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Sky Charts 


Galaxies observation : M84 and M86

First we produce a large scale chart to locate the galaxy field using the telescopes finder telescope.

  • Click "Catalog parameters"  then  "Stars" page. 
    • Check the TYCHO catalog box (or SKY2000 if not installed). Verify that "Field min" =0, and "Field max" =30. 
    • Check "Limit" box in "Star magnitude limit". Enter the upper magnitude that you can easily see in your finder ( i.e. 9 ) in the "8-15°" column and  that of your telescope( i.e. 12)  in the "0-7°".
    • Select  "Nebulae" page. 
    • Check "3' Ref. Cat. Bright Galaxies" catalog box. Verify that "Field min"=0, and "Field max"=90. 
    • Check the "Limit" box in "Nebulae size limit". For "8-15°" column enter "magnitude 11" and "size 1". For "0-7°" column enter "magnitude 14" and "size 0.1".
    • Click "OK". 
  • Click "Star appearance
    • Enter the field of view of your finder and telescope in arc minutes. (i.e. 300 and 30). Leave the third field blank if not used.
    • Click "OK".
  • Click "Show Eyepiece" 
  • Click "Field width"  
    • Drag cursor to "+10° 0' ". 
    • Click "OK". 
  • Click "Find"  
    • Select "Messier". 
    • Then in "Cat. Id." enter 84. 
    • Click "OK". 
The following screen will be displayed: 

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This chart will allow identification of the objects visible in the finder without adding confusion from objects that are too faint.

You can print this chart on paper using , or save it in a format useable for a later reload to the program using , or copy to clipboard or save as image file using 

To identify all the galaxies visible in the telescope we need a more detailed chart. As we have already preset the catalog value in the first operation, this is an easy task :

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The inner circle in the galaxy drawing shows the "effective aperture", the circle centered on the nucleus within which one-half of the total B-band flux is emitted. It gives a better approximation of the size of the galaxy as seen in a small telescope than the external ellipse that shows the isophotal diameter at surface brightness level  25 B/mag2.
On this scale it will be interesting to use a more detailed star catalog such as Tycho-Input, Guide Stars or USNO-A. Click "Catalog parameters"  to change the active catalog and limiting magnitude. When the parameters are correct for your telescope, you can record it by clicking "Save" and give a name to the file (i.e. "LX200.opt"). Remember not to show too many faint objects as the chart should remain simple for use at the telescope.

To obtain a list of all object in this field, simply click 

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