Deseret evening news. [volume] (Great Salt Lake City [Utah]) 1867-1920, 1891-03-18
TAXING TIME FROM THE STARS.
pox "c.nbridrc Tine" Il Secured In
thu Observatory ut Harvard.

No. .C.rnbridKc Time" Il Secured In
the observatory ut Harvard.
No timcpicce 10 perfect. and there
ar, no means on earth Of keeping per.
49,, time The stars, however, furnish
,he necessary means. At the observa-
tory In Cambridge thcr are two prin.
anal clocks employed In keeping tho
v,apdnrd timc-.thc standard mean
fine clock, which tclcgraphs ~ signals
over the surrounding country, and The
normal sidcreal clock, which Is the
main standard Of the observatory, to
which everything Is referred. Tho u.
dercal clock. a. It's maine implies, keeps
sIdcrral or star time, which gains about
three minutes and iifty-cight seconds
per day over mean solar time, with
which We arc all familiar
The clock Is Of the finest workman
ship and Is kept In brick vault, an.
dcrnc1th the observatory, where the
temperature Is ms nearly constant as
possible.
Every effort IL made 10 protect II
from any influence which might affect
IT, "mtc.' or. Ia other words, the
amount Of rs gain or loss per day.
This isneccssary inordcr TINT the rate
may be depended upon to give the cor.
net time during spells Of cloudy wealth.
or. when no observations can be made.
On every clear morning the error Of
this clock is carefully determined by
observing certain bright stars with nm
instrument known rs tho meridian
eirrlc.
Thislnsiruncnt consists Of n telescope
mounted on trunnions like u cannon
and supported by pier Of solid ma.
Ionry. IL Is 80 arranged that Il can DO
directed toward any point on tho mo.
ridlan, but cannot be pointed away from
tho meridian line. On looking into tho
sycpiccc Of this telescope ono secs n
series OF line parallel line, running
north and south across the Held Of
view. thoeniddlo limo marking tho
meridian.
When n time observation Is 10 DO
mndo tho observer lint selects n suit
able star from printed star list, which
gives tho cxact time nj which each 81
tho principal st..rs crosscs the meridian.
lie then sets the telescope ut tho proper
point on tho meridian TO intercept tho
,tar. and putting his oyc TO the cyo-
piece wnits for tho star TO appear
As the star crosses each OF the lines
before mentioned he pn'sscs an electric
key which hc holds Ia his hand. The
Signals thus given arc recorded clcc.
trically on registering instrument
called chronogrnph, on which arc also
being recorded the seconds Of tho sid.
ercal clock. Tho chronogrnph consist.
81 n cylinder made To rcyolyo by clock
worl. at tho ratio Of about once a min
ute.
4 paper. wrapped around this cylin'
der. receives the record traced by pen,
which Is connected by an electro mng-
not la such n manner that any signal.
mado either by tho operator or tho
clock. causes tho pcn to make n mark
on the paper.
IIy examining this paper tho observer
Is able To toll within tenth OF a see
ond the time which the normal oloch
indicated when tho star crossed tho mo
ridian.
Comparing this with tho time takcr
from the star lit shows tho error OF tli,
clock. A comparison Is then made DO
tween the tldercd and mean tim,
clocks, which, after allowing for ia,