The following images demonstrate the reach offered by sensitive,
cooled astronomical CCD camera to astronomers. The instruments used
were the 35 cm (approx.
13.8 inch) Newtonian
telescope with 166 cm focal length
(f/4.7) and G2CCD-0400 camera with Kodak KAF-0402ME
CCD chip. Observing conditions were average.
The first field shows the neighbor of the M1 Crab Nebula,
captured without filter. DSS-2 image of the same field in the red
light is provided for reference. Although stars on the DSS-2 (Digitized Sky
Survey - 2) image has better FWHM (Full-Width Half-Maximum) due to significantly
greater telescope aperture and also better seeing, the limiting
magnitude is almost the same.
The nebulosity on the DSS-2 image looks sharper
because of the red filter used—the nebula
filaments shines in the red Ha line.
Unfiltered M1 Crab Nebula field captured by
G2CCD-0400 (left) and DSS-2 red-light image (right)
Brightness of both marked stars is 21m. The contrast
of the image areas with the marked stars was enhanced to make both
stars easier visible.
The G2CCD-0400 image was captured on the January
24th, 2006. Exposure time was 50 min, from 21:10 to 22:00 UT. The exposure was
co-added from 100 exposures (30 s each) to eliminate telescope mount
errors. Resulting S/N ratio is still very good thanks to very low
camera read noise.
NGC 2419 field
The filed of globular cluster NGC 2419 shows slightly lower
reach—approx. 20.7m—compared to 21m of the DSS-2 red-light
image. The star FWHM of the DSS-2 image is noticeably better due
to better seeing on the Mt. Palomar.
Unfiltered NGC 2419 field captured by G2CCD-0400 camera
(left) and DSS-2 red-light image (right)
The marked galaxy brightness is 19m. The G2CCD-0400
image was captured on the January 25th, 2006 with
exposure time 18 min,
C/2003 WT42 (LINEAR)
The C/2003 WT42 comet magnitude was approx. 14m when
the image was taken on February 17th, 2006. The exposure time is
20 minutes, from 20:02 to 20:22
Unfiltered 20 min exposure
of C/2003 WT42 (left) and corresponding DSS-2 red-light image
Images from G2CCD-0400 captured and processed by Kamil Hornoch.
The Digitized Sky Survey was produced at the Space Telescope
Science Institute under U.S. Government grant NAG W-2166. The images
of these surveys are based on photographic data obtained using the
Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt