AstroNotes 1968 March Vol: 7 issue 03

EDITORIAL . OBSERVER'S GROUP MEETING FEBRUARY 1968 . IDENTIFYING AN UNKNOWN STAR . JANUARY DINNER MEETING- OTTAWA CENTRE, RASC . LIBRARY NOTE . COMET IKEYA-SEKI I967n . AN INTERESTING LUNAR GRAZE IN APRIL . SWAP SHOP . CURRENT STANDINGS IN THE MESSIER CLUB . JANUARY ELONGATION OF MERCURY

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AstroNotes

The Newsletter of the Ottawa Centre, RASC

Volume 7 March 1968 Issue 3

Editor: Peter MacKinnon 574 Westminster Ave., Ottawa 13, Ont. 728-7103
Circulation: Rick Lavery 1159 Cobden Road, Ottawa 5, Ont. 828-8213

EDITORIAL

An interesting point was brought forward at the February Observer's Group meeting. It was proposed that a second award, like the Observer of the Year medal, be given on  the basis of 'service' to the centre. This is not to be confused with the RASC service award, but one solely for the Ottawa centre. The exact grounds for such an award have not been specifically layed down, but it is the opinion of many, including myself, that such an honour should be granted. The Group executive would appreciate hearing from
members on this topic.

A feeling has developed among some members that a paper or article describing the experiments and equipment facilities of our centre should be published in a science journal. First choice for such an article could be 'Sky and Telescope', but one wonders whether our own Society journal would accept papers of this type. I would be very interested in hearing about the latter case.

It was mentioned in last months editorial that Astronotes'  circulation was over one hundred and eighty. Well, that it is, for in the past month circulation has jumped from one hundred and eighty three to two hundred and forty. A good sign for our efforts.


OBSERVER'S GROUP MEETING FEBRUARY 1968

Chris Martin

The attendance at the February meeting was up again, indicative of an increase in membership and astonomical interest. Steve Kipp assumed the responsibility for all publications in the library. He will be organizing lists of journals and newsletters available as well as content tables.
A report was given by Steve Craig concerning the formation of a solar patrol. The new group will keep a constant watch on the sun, recording sunspot data. He continued with a few slides and drawings of the naked eye spot of late January.
Rick Lavery, Small Dome co-ordinator, summerized the release form situation at the Dome. Rick also reported his observations of the comet, nova, and the elongation of Mercury.
The deep sky co-ordinator, Ken Kewitt-White, announced that a Messier club was being formed. There was a discussion concerning the rules for this venture.
The main speaker for the evening, Tom Tothill, described the construction of his eight inch reflector, most of which was his own design.
A report on the computer statistics for the Quiet Site meteor team was also presented.
The meeting adjourned at eleven o'clock.

h o t s

Gord Grant will have copies of a siderial time table available at the Observer's Group meeting. page 10

THE STELLAR VIEW

Ken Hewitt-White, Deep Sky Co-ordinator

At the February Observer’s Group meeting it was decided to establish a Messier Club. The newly founded group has replaced the former organization of the same name which had petered out several years ago.
Four basic rules were layed down concerning methods of observing. They are as follows:
1. All observers start at zero M objects.
2. An observer must locate the objects himself.
3. Any optical system may be used.
4. No setting circles are allowed.

The club’s aim is to create keen competition among members in observing deep sky objects. The ultimate target is for each observer to complete the Messier list of clusters and nebulae. First attempts at observing in the club was a trifle disappointing for some. Therefore,it might be helpful for new observers if I give a few hints on locating and observing these objects.

The first problem for new observers is locating a selected object. Few "Messiers" are bright enough for the naked eye but many can be seen in binoculars. For ease in observing I suggest that you mount a pair of binoculars on your telescope. To align this finder you can sight some of the brighter planets. The wider field and increased light gathering power of the binoculars will enable you to find a good number of objects directly, and aid in locating guide stars for fainter ones.

It is important to study your atlas carefully and identify the general region in the sky with your eye before attempting to use your finder. Further,familiarize yourself with the region in the binoculars,and then make your move. "Index" from the the guide star Of your choice to where the object should be, making sure to move in the same direction as in your atlas or chart. Use north-south, etc., instead of "moving across" from the star, for ’’ across" in your star chart may not be across in the sky if the object is not on the meridian. A close look through the eye-piece, and with a few alterations in RA and/or Dec, should bring the object into view. If it doesn't, start over again, for you probably "indexed" incorrectly.

The second problem for beginners is the brightness of deep sky objects. As already mentioned, few objects are bright enough for the naked eye and only a select few are conspicuous in binoculars. However, most can be seen in a small telescope but don't expect them to "shoot out" at you unless the object is particularly spectacular such as M44 in Cancer. It is, therefore, necessary to familiarize yourself with the relative intensity of deep sky objects. The sun and moon are easy targets but you must adapt yourself to the greater difficulty of observing the planets as they are smaller and fainter. Similarly you must adapt to the further faintness of deep sky objects and once you do this the clusters and nebulae will come easier, for you will know what to expect. M35 is a good "first object",being an average open cluster.

I will be glad to answer any querries that you might have.

You can get in touch with me at 733-4949.


IDENTIFYING AN UNKNOWN STAR

J. E . Lilly

A few years ago I spent a couple of weeks in the Bahamas.
One evening about eight o'clock I noticed a very bright star low in the
south, and decided to try to identify it. I had no star maps with me, but had
my Observer's Handbook". If I could determine the right ascention and declination
of the star I would no doubt be able to find it in the list of "The Brightest Stars".

Polaris was visible at the time, and the indication was
that the unknown star was quite close to the meridian, and about fifteen
degrees above the southern horizon. In other words,the star was approximately
seventy five degrees south of the zenith. The declination of the zenith is
always the same as the latitude of the place of observation, and I found
that the latitude of Nassau is about twenty five degrees north. Hence the
declination of the zenith was plus twenty five degrees, and the declination
of this star was seventy five degrees less than this figure, or minus fifty
degrees.

To determine the right ascension I made use of Sirius, which I estimated would cross the meridian in about half an hour. Hence the
right ascension of my unknown star must be roughly half an hour less than
that of Sirius, and reference to the list of "The Brightest Stars" showed the
right ascension of Sirius to be 6 hours 43.4 minutes (1964 Handbook). This
gives about 6 hours 15 minutes for the right ascension of the unknown star.
The identification of the star was now a simple matter. A
brief search in the list of "The Brightest Stars", looking for a bright star
with co-ordinates approximately the same as those derived, showed up Canopus,
magnitude - 0.72, right ascension 6 hours 23.1 minutes, declination - 52° 4 0 '.
There could be no doubt this was the star, the second brightest star in the
sky, and one of the three stars with negative magnitudes (the other two are
Sirius, magnitude - 1.42, and Arcturus, magnitude - 0.06).


JANUARY DINNER MEETING- OTTAWA CENTRE,RASC

Dan Brunton, Recorder

The attendance at this affair was much reduced from that
of last year, but most of this can be attributed to illness. Though lesser in
attendance, those present, (67 in all), were greatly enthusiastic.
The cold of January 16 did not stop anyone from thoughly
enjoying the meal at the Sampan. Aside from the food itself, the high-light
of the meal was Dr. P. M illman's private exhibition of dexterity with chopsticks!
To start things off, M r. M. Thomson, President of the
RASC, presented the 1967 Observer of the Year Award to Rick Lavery.
The reports of the officers of the Ottawa Centre for 1967
followed this presentation. Very encouraging reports they were too; increased
use of the library and a monetary increase (to $ 760) for the centre.
Tom Tothill gave his report on the activities of the Observer's
Group for 1967. (For a discussion of these activities, see his article
in Vol. 6,Issue 9, Dec. '67 of Asto-Notes.)

Our President for 1967, Mr. Earl Dudgeon, gave an informal
"wind-up" oration on the centre. He noted with pleasure the increase in
membership and the new effors and enthusiasm of the student members. After
thanking his fellow 1967 officers, he introduced to the members the new
executive.

Dr. "Archie" Gillieson took over the duties of M r. F il Park,
our new President. Unfortunately, although Mr. Park was present, he was unable
to get around very easily, he had broken his ankle only a few days before the
meeting.

Mr. Earl Dudgeon gave the main address on the subject of
"Stars on Earth". As expected,it was a very good talk. It began with the dawn
of history and traced the search for knowledge of the sun and its composition.
Through a logical progression,and excellent slides, Mr. Dugeon was able to
clearly show the attempts made by the scientific community to learn how the
sun is able to create such intense quantities of power, and how to control
such reactions in hte laboratory. Indeed, a good talk, enjoyed by all.
With that, contented by a good meal and an iteresting
address, the assemblage was adjourned.


LIBRARY NOTE

Stan Mott, Librarian

In recent months the library has aquired a number of new
volumes. The following list gives some indication of this growth.
Galaxies, Nuclei, and Quasars (1965)
Fred Hoyle
Getting Acquainted with Comets (1967)
Robert S. Richardson
Giant Meteorites (1966)
S. L. Krinor
Mars (1965)
Richardson and Bonestell
Meteor Astronomy (1954)
Lovell
Observing Earth Satellites (1966)
Desmond King-Hele
Starlight -What it Tells about the Stars (1967)
Page and Page
Telescopes -How to Make and Use Them (1966)
Page and Page
The Amateur Astronomers Glossary (1967)
Patrick Moore
The Moon, Meteorites, and Comets (1965)
Middlehurst and Kuiper
The Mystery of the Expanding Universe (1965)
William Bonner
The Telescope Handbook and Star Atlas (1967)
Howard


COMET IKEYA-SEKI 1967 n

A summary of recent observations of comet 1967 n is given
in the table below.As of February 20, the comet was located close to the Key
Stone in Herculis. At 4:30 am the comet is found 60° above the eastern horizon.
On March 1, Ikeya-Seki is near M92.
Date
Jan. 24/25
Feb. 7/8
Feb. 15/16
Feb. 18/19
Feb. 18/19
Observer
R. Lavery
D. Brunton
R. Lavery
D. Chapman
R. Lavery
Magnitude
8.5
7.6
7.5
7.4
7.4
Remarks
diffuse, oval shape
even density, diffuse
40", diffuse
diffuse
no well defined
nucleus

This month's problem has been submitted by Tom Tothill.
Using the necessary data from the Handbook, calculate how
long it should take for Io, Europa, Ganymede, and Callisto to pass into (or
out of) Jupiter's shadow.

The following is a solution for problem # 4.
problem; At what point along the line from the earth to the moon
is the gravitational pull of the moon equal to that of
the earth? At this point a moon rocket would leave the "influence" o f earth
gravity and enter the "influence" of moon gravity. Express your result as a
percentage of the distance from the center of the earth to the center of the
moon. The mass of the moon is taken as 0.0123 times that of the earth,
solution: let m 1 be the mass of the earth.
let m2 be the mass of the moon.
let m 3 be the mass of the moon rocket.
let F 1 be the gravitational force acting on the rocket from
the earth.
let d1 be the distance from the rocket to earth when F1=F 2.
let d2 be the distance from the rocket to the moon when
F1=F2.
Where F2 is the gravitational force acting on the rocket
from the moon.


AN INTERESTING LUNAR GRAZE IN APRIL

Tom Tothill

April 12-13 is a Friday night with a total eclipse of the
moon. At 11:22 pm, as totality begins, there will be a grazing occultation
of an 8.7 magnitude star visible from Cumberland, only twelve miles east of
Ottawa.
The graze will not be too easy to observer because it
occurs at PA 218°, while the PA of the brightest limb will be 238° and sweeping
rapidly towards the graze point. However, we plan to mount an expedition
to observe the graze and will probably stay there for the rest of the eclipse,
weather permitting.
This is a rather short eclipse for two reasons. First, the
moon will not cut the centre of the umbra, its nearest approach point being
55 % of the urnbral radius. Second, the moon will be almost at perigee when its
motion is most rapid.
The brightness of the moon during totality will depend
largely on the weather in the southern Pacific Ocean and Antarctica. Bad weather
with high clouds there,will give us a dark eclipse, good weather a very
bright one.
An interesting thing to observe during the eclipse would be
the change in colour of the area around Aristarchus when the umbra sweeps
across it.


SWAP SHOP

FOR SALE: A 60 mm refractor, 35 inch focal length, clock-drive
accurate to 3 minutes per day; 3 eyepieces, 6 mm, 12.5 mm
orthoscopic, 2x Barlow lens, 25 mm illuminated reticle on
finder eyepiece; excellent optics - outperforms Dawes’
limit of resolution; 10 inch dewcap; 60 inch tripod; slow
motion controls and adjustable camera mount.
PHONE: Chuck Bulger 733-5470


CURRENT STANDINGS IN THE MESSIER CLUB

From time to time the top observers in the Messier Club will
be published. With a little effort you can be in this list too. Let's see who
can be the first to get ahead of our current leader, Dan Brunton.
These observationshave all been made since February 5.
Dan Brunton 22
Ken Hewitt-White 15
Rick Lavery 9
Les MacDonald 9
Joe Dafoe 9
Chris Martin 7
Dave Paterson 6
John Conville 4
Dave Chapman 4


JANUARY ELONGATION OF MERCURY

Rick Lavery

The elongation of Mercury in January, though not listed
as favourable, was observed with relative ease in comparison to the three
eastern elongations in 1967.

I began my hunt for the elusive planet at 5:30 pm. on
January 21. Knowing that most of the planets are close to the ecliptic,I
extended a line from Saturn to M ars towards the western horizon to get an
idea of where the planet should have been. At 5:35, in a fiord of black
clouds on the horizon, Mercury twinkled away at about magnitude - 0.5, very
easily visible to the naked eye. Dispite its low altitude above the horizon
( 10 degrees ) it was just as bright as Mars about 15 degrees east of it.
Because of the cloud on this night and January 24 no pictures were taken.

On January 25 the western horizon was perfectly clear
of clouds. Mercury was now about 12 degrees above the horizon and in good
position to be photographed. Remembering past experiences with elongation
photography I waited until the twilight darkened sufficiently (6:15 pm) so
I could take a twenty second exposure on High Speed Ektachrome.
Maximum elongation was observed on January 30, Mercury
was about 12 degrees west of Mars, and approximately 15 degrees from the
horizon. At 6:20 I took another photograph, this time a 25 second exposure.
As usual for Ottawa, the weather didn't hold for the
anticipated configuration of Mars and Mercury with the crescent moon. The
slides of this elongation will be shown at the March meeting.


THE EYEPIECE

The Silent Skywatcher

March skies are filled with many objects of interest.
The following is a resume.
- on March 1, Jupiter comes very close to Regulus. This
would be a good object for photographically recording Jupiter's motion over
a few days.
- many interesting planetary configurations: consult the
Observer's Handbook, page 37.
- Mercury makes a poor elongation, but for those who
haven't seen it, it will be easy to identify on the morning of Thursday March
7 when Mercury will be one degree north of Venus. It will reach maximum
elongation on Tuesday March 12.
- Venus rises in the southeast morning sky at - 3.3 about
an hour before the sun.
- Mars moves from Pisces into Aries, at magnitude 1.5 it
is low in the west, setting approximately two hours after the sun.
- On Wednesday March 20 at 08:20 we reach the spring
equinox. IT 'S SPRING (I hope)
- comet Ikeya-Seki 1967 n is prominent in the early morning
sky.
- Nova Delphini 1967 is still bright, magnitude 5.7, but
it may start fading any day now.
- There is a favorable minimum of Algol on March 21 and
again on March 24. This covers one cycle of this famous variable.
- One might also keep an eye out for aurora due to increased
solar activity.
- There are also a number of occultations: see page 65 in
the Handbook.