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Astrophotography by Bob Franke

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R Leporis - Carbon Star

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Click the image for an ~ 50% size view. (1800 x 1200 - 735 KB)

Instrument

12.5" RCOS @ ~ f/9 (2880 mm fl) at 0.64 arcsec/pixel. Shown at 1.32 and 3.16 arcsec/pixel.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ FW8 filter wheel & AstroDon Gen-2 RGB filters.

Acquisition Data

6/11/2011 to 7/2/2011 Chino Valley, AZ. with CCDAutoPilot3 & CCDSoft.  AOL guided

Exposure

RGB

480 min (40 x 4 min. each channel) Bin 1x1

eXcalibrator RGB ratios are 1.00, 1.08 & 1.26

Software & Processing Notes

  • CCDSoft, CCDStack, PixInsight, Photoshop CS6.

  • eXcalibrator v5.0 for (g:r) color balancing, using 63 stars from the APASS database.

  • CCDBand-Aid to repair KAI-11000M vertical bars.

  • CCDStack to calibrate the sub exposures.

  • PixInsight to register, normalize, data reject, stack, create the RGB, gradient removal and non-linear stretching with HistogramTransformation.

  • PhotoShop for the final touch-up.

Comment

North is to the top.

R Leporis, sometimes called Hind's Crimson Star, is a variable star in the constellation Lepus. Its magnitude varies from +5.5 to +11.7, with a period of 427 days. Being a carbon star, it appears distinctly red. As the star dims it becomes visually redder.

With its two bluish neighbors, R Leporis presents a spectacular view with a small telescope.

To objectively quantify star color, astronomers use the B-V color index. To obtain this value, they use B (blue) and V (visual or essentially green) filters. The color index is obtained by simply subtracting the V magnitude from the B. Blue-white Spica has a BV index of 0.3 and our slightly yellow Sun is at +0.65. R Leporis is very red, with a B-V value of +5.7.