Posts Tagged ‘peripheral vision’

Stargazing tips: Make the most of a starry night

October 18, 2007

Last week I posted a blog listing a number of stargazing necessities.  This week I’ll be going over some stargazing tips.   Or, more specifically, ways to make the most of a starry night.

On Oct. 16, I talked to astronomy graduate student Matt Davis, and he gave me a list of suggestions for the amateur stargazer.

Davis said it’s important for a stargazer using a star map or a star chart to determine which way is north and to get oriented with the night sky.  “The best way to do that is to find Polaris, the North Star,” Davis said.  He said the easiest way to find the North Star is to first find the Big Dipper– which isn’t really a constellation but an asterism* that is part of the constellation Ursa Major— and draw an imaginary line from the two stars that make up the edge of its bowl, called the pointers, because they roughly point to the North Star.  (An added bonus:  The North Star is the tip of the handle to another asterism called the Little Dipper, part of the constellation Ursa Minor.)

Not only does the Big Dipper make spotting the North Star easier, it also acts as a signpost to other asterisms and stars.  Pathways to Astronomy says to try this:  Visually extend the arc formed by the stars of the handle of the Big Dipper and find the orange star Arcturus in the constellation Bootes.  I’ll definitely be looking for Bootes the next time I go stargazing.

Davis also suggests stargazers use their hand to measure distances and get a better idea of the location of stars and constellations.  “The sky is broken up into degrees, so if you want to measure how many degrees something is from the horizon you can either use a fancy instrument or you can use your fists,” Davis said.  “There are a bunch of different tools you can use:  your hand spread at arm’s length covers an angular size of about 20 degrees, your fist is about 10 degrees, your thumbnail is about two degrees and your pinky fingernail is about one degree.”  (For more information about locating stars and constellations, see StarDate Online’s cooresponding FAQ answer.)

Stargazers can also use the hand-measuring method to find their latitude, he added.  “If you want to know your latitude, go outside, find the North Star and find a way to measure how far the North Star is away from the horizon– [that’s] your latitude.  Just start stacking fists.”

Should stargazers have any difficulties seeing a faint star, Davis advises them to use their peripheral vision to look at the star instead of looking directly at it.  “When you look straight at something you’re using the color-sensitive parts of your eye,” he said.  “At night you start to lose the ability to see colors.  At night everything looks gray, so we sort of switch to using the light-sensitive parts of our eyes.  Your peripheral vision is most sensitive to light and dark.”  I had a friend tell me about this little trick, too.  Looking off to the side really does help.

Don’t forget to check out StarDate Online’s seven-day star forecast covering the nights from Oct. 18 to Oct. 24.

*Pathways to Astronomy defines an ‘asterism’ as “an easily identified grouping of stars, sometimes a part of a larger constellation (such as the Big Dipper) or extending across several constellations (such as the Summer Triangle).”  Asterisms are not included in the 88 constellations officially recognized by astronomers.