Setup -> Eyepieces

This is a complex dialog, but we hope you will find each function useful.

• Style and Size These sections control the shape, size and orientation of the next eyepiece placed on the sky chart, see Sky popup. All sizes are in arc minutes, orientation is in degrees East of North. As a special case, the "eyepiece" may be specified to match the view seen through the venerable Telrad finder.

• Favorites This section allows you to save the eyepiece settings you use most often. Tap Add to save the current Style and Size. Select an existing favorite in the list then Tap Use to install it in the Style and Size fields above. To delete an eyepiece from the list, select it then tap Del.

• Calculators This section offers two handy methods to calculate field of view. Editing any field immediately updates its result. The sky angle computed by either of these tools can be installed into the current working eyepiece width or height by tapping the W or H buttons at the right. The first method computes sky angle from the overall optical focal length and the size of the object projected onto the focal plane, both dimensions in mm. For example, a 1024x1024 CCD with 25µ pixels in a telescope with 2000mm focal length, captures nearly 43 arcminutes of sky across the chip.

  The second method uses the apparent field of view looking through an eyepiece and the focal lengths of the eyepiece and the primary mirror. For example, a nice wide field 50° eyepiece with 32mm focal length on a telescope with a 2000mm primary shows a field 48 arcminutes across.