Ordinary Meeting, 2002 February 23

 

Observing Variable Stars with Binoculars

The speaker started by promoting binoculars as an ideal observing instrument for novices. He argued that a pair of 10x50 binoculars offer a saving of possibly £1,000 compared to a useful telescope, and are also useful outside astronomy. It should be remembered that all of George Alcock's discoveries were made by binocular astronomy.

Mr. Taylor saw the biggest emphasis in binocular astronomy to be comfort and ease of use. To demonstrate this he showed slides of several ingenious setups for aligning the binoculars to sit nicely over the observer's eyes, including a yoke on which the observer rests his head, and even a specially designed observing chair with binoculars mounted. He emphasised that there was no great restriction on the aperture available to binocular observers, using an image of a full garage binocular observatory to demonstrate this. The limiting magnitude is often determined by the quality of mounting, and the speaker urged observers looking for faint objects to seek very stable mounts. Binoculars are good for a very wide range of targets, ranging from comets and deep sky to meteors and solar work (with appropriate filters). They are also ideal for eclipses.

In variable star observation, the speaker warned that numerous errors can creep into the observations of the unwary. He urged that the eyes should be given at least ten minutes to adjust to night vision before starting scientific work. He also warned of the danger of bias, where expectation can sway one's interpretation. Mr. Taylor recommended RZ Cassiopeia as a good variable star to practice observing, as it is relatively easy to locate and varies on a timescale of around five hours. For eclipsing binary systems, observations every 10-15 minutes were recommended to determine the period.

To close, the speaker stressed that expensive equipment was by no means a requirement in amateur astronomy. To illustrate this he showed a broken half-binocular which had been used to discover a mag 7 variable system.

Following the applause for Mr. Taylor's talk, the President added a personal comment that the tale of a discovery made with a broken pair of binoculars should go to show that it is possible to get results with minimal equipment. On that note, the meeting was adjourned until 2002 March 16.

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Dominic Ford

© 2002 Dominic Ford / The British Astronomical Association.

Fairfield

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