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Sky observation programs, month by month

Astro club "Les Gémeaux", MJC, Monistrol sur Loire, FR

JANUARY

In January, to the west, Altaïr, Véga and Deneb lie down, winter is here ... and with it the constellations of season. We will have the opportunity to see them scroll in turn until the beautiful season.

The HERO (PERSEUS - Per)

By extending "gamma -delta Cas", we arrive on a group of stars of the constellation Perseus. On the way, with the naked eye or better still the binoculars one distinguishes a blurred spot. Observation to detail with various instruments. What is the nature of this object? Continuing to descend, one arrives on the main star of Perseus "alpha Per". What is its color? Try to determine its magnitude by comparing it to Aldebaran (m = 1) and the main star of Aries (m = 2). From "alpha Per", we distinguish two "branches" of stars, the one on the right ends in 2 stars, the last one is the famous Algol. Try to estimate its magnitude by using the surrounding stars, redo the estimate a few hours later and then next day. The other longer branch curves towards the superb little group of stars well known: the "Pleiades". The constellation contains two Messier objects. - The first : M 34, which is difficult for the naked eye, can easily be seen with binoculars from the star Algol: one moves 4° to the West and then goes 2.5° to the North. Then we are about halfway between "beta Per" and "alpha And". What are its shape and nature? - The second : M 76 is not accessible to the naked eye or binoculars; Observe it whith a telescope. To do this we will make a first locating of the zone with the naked eye then with the binoculars before going to the telescope. This object is at the limit between Andromeda and Perseus, it lies at 10° North North-West of "gamma And". A star magnitude 4 makes it easy to spot. What is it ?

The BULL (TAURUS - Tau)

Consisting of two easily identifiable stellar groups: the Pleiades and the Hyades. - the Pleiades are listed in the Messier catalog under the reference M 45. With the naked eye one can already distinguish its nature. How many stars do you see? Push the observation to the binoculars, same question. Then to the telescope, with the latter what do you notice ? - the Hyades form a lying "V", with Aldebaran principal star and very brilliant of the constellation. What is its color? To compare with color of the stars of the Pleiades. The two horns of this bull are very long, the end of the upper horn "beta" is common with the Charioteer constellation. The end of the second horn "dzeta Tau" allows, if centered in the field of the binoculars, to see a very small blur, it is M 1. To observe with a telescope, what do you see? To appreciate it, eliminate the shining star of the field of the eyepiece.

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The CHARIOTEER (AURIGA -Aur)

Cut by the Milky Way, opposite the galactic center, this constellation is easily identified thanks to the shape of pentagon connecting its five stars most glossy "alpha, beta, theta Aur, beta Tau and iota Aur". A little more than half the segment Polaris star - the Hunter is located Capella ? Aur. What is its color? Compare its brightness to Aldebaran. South of Capella is NGC 1664 little known of the amateurs. What is the nature of this object? It is interesting to compare its magnitude to M 1. What do you think? Easiest objects are: - M 38 halfway between "beta and iota Aur". Try to estimate its apparent diameter by using the field of your binoculars. Personally I perceive a form of cross in my binoculars and you? - At 2° South-East of M 38 is M 36 compared to M 38 (shape, size, brightness of stars) - At 2° East South-East of M36 is M 37. Same work as before. Note with 7x50 binoculars, these three clusters must be seen together.

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The GIRAFFE (CAMELOPARDALIS - Cam)

The circumpolar zone: around the Polaris star, the constellations that do not never sleep: the Great Bear, the Seated Queen, the King, the Giraffe, the Lesser Bear, a part of the Dragon, the Charioteer and the Hero ... The Giraffe is a constellation often neglected because difficult to identify with the naked eye. To locate it, it will be surrounded by the quadrilateral "beta Umi, alpha Per, alpha Aur, omicron UMa. We will then search the main stars of the Giraffe using the binoculars. We will search from Polaris, at right angle with "delta Umi", at the opposite of Cepheus and at about 7° (field of 7x50) two interesting objects are to be found, with binoculars of course but also with a telescope in order to determine their nature. Halfway between the star noted "L" chart n°2 « La Revue des Constellations » and the star "omicron UMa" is a very easy galaxy with a T 115/900. Between the legs of the animal, forming an equilateral triangle with the stars "A" and "B" (of the same chart), an object is to be observed. What is its form? Its nature?

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