# Star Charts

How to create a star chart from a catalogue provided by Virtual Observatory.

# Open Cluster NGC 637

NGC 637 is an open cluster in Cassiopeia. Stars are distributed randomly but the look is similar to upside-down silhouette of owl: Wings are spread and two brighter stars placed to its head suggests big eyes. The cluster is looking pretty good in a binocular.

## Catalogue Search

To get coordinates of NGC 637, we are searching a selected catalogue UCAC5 with center α = 25.775° and δ = 64.03° and the cone radius 0.1°:

    $ munipack cone -o ngc637.xml -c UCAC5 -r 0.1 -- 25.775 64.03

All found stars are saved to VOTable (Virtual Observatory transfer table).

## Plotting

The output VOTable can be converted to SVG and be used for drawing of star charts:

    $ munipack votable -o ngc637.svg -pa 25.78 -pd 64.03 -ps 2000 -ml 12 \
             --col-mag f.mag --col-ra RAJ2000 --col-dec DEJ2000  ngc637.xml
    $ firefox ngc637.svg

Open Cluster NGC 637 (file)

## Tips

- Best viewed with Internet browsers (Firefox, Chrome).
- Try interesting regions like globular clusters, neighborhood of bright galaxies
- SVG format is a kind of XML format and can be easy modified: added text descriptions, graphics elements like axes, etc.
- The output can be easy included to web pages.

## See Also

- VOTable
- Cone Search