Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atmob.org/about/observing/awards/files/double_star_instructions_2011-02-01.pdf Дата изменения: Mon Feb 21 07:14:46 2011 Дата индексирования: Mon Oct 1 21:54:30 2012 Кодировка: Поисковые слова: принцип мопертюи

ATMoB "Double Star Award " Guidelines
Purpose: To promote observing among the membership of the Amateur Telescope Makers of Boston ­ in particular, double, triple, and multiple stars. Introduction: Double, triple, and multiple stars are the "Rodney Dangerfields" of the night sky. They "don't get no respect! " That's unfortunate, because double stars like the gold and blue Albireo in Cygnus or the pure-white twin pair gamma () Arietis rank among the loveliest of celestial sights. Unlike galaxies and nebulae, double stars suffer little from light pollution. W hile they can be observed under a variety of sky conditions, double stars ­ especially close ones ­ are best viewed on nights when the seeing is steady. The Amateur Telescope Makers of Boston encourages its members to explore double, triple, and multiple stars by observing some or all of the ones posted on our list. The ATMoB double star list is comprised of 218 of the finest double stars visible from mid-northerly latitudes. All are brighter than 6th magnitude and most are readily split with telescopes with apertures as small as 3-4 inches and magnifying powers between 75-150X. Rules: 1. Participant must be a current member of the Amateur Telescope Makers of Boston. 2. Certificates are awarded in three categories: Beginner ­ at least 15 double stars; Intermediate ­ at least 25 double stars; Master ­ 50 or more double stars on the list. 3. There is no time limit on completing your observations, but all 218 double stars can be viewed during a calendar year. What You Need: · Telescope: Any telescope will suffice. Most of our double stars can be split with a common 60mm refractor; all are within reach of 6 inch scopes and larger. Magnifications between 75 and 150X will do the trick. Use of the Star-hop method to locate each double star is recommended, but Go-To technology is accepted. · Star Atlas: You'll need a star atlas or decktop planetarium to find the location of each double star. Any source that plots stars down to 6th magnitude will work. · Double Star Checklist/Data Sheet (see attached) · Red Flashlight, Clipboard, Pencil: Use to record data/sketches on the checklist/worksheet. Challenge Levels: Beginner Intermediate Master Observe and record information on 15 double stars in the attached worksheet. Include a rough drawing of the stars in the FOV. Observe and record information on 25 double stars in the attached worksheet. Include a rough drawing of the stars in the FOV. Observe and record information on 50 or more double stars in the attached worksheet. Include a rough drawing of the stars in the FOV.

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: Position Angle Reference: http://bestdoubles.wordpress.com/2010/12/12/left-is-right-and-right-is-left-a-simple-users-guide-to-pa/ Brief Description: The angle formed by the great circle running through two celestial objects and the hour circle running through one of the objects. In measuring double stars, the angle formed between the great circle running through both components and the hour circle going through the primary measured from the north through the east from 0 to 360° . Guidelines: The source of all the confusion is that stars move in circles around the celestial poles ­ not straight lines ­ and the circles get smaller as you approach the poles. This is different from the apparently flat, common sense world we walk around on each day. So here are two new rules to apply to help you get things right in the stellar environment. 1. W hatever direction the stars appear to move, that is west. 2. The direction from a star to Polaris is north. 3. If you are using a telescope with a diagonal mirror (refractor, SCT, or Maksutov), then the other directions are read clockwise from west ­ north,east, south. 4. If you are using a Newtonian reflector, whether on a Dobsonian mount or equatorial, then the other directions are read counterclockwise from west ­ north, east, south W e are not talking about the cardinal directions ­ north, south, east, and west ­ as they appear on the horizon, though these are closely related. These sky directions are a bit different because we are looking at a sphere from the inside ­ the dome of the sky. Terms such as "above" and "below" are relative and not always that helpful when trying to find your way around the sky dome. Nor is it helpful to relate what you see in But the PA is a number?: You are probably familiar with these numbers. They frequently appear on a compass. They are used to determine "azimuth" on land. And they are simply the 360 degrees of a circle. All you have to remember is that they start with "0 as north and progress around the circle.

Limiting Magnitude Assessment: