Evening star. [volume] (Washington, D.C.) 1854-1972, 1920-12-19
A WASHINGTON SCIENTIST PERFECTS AN
INSTRUMENT TO MEASURE HEAT OF STARS

sivity of the different parts Of the starr
spectrum. 1t is true that II gives
information Of only two parts OF IN
spectrum; but. from our knowledge
the solar spectrum, and OF the spectr
of terrestrial substances. this informa
ton enables US to make important az
auctions as regards the distribution
energy in the spectra OF stars.
Among all the data collected on
stars, there are no exceptions 70 u
general classification. viz, the redde
the star the greater amount OF tota
radiation emitted. To some. or couIss
this information is not unexpected
However, If you will pause for mo
ment and consider that some OF tines
measurements were made on starllgn
which left its source several hundres
years ago, and that stellar distance
are so inconceivably great that sew
eral hundred years more must eiaps
before the arrival of starlight which
is being emitted at the present mo
ment, il will be evident that ever.
measurement has a value OF far greatG
Importance than merely confirming
our expectations which are based up
on our preconceived notions OF wha
is occurring on a star and in passint
through interstellar space.
Tell us something about the prob
lens you hope to solve in the future,
was the final question the Intervene
asked the scientist
y X +
at is an easy matter to tell OF TIN
problems demanding solution" he re
Piled. But it is quite different mat
ter to produce the instruments 10
their solution. The advance mad
thus far in developing astroradiome
trio instruments is very small in COM
parison with what will be requires
I'm order to make real progress in tia
work For example. in the pioneering
work of Nichols about fifteen year
ago the radiation sensitfvity OF nv
instruments was such that a de1ectioi
of one NM would have been produce'
on his observing scale by a candle re
moyed to a distance OF nve miles
The sensitivity of the radiometric ap
paratus used in the present work wa
more than 100 times as great, SO Una
one millimeter detection would nave
heen produced by candle removed u
a distance of fifty-three miles. How
ever the real knowledge viii not %
gained by measuring the totai rdoi1
ton from stars, but by dispensing tn'
starlight and measuring tne oIs'r Thi,
ton II energy in its spectrum, Inl
Is the dream have in my MIND, ans
II is the goal toward which L havt
turned my efforts.
but. in order to accomplish useiu
results, the present investiganio,
must be still further increased oy
hundredfoId. In other words, the ra'
fiometric outfit, ipcluding the renect'
ing mirror, must be sufficiently sens'
tive to detect the radiation from
"a ndle at a distance of more than Dos
miles. The instrument must be 10.oqi
times more sensitive than the ont
used by Nichols fifteen years ago, ane
nerhaps from 100000 to 100000 times
more sensitive than those useo IN .hs
earliest attempts by Higgins ana oth'
ers. almost half a century ago.
rThis shows how insignificant has been
the gain in sensitivity in comparison
with what will be required in order to
accomplish much on the radiation from
yestigation; but it is not SO appalling az
these. figures may indicate. Large re.
Electors are becoming more common
every year. However. a very large re.
flecting mirror may not be desirable.
The gain in light-gathering power IN 9
very large rejecting telescope is not az
ali proportionate to the cost OF manus
facture and convenience OF operation.
In my experiments / used three-fooe
reflector. which. although operNfed BY
hand, could be set very quickly. II Q
six-foot reflector had been ut my dise
posal the sensitivity would have been
increased by only fourfold. iris shows
how little is contributed by tho mirror.
and how much of the burden ~ res
CARDS gain in sensitivity fans upon the
'The aforementioned extra hundred.
fold gain in eensitivity required may
be attained by the use Of q rejecting
telescope having . mirror seven feet
in diameter. and by Increasing the
sensif;vity twenty times II
the sensitivity OF the thsfmccoupaes
used In the present work can BE- ID.
creased twofold. this viii leave the
sensitivity to Be increased
tenfold. BY using q special pier for
the galvanoneter, and by using night
suspension In Q vacuum,
1t will not be a very difficult task u In
crease the galvaEometer sensitivity ten
to twentyfold. issn
''It looks, then, as though everything
were In our grasp-everything except q
six to seven foot mirror, set apart
primarily for astroradimetric work.
When one thinks OF an the money
wasted in idle pleasure, and In the wars
of nations. It IL pathetic to realise nat
but for q few hundred thousANd dollars
the people OF this generation might live
to see something practical Forthcoming
from the investigation Of the radiation !.
II atarz.. -