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ATMoB "Open Cluster Observing Award " Guidelines
Purpose: To promote observing among the membership of the Amateur Telescope Makers of Boston through participation in the Open Clusters Observing Awards program. Introduction: This awards program is oriented towards visually observing open clusters above magnitude 9.9. (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 Obser Do a r Obser Do a r Obser Do a r are a total of 265 open clusters in our list, going down to magnitude 9.9. ve and record information on 25 open clusters in the attached worksheet. ough sketch of 5 of those observations, including apparent cluster outline and brighter stars in the field of view. ve and record information on 50 open clusters in the attached worksheet. ough sketch of 10 of those observations, including apparent cluster outline and brighter stars in the field of view. ve and record information on 100 open clusters in the attached worksheet. ough sketch of 20 of those observations, including apparent cluster outline and brighter stars in the field of view.

General Rules:

The objects can be located either manually or with setting circles/goto telescopes. Fill in all of the information in the YELLOW columns of the attached worksheet. Forward completed information and sketches to a member of the ATMoB Observing Committee or:

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 observe 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: Trumpler Classification: Reference: http://x.astrogeek.org/articles/article.php?article_id=14 Brief Description: Degree of Concentration: I - Detached clusters with strong central concentration II - Detached clusters with little central concentration III - Detached cluster with no noticeable concentration IV - Clusters not well detached, but has a strong field concentration Range of Brightness: 1 - Most of the cluster stars are nearly the same apparent brightness 2 - A medium range of brightness between the stars in the cluster 3 - Cluster is composed of bright and faint stars Number of Stars in the Cluster: p - Poor clusters with less than 50 stars m - Medium rich cluster with 50-100 stars r - Rich clusters with over 100 stars Nebulosity: Some open clusters may be in, or surrounded by nebulosity. The Trumpler system denotes open clusters with any type of nebulosity (including light and dark nebula) with an "n" at the end of the classification. E.g. For example, a nebula surrounds the open cluster NGC 3293; therefore, the Trumpler classification for NGC 3293 is I3rn.

Limiting Magnitude Assessment: