PROJECT BLUE BOOK

PROJECT 10073 RECORD
DATE · TIME GROUP 2. LOCATION
October 65 . Northarn Henisphere
3. MODRCE 3. MODRCE 0. CONCLUSION . CONCLUSION
Multiple Comst (IKEYA-SEKI)
4. NUMBER OF OBJECTS
Ons Sse case file Sse case file
5. LENGTH OF OBSERVATION 11. BRIEF SUMMARY AND ANALYSIS 11. BRIEF SUMMARY AND ANALYSIS
N/A Ar/A
6. TYPE OF OBSERVATION
Ground-Visual
7. COURSE
Stationary
8. PHOTOS
XL Yos
0 No
9. PHYSICA DENCE
Yes
No
FORM
FTD SEP 63 0-329 (TDE) Previous aditions of thia form may be usad.
I

L
Photographs
of Comet
Ikeya-Seki
These five pages of Comet Ikeya-Seki
photographs record its changing appear-
ance during the two wecks following peri-
helion passage or October 2lst. However,
only a small sample of the pictures that
continue to arrive at SKy AnD TELEscoPE
can be included here.
.
Above: On October 26th, only five days after perihelion passage, Comet 1965f Above: On October 26th, only five days after perihelion passage, Comet 1965f
I was observed to have a I7-degree tail, from Table Mountain Observatory in
California, operated by the Jet Propulsion Laboratory. J. Young and C. Capen
started this I3-minute exposure at 12: 1 UT, with a 135-mm. telephoto lens.
The comet appeared to them about magnitude zero.
Lelt: Note the spine in the tail in Mr. Capen's Table Mountain pictare on
October 27th (15:00-13:01 UT), taken with a 6-inch f/15 refractor.
2/- T
+1 I
Above: American amateur J. Ruiz obtained this picture
while visiting Tonaatzintla Observatory in Mexico. The
tail rose nearly vertically at his latitude of I9 degrces
north. This exposure is one minute at i/2.8.
Right: On O.tober 28th, R. B. Minton, observing from
I place 15 mailes cast of El Paso, Texas, recorded 20
deaues of tail on a 10.midnte exnosure with an 67

Above: A starlike coma supporting a wile curving tail is captored in this Above: A starlike coma supporting a wide curving tail is captured in this
picture by Eugene A. Harlan, Moumt Hamilton, California. He took it at
13:o6 UT', October 29th, when Ikeya-Seki was 41 million miles from the sun 13:o6 UT'. October 29th, when Ikeya-Seki was 41 million miles from the sun
and 97 million from the earth. In this reproduction. one inch eguals about
3.4 degrees. Note the central bright core of the tail (also weli shown in the
photograph at npper right), which was brighiest where the diagonal streamers photograph at opper right), which was brighiest where the diagonal streamers
begin. The pair of bright stars near the head are (left) Eta and Delta
Corvi. Mr. Harlan used a small Schmidt camera for this two-minate exspostre.
Above right: Taken at 12:oo UT, only an bour before Mr. Harlan's picture,
this one by Glenn W. Shaw shows aleiost imperceptible motion of the comet.
The Et Paso, Texas, observer used a Nikkorex-F' camera with an f/2.5 lens
of 205-mm. focus for this 20-secoud exposure.
Right: in the northern pat of the nasion. the conoet was more dtlunlt to
see, On Ortober Soth. Richard Davis of Sciuate, Massadhusetts, took this
five-mhaate exposure at 9:50 UT. He used an f/2.5 Acro-Ektar lens.

.
A
.
Above: At Las Cruces, New Mexico, Gordon Solberg. Jr., used a reversed Moon-
watch telescope (his f/2.8 camera lens held next to the objective) to obtain this
picture of the comet and the zodiacal lighr below Leo. The lominute
exposure on October Slst was started at I1:5l UT.
Kight: Alan McClure's record on November Ist from I2:i3 to 12:54 UT. Ac his
site on Mount Pinos, he used an f/3.s Zeiss lens of I0 inches focal length.
Below: October 3lst large- and small-scale views by Evered Kreimer, Scottsdale,
Arizona. At left, with a 135-mm. f/4 lens, the four-miaute exposure begaa at
12:35 UT; at right, 55-mm. f/5.6, six mimutes exposure at 12:20 UT.
T

Above: Photographs on the mornings of October 3lst (left), by Bradford A. Smith, and November Ist (right) by Tamie-
A. Smith. They both work at New Mexico State University' Observatory. The bright star near the head is Gamma
Corvi. At that time the comet was moving i) degrees soutltwest per day. K. Ikeya's last comet discovery (l964f) passed near
this same spot in the sky in mid-August, i964.
---
il
Above: This is a 15-second exposure
by Walter A. Feibehnan, Pitt hurgh.
Pennsyivania. He took it on the
morning of November Ist from the
sixth door of an apartment building.
A 35-nm. Leica camera was used at f/2.
Lcte Sheroan W. Schalgz of S. Paul,
Minnesota. took this picture on the
momiag of October 2Sth. His Aero-

PROJECT 10073 RECORD
1. DATE · TIME GROUP OCATION
October 65 Northern Henisphere
3. SOURCE . CONCLUSION
Multiple Comet (IKEYA-SEKI)
4. NUMBER OF OBJECTS
One See case file
5. LENGTH OF OBSERVATION 11. . BRIEF SUMMARY AND ANALYSIS
N/A
6. TYPE OF OBSERVATION
Ground-Visual
7. COURSE
Stationary
8. PHOTOS
XX Yes
7 No
. PHYSICAL EVIDENCE )
Yes
No
FORM
FTD SEP 63 0-329 (TDE) Previous editions of this form mey be used.

•
L UNCLASSIFIED
DEPARTMENT T OF THE AIR FORCE
STAFF MESSAGE BRANCH
INCOMING MESSAGE
AF IN : 55787 (26 0ct 65) A/sah Pg l of 2
- — - (29)
SMB A006#1-5 15Z CEJB3 19
00 RUEAHQ
DE RUHLKH H 779822#2
ZNR UUUUU
0 2522 10Z ZEL
FM 326AIR DIV V KUNIA FAC HA
TO RUHL KM/PACAF HICKAM AFB HA TO RUHL KM/PACAF HICKAM AFB HA .
RUHKH/COMHAWSEAFRON
C INFO RUEAHQ/CSAF
RUE CW/CNO
RUECW/SE CNAV RUECW/SECNAV
RUWGALB/CINCNORADD RUWGALB/CINCNORADD
RUHL HQ/CINCPAC
RUHLHS/CINCUSARPAC
RUHL HL/CINCPACFLT
RUAUAZ/COMUSJAPAN
RUAMC/COMUSKOREA
RUAGFL/COMUSTDC
RUCSC/CINSAC
RUCDSQTDE AFB OHIO
AFHQ JAN 65 FORM 0-309C
UNCLASSIFIED

.
UNCLASSIFIED
DEPARTMENT OF THE AIR FORCE
STAFF MESSAGE BRANCH
INCOMING MESSAGE
Pg 2 of 2
) BT
UNCLAS 326AD-CO 01164
1 CIRVIS REPORT
2 MATS 9528 MATS 10092
3 Ao ONE
Do MATS 2bS2O KLT ORTS TL SAn WAT AIT
SEARCH LIGHT POINTING SKYWARD MATS 10092 SEARCH LIGHT POINTING SKYWARD. MATS 100
) BUT ADVISED OBJECT WAS ABOVE THE HORIZON AND T BUT ADVISED OBJECT WAS ABOVE THE HORIZON AND TAIL IS OUT
O
OF SIGHT BELOW THE HORIZON.
4 A POSITION WAS 4A POSITION WAS 110 110 DEGREES DEGREES FROM 25 12 NORTH 15508 EAST AT FROM 25 12 NORTH 15508 EAST AT
1844Z
PAGE 2 RUHLKH 7 UNCLAS RACC LI UNCLAS
525/1829Z
6 UNKNOWN
Tee
7UNKNOWN
8UNKNOWN
9MR BRONSON OF BISHOP MUSEAUM, HONOLULU, HAWAII TENTATIVELY
I NDE NT IFIED IKEYA SEKI COMET.
BT
NNNN CORRECTED COPY OF AF IN 55726 (26 Oct 65).
RETRANSMI T CIA PER AFHQ FORM 1392#453.
AFHQ JAN 65 FORM 0-309C
UNCLASSIFIED

• •

Early.Morning Rising Necessary
Newly-Sighted Comet Visible Here
The neviv-discovered Ikeya- ot the city and be at an ela-.
Sekt comer. named. for two vated- location to sight the
Japanese astronomers w h o coinet, but he added that resi-
first signted it Sept. 18, has dents of Dayton area suburbs
been sighted and photographed may be able to see the comet
by a Wright-Patterson Air from-their' homes.
Force The last comet visible to the
base aerospace engi- naked eye was sighted in 1954,
neer. he said. and "The World Al-
Harold Schuetz. of 1095 Bos- anae" says that barring any
court. Xenia. photographed other unexpected event, such
the eomet with a Polariod as the appearance of the
eamera mounted on a triped Ikeya-Seki comet,  the next
on the rooi of his home. visible comet will be Halley's
He said yesterday the comet which will be seen in 19s6.
is'visibla on the eastern hori- Schuetz. an amateur astro-
won from about 5:l5 a.m. to nomer. said no one-kmows now
3 15 a.in. each morning and when the Ikeya-Seki comet will
should be vistnle through the be seen again. This will depend
end ot this month. on its orbit, he explained, pre-
Schuetz suggested city resi- dicting it won't reappear in Harold Schuelz
dents would need to drive out. his lifetime. .. Sights comet
>
shown here as photographed by Harold
Comet At Xenia
Schuetz froin the roof of his home a.
1095 Boston Court, Xenia. The flecks lo95 Boston Court, Xenia. The flecks
Terined by astronomers the most spec- Terined by astronomers the most spec- of light throughout the sky are the paths
tacular comet seen on earth in more of stars recorded in this time expo-ure tavular comet seen on earth in more of stars recorded in this time expo-ure
han 69 rears, the fkeya-Seki comet is which wa taken at about 5:30 a. . than 60 years, the (keya-Seki comet is which wa: taken at about 5:30 a. .
E

N.C1
MEMO FOR THE RECORD
Mrs. called 20 Oct 65 regarding the comet which supposedly
Sgt. Moody said that it is
the weather. It is also difficult
Sgt. Moody suggested that she call
agsin Friday about lo o'clock.

Comet Ikeya-Seki
AVORAI PLAGED observers on
F October 2o-21 viewed a comet so bril.
liant that it could be seen with the naked
eye in broad daylight, if the sun was hid-
den behind the side of a house or even
an outstretched hand. This beautiful
phenomenon is rave: the most recent day-
light comets had been 1927 1X, 1910 I.
190l I. and the great comets of 1882,
1843, and 1811.
Many more professional and amateur
astronomers viewed Comet Ikeya-Scki in
the dawn skies of late September and
October as a fuzzy patch that brightened
noticeably from day to day. And after
perihelion passage on October 2ist, the
comet's tail became three-quarters of the
carth-sun distance in length. It was seen
curving upward from the southeastern
horizon during morning twilight.
At observatories around the world, the
great comet of 1965 gave an cagerly great comet of 1965 gave an cagerly
awaited opportunity to apply new and awaited opportunity to apply new and
more powerful methods of observation.
In this issue. Brian G. In this issue, Brian C Marsden tells of
this work by professional this work by professiona astronomers. tronomers.
His account supplements His account supplemen description
on page 284 in Nov on page 284 in N vember of the comet's of the comet's
discovery and early ob discovery and early ervational history. ational history.
Also in this issue Also in this portfolio of
photographs of Ikeya-Seki during the fort-
night after perihelion passage. But the
amount of observational material reported
tO SKY AND TELESCOPE is so great that
much of it must be reserved for our Jan-
uary number. That is scheduled to con-
tain a roundup of amateur reports.
During December. Comet Ikeya-Seki
will be visible with small telescopes in
the southern sky in the middle hours of
night, as it travels from Antlia through
northern Vela into Puppis. However, the
strong southerly decijnation will hamper
viewing from most of the United States.
The following positions have been com-
puted at the Smithsonian Astrophysical
Observatory from the orbital elements by
L. E. Cunningham (page 332). Given
here for Oh Universai time at five-day
intervals are the comet's right ascension
and declination (1950 coordinates), and
probable magnitude:
November 21, 11h03m.4, -29 55', 6.4; novenoet  -x,
26, 104 42m.7, -32° 27,6.8.
December 1, J04 2om.1. December 1, 104 20m.1. -3142, 7.2;
6 9h55m.5. -36°35', 7.6; 11, 9h 29m.0. 6 9h55m.5. -36° 35', 7.6; 11, 9h29m.0.
-3759, 7.9; 16, 9"01m.2, -38°48, 8.2; -3759, 7.9; 16, 9"01m.2, -38° 48, 8.2;
21, 8h 33m.3, -38°59, 8.5; 26, 8h06m.1,
-38° 31, 8.8; 31, 7h 40m.8, -37 30', 9.1.
During December, the distauce of During December, the distance of
Conet ikeya-Seki from us increases from Conet Ikeya-Seki from us increases from
98 to 112 million miles, while its distance
from the sun grows from 121 to 174 mil-
lion.
So far, the path around the sun fol-
lowed by Comet Ikeya-Seki has been quite
close to a parabola, but deviations be-
gin to indicate that it is in fact a very
elongated ellipse.

. Tas
+
a -
The motion of Comet Ikeya-Scki within 67 minutes is evident in these dayrime pictures taken October 2lst in Japan. at The motion of Comet Ikeya-Scki within 67 minutes is evident in these dayrime pictures taken October 2lst in Japan. at black disk, which is
Tokyo Observatory's Norikura solar station, 9,4oo feet high. The sun is behind the O°.57-diauneter black disk, which is Tokyo Observatory's Norikura solar station, 9,4oo feet high. The sun is behind the O°.57-dianeter
here fringed by seattered sunlight (not the corona). North is up, cast to the left. The tail lagged far behind the comet- here fringed by scattered sunlight (not the corona). North is up, cast to the left. The tail lagged far behind the comet- greater thau thiat of outllow along the tail. F. Morivama and six co-work-
sun line, because the comet's velocity was much greater thau thiat of outlow along the tail. F. Moriyama and six co work- wasn
ers took these pictures at 2:20 UT (left) and 3:27 with a 4.7-inch f/12.5 coronagraph in 4700-60o0-angstrom light. In
sending these pictures, Tokyo director I1. Hirose writes: "Observers at the corona station noticed at 3:50 that the comet
head was disintegrating, and at 4:37 was divided into three parts, one far brighter than the others."
1965f was brightening in accord with
The Great Comet of 1965 expectation, and that the empirical fo-
verse-fourth-power rule scemed to he
BRIAN G. MARsDEN, Smithsonian Astrophysical Observatory obeyed, even when the cornet was only
a few million miles from the sun.
COMET" was how observing t the comet part of the in- On the morning of October Srd (local
SCIENTISTS' tended Gemini 6 mission. it was also date), the staff of the Smithsonian station
comet expert Fred Whipple at Woomera, Australia, noted that the tail
described Ikeya-Seki as we viewed hoped that significant new findings would was 4° long; three days later it had grown
it together by daylight iI one of result from ground-based observations, to 8°. The early photographs showed a
Harvard Observatory's telescopes on the both of the general appearance of the typical "gas" tail with characteristic
hazy afternoon of October 20th. Reports comet and of its spectruin over as large straight streamers.
had been coming in to us all day of a range of wavelengths as modern tech- During the second week of October,
fruitless predawn vigils by people looking nology permits. the head of Comet l965f was large, very
for the comet's tail, but on the other hand The reason 1965f was expected to be- bright, and almost round on shorter
of new and important scientific observa- come a spectacular object was its small exposures, such as those taken at Lick
tions. 1OR perihelion distance. The activity shown Observatory by S. Vasilevskis and E. Har-
Although a Although a great disappointment to disappoinument to by a comet increases very sharply as it Observatory by S. Vaslievskis and E. riar
it neared nears the su; for example, brightness nears the sun; For example, brighuness lan, at the Mexican National Observatory lan, at the Mexican National Observatory
most of the general public as it neared most of the general public as i fourth by M. Mendez, and at Table Mountain
the sun in October, Ikeya-Seki put on a typically varies as the inverse fourth typically varies as the inverse Observatory in California by C. Capen
spectacular display for ainateur and pro- spectacular display for amateur and pro- power (approximately) of heliocentric dis- power (approximately) of heliocentric dis- and J. Young. and J. Young.
fessional astronomers. So far, its general tance And as the orbital elements by But as the comet approached the sun, But as the comet approached the sun,
behavior has been so similar to that of L. E. Gunninghan that are cited here L. E. Gunninghaun that are cited here it became increasingly difficult to observe,
the great comet of 1882 that it is unlike- imply, Comet Ikeya-Seki was to pass only
ly its performance is now over. Even in ly its performance is now over. Even in 290.oo0 miles from the sun's surlace on 290.coo miles from the sun's surlace on ORBITAL ELEMENTS
Deceinber, Comet 19o5f may be a very December, Comet I9o5f may be a very October 21st at 4:15 Universal time (1:23 OF COMET 19551 OF COMET 19651
striking object in the morning sky, for as scen from Earth).
Southern Hemisphere observers at least. Southern Hemisphere obs s at loast. Prior to passage of the comct through Prior to passage of the comct through Time of perihelion (7) 1905 Oct. 21.17757 ET Time of perihelion (7) 1905 Oct. 21.17767 ET
As told on page 284 of month's perihclion, the Smithsonian Astrophysical Longituade of ascending nods (D) 36-921
issue, the comet was discovered on Sep Observatory received abont 109 reports Node to perihclion () 6%666
tember ISth by two Japanese anateurs from its worldwide chain of observing sta- Indination 14,305
as an Sth-maguioude nebulous object in tions, which are cquipped with the large. Perihclion distance (q) 0.00777559 a.0
Hydra. Ever since September Soth, when short focus Baker-Nunn cameras noimal The angular eiements are referred to the
it becane definite that a new member of ly used for tracking artificial satellites. equator and equinox of rosa. From cofaula-
the famons group of "sun-grazing" comets. Their photographs should provide usefnl tions by i. T. Cuaninghan. fauchr
had been found. excitement has been photometric infotmation about the canel, Obscratory, in Cirrdor joi7 of thre inara
bncresing. Scientists planned rocket as well as data on the motions ol pantickes tional Astronomical Union Bed a ubitsa-
Luanddies. arranged jet fights, and mnde in its tail. These reports iadicated that tions on September 22, Oxtoper i and 7.

lion passage, Woomera astronomers could
see no taud at ali, though the head was
as bright as magnitude zero.
On October 20th, although haze pre-
vented observations without a telescope
in the castern United States, Ikeya-Seki
was a conspicuous object with the naked
eye or binoculars in broad daylight at
many locations in the southwestern states
and across the Pacific Ocean.
At McDonald Observatory in Texas,
the comet was casily seen with the naked
eye at noon (18:00 UT). when only 2°
from the sun. G. de Vaucouleurs writes
"the appearance ..
was reminiscent the descriptions of the
daytime comets of 1882 and 1927: a very
bright nucleus and silvery tail of 1 to 2
visible length." He estmared the total
visual magnitude of the head as -10,
about one magnitude brighter than had about one magnitude brighter than had
been predicted.
Just half an hour later. Norbert Roth
and Darrell Fernald saw the comet from and Darrell Fernald saw the comet from
For this 4!-minate exposure on Octo- For this 41-minut sposure on Octo- the Smithsonian station at Organ Pass,
ber 6th. C. Capen and J. Young at New Mexico. Approximately 1 long and
Table Mountain Observatory used a Table Mountaia servatory used a slightly curved, the tail scemed of aboot
telephoto lens of 250-mm. focal length. telephoto lens of m. focal length. the same brightness as the 25j-day-old
moon visible at the time.
especiaily from the Northern Hemisphere. especially from the Northern Hemisphere. At Kitt Peak National Observatory in
Even in the southern continents, morning Arizona, Stephen Maran observed with
twilight masked most of the tail, and on twilight masked most of the tail. and on 16 x 50 binoculars from within the shadow
October 18th, just 80 hours before perihe- of a 24-indt black disk erected to hide
the sun. "The niost splendid thing I have
ever seen," he notes. From a distance
of 125 feet behind the disk he successfully Delicate tail structure is visible in
photographed the comet with an Exakta this 20-minute exposure on October
camera mounited on a Questar telescope. 7th with the 40inch reffector at
Comet I965f was clearly visible with the Flagstaff, Arizona. Official U. S. Navy
unaided eye all day at the U. S. Naval photograph by Elizaheth Roemer.
Observatory's station in Flagstaff, Arizona. At 3:50 UT on October 21st, only half
There, H. Ables. J. Christy, H. Guetter. an hour before perihelion passage, a "dis-
and J. Priser were able to photograph it ruption" of the comet was observed from
with the 6l-inch astrometric reflector. At the Mount Norikura coronagraph station
0:00 UT (of October 2ist) Elizabeth
Roemer judged the head to be magni-
tude -lo or -l1: the nuclens was stellar
and the 2 tail showed marked curvature.
That same aiternoon, though he could
not see the comet without binoculars, G.
Van Biesbroeck in Honolulu noted the
tail's curvature; considerable develop
Mid exposure was 11:32 Universal time Mud exposure was Il:32 Universal time ment had taken place since morning. ment had taken place since r morning.
on October 13th for Manuel Mendez on October I3th for Manuel Mendez Ikeya-Seki was a striking object from the
I6-minute plate, taken with the Carte California Institute of Technology's cam-
du Ciel refractor of the Mexican Na-
tional Astronomical Observatory. The pus in Pasadena.
comet, which was near Gamma Cra- In Japan the comet was described as
teris, showed a tail 42 minutes long. "I0 times brighter than the full moon." "I0 times brighter than the fulli moon.
Left: The comet on Oc Lefe: The comet on Oc
toberI1th (left) and tober Ith (left) and
1ith. For these shout Wth. For these short
exposures, Messrs. Ca-
peu and Young used a
6-inch t/15 refrattor, at
the Table Mounitaia
Observatory of Jet Pro
pulsion Laboratory. Just 4y days beiore perihelion passage.
hear Wrighnwood, Cali- Comet Ioost appeared as magnitude
fornia. By the time of s0.2 to A. A. Page at Brisbaue. Ans
the serond pictuae, Cont talia. On Oatober t6th, 18:10 UT. he
et I96st wds 36 million and Mrs. Page made this Z-minute ex-
miles from the sun. posute with ant f/5.6 iens of 1sdson.

Daytime drawings by Geraed de Vatt
couleurs at McDonald Observatory.
Right: October 20, 22:30 UT with the
10 inch finder of the 82 inch reflector.
Left: October 21st. 16:0o with the
4-inch finder of the 36-inch telescope.
Swirls in the tail were noted on the
27th at Organ Pass and in Florida. By
the 29th, the tail was readily noticeable the 2oth, the tail was readily noticeable
an hour or so bclore sunrise in the cli-
With his unaided eye, David Meisel made these daylight skerches trom Flagstaff, With his anaided eye, David Meisel made these daylight skerches trom Flagstaff, matically less favored New England states, matically less favored New England states,
Arizona, as the great comet approached perihelion. -The drawing at left was Arizona, as the great comet approached p perihelion. -The drawing at left was but in the encroaching dawn the head but in the encroaching. dawn the head
made October 20th at 21:00 Ut, the other two hours later. He saw about 24 made October 20th at 21:00 U't, the other two hours later. He saw about 24 could not be seen without binoculars or
degrees of tail and a coma two minutes of arc (or less) in diameter. a telescope. During the first week of a telescope. During the first week of
of Tokyo Observatory. See picture cap- United States, 19o5f was again a naked- United States, 1965f was again a naked- November the comet became more easily November the comet became more easily
tion page 332. eye object on October 2lst. At about eye object on Octol r 2lst. At about visible as it moved away from the sun.
Few observations have been reported 17:00 UT, McDonald Observatory as- The "dust" tail was about 30° in length The "dust" rail was about 30° in length
during the following few hours; this is trononers judged the magnitude as -8, trononers judged the magnitude as -8, (corresponding to 70 million miles).
believed to be due to generally cloudy and took black-and-white and color photo- The nucleus had become double, How The nucleus had become double, How-
ard Pohn found on November ith with ard Pohn found on Noverber dth with:
conditions. Clear in Prague, how- graphs through the finders of both the the 30-inch f/15 reftector at the Astro-
ever, did allow nomners there to pick 82-inch and 36-inch reflectors. Extensive U. S. Geo-
up the comet with the unaided eye shortly observations in broad daylight have been geology Department of
after sunrise. According to L. E. Cunning- reported from Organ Pass, Flagstaft, and logical Survey, Flagstaff, Arizona. He
ham's calculation, the comet should have Table Mountain. observed visually and photographically a
passed within a quarter-minute of arc Telescopic daytime viewing was also second nuclear condensation. situaiedd
of the solar disk at 5:25 UT. possible on October 22nd, when the com- about 14 seconds of are up the tail spine
That morning in France (©:00 UT on et's magnitude was estimated as zero at from the first, ar about 1 magnitudes
October 21st), Provence Observa- 17:15 UT fromn Lowell Observatory, and fainter than it. following morning.
tory reported the tai was only one minute as 2 three hours later from McDonald. the magnitude diffe was only  and
of arc lorig. A few hours later at Bochum The carliest observation in the dawn the separation 16 seconds; if the second
Observatory, West Germany, the daylight sky following perihelion passage was made mucleus was really in the tail spine, the
comet was estimated as of magnitude -6 at the Pretoria, South Africa, Moonwatch distance between the two would have
or -7. A similar estimate was made in station on October 23rd, and the next been 8,000 miles..
Cambridge, Massachusetts, at 9:00 a.m. morning a 5 tail was visible there with A possible third condensation was sus-
Eastern standard time (14:00 UT). when the naked eye. On October 25th at the pected, twice ay as the second.
only the bare beginning of a tail was Smithsonian station in Arequipa, Peru, and more than three magnitudes fainter
visible. a tail 20 loung and 3° wide at its ex- than the first. Other astronomers reported
In the clearer skies of the western tremity tapered out from a head of mag- additional nuclei, probably transient in
nitude -2.
Contrast the preperihelion aspect at
left (October 20th, 22:01 UT) with the
postperilelion one above (October 21,
15:3b UT). Observers at Sacramento
Peak Observatory, where these red.
light pictures were taken with the 16. On October 21st at 18:17 UT. H. Ables
inch coronagraph, moted that the rail and I. Chisty secnred this 15socont
was redned in brighoness after peri. exposure whh the U. S. Navy's bi boch
helion. Linagraph Shell Buist hlm was astrometrie reflestor ar Flegstatl. Note
used for these i/so-second exposures. the lyre-shaped tail, also well shown in

as a member of the sungrazing lamily becatse similar lines were never found
that incindes 15gst. less than is hours in stbsequent comets. Bat then, no later
alter perihelion. comet was observed so close to the sun,
Copeland and Lohe saw the D lines until now.
immediately, red shifted fron their nor- In an article published carly in 1965.
mal wavelengths by the comet's velocity the well-known Belgian expert on com-
of recession. I he Swan bands were very etary spectra, Polydore Swings. expressed
weak, but a mumber of additional bright his belief that liues of calchum and other
lines could be seen in the green and clements would cventnally be fouad in
orange. The Dunccht observers thought comets of very sinall perihclion distance.
that most of these lines were due to iron. His hopes have becn quickly realized!
with some possibly from titaniun and On the morning of October 20, 1965,
calcium. A. D. Thackeray at Raddiffe Observatory,
For eight decades this report of addi- in South Africa. obtained spectrograms
tional bright liues has been controversial. of the mudeus of Comet Ikeya-Seki, then
In 1927. the Russian astronomer S. V. only cight million miles from the sun.
Orlov rediscussed the Copcland-Lohse ob- These showed bright lines of neutral
servations, and agreed that the green lines iron, and also the H and K lines of
were probably of iron. but he hesitated ionized calcium. (Copeland and Lohse
to identify the othcrs. Many astronomers could not have detected the H and K
did not believe the observations, mainty lines, which are outside the visual range
The comet's nucleus appeared elongat-
ed on November 5th (top) and defnite-
ly split the next day. The five-minute
exposure on the 5th began at 13:14
UT, the one minute one on the 6th at
13:25. C. Capen and J. Young used the
6-inch Table Mountain f/15 refractor.
nature. In the case of Comet I8s2 II, one
month after perthelion passage, five sep-
arate condensations were seen along a
40-second arc. (See a picture of them in
February, 19G0, SKY AND TELescope, page
204.)
To professional astronomers. Comet
Ikeya-Seki provided a very welcome op
portunity to observe the spectrum of a
great comet at small heliocentric dis-
tance. The last comparable chance was
in 1882, when spectroscopic techniques
and interpretations were both very primi-
tive.
In the visual spectrum of an average
comet. the most conspicuous features are
three bright bands-the Swan bands, due
to the diatomic carbon molecule. C.
Most comets also show a pronounced
continuous spectrum. often with super-
imposed dark lines that match the solar
absorption spectrum.
Photography of cometary spectra began Photography of cometary spectra began
in 1881, leading to the observation of in 18s1, leading to the observation of
new bands toward the violet. These in-
cluded features due to triatomic carbon
(C,). cyanogen (CN). and the CH radical. (C,). cyanogen (CN). and the CH radical.
Then, in Comet 1Ss2 I the sodium D Then, in Comet 1S82 I the sodium D
lines (at 5896 and 5890 angstroms) were
observed in cmission, and these have observed in emission, and these have
since been recognized as a normal feature since becn recognized as a normal feature
of comers at rclatively small distances from
the si.
On September 18, 1882, the first spectro-
scopic observation of a comet in daylight
was made by Ralph Copeland and J. G.
Lohse, with a visual spectroscope attached The comet over Maui, Hawali, at about 15:00 UT on October 28th. A 35-mm.
to the 15-inch relractor of Dunecht Ob camera was used for a oneminute exposure by persoanel of the Baker-Nuan
wervatory, in Scorland. They viewed the tracking station oi the Smithsonian Astrophsical Observaory. Probably an
Great Conet I8s2 IL. already mentioned artificial satellite made the trail at upper right.

.
This unusual photograph of Comet Ikeya-Seki (19osl) was taken by Alan McClare on the morning of Novenher 1. 1965.
It is an li-minute exposure begun at i2:43 Universal time. Well seen here on a large scale are the small bead and
the structure in the tail near it. At that time, the comet was ahout 5i million miles from the sum and os million tron the
carth. On this reproduction one indh equals about o.os degree. The pictue was taken from the S,sou foot level on Mount
Pinos in California. Mr. MeClure used an f/5 Zeiss acrial lens of 5 inches aperture and a pauchromatic emulsion.
1.