The Milky Way: November-December
As autumn turns to winter for northern observers we are still in those parts of the sky that are rich in Milky Way objects. However, some of the constellations are getting very low during the southern summer months and may prove difficult for southern telescopes (see Figure 4.1).
KeywordsOpen Cluster Variable Star Planetary Nebula Bright Star Large Telescope
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- 1.See Appendix 1 for details on astronomical coordinate systems.Google Scholar
- 2.The bright stars that extend from Perseus, Taurus and Orion, and down to Centaurus and Scorpius, including the Orion and Scorpius-Centaurus associations, He at an angle of about 1.5° to the Milky Way, and thus to the equatorial plane of the Galaxy. This group or band of stars is often called Gould’s Belt.Google Scholar
- 3.Not forgetting that it is perfect for observation!Google Scholar
- 4.It is, however, the only galaxy that can be seen in small telescopes.Google Scholar
- 5.Astronomically speaking, of course!Google Scholar
- 6.It is ironic that the most famous nebula is also probably the most difficult to observe. Such is the life of an astronomer.Google Scholar
- 7.A full description of M45 and many other celestial objects can be found in my book, Field Guide to the Deep Sky Objects, Springer-Verlag.Google Scholar
- 8.The photographic magnitude change has been measured to be some 4.49 magnitudes.Google Scholar
- 9.It is always a problem knowing what to include in the book, and what to leave out, but as I mentioned in the first chapter, I try to stick rigidly to the premise that an object can be included if it lies within the boundaries of the Milky Way as defined by the Dutch Astronomer Antonie Pannakoek (as used in the star atlas Sky Atlas 2000.0), who measured the approximate brightness levels of the Milky Way. Anything outside of this is not mentioned. This does leave out a lot of famous and bright objects, but if I were to include them, this book would run to several volumes, and possibly a few bank overdrafts.Google Scholar
- 10.But not completely so. I eventually found it on a clear transparent night. Try it for yourselves.Google Scholar
- 11.If you have to use a star which does not lie on or close to the celestial equator, then the formula 15t cos δ where δ is the declination of the star, can be used to find the apparent field diameter of the eyepiece in minutes and seconds of arc.Google Scholar