Bob Moler's Ephemeris Blog

November 18th.*  The sun will rise at 7:43.  It’ll be up for 9 hours and 28 minutes, setting at 5:11.   The moon, 3 days before full, will set at 5:39 tomorrow morning.

There’s a bewildering choice of telescopes, and tomorrow I’ll show you where to go to find that choice.  But for a first telescope, there’s nothing better than a pair of binoculars.  Binoculars beside quality, have two numbers that describe its capability.  They are like 7X35, 8X50, 10X50, and so on.  The X is pronounced “by”.  The first number is magnification, which is usually fixed in binoculars.  The second is the diameter of the front or objective lens in millimeters.  The best binoculars for astronomy are those where the second number divided the first comes out to be 5 to 7.  A 10 by 50 binocular gives an answer of 5.  All real binoculars use prisms to make the image upright.  Telescopes give upside down images.

* Times, as always are for the Traverse City/Interlochen area of Michigan.