M103 (NGC 581)
Characteristics:
Magnitude: 7.4
Size: about 6'
Distance: 8,500 light years
RA: 1h 33m 22s
Dec: 60 degrees 39' 29"
Description:
This beautiful open cluster is an
under-appreciated target in the constellation Cassiopeia, which
contains many other clusters such as M52 and NGC 663. Although it
is called M103, it was not discovered by Messier but rather by Pierre
Mechain in 1781. This little jewel can easily get lost in the
background of Milky Way stars, and it can be difficult to appreciate
during visual observation. Nonetheless, this cluster makes a
wonderful target for astrophotography, especially with the nice
contrast provided by several red giants in the field. At 8,500
light years distant and with dimensions of 6 arcminutes, its 172
members span about 15 light years across. Here is another image of
M103 taken by Rob Gendler. More information about this open
cluster may be found here.
Photographic Details:
Date: November 25, 2005
Scope: Takahashi
FS-102 at f6 with TOA-130 focal reducer, on the G11 Losmandy
Mount.
Autoguider: SBIG STV with
e-finder.
Camera: SXV-H9.
Filter: Astronomiks
Type II RGB filter set; IDAS-LPS filter.
Exposures: Luminance filter, 6
x 4'; R, G, B 5 x 4'
(all
unbinned). Total exposure: 84 minutes.
Conditions: Temperature 22 degrees F; average
transparency, average seeing; calm; clear.
Post-processing:
No darks were needed for this image.
Subs were bias subtracted, aligned, and combined in
Maxim.
DDP
performed in ImagesPlus (IP), with further processing in Photoshop CS (16
bit format). Diffractions spikes created with two pieces of kite
string placed perpendicularly in front of the telescope.
Please
note: Graphics on this website
may not be reproduced without author permission.
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