MPT Catalogs - Examples

Several examples of input catalog formats to be used in the MSA Planning Tool are presented.

On this page

The NIRSpec MSA Planning Tool (MPT) uses catalogs to plan observations for MOS Spectroscopy or target acquisition that uses the NIRSpec Micro-Shutter Assembly.  These source catalogs used in the MPT are ASCII files and can be imported with a few different formats.  If the catalog format is different than what is specified when the load option into MPT, then errors in the automatic column recognition can occur.  For optimal ingest of catalogs into MPT, they should be created with a few simple rules simple rules in mind:

  • Two columns are required for the equatorial celestial coordinates (J2000) RA and Dec for each source. These can be expressed in units of degrees or in hexadecimal format. 
  • It is useful for at least one column to have the source fluxes or magnitudes (optional field). 
  • The catalog may optionally contain a line at the top of the file indicating column headers separated by whitespace. The line must begin with a "#".
  • Other columns can be included and used by the tool for creating candidate sets if properly identified during ingest (e.g. an optional column of source weights.)

Here we provide some examples of acceptable catalogs. Only the first three sources in each Catalog are listed as example.

NOTE: The column "Reference" in the below catalog examples is used to designate a source as a candidate NIRSpec target acquisition reference object.  Inclusion of this column is not needed for proposals, but will be required for flight-ready program updates for NIRSpec MOS or target acquisition observations. 



White space separated values

Each column element has to be separated by a white space. Example catalogs 1 - 6 are included below.

Catalog 1

# RA

Dec

53.16054039

-27.79774121

53.17103742

-27.78765924

53.16553235

-27.77259145


Catalog 2

# ID    

RA

Dec

1

53.16054039

-27.79774121

2

53.17103742

-27.78765924

3

53.16553235

-27.77259145


Catalog 3

# RA

Dec

Weight

53.16054039

-27.79774121

100

53.17103742

-27.78765924

1

53.16553235

-27.77259145

100


Catalog 4

# RA

Dec

MAG_F160W

MAGERR_F160W

53.16054039

-27.79774121

17.85

0.01

53.17103742

-27.78765924

19.21

0.10

53.16553235

-27.77259145

20.10

0.05


Catalog 5

# RA

Dec

MAG_F160W

MAGERR_F160W

Reference

53.16054039

-27.79774121

17.85

0.01

FALSE

53.17103742

-27.78765924

19.21

0.10

FALSE

53.16553235

-27.77259145

20.10

0.05

TRUE


Catalog 6

# RA

Dec

MAG_F160W

MAGERR_F160W

Reference

Stellarity

53.16054039

-27.79774121

17.85

0.01

FALSE

0.15

53.17103742

-27.78765924

19.21

0.10

FALSE

0.33

53.16553235

-27.77259145

20.10

0.05

TRUE

0.98



CSV - Comma Separated Values

Each column element has to be separated by a comma (,).  Example catalogs 1 and 2 are included below.

Catalog 1

# RA

,

Dec

53.16054039

,

-27.79774121

53.17103742

,

-27.78765924

53.16553235

,

-27.77259145


Catalog 2

# ID    

,

RA

,

Dec

1

,

53.16054039

,

-27.79774121

2

,

53.17103742

,

-27.78765924

3

,

53.16553235

,

-27.77259145



TSV - Tab Separated Values

Use the tab key on a your keyboard to separate the column elements in each column.  An example catalog is included below.


Catalog 1

# RA

<tab>

Dec

53.16054039

<tab>

-27.79774121

53.17103742

<tab>

-27.78765924

53.16553235

<tab>

-27.77259145



VOT - Virtual Observatory Table

VOTables are XML format files that contain astronomical data. More information on the format for VOT tables can be found in the website of the International Virtual Observatory Alliance

Using Aladin

The Aladin tool can export catalogs to VOTable. In order to export a catalog already imported in Aladin as a VOTable, with the Aladin viewer active simply do:

File >> Export planes (FITS, VOTables, ...) 

and select the output name for the catalog.  

Using astropy.io.votable

The astropy sub package astropy.io.votable allows users to read and write VOTable XML files.

Example

Use the file vot-catalog.xml as an example catalog in the VOT format.




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