Creating a Finder Chart.

This form will create a "finder chart", a map of a small area of the sky that is very useful in locating objects at the controls of a telescope. You enter the coordinates of the chart's center, the size of the chart in degrees, the size you want it to show on your computer, and the minimum brightness of the variable stars to plot on the chart.

Field Details:

Coordinates:

  • RA: The right ascension of the Chart's center. Format: HH:MM:SS.ss
  • Dec: The declination of the Chart's center. Format: DD:MM:SS.ss
Or you can enter an object and Finder Chart will attempt to find the object for you and create a chart centered on your object. The object can be an NGC item, a Struve double star or a variable star. Fill in the NGC number, the Struve number or the variable start designation. If these items are in the database, a finder chart will be created. If not, an error message asks you to go back and try again.

Other field parameters:
  • Chart size, in degrees: The number of degrees the chart spans. 3, for example, creates a 3x3 degree chart.
  • Chart size, in pixels: The number of pixels the chart spans on your screen. 900, for example, creates a 900x900 pixel chart.
  • Show only variables with maxima brighter than nth magninude: The minimum brightness a variable's maximum must reach to be plotted on the chart.
  • Show an eyepiece field of MM arc minutes: This inscribes a cirlce of MM arcminutes in the center of your chart. Allowable values are between 5 arc minutes and the edge of your field. The default value is 60 arc minutes, one degree.
  • The chart can either show dark stars on a light background, or light stars on a dark background (default).

Notes:

  • Cooordinates (RA & Dec) are epoch J2000 (As the sky was at the beginning of this millenium)
  • The default coordinates will make you a chart of the Pleiades.
  • This is a work in progress. Suggestions and comments are welcome. Please drop me a line.

The charts include data from the following catalogs:

  • Bright star (GSFC, NASA)
  • GCVS, Variable stars (Sternberg Instutute, Moscow)
  • WDC, Double stars (US Naval observatory)
  • SAO, Stars brighter than 10th mv (SAO)
  • NGC, Bright nebulae, clusters and galaxies (NGC/IC Project LLC)
  • Hipparcos, Stars brighter than 12th mv (US Naval observatory)