AstroNotes 1966 December Vol: 5 issue 03

EDITORIAL . Messier Observers . Deep Sky . METEOR OBSERVING . CONSTELLATIONS . EXPOSURE TESTS . INDEX ASTRONOTES . DECEMBER METEOR SHOWERS . Observer's Group -November Meeting

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AstroNotes

The Newsletter of the Ottawa Centre, RASC

Volume 5   ISSUE 3    December 1966

Editors Dan Brunton 2965 Elmhurst Street, Ottawa 14 , Ont. 828-1473
Circulations Bill Dey 2687 Ayers Avenue, Ottawa 8 , Ont. 733-0518

EDITORIAL

At the end of this issue you will notice an index to ASTRONOTES. I also have the
index for 1964 and 1965-66 and these will be published at a rate of one set per issue. Next
year I hope I will have the 1967 index in the December 1967 or January 1968 issue.
I sincerely hope this will make ASTRONOTES easier to use and encourage members
to retain their issues. If you find, however, that your collection is very incomplete, I
would very much appreciate your back issues so that members who need but a few issues to
complete their set will be able to contact me and thus receive their missing issues.


Messier Observers

The following is the list of members who have indicated they have seen over 50
Messier Objects. I strongly suspect this list to be highly inaccurate and hope that you
will inform me of the mistakes. Let's keep this list up-to-date! It is for our own interest!

The Planetary list is so inaccurate that it is useless to mention it. How about bringing
this up-to-date too?
The Messier Group consists of:
John Stairs          107
Dan Brunton        78
Fred Lossing      100
Jack Horwood      68
Philip Cheffins     92
Bill Dey               57
Rick Salmon       80
Les MacDonald  52
As you have noticed, the November and December issues are stapled together.
Unfortunately, lack of time and production problems last month prevented us from getting
it out on time. It has, however, very worthwhile articles and we feel you will enjoy it
anyway.
In conclusion I would like to wish everyone a very merry Christmas and a HAPPY CENTENNIAL YEAR!!


Deep Sky

Co-ordinator J.A.Stairs.

The star chart this month shows the position of the largest asteroid, Ceres, from
November 1 1966 to March 31 1967. Bracketed numbers are magnitudes. Background stars go
down to 71⁄2. Observations are best made with binoculars. Also easily seen in binoculars are
beautiful open clusters M-35, M-36, M-37 and M-38. Here is some data on these objects:
M-35      Size 29'         Mag . 6        Distance 2700 l.y.
M-36      Size 16'         Mag . 6        Distance 4100 l.y.
M-37      Size 24 '        Mag . 6        Distance 2700 l.y.
M-38      Size 18'         Mag.7          Distance 2800 l.y.

Alongside M -35 is the open cluster NGC 2158 that can be seen with a Skyscope
(3"1⁄2 35X) on a dark clear night. Other open clusters for a small telescope are NGC 1907
and NGC 1893.

Near Zeta Tauri is the Crab Nebula, M-1, the remnant of a super nova recorded
by the Chinese in 1058 A.D. and possibly also by the inhabitants of Navaho Canyon in
Northern Arizona ( Scientific American, March 1957). Oddly enough no record has yet been
found from Europe though the star was bright enough to be seen in full daylight. The
nebula was first discovered in 1731 and its rediscovery by Messier in 1758 led him to
compile his catalogue. Its size is 6 ', flag, between 10 and 11, and Distance 8100 l.y.
The star 88 Aurigae ( Flamsteed's No.) is a Cepheid, period 3.73 days, Mag. 3.7
to Hag. 8.3. While watching Ceres one might also wish to observe these as well. Theta
Aurigae is a double that is a test star for a 8 inch telescope. Mags. 2.7 and 7.2, Dist.
2" . 8 , P.A. 332° .Lastly, a few words on Asteroids. Ceres was discovered by Piazzi in Palermo,
Italy, on January 1 1801. This was followed by Olbers and Harding discovering Pallas, Juno
and Vesta during the next seven years. The fifth was found in 1845 and after 1847 new
discoveries became quite common each year. The sizes of the first four are 477, 304 , 120
and 23 9 miles respectively. Most asteroids are only a few miles across. Baade estimated
that between 30.000 and 40 .000 of them are brighter than the 19 th magnitude.


METEOR OBSERVING

The R.A.S.C. Committee on observational activities, Meteor Section, recommends
the following Atlas list for members interested in beginning to Meteor observe:
1. Norton’s Star Atlas.
2. Deep Sky Calatogue.
The Committee also recommends the books:
1. Between the Planets.
2. Meteor Science and Engineering.
If you are interested in these books, Mr. Mott, our Meteor and Comet co-ordinator,
will be able to help you.


CONSTELLATIONS

Frank Evraire, Deep Sky Section.

One of the more prominent constellations in the late Autumn sky is Perseus,
looking somewhat like a headless dancer walking to the east.
More than half of Perseus lies in the Milky Way and just above the star Eta Persei,
there are two beautiful clusters which can be seen on very clear nights as faint and hazy
masses among the countless stars of the Milky way. These two clusters are known as M-34
and M-76.

Perseus, like Cepheus, has one of those intensely interesting phenomena, a
visible variable star. This star, near the bottom of the western leg of Perseus and lying
almost on the meridian, is Beta Persei, Algol. Algol is a prototype of the eclipsing
variable, whose variation is due to their eclipse by a fainter companion which revolves
around the brighter star. When the faint star is beyond the brighter one, we receive the
full unobstructed view of the brighter star. When the two stars are side by side, as the
companion revolves around the brighter one, we gain slightly in brilliance because we are
then receiving all the light of both stars. When the faint star is between us and the
brighter one, only that light is seen by us as this eclipsing act is performed.
Algol varies from a maximum of mag. 2.2 to a minimum of mag. 3.2 every two days,
20 hours and 48 min. It reaches the low point in luminosity in 41⁄2 hours, stays dim for
about 20 min. and then returns to full brilliance. It is no wonder the early people
referred to it as Algol or "the demon" .

The bright star in the Algol binary is 2.700.000 miles in diameter, slightly
more than 3 times that of our sun, but giving off
160 x more light than the sun. The fainter
of the pair is even larger and would be just about
visible to the naked eye were it alone.

The stars are main sequence and are fairly close together ( astronomically speaking),about
2.000.000 miles apart. The system is about 150 l.y. away.
The western leg in which Algol is found is rather faint. The only other star
brighter than a mag.4 is Rho, another variable. It rises to mag. 3 .4 from 4 .2.
The eastern leg of Perseus is much more brilliant and features Alpha Persei,
Algenib, sometimes known as Mirfak. This star is mag. 1.9 and lilac in colour. Its distance
is 570 l.y. and has a proper motion of 1 M.P.S. ( miles per second), and a minus radial
velocity of 7 M .P.S. It is a spectroscopic binary and is surrounded with so mary stars it
appears to be in a cluster.

Lastly, Algenib is the centre of a curved line of stars known as the Segment of
Perseus.


EXPOSURE TESTS

Rick Salmon, Co-ordinator Small Dome.

Since all exposure tests previously taken at the Small Dome, and the exposure
times obtained from them have been taken from single tests sheets, the possibility occurred
to me that between individual plates of the same type, quite
a difference in densities might occur, even at the same exposure, due to slight differences in developing technique
and in sky conditions under which the photos were taken.

To test the extent of such differences, two exposures were made on Super XX film.
Taken on different nights and developed very carefully in D-19 at 68 degrees F. for 4 min.,
their exposure graphs were amazingly similar. The times required to reach a density of 0.7
differed only by a few seconds and in densities only by 0 . 0 3 .
From this it is evident that on the best nights, although slight differences in
sky conditions and developing cause minor differences in the densities of separate plates,
no difference in density manifesting a change in exposure time of more than 1 1⁄2 min.,
should occur. This means that the exposure times mentioned in previous articles should be
accurate to about 2 min.

The exposure for Super XX, as well as the time required to reach a background
sky fog density of 0.7 for extended objects and 0.9 for point source objects, is given
below.
Exposures for Super XX sheet film
Extended objects 17 min.
Point source 3 4 min.


INDEX ASTRONOTES

The following is the index of the contents of ASTRONOTES for 1962-1963. Next
month's issue should see the 1964 index out. I hope this will enable our members to make
quick and efficienc use of ASTRONOTES.
1962 - 1963
A- Editorial:

1. Annual Banquet - Vol. 2 Iss. 2
2. ASTRONOTES - Vol. 1 Iss.1; Vol. 2 Iss.2 , 4 , 10.
3. General Assembly - Vol.2 Iss. 5, 6.
4 . Observational Winter Activities - Vol. 2 Iss.3
5. Solar Eclipse - Vol. 2 Iss. 7, 8.
6. Star Night - Vol.2 Iss.9
7. Visitors to the Centre - Vol. 2 Iss.6

B - Comets and Meteors:

1. Comet Alcock - Vol. 2 Iss . 5
2. Comet Ikeya - Vol. 2 Iss.5
3. Eta Aquarid Meteors - Vol.2 Iss.5
4 . Leonid Meteors - Vol. 1 Iss.1

C - Deep Sky:

Auriga - Vol.2 Iss.3
Barnard's Star - Vol.2 Iss.8
Bootes - Vol.2 Iss.6
Cassiopea - Vol. 1 Iss. 1, Vol.2 Iss.1
Cepheid Variables - Vol.2 Iss.7
Ceres ( other Asteroids) - Vol.2 Iss.3
Coma Virgo - Vol.2 Iss.4
Galactic Clusters - Vol.2 Iss.10
Ursa Major - Vol.2 Iss.9
3C-273 - Vol. 2 Iss.9

D - Instrumentation:

1.Setting Circles - Vol.2 Iss. 6, 7
2. Telescope Makers - Vol.2 Iss.2
3. Variable Speed Drive Control - Vol.2 Iss.5
E - Lunar:
1. Objects of Interest - Vol.2 Iss.4
2. Observations of the Moon - Vol.2 Iss.1
F - Artificial Satellites:
1. New Designations - Vol.2 Iss.2
2. Recent Observations - Vol.2 Iss.1

G - Planetary:

1. Jupiter: a. Central Meridian Transits - Vol.2 Iss.8
b. General Information - Vol.2 Iss.9
c. Recent Observational Conditions - Vol.2 Is s.4
2. Mars - Vol.2 Iss.2
3. Neptune - Vol.2 Iss.6
4 . Uranus - Vol.2 Iss.2
5. Venus - Vol. 1 Iss.1.. 6 ..

H - Radio Astronomy:

1 . Radio Astronomy for Amateurs - Vol. 2 Iss. 3 , 6
2 . History - Vol. 2 Iss. 9
3 . Meteor Counting by Radio Astronomy - Vol. 2 Iss. 3

I - Solar :

1 . Drawing th e Sun - Vol. 2 Iss. 3
2 . Eclipse Photography - Vol . 2 Iss. 7

J - Miscellaneous:

1 . Galileo - Vol. 2 Iss. 1 0
2 . R.A.S.C. pins - V o l.2 Iss. 2
3 . Student Member Activity - V o l.2 Iss. 5


DECEMBER METEOR SHOWERS

Stan Mott, Co-ordinator Meteors and Comets.*

This month, we are fortunate in having one of the best meteor showers of the year.
The GEMINIDS, lik e the Perseids, are classed among the *old reliables* of
Meteor Showers. The radiant is near Castor, the period of greatest activity is between the
9th and 14th of December, and the maximum will occur on the night of 13-14 December, when
the hourly rate should reach 50 meteors. The Geminids tend to be rather slow (not as slow
as the Taurids), and bright - this is a good shower to try your luck with acam era, taking
precautions to prevent the lens from dewing or frosting over! Culmination of the radiant
takes place about 2 a.m.

The URSIDS are normally a weak shower of faint meteors, but they apparently gave
rise to a minor storm 1945. Their maximum falls on the night of 22-23 December; the
radiant is near Beta U rsae Minoris, in the bowl of the Little Dipper.

* The previous article is a segment of a bulletin of the
Standing Committee on Observational Activities; Meteor
Section. Stan Mott, our Meteor and Comet Co-ordinator, is
the national Meteor Co-ordinator.
ED


Observer's Group -November Meeting

The last meeting of the Observer's Group, R.A.S.C. was held on November 5 1966.
Unfortunately, our speaker Capt. W.R. Inman, was suddenly taken ill and unable to attend.
Despite this, the welcome return of Dr. Len Orr (a charter member of the Observer's Group),
after a four-year absence, made it a worth-while meeting. Dr. Orr told the group of 36
members of some of his activities overseas. Dr. Orr is presently at St.Hubert, P.Q.

Dome,

Also at this meeting, Rick Salmon took over from me as Co-ordinator of the Small Dome,
I found that the Small Dome and ASTRONOTES just took too much of my time.

Jack Horwood informed the members of some very interesting happenings on Saturn.
For details, please contact him .
Joe Dafoe, one of our active Student Members, told the Group of the recent activities of the Queensway Terrace Meteor Observing Group and briefly described the methods
employed by the Group.
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