Processing Images – NGC 6618 (Part 1 of 3)

One of the nebula visible from Sydney at the moment is NGC 6618, or M17. It is also known as either the Omega Nebula or the Swan Nebula or the Horseshoe Nebula.

The Swan Nebula as we will call it is the next target of our image processing. This could be an interesting one to process and the result is not certain after looking at the exposures as shown below. The exposures range from red on the left, green in the middle and blue on the right.

As you can see most of the detail of the Nebula appears to have been captured by the Hubble using the red filter F814W. So it would appear that this nebula will be predominantly red in color.

Interestingly enough there are images of NGC 6618 which show Hubble images of the nebula as being either red or in some cases a blue-green sort of color. This would be no doubt due to the type of filters that they are using for each image and the blue-green images are a lot more detailed.

Different filters would be selected depending on what detail they are tryng to capture from the object. Hydrogen clouds for example would be captured using a red filter.

NGC 6618 exposures 2002-04-01 (Click to Enlarge)

/ TARGET INFORMATION
TARGNAME= ‘NGC6618                       ‘ / proposer’s target name
RA_TARG =   2.751404166667E+02 / right ascension of the target (deg) (J2000)
DEC_TARG=  -1.615671111111E+01 / declination of the target (deg) (J2000)

DATE-OBS= ‘2002-04-01′         / UT date of start of observation (yyyy-mm-dd)

TIME-OBS= ’19:06:42’           / UT time of start of observation (hh:mm:ss)

EXPSTART=       52365.79632543 / exposure start time (Modified Julian Date)

EXPEND  =       52365.80050298 / exposure end time (Modified Julian Date)

EXPTIME =                360.0 / exposure duration (seconds)–calculated

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~ by sydneystargazers on July 3, 2010.

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