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IAUC 2251: N Cyg 1970; RADIO EMISSION FROM HCN; LUNAR Occns OF IR OBJECTS; 1970f; 1969i

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                                                  Circular No. 2251
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.

     Dr. Francis M. Stienon, Warner and Swasey Observatory, telegraphs
that an objective-prism plate taken with the 61-cm Schmidt
shows the spectrum of a nova as follows:

     1970 UT          R. A. (1950) Decl.     mpg
     June  8.3       20 50.9     +35 48     11.8

Emission lines of hydrogen are strong and broad, and the continuum
is weak.  The nova is evidently 3 to 3.5 magnitudes below maximum.
A visual plate with limiting magnitude about 16.5 taken of the
region on May 7 does not show the star.  The object is distant from
HBV 475 by dR.A. = +1m.9, dDecl. = +24'.4.

     Dr. William E. Howard, National Radio Astronomy Observatory,
reports: "Hydrogen cyanide (HCN) has been detected in a number of
galactic sources.  This discovery was made by David Buhl, National
Radio Astronomy Observatory, and Lewis E. Snyder, University of
Virginia.  The line was found in emission at a frequency of 88.6
GHz (wavelength 3.4 mm) in W49, W51, W3, Ori A, DR 21, and at the
position of the ammonia cloud in Sgr A.  In these sources the line
was first observed on June 1 with the 36-foot (11-m) telescope of
the National Radio Astronomy Observatory at Kitt Peak.  The HCN
line in Ori A is at the same radial velocity as the CO line reported
by Jefferts, Penzias and Wilson in April (IAUC 2231).  The
other sources have radial velocities which approximately correspond
to the velocities of the interstellar formaldehyde absorption
reported by Snyder, Buhl, Zuckerman and Palmer (1969, Phys. Rev.
Lett. 22, 679)."

     Dr. George Wallerstein, Department of Astronomy, University of
Washington, writes: "The peculiar infrared object IRC +10216
(Becklin et al. 1969, Astrophys. J. 158, L133) will be subject to a
series of lunar occultations starting 1970 September 27 and
continuing monthly through 1971 April.  Occultation observations will
permit a determination of the radius of IRC +10216 for radiation of
different wavelengths from 1 to 20 microns.  A direct plate taken
by Arp and shown by Becklin et al. indicated that IRC +10216 has
dimensions of about 2" x 4" in the band 5000-7000 A.  A similar
series of lunar occultations will affect the infrared object IRC
+10011 starting 1971 July 15.  For the first five months the
occultations will be most favorable for southern hemisphere observers.
This object is an OH source as well as an infrared emitter."

     Mr. Graeme L. White, Barrack Point, New South Wales, writes
that the comet was observed on May 18.32 only with 12 x 50 binoculars.
The comet had a starlike head (contrary to the statement on
IAUC 2246) of magnitude 1 to 2, and there was a tail approximately
1o in length.  He strongly suspected that he saw the comet again on
May 19.33 (from Sydney Observatory, and with interference from city
lights) in the very approximate position R. A. = 4h45m, Decl. = +16o.  On
May 20.33 he observed the comet with binoculars and with the naked
eye, the tail being then more than 10o long.

     Mr. Z. M. Pereyra, Cordoba Observatory, writes that the Rev.
F. W. Gerber, Lucas Gonzalez, Argentina, independently reported (in
a telegram that took three days to reach Cordoba) the discovery of
the comet on May 22.938.  The comet's tail was 15o long.

     The name of the observer at Mercedes, Uruguay, was incompletely
given on IAUC 2250.  The comet was discovered there by Jorge
Balseiro Savio, Secretary General of the Asociacion de Profesores
de Cosmografia Litoral Oeste, on May 23.96.  The comet was in
western Orion, with a head of magnitude 3 or 4 and a tail 15 to 20o in

     Dr. V. L. Matchett, Brisbane, communicates further approximate
observations by M. V. Jones, S. C. McMillan and himself:

     1970 UT       R. A. (1950) Decl.  Mag.       Tail          Observer
     May  31.342    5 47      +10 20         3o.5 in p.a. 108o  Jones
     June  1.336    5 50.4    +10 04    5.6               115   McMillan
           1.342    5 50.2    +10 05    8.0  3            108   Jones
           1.344    5 50.3    +10 00   <7.0  7            105   Matchett
           2.332    5 54.0    + 9 45    5.6  5            117   McMillan
           2.340    5 53.2    + 9 48                            Jones
           2.347    5 53.6    + 9 51         3            115   Matchett
           4.347    6 03      + 9.5          5

     Corrigendum:    IAUC 2232, line 3 from end.  For  (0,0)  read

1970 June 10                   (2251)              Brian G. Marsden

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