The early (1996-2001) Black & White and Color images displayed
in this web page were obtained with an
Apogee AP7 camera (or its
predecessor, the HPC-1 camera) running under
MaxIm DL/CCD
(Cyanogen Productions). The only image processing used for
the majority of the images was conversion of raw CCD FITS format
images (after appropriate bias, dark, and flat field processing)
into Red (R), Green (V), Blue (B), and Infrared (I) or Black &
White grayscale Tiff images in Mira (Axiom
Research), MaxIm DL/CCD, or
CCDSoft.
For color imaging, the R, V, B, and, in some cases the I,
grayscale images were then combined in Adobe PhotoShop to produce color Tiff and JPEG images.
The R, V, B, and I filters are STANDARD
JOHNSON-COUSINS PHOTOMETRIC FILTERS. Therefore, there is
usually excellent color rendition that accurately reflects the color
emission of the objects imaged, and there is no need to worry
about infrared leakage through the filters. Moreover, the
separate R, V, B, and I images contain potential valuable
professional photometric data. All raw
data is saved, because the Observatory's images have the
potential for later scientific study.
The Grasslands Observatory now uses a large format CCD camera
for much of its imaging at the f/5 focus of the 24-inch
telescope. 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. 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).
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 is performed using a Luminance
technique with Open or Clear exposures used for the Luminance
(L) part of the color composition.
In late 2007 a Quantum
Scientific Imaging (QSI) 532 CCD was acquired with an LRGB
filter set as well as a hydrogen alpha filter all residing in
the QSI 532 internal color wheel. The QSI 532 CCD has a
Kodak KAF-3200ME 2184 x 1472 chip with 6.8 micron pixels.
This camera can give very high resolution images with the
24-inch telescope, but guiding is critical, and 2x2 binning is
sometimes used for imaging. Typical exposures for black
and white pictures are 5-minute single exposures or three to ten
5-minute exposures median combined. For color imaging, the
black and white exposures are combined with 5 minute or longer
exposures through red, green, and blue, or hydrogen alpha
filters.
Recent equipment upgrades also 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
is done with a Canon 20da digital camera back or the
QSI 532 CCD camera. The Canon 20da or the QSI 532 can
also be used with a Takahashi Epsilon 180 Astrograph
which is sometimes mounted on
the 24-inch telescope. Moreover, in early January 2007 a
Celestron C-14 with exquisite optics was permanently mounted
inside of the observatory building. This
telescope is used for visual observing and web cam imaging of
the Moon and Planets.
tbh 18 April 2010
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