Wholesale prices are available on request.
A 15 cm (6 inch) diameter circular "slide rule" that allows a quick calculation of you imaging exposure.
You input - the object type
- effective ISO and focal ratio
- height of object in the sky
- filters (if any)
Then, read off the exposure!
It may be used to determine the exposure for the bright planets and faint galaxies. It covers an exposure range of 1 million (15 magnitudes)! You may down load the User's Manual for the calculator here (770 k). You may also download additional tips and advice on the use of the Whiz Wheel here (1.3 meg).
Price: $25 ea. plus $12 shipping and handling. 