Sir Patrick Alfred Caldwell-Moore, one of Britain's most
respected astronomers and one of the world's most renowned
astronomical writers, compiled a list of 109 deep-sky objects
for those who wish to go beyond the Messier Objects.
This list
was first published in the December 1995 issue of Sky &
Telescope, and it has been supported and popularized by Sky &
Telescope. These objects are both challenging and spectacular.
They cover a wide range of sizes and magnitudes. Some are large,
bright, and well known. Others are faint, small, and very
difficult. It is impossible to image them with the same
instrument and the same imaging parameters. Unlike the Messier
Objects, they can not be observed only from the Northern
Hemisphere. At least 30 of the objects require Southern skies
for proper observation.
Unlike most other observing lists, the
Caldwell Objects are presented in order of declination from
North to South. To learn more about the Caldwell Objects, the
following books are highly recommended:
1. O'Meara SJ. The Caldwell Objects. Sky Publishing
Corporation, 2002.
2. Ratledge D. Observing the Caldwell
Objects. Springer, 2000.
The present color images of the Northern Caldwell Objects were
taken at the Grasslands Observatory. They
required the use of many different instruments, including a
24-inch f/5 telescope, an 8-inch f/4 telescope, a 5-inch f/3.3
astrograph, a 7-inch f/2.8 astrograph, and telephoto lenses coupled with a variety of CCDs, a Nikon D100 digital camera, and Canon 20da and Canon 60da digital cameras.
At the present time all imaging is done remotely using a PlaneWave CDK24 24-inch f/6.5 telescope and FLI Proline 9000 CCD, an ASA 20-inch f/3.5 astrograph and FLI Proline 9000 CCD, or a Takahasi Epsilon 180 f/2.8 telescope with a Canon EOS Ra camera. See our Operations for more details.
Some of the older, more inferior Caldwell images are gradually being replaced using the current imaging systems.
First posted Saturday February 04, 2006
Minor revision Sunday February 16, 2014
Minor revision Sunday March 25, 2016
Major revision Tuesday May 21, 2019
Minor revision Tuesday November 24, 2020
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