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Subject: Re: Time from 2102-D starfinder
From: Greg Travillian (gtravill@XXX.XXX)
Date: Mon Feb 11 2002 - 23:28:02 EST
At 10:52 AM 02/11/2002 -0500, you wrote:
>In David Burch Starfinder book, there is an illustration showing time
recorded on the starfinder wheel. The caption says something like "Once
you determine a specified time...."
>
>I can't find any reference to how you go about determining a specified time.
>
>Does anyone have a clue for me?
Here is something I found in an online artillery training manual:
"7-24. HAUGHT (FIELD-EXPEDIENT) METHOD FOR ORIENTING THE STAR IDENTIFIER
This is a simple method of computing the LST for orienting the star finder
and identifier. The results are accurate to within 1° and can be used for
any time or location. The final result is the LST for 1900 on the date of
observation. Use the time-arc relationship to adjust for different
observation times. One hour is equal to 15° of shift on the star finder and
identifier, and 4 minutes is equal to 1° of shift. To compute the LST by
using the Haught method, follow the procedures discussed below.
a. Count the number of months this year preceding the observation month.
Multiply that number by 30.
b. Add the observation date.
c. Add a constant of 24.
d. Determine the difference between the observer's longitude and the
longitude of the central meridian of the observer's time zone. Add the
difference if the observer is east; subtract if west.
e. If using daylight saving time (DST), subtract 15. DST in the US is from
the first Sunday in April to the last Sunday in October. The result is the
LST (orienting angle) to set on the star identifier for 1900.
f. Determine the difference between 1900 and the time of observation. (Each
hour is equal to 15°, and each 4 minutes is equal to 10.) Add if the
observation time is after 1900, and subtract if the observation time is
before 1900."
Greg Travillian
gtravill@XXX.XXX
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