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Astrophotography by Bob Franke

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NGC 281 - The Pacman Nebula - Color Mapped


      Click the full screen zoom button           ^
     
Click the image to Zoom and Pan              

Click here to view the image without Zoomify (1800 x 1300)  

 
 


      Click the full screen zoom button           ^
     
Click the image to Zoom and Pan              

Click here to view the image without Zoomify (1860 x 1300)    

Instrument

12.5" RCOS @  ~f/9 (2880 mm fl) 0.643 arcsec / pixel.  Zoomify image scale is 1.28 to 3.33 arcsec / pixel.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ internal filter wheel, AstroDon 6nm Filters

Acquisition Data

8/26/2009 to 10/16/2009 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.

Exposure

SII   540 min. (18 x 30 min. bin 1x1)

Ha   450 min. (15 x 30 min. bin 1x1)
OIII  540 min. (18 x 30 min. bin 1x1)

RGB  270 Min  ( 6 x 15 min. each, bin 1x1)

 

SII,Ha & OIII are mapped to RGB respectivly. 

An RGB overlay of star colors was added.


Click here for an RGB natural color version.

Click here for an Ha filtered b/w version.

Software

CCDSoft, CCDStack, Photoshop CS w/ the Fits Liberator plugin and Noel Carboni's actions.

PixFix32 (pre-beta) to repair hot/cold pixels and column defects.

CCDStack to calibrate, register, normalize, data reject, combine the sub exposures.

PhotoShop for on-linear stretching.

Comment

North is to the left.

NGC 281 is an HII region in the constellation of Cassiopeia. It includes the open cluster IC 1590, the double star HD 5005, and several Bok globules. NGC 281 is about 10,000 light-years away. Sometimes called the Pacman nebula, because when viewed though a telescope it resembles the video game character.

This false color image was acquired with Ha, SII and OIII filters mapped to the RGB channels respectively. The colors of top image more closely follow the Hubble Palette. The presence of sulfur, hydrogen and oxygen are more clearly shown. Red indicates the presence sulfur, green hydrogen and blue oxygen. With no color manipulation, the image would be basically green, due to the dominance of hydrogen.

The lower image was severely processed to produce ever popular orange and blue colors, but still reveals a similar structure to the nebula.