Idaho Skies Transcript for March 11th and 12th

RACHEL
Welcome to Idaho Skies for March 11th and 12th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The moon is passing through two star clusters at the beginning of this week.

PAUL
The star clusters are the Pleiades and the Hyades. Both are perfect for your binoculars. In fact, most telescopes will magnify them too much. That is, except for rich field telescopes. These telescopes have very short focal lengths in comparison to their diameters. Astronomers and camera enthusiasts call this the f-number and the lower the f-number, the wider the telescope’s field of view. 

RACHEL
Since most binoculars have an f-number of around four, they have very wide fields of view. Common binoculars have fields of five or six degrees, which is between ten and twelve times wider than the moon’s apparent diameter. The Hyades and Pleiades star clusters have diameters of five and two degrees respectively. It’s no wonder binoculars are perfect for observing them.

PAUL
Under dark skies, you should be able to see over a dozen stars in each star cluster. Even in town, the star clusters will be very attractive in your binoculars. However, it’s best if you could get out from underneath a street light and away from your porch lights. Your view is better if you can prop up your binoculars. 

RACHEL
Without propping binoculars, your hands shake them. So fewer photons of light reach the rod and cone cells in your retina. With fewer photons, retinal cells are less likely to register faint stars. So try propping your arms or elbows on a solid surface, like a car or a wall. Then watch as the moon passes through the Hyades star cluster on the 12th. 

PAUL
That’s Idaho Skies for the 11th and 12th of March.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.