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Richard McMahon, 02/12/2014 11:51 AM

SVA1 Data Analysis

This wiki page will record information gleaned from the biweekly Monday SVA1 Analysis telecon. In the end, this will build up a compilation of best-practices and systematics for different magnitudes; star/galaxy separation; photometric zeropoints; masking; etc.

Telecon Information

Call-in instructions:

1. Dial Toll-Free Number: 866-740-1260 (U.S. & Canada)
2. International participants dial:
Toll Number: 303-248-0285
Or International Toll-Free Number:

UK: 0800 496 0576
3. Enter your 7-digit access code, followed by “#”

Your access code: 7691719

Agenda And Minutes for 10/14, 10am CDT
Agenda And Minutes for 10/28, 10am CDT
Agenda And Minutes for 11/11, 10am CST
Agenda And Minutes for 11/25, 10am CST
Agenda And Minutes for 12/09, 10am CST
Agenda And Minutes for 12/18, 10am CST
Agenda And Minutes for 1/22, 10am CST
Agenda And Minutes for 2/3, 10am CST

Gold Catalog v1.0

The SVA1 Gold Catalog v1.0 is described here.

Punch List

SVA1 Catalog Punch List

Which Magnitudes?

DETMODEL for colors...

Star/Galaxy Separation

The SG separation challenge.

On this page, you can find some results of tests on the COSMOS field, including star/galaxy separation.

Some studies on star/galaxy separation for final cut and coadd objects in the SN fields S/G SVA1 SN fields

Some interesting spread model maps are at Spread Model Maps

And A Modest Proposal for Preliminary Star/Galaxy Separation (Eli)
With Bright Galaxy Impurity
And Bright Star Spread Model Issues.

Problematic issues when Comparing to Homogenized Coadds
And a follow up on Comparing Photometry to Homogenized Coadds

Photometric Zeropoints

Currently, Bob Armstrong's SLR zeropoints have been tested and work reasonably well, but finer scale SLR is being worked on.

Survey Masks

On this page, you can find the links to Mangle info.

Translating Mangle Masks Into Data Units

Galaxy depth and completeness using Mangle Mask

Sub-Pixelizing Mangle Masks

Cosmic ray rejection from catalogues

I might be useful to have the peak intensity value at xpeak, ypeak [Richard McMahon]

Coadd catalogue objects provenance

Coadd catalogue provenance link to input catalogue files. It would be useful to have the source id from
the input catalog files



TTYPE1 = 'NUMBER ' / Running object number

This would allow joins between COADD_OBJECTS and OBJECTS_CURRENT and allow end-to-end checks.

OBJECTS_CURRENT has columns called:


Coadd catalogue objects deblending information

It would be useful to know which objects are members of a blend so that one can
determine the magnitude difference and pairwise separattions so that the effect of
blending can be estimated.

Other DESDM COADD catalogues oddities

There are columns without the waveband identified


Image shape parameters


but we have THETA_IMAGE_[GRIZY] but not A_IMAGE, B_IMAGE

Ellipticity seem to be missing.


flux_psf values are in object catalogues but not in the coadd table

Other Pages

Regions of Bad Photometry
Bad Photometry Maps
An Ugly Image
On the Bias Jumps
Some tests on depth with Mangle Mask
Tile dependence of star-galaxy classification

Column documentation at DESDM users group wiki page: