Photo Gallery
Follow the links under "Photo Index" to view photographs of celestial
objects made by members of the Bluegrass Amateur Astronomy Club. Click on
thumbnails to see a full-sized photograph. To find out more about the
photographs, follow the links under "How They Were Made."
To obtain the color images, we used a new quad-color technique.
Previously, to get a color image, we had to take 3 images through
three color filters (red, green, and blue), and then combine them
into a full tri-color image. The problem was that the filters
blocked a lot of light, so the resulting single-color images along
with the resulting tri-color composite was weak and grainy.
Technically, there was a poor signal-to-noise ratio. The relatively
slow C-14 (it is also not multicoated) just couldn't punch enough
light through the filters. The black-and-white unfiltered image
of the same object was much deeper and smoother looking, so we
decided not to do color.
However, we tried a new technique called LRGB (luminance, red,
green, blue) whereby the color of each pixel is determined by the
tri-color RGB composite...but the luminance (or brightness) of each
pixel is determined by a deep, unfiltered exposure. So, theoretically,
a full color image with the same strength, depth, and smoothness
as a black-and-white image could be obtained. In practice, the
unfiltered exposure is still stronger, because we are forced to
use an infrared blocking filter in-line with each of the 4 LRGB
images (to get a correct color balance). Since the CCD chip is
very sensitive in the infrared, this is a significant loss of total
light. Another disadvantage of LRGB is having to take 4 images,
4 flat fields, and 2 dark frames (for a total of 10) instead of 1
image, 1 flat field, and 1 dark frame (for a total of 3) for each
object.
Still... not too bad for imaging 1000 feet from Palomar shopping center!
(the location of Dr. George Dozier's
Lexington Observatory,
where the CCD images were made)
On the evening of April 7, 1999, Two back-to-back images of the
comet were imaged through a 200 mm f/3.3 telephoto lens riding
piggyback on a motor driven Schmidt-Cassegrain telescope. The film
used was Fujicolor Super-G 800. The exposure times were 9 minutes
each. The location was Shaker Village, KY. The film was developed
at a local 1-hour photo shop. The negatives were directly scanned
on a high resolution negative scanner to produce two 28-megabit,
16-million color TIFF files. These two scanned images were combined
in register using a program called Picture Window. This "combining"
intensifiee the image and reduces the image graininess. Working
with the combined image, some slight optical vignetting was repaired
using Adobe PhotoShop. PaintShop Pro was used to slightly sharpen
the image, and increase the color saturation. This made the blue
ion tail show up better. The image was then reduced in size and
saved as a JPEG file.
These photographs were taken by club members Rick Schrantz and George Dozier at Dozier's Lexington observatory. They were taken with an ST-6 CCD camera through a Celestron Compustar-14.
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