Binocular Messier

You are free to use any pair of binoculars for your observations, but it is recommended that those with objectives ranging between 20MM and 80MM in diameter be utilized. To document your observations, log sheets available in the rear of the Astronomical League’s manual "Observe: A Guide to the Messier Objects" or any similar log sheet can be employed. The necessary information for each observation includes:

- The name of the observed object

- Date and time of the observation

- Latitude and longitude of the observation site

- An estimate of the seeing and transparency conditions

- The size and power specifications of the binoculars used

- Optionally, a brief description of your observations.

Regarding the definition of binoculars allowed for observations, the Astronomical League categorizes a binocular telescope as an observing tool with two optical tubes and two eyepieces, where the eyepieces can be swapped with others of different focal lengths. On the other hand, "Bino-Viewers" feature a single optical tube but two eyepieces. Both "Bino-Viewers" and Binocular Telescopes are acceptable for any Observing Programs that are telescope-based but are not allowed in binocular programs.

Observing devices equipped with two optical tubes and two eyepieces, where the eyepieces cannot be changed, are classified as binoculars. Binoculars can be used in any Observing Program that calls for telescopes or binoculars. However, it's worth noting that most binoculars lack sufficient magnification to serve as substitutes for telescopes.

For those unsure about which Messier objects to observe or those seeking a structured program, we've provided Appendix 1 and Appendix 2 for your convenience. Appendix 1 caters to binoculars with diameters between 20MM and 50MM, while Appendix 2 is designed for binoculars ranging from 56MM to 100MM in diameter. Each appendix outlines the suitable Messier objects for the respective instrument sizes, categorized as Easy, Tough, and Challenge objects. Easy objects are characterized by their size and brightness, making them readily observable. Tougher objects, smaller and dimmer, require reference to star charts for identification. Challenge objects are faint and small, often necessitating averted vision and precise pinpointing with a star atlas.

In the smaller binocular category (Appendix 1), there are 42 objects classified as easy. To earn your certification, you only need to choose 8 objects from the tougher category. For larger binoculars (Appendix 2), all 50 objects required for certification can be selected from the easy category. The emphasis is on the accessibility of serious astronomy for anyone, regardless of their binoculars' size, shape, condition, or cost.