|John Feldmeier||Chris Mihos|
|Paul Harding||Heather Morrison|
Images taken on the Kitt Peak National Observatory 2.1 meter telescope in Arizona.
Bias Subtraction and trimming:Using IRAF tools, we removed the electronic pedestal level from all the images and trimmed off the overscan region. more
Zero combination and subtraction: We combined the zero frames for each of the four nights and used IRAF again to smooth out the underlying bias structure which was not removed by the bias subtraction.more
Flat fielding: We combined the flat-field exposures and flattened the data. This initial flatfielding was enough for our first run of image analysis, but a more sophisticated flat-fielding procedure was required to bring the images to the necessary photometric quality. more
With the aid of CWRU post-doc Denise Hurley-Keller, we utilized an IRAF script to produce better sky flats for our flat-fielding. Each iteration of this script produces a sky flat to be used for flat-fielding the cluster images. Successive iterations improve on the quality of this flat. more
Preliminary Image analysis: The images were visually inspected and catalogued. We weeded out any out-of-focus or otherwise unusable images. more
Cluster Image combination: We have combined the images of each cluster into composite images. We began by sky-subtracting the flat-fielded images. We then recorded reference stars in each cluster and marked the coordinates of those stars in each image. This allowed us to shift the images so that they shared a common coordinate system. The images were stacked and added together. more
This page created and maintained by Steve Rodney, CWRU.
Last updated on ... January 18, 2001