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Grasslands Observatory: NGC & IC Objects
 
NGC4038/4039

Color images of NGC objects, IC objects, and objects in other assorted catalogs have been obtained with the 24-inch f/5 reflector at the Grasslands Observatory from 1996 to the present. The early images were taken either with a Spectra Source HPC-1 CCD camera or with an Apogee AP7 CCD camera. The HPC-1 contains a Texas Instruments chip with 1024 x 1024 twelve micron pixels. It is a very good camera and works reasonably well for Tri-Color CCD imaging using Photometric R, V, B, and I filters (see discussion in Image Gallery), but its overall sensitivity and quantum efficiency is less than the Apogee AP7 camera, especially in the blue portion of the spectrum. The Apogee AP7 contains a SITe 24micron 512 x 512 CCD chip that has excellent quantum efficiency throughout the visible spectrum and into the near-infrared portion of the spectrum.
 
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AP7 CCD camera attached to the 24-inch telescope at the Grasslands Observatory. Notice also the Isis FW1 filter wheel and JMI digital electric focuser.

Exposures typically ranged from R = 1 minute, Green (V) = 1 minute, B = 1.5 minutes to R = 4 minutes, Green (V) = 4 minutes, and B = 6 minutes for the Apogee AP7 camera. Exposures for the HPC-1 camera were somewhat longer, especially in Blue (B). In general, short exposures were used for bright clusters, and long exposures were used for faint galaxies and nebulae. For some objects, clear exposures were also taken and added to the exposures through the photometric filters to produce a final color image.

The Grasslands Observatory now has a large format CCD camera. In March 2001, a Finger Lakes Instrumentation Dream Machine CCD camera was installed at the observatory. This camera has a high quantum efficiency SITe 1024 x 1024 twenty-four micron CCD chip. It provides a nearly 28 minute field of view on the 24-inch f/5 reflector at the Grasslands Observatory. The Dream Machine is used in operation with a Finger Lakes Instrumentation CFW-1 Color Filter Wheel and an Optec TCF temperature compensating focuser. The filter wheel contains Photometric R, V, and B filters and also has an Open slot (O). This instrument combination is now used for most of the imaging at the Grasslands Observatory.

Exposures typically range from R = 1 minute, Green (V) = 1.5 minutes, B = 2 minutes, and O = 1-2 minutes to R = 4 minutes, Green (V) = 6 minutes, B = 8 minutes, and O = 5-20 minutes for the Dream Machine CCD camera. Short exposures are used for bright clusters, and long exposures are used for faint galaxies and nebulae. Most color imaging now is performed using a Luminance technique with Open of Clear exposures used for the Luminance (L) part of the color composition.
 
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Dream Machine CCD Camera combined with a Finger Lakes CFW-1 Color Filter Wheel

Recent equipment upgrades include an 8-inch f/4 Meade LXD55 Schmidt-Newtonian telescope which has been mounted onto the side of the 24-inch telescope. Imaging through the 8-inch telescope can be done with a new Nikon D100 CCD camera back, a Nikon F1 film camera back, or an Apogee KX260 CCD camera. In addition, a Takahashi Epsilon 130 Astrograph is available for mounting on the 24-inch telescope.
Main | NGC: 1 - 3600 | NGC: 3601 - 7840; IC Objects | Back to top
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