Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atmob.org/about/observing/awards/files/galaxy_instructions_2011-02-01.pdf Дата изменения: Mon Feb 21 07:14:48 2011 Дата индексирования: Mon Oct 1 21:51:26 2012 Кодировка: Поисковые слова: galactic center

ATMoB "Galaxy Observing Award " Guidelines
Purpose: To promote observing among the membership of the Amateur Telescope Makers of Boston through participation in the Galaxy Observing Awards program. Introduction: This awards program is oriented towards visually observing galaxies above magnitude 10.5. (See Neil Fleming if you have interest in a more comprehensive list.) There are three levels of awards; Beginner, Intermeduate, and Master. See "Challenge Levels " below for details. Rules: 1. Participant must be a current member of the Amateur Telescope Makers of Boston. 2. Observing may be done from any location. Not confined to the ATMoB Clubhouse. 3. For each object observed, fill in the information on the attached spreadsheet in the yellow boxes, and include the required number of sketches. 4. To qualify for your Observing Award Certificate, turn in your Messier checklist to an ATMoB Observing Committee member. Be sure to include your name as you want it to appear on the certificate. 5. The most important rule ­ HAVE FUN! After all, it's a friendly competition. 6. Forward completed information and sketches to a member of the ATMoB Observing Committee or . What You Need: · Any observing tool - binocular or telescope of any size: The use of the Star-hop method to locate each object is recommended, but not mandatory. · Star Atlas or finder charts Challenge Levels: Beginner Intermediate Master There are a t Observe and Do a rough s Observe and Do a rough s Observe and Do a rough s otal of 159 galaxies in our list, going down to magnitude 10.5. record information on 15 galaxies in the attached worksheet. ketch of 10 of those observations, including apparent galaxy outline and brighter stars in the field of view. record information on 30 galaxies in the attached worksheet. ketch of 20 of those observations, including apparent galaxy outline and brighter stars in the field of view. record information on 60 galaxies in the attached worksheet. ketch of 40 of those observations, including apparent galaxy outline and brighter stars in the field of view.

Information on Classifications:
Antoniadi Scale Seeing Classifications: I. Perfect seeing, without a quiver. II. Slight quivering of the image with moments of calm lasting several seconds. III. Moderate seeing with larger air tremors that blur the image. IV. Poor seeing, constant troublesome undulations of the image. V. Very bad seeing, hardly stable enough to allow a rough sketch to be made. It turns out that a very unprejudiced and convenient method to dermine the limiting magnitude is to count the number of visible stars in certain areas on the sky. There are 27 regions all over both the northern and southern hemisphere. The more stars you can see the fainter is the limiting magnitude. · Use 2 or 3 areas where you determine the star numbers, the choice of the areas may change during the night. · Average the limiting magnitudes of these areas to obtain a mean limiting magnitude. · Determine the star numbers about every half to three-quarters of an hour. · Do not use areas being very low at the horizon (<40° elevation), neither it is recommended to obser ve there at all. · Different observers will have different limiting magnitudes; every observer should determine his own limiting magnitude. · An accuracy of +-0.5m of the limiting magnitude is not sufficient for a serious analysis of your data. See this link for further details, limiting magnitude charts, and star count tables: http://www.imo.net/visual/major/observation/lm Proof Point Information: Hubble Sequence Classification: Reference: http://en.wikipedia.org/wiki/Hubble_sequence Brief Description: Ellipticals: Elliptical galaxies have smooth, featureless light distributions and appear as ellipses in photographic images. They are denoted by the letter E, followed by an integer n representing their degree of ellipticity on the sky. The ellipticity increases from left to right on the Hubble diagram, with near-circular (E0) galaxies situated on the very left of the diagram. It is important to note that the ellipticity of a galaxy on the sky is only indirectly related to the true 3-dimensional shape (for example, a flattened, discus-shaped galaxy can appear almost round if viewed face-on or elliptical if viewed at an angle). Examples of elliptical galaxies: M49, M59, M60, M87, NGC 4125.

Limiting Magnitude Assessment:


Spirals: A spiral galaxy consists of a flattened disk, with stars forming a (usually two-armed) spiral structure, and a central concentration of stars known as the bulge. Roughly half of all spirals are also observed to have a bar-like structure, extending from the central bulge, at the ends of which the spiral arms begin. In the tuning-fork diagram, the regular spirals occupy the upper branch and are denoted by the letter S, while the lower branch contains the barred spirals, given the symbol SB. Both type of spirals are further subdivided according to the detailed appearance of their spiral structures. Membership of one of these subdivisions is indicated by adding a lower-case letter to the morphological type, as follows: - Sa (SBa) - tightly-wound, smooth arms; large, bright central bulge - Sb (SBb) - less tightly-wound spiral arms than Sa (SBa); somewhat fainter bulge - Sc (SBc) - loosely wound spiral arms, clearly resolved into individual stellar clusters and nebulae; smaller, fainter bulge - Sd (SBd) - very loosely-wound, fragmentary arms; most of the luminosity is in the arms and not the bulge Examples of regular spiral galaxies: M31 (Andromeda Galaxy), M74, M81, M104 (Sombrero Galaxy), M51a (W hirlpool Galaxy), NGC 300, and NGC 772. Examples of barred spiral galaxies: M91, M95, NGC 1097, NGC 1300, NGC1672, NGC 2536, and NGC 2903.

Lenticulars: At the centre of the Hubble tuning fork, where the two spiral arms meet the elliptical branch lies an intermediate class of galaxies known as lenticulars and given the symbol S0. These galaxies consist of a bright central bulge, similar in appearance to an elliptical galaxy, surrounded by an extended, disk-like structure. Unlike spiral galaxies, the disks of lenticular galaxies have no visible spiral structure and are not actively forming stars in any significant quantity. The bulge component is often the dominant source of light in a lenticular galaxy. Face-on lenticulars are difficult to distinguish from ellipticals of type E0, making the classification of many such galaxies uncertain. W hen viewed edge-on, prominent dust-lanes are sometimes visible in absorption against the light of stars in the disk. Examples of lenticular galaxies: M85, M86, NGC 1316, NGC 2787, NGC 5866 (Spindle Galaxy), Centaurus A. Irregulars: Galaxies that do not fit into the Hubble sequence, because they have no regular structure (either disk-like or ellipsoidal), are termed irregular galaxies. Hubble defined two classes of irregular galaxy: - Irr I galaxies have asymmetric profiles and lack a central bulge or obvious spiral structure; instead they contain many individual clusters of young stars - Irr II galaxies have smoother, asymmetric appearances and are not clearly resolved into individual stars or stellar clusters In his extension to the Hubble sequence, de Vaucouleurs called the Irr I galaxies 'Magellanic irregulars', after the Magellanic Clouds - two satellites of the Milky W ay which Hubble classified as Irr I. The discovery of a faint spiral structure[10] in the Large Magellanic Cloud led de Vaucouleurs to further divide the irregular galaxies into those that, like the LMC, show some evidence for spiral structure (these are given the symbol Sm) and those that have no obvious structure, such as the Small Magellanic Cloud (denoted Im). In the extended Hubble sequence, the Magellanic irregulars are usually placed at the end of the spiral branch of the Hubble tuning fork. Examples of irregular galaxies: M82, NGC 1427A, Large Magellanic Cloud, Small Magellanic Cloud. E.g. M31: Sa