6.3 Catalogues
69
Messier Catalogue
Charles Messier was an eighteenth-century astronomer with a passion for comets.
Unfortunately, eighteenth-century optics were not of the quality we now enjoy, and a
very large number of non-comet objects looked like comets to Messier, so he created
a catalogue of 110 objects in order to avoid later confusion. This catalogue is the now
famous Messier catalogue. Given that Messier was operating from France, many of
the objects are not visible from the southern hemisphere. Also, given that some of the
objects, such as M31 (the Andromeda galaxy) and M45 (the Pleiades) are very well
known naked-eye astronomical objects, it is unlikely that all of the objects in the list
would be mistaken for comets. However, the 110 objects in the Messier catalogue
are favourites among amateur astronomers for being bright, spread out over the sky,
and comprising a mixture of deep sky astronomical object types, objects too faint
to see with the naked eye and external to the solar system.
Caldwell Catalogue
Compiled in the 1990s by famed amateur astronomer and broadcaster Sir Patrick
Moore (or more correctly Patrick Caldwell-Moore), the Caldwell catalogue is a list
of deep sky objects omitted from the Messier catalogue due either to error, deliberate
omission, or the object being too far south. The Caldwell catalogue contains 109
objects, including star clusters, planetary nebulae, and galaxies.
United States Naval Observatory Catalogues
The United States Naval Observatory has produced a series of catalogues, some of
which are now considered obsolete. USNO A2.0 is the re-digitisation of the plates
from three previous catalogues. USNO-A2.0 contains in excess of 500 million objects
with R and B magnitudes down to magnitude 20. USNO A2.0 has now been largely
replaced by USNO-B1.0, which contains in excess of one billion objects down to
magnitude 21. Both USNO-A2.0 and USNO-B1.0 are accessible via SAO DS9.
UCAC2 and its replacement UCAC3 are high-precision (with regard to astrometry) catalogues to magnitude 16 in band f created from CCD images taken at
Cerro Tololo Interamerican Observatory (CTIO) in Chile and the Naval Observatory
Flagstaff Station (NOFS) in Arizona. The catalogue includes B, R, and I magnitudes
from the SuperCOSMOS survey. Both UCAC3 and UCAC2 are accessible via SA0
DS9.
The Naval Observatory Merged Astrometric Dataset (NOMAD) is a merged catalogue using the sources found within the Hipparcos, Tycho-2, UCAC2 USNO-B1.0,
and 2MASS surveys. Hence NOMAD covers the B, V, R, J, K, and H bands down
to approximately magnitude 20, depending on the source catalogue.
Hipparcos and Tycho
Hipparcos is a European Space Agency Telescope launched and operated between
1989 and 1993 with the goal of producing high-precision proper motions and parallaxes to stars within 200 parsecs. Observations were made in the B and V bands with
a limiting magnitude of 12.4 in V, resulting in a 118,218-source catalogue. Objects
in Hipparcos are numbered and prefixed with HIP; hence α Ori is HIP 27989 in
69
Messier Catalogue
Charles Messier was an eighteenth-century astronomer with a passion for comets.
Unfortunately, eighteenth-century optics were not of the quality we now enjoy, and a
very large number of non-comet objects looked like comets to Messier, so he created
a catalogue of 110 objects in order to avoid later confusion. This catalogue is the now
famous Messier catalogue. Given that Messier was operating from France, many of
the objects are not visible from the southern hemisphere. Also, given that some of the
objects, such as M31 (the Andromeda galaxy) and M45 (the Pleiades) are very well
known naked-eye astronomical objects, it is unlikely that all of the objects in the list
would be mistaken for comets. However, the 110 objects in the Messier catalogue
are favourites among amateur astronomers for being bright, spread out over the sky,
and comprising a mixture of deep sky astronomical object types, objects too faint
to see with the naked eye and external to the solar system.
Caldwell Catalogue
Compiled in the 1990s by famed amateur astronomer and broadcaster Sir Patrick
Moore (or more correctly Patrick Caldwell-Moore), the Caldwell catalogue is a list
of deep sky objects omitted from the Messier catalogue due either to error, deliberate
omission, or the object being too far south. The Caldwell catalogue contains 109
objects, including star clusters, planetary nebulae, and galaxies.
United States Naval Observatory Catalogues
The United States Naval Observatory has produced a series of catalogues, some of
which are now considered obsolete. USNO A2.0 is the re-digitisation of the plates
from three previous catalogues. USNO-A2.0 contains in excess of 500 million objects
with R and B magnitudes down to magnitude 20. USNO A2.0 has now been largely
replaced by USNO-B1.0, which contains in excess of one billion objects down to
magnitude 21. Both USNO-A2.0 and USNO-B1.0 are accessible via SAO DS9.
UCAC2 and its replacement UCAC3 are high-precision (with regard to astrometry) catalogues to magnitude 16 in band f created from CCD images taken at
Cerro Tololo Interamerican Observatory (CTIO) in Chile and the Naval Observatory
Flagstaff Station (NOFS) in Arizona. The catalogue includes B, R, and I magnitudes
from the SuperCOSMOS survey. Both UCAC3 and UCAC2 are accessible via SA0
DS9.
The Naval Observatory Merged Astrometric Dataset (NOMAD) is a merged catalogue using the sources found within the Hipparcos, Tycho-2, UCAC2 USNO-B1.0,
and 2MASS surveys. Hence NOMAD covers the B, V, R, J, K, and H bands down
to approximately magnitude 20, depending on the source catalogue.
Hipparcos and Tycho
Hipparcos is a European Space Agency Telescope launched and operated between
1989 and 1993 with the goal of producing high-precision proper motions and parallaxes to stars within 200 parsecs. Observations were made in the B and V bands with
a limiting magnitude of 12.4 in V, resulting in a 118,218-source catalogue. Objects
in Hipparcos are numbered and prefixed with HIP; hence α Ori is HIP 27989 in