about jointcal photometry These are notes I took during a conversation between @KSK, @RHL, @jbosch, and @parejkoj about how to move forward on how to output jointcal's fitted results, what we need to … --- ## [Reference catalog notes](https://www.rubin.community/t/reference-catalog-notes/715)
**Author:** [@price](https://www.rubin.community/u/price)\ **Replies:** 9\ **Last updated:** [December 21, 2016, 10:23pm UTC](https://www.rubin.community/t/reference-catalog-notes/715 "2016-12-21T22:23:35Z")
Here are a few notes about astrometry/photometry reference catalogs: If you're using the sdss-dr9-fink-v5b astrometry.net catalog (SDSS DR9 with photometric corrections by Doug Finkbeiner), there is a paper you can re… --- ## [How do I use color terms when calibrating fluxes?](https://www.rubin.community/t/how-do-i-use-color-terms-when-calibrating-fluxes/93)
**Author:** [@jsick](https://www.rubin.community/u/jsick)\ **Replies:** 2\ **Last updated:** [August 28, 2015, 3:48pm UTC](https://www.rubin.community/t/how-do-i-use-color-terms-when-calibrating-fluxes/93 "2015-08-28T15:48:54Z")
How do I use color terms when calibrating fluxes? --- ## [How do I get a zeropoint for a particular sensor from the Butler?](https://www.rubin.community/t/how-do-i-get-a-zeropoint-for-a-particular-sensor-from-the-butler/94)
**Author:** [@jsick](https://www.rubin.community/u/jsick)\ **Replies:** 3\ **Last updated:** [August 20, 2015, 5:40pm UTC](https://www.rubin.community/t/how-do-i-get-a-zeropoint-for-a-particular-sensor-from-the-butler/94 "2015-08-20T17:40:01Z")
Does anyone know how I get a zeropoint for a particular sensor from the butler?