|
Precision
Time Source for Meade Autostar
Why is the Exact Time important?
There are 1440 (24 x 60) minutes in a day while the Earth
rotates 360°. That means the Earth rotates 0.25 degree/minute.
The field of view of a 26 mm eyepiece on ETX-90EC is 1.1 degrees.
If the telescope is not tracking the target object, it will
go out of view in 4.4 (1.1/0.25) minutes.
Every
one minute of error in the Autostar's time, the target object
will be off by seconds or 0.25°. If the time is off by
4 minutes, the target object will be off by 1°. Needless
to say, if you do not set the Autostar's time to the exact
time, the telescope will not point to the exact location of
your target object either. Remember, a half of a degree off
here, a quarter of a degree off there, and you will miss the
target. Your Polar alignment and Alt/Az alignment with affected.
Your
DC3-updated PC System Time
DC3
is a freeware utility program that will synchronize your PC
system time an atomic clock server to hundredth of a second.
See Precision Time Source.
Radio
Digital Atomic clock
NIST (National Institute of Standards and Technology) radio
station WWVB continuously broadcasts time and frequency information
on its 60 kHz carrier frequency from Fort Collins, Colorado.
WWVB provides coverage to the United States, Mexico, and Canada.
The WWVB time code provides a convenient reference for many
consumer electronic products such as desk clocks, wall clocks,
and wristwatches.
Radio
digital atomic clock receives a special radio signal up to
four times per day to ensure accurate time within a nanosecond.
Radio digital atomic clocks are not expensive, priced at about
$40.00. Some of the radio digital atomic clocks even come
with a thermometer. These atomic clocks are about the size
of a pack of cigarettes.
Synchronizing
Your Digital Watch with Computer Time
Your computer should now be updated with DC3. You may want
to synchronize you digital watch with the computer time. Since
different digital watches work differently, I will just use
my Casio digital watch as an example. In my case, I bring
up the PC clock and set my digital watch to about 30 seconds
ahead of the PC time. My watch allows me to set the seconds
to "00". Let's say the PC time is 6:32:30, I would
set my digital watch to 6:33:00, when PC time reaches 6:33:00,
I release the button on my digital watch. My digital watch
is now synchronized with the very accurate PC time. I therefore
always set my watch before I start my star gazing session
if I'm not using my computer.
Different
digital watches work differently; please refer to your digital
watch's manual.
|
