AstroNotes 1969 March Vol: 8 issue 03




Download PDF version: 

Vol. 8 No. 3   ASTRONOTES March 1969

Editor: Tom Tothill 22 Delong Dr. Ottawa 9
Circulation: Rick Lavery 1227 Morrison Dr. Ottawa 6


Astronomers have always been punctilious in giving due
credit to the original discoverers of new phenomena or methods,
yet strangely reluctant to replace outmoded, cumbersome
systems inherited from the past.

Thus we suffer from a calendar with fictitious months,
of various numbers of days divided into hours, minutes, and
seconds - the latter two also naming the divisions of a
degree. Calculations involving arc and time are fundamental
to astronomy, yet they are still made by hard labour in
this antiquated system.

The brilliant originators of the metric system made
logical arrangements for the measurement of lengths and
weights, but they failed to grapple with arc and time. Had
they divided the right angle into 100 "arcs", one "centiarc"
on the earth's surface would be one kilometre, facilitating
the calculation of distances from latitudes and longitudes.
Dividing the day into 40 "tims", one "tim" would be an
angle of 10 "arcs", facilitating the conversion of arc to

For those who feel that the whole day and the whole
circle should be decimally divided, the metric system is
inappropriate. The unit of length would be 4 metres, or
more likely 0.4 metre (a handy 1.312 ft.). The unit of
weight would be that of a 4-cm cube of H2O (64 grams or
0.141 lb - fairly convenient). But they would have to put
up with a right angle divided into 25 "centicircs" (too
large) or 250 "millicircs" (too small) and a "deciday" of
2.4 hours (too long) or a "centiday" of 14.4 minutes (very

So we'll see you at 33 tims or 83 cd, as you prefer;
but not for ever, we hope, at 8 p.m.
...Unless, of course, we scrap System Ten and go to
System Twelve - which gives us a whole new ball game, the
best available according to number theory. The reason for
this is that Twelve has more factors in relation to its
size than any other number.


Ken Hewitt-White

Those interested recently in quasars, pulsars, and
high-density neutron stars will be getting a new look at the
problem of these deep sky radio objects. The Algonquin
Radio Observatory, whose scientists first hooked up large
scale interferometry programmes with Penticton, B.C. some
time ago, will also be the first to commence an international
interferometer programme.

Australia's Parkes Observatory is the complementing
agent at the other end thus providing an effective baseline
of some 8000 miles between the two dishes. Pulsar diameters
will be the crux issue during the five day programme period
beginning Feb 21; tentatively scheduled for the following
week (about the time you will be reading this) is a second
hookup involving the Parkes and Penticton dishes. The baseline
here will exceed 7000 miles.

Perhaps this co-operation between ourselves and our
friends from New South Wales will provide scientists with
some valuable information concerning these elusive objects.
It would seem that international co-operation is the most
logical and indeed the only feasible means of effecting a
programme of meaningful research into the quasi- and pulsistellar

While on this topic, note should be taken of recent
connections made between Pulsars and Supernovae. The theory
goes that particularly massive stars eventually collapse
upon total consumption of their nuclear energy and form
dense spheres consisting solely of neutrons. During the
collapse, matter is hurled out at an astounding rate in the
form of a supernova explosion. The neutron star's intense
magnetic field traps the hot gas and generates radio waves,
the gas cloud turning with the star. If radio radiation is
emitted by only part of the cloud it would be observed as
pulses; not unlike the pulses received from a rotating
lighthouse beacon. Hence pulsars and neutron stars would
seem to be one and the same. But, can we identify a pulsar
within the confines of a nebula considered to be the site
of a supernova and add substance to this theory?

Distances of deep sky radio objects are found by the
time lag between the high and low frequency parts in each
radio pulse. With this method, R.B.E.Lovelace using the
1000 ft dish at Arecibo in Puerto Rico has placed Pulsar
NP 0532 within 10’ of arc of the centre of the Crab nebula
in Taurus. Assuming that Pulsar and Neutron Star are synonymous,
there would seem to be something in common between
the pulsar and the Crab nebula; namely, both were the product
of the supernova explosion of 1054 A.D.

For further information concerning these theories, the
reader is referred to the January issue of 'Sky and Telescope'
and also to an article by Thomas Gold of Cornell
University in 'Nature' for May 25, 1968.
* * * * * * * * * * *


The Annual Dinner meeting of the Ottawa Centre was
held in the Junior Officers' Mess at Rockliffe Air Station,
drawing a large attendance despite the prevalence of 'flu
in the City.

After a thoroughly enjoyable smorgasbord dinner there
was a short business meeting in which, as has become
customary, the Council was re-elected for a second year,
the Treasurer reported a state of reasonable solvency, and
the Secretary reported on Centre meetings and the activity
of the Observers Group during the year.

The guest speaker was Dr. Roy M. Pritchard, Professor
of Psychology at McMaster University, on the subjects
"Psychological Aspects of Vision."

According to Dr. Pritchard, your eyes can fool you
more often than you are aware of, especially if your mind
has been conditioned to expect something other than what
is presented to them.

There was a lively discussion, ranging over UFO's,
radar interpretation, and astronomical observations.
* * * * * * * * * * *


At the time of going to press, two February meetings
were forthcoming.

On the 20th, the Centre would meet at the Neatby
Building to hear Dr. Clifford D. Anger of the Physics
Department, University of Calgary, on "Scanning the Aurora
from Above and Below".

On the 22nd, a party of the Observers Group planned
to visit the Montreal Centre and the Dow Planetarium.
A GRAZE ON MARCH 21 Tom Tothill

March 21 is a Friday evening. The moon will be a bit
low in the west (16.3 ° altitude) so we need rather good
sky conditions. The star, ZC 425, is Mag 7.1 but as the
moon will only be 15% sunlit, and the graze is 6.2° around
the dark limb from the cusp, I think it should be easily

The star will appear to approach from the dark side
at the north end of the moon. Central graze is at EST
20h 48m 13.8s as seen from a site about 5 miles south of
Rideau Ferry. This is a bit farther out than we have been
before and will necessitate a prompt start right from work
with everything already packed in the noon hour.

Teams should definitely have a car each, a telescope
preferably of 4" or more aperture with an observer experienced
in its use, an eyepiece to give about 100 power,
a good radio with fresh batteries for CHU, and the best
battery tape recorder you can lay your hands on - plus
someone to work it who can do it blindfold, and who will
keep tabs on how long to go and how long to keep observing.
So start organising your team and your equipment - a
last-minute lashup is utterly useless - and do call me in
case of difficulty, and to signify your intention to go.

The final decision to go or not will have to be made
about 4 p.m. on the day. Would car drivers kindly call me
at work (993-2288) as soon after 4 as possible?
* * * * * * * * * *


Tom Tothill

On Saturday evening, March 22nd, the moon will pass
quite centrally through the Pleiades, occulting all the
brightest stars, and many fainter ones, between 7:47 p.m.
and 11 p.m.

Here is a marvellous opportunity to get some experience
in timing occultations - there will be one every few
minutes all evening - and you can work at home with your
usual setup and power available for radios and tape-recorders.
The list overleaf is all stars down to 9th mag, from
Joan Bixby's larger list computed for Ottawa. See the
January Astronotes for methods (p. 2)

Fair skies and good luck!

Observers Group, Ottawa Centre
Royal Astronomical Society of Canada
Observer: ___________________________________ ___________
Assisted by:
Telescope: Type; ________________ Dia:____ f/ Power used:
Exact Location: Lat: ____________ Long: Height:
Method of Timing: _____________________________________
Mag PA ° Time EST
h m s
Star # Mag PA°
Voice Time
h m s
Occ. Time
h m s
± sec.
9.0 71 19 47 05 P 025
3.8 80 20 01 42 P C50
5.5 36 20 13 42 P 044
8.6 47 20 18 25 P 062
8.0 103 20 20 16 P 083
7.8 106 20 34 08 P 114
7.1 30 20 42 17 P 097
6.1 73 20 45 35 P 137
7.9 75 20 46 27 AP 139
4.0 20 20 53 39 P 111
4.3 139 20 58 44 P 145
8.4 97 21 15 45 P 220
8.3 94 21 16 59 P 228
6.2 100 21 18 13 P 232
2.9 104 21 22 33 P 249
6.7 61 21 25 38 P248
8.6 100 21 40 15 P 305
8.2 60 21 47 00 P 311
9.0 94 21 52 45 AP 340
6.8 55 21 56 01 p 331
5.3 109 22 10 56 P 397
8.0 84 22 16 06 P 420
3.7 133 22 16 36 Ap 392
7.4 47 22 19 37 P 407
6.6 52 22 20 14 P 414
7.8 87 22 24 54 P 458
7.3 25 22 59 20 P 506


Les MacDonald

Tom Tothill has already reported the latest failure of
the grazing occultation crew, at the January Observers Group
meeting. We were successful in recording one occultation
(AP 392), observed by Debbie Wood using a 2.4" refractor.
The time of occultation was recorded on a battery-powered
tape recorder along with CHU time signals from a transistor
short-wave radio.

While transferring the occultation time from the tape,
I became aware of several methods of improving the accuracy
and reliability of occultation timings.

Probably the most accurate way to deduce the "voice
time" of the occultation is to make the invisible information
on the tape visible by marking the location of each
event (CHU signals and "CUT" signal from the observer)
directly on the tape. This is done by pressing the "pause"
lever on the tape recorder at the beginning of the event
and penciling a line on the tape using a fixed straight
edge such as the side of a tape head. By repeating this
procedure several times, a group of closely-spaced lines
mark the location of each event on the tape. The width of
each group of lines is a measure of the uncertainty in their
exact position.

T1 = "21:58:50"
T2 = "OUT"
T3 = "21:59:00"
0.0 cm
94.1 cm
103.2 cm
0.35 cm
0.30 cm
0.25 cm
0.05 cm
0.05 cm

Distance T1 - T3 is equivalent to exactly 10 seconds,
and T2 - T3 is equivalent to t seconds before "21:59:00".
Here, t = 0.88 ± 0.06 seconds.

The uncertainty of 0.06 seconds is obtained from the
sum Δ T1 + Δ T2 + .05 (the uncertainty in the measurement
of T2 - T3 ). Thus, the "OUT" signal occurred 0.88 ± .06
seconds before 21:59:00. In other words the "voice time" is
21:58:59.12 ± .06 seconds.

So far I have assumed that the battery-powered tape
recorder was operating at a constant speed. By measuring
the distances between seconds pulses near the time of
occultation, I found the original tape speed varied by
about 4% over periods of 10 seconds. This makes the "voice
time" 21:59:59.12 ± .10 sec.

To obtain the occultation time from the "voice time"
we must subtract the "lag time", which is the observer’s
estimate of the time interval between disappearance of the
star and the time she said "OUT". The "lag time" was estimated
to be 0.2 ± 0.1 second, giving an occultation time of
21:58:58.9 ± 0.2 sec.

This uncertainty of 0.2 second can be resolved into
three parts:
1) uncertainty in measuring the relative positions of
events on the tape;
2) uncertainty in the recording speed of the tape;
3) uncertainty in "lag time".

The first uncertainty can be reduced to about ± .03
sec by using a higher tape speed. The uncertainty due to
variations in tape speed can almost be eliminated by using
a capstan-driven tape recorder. The greatest error is
caused by the subjective estimate of "lag time". This can
be reduced through experience but the estimate remains
subjective and unreliable.

Dark limb occultations can be simulated and lag time
can be measured to ± .02 sec using a capstan-driven tape
recorder at 7½ i.p.s. A small light source (such as a neon
bulb) can be controlled through a variable resistor to
simulate stars of different magnitudes. A microphone near
the switch would record the "click" as the switch is closed
(simulating an egress) or opened (ingress). An observer

using a low power telescope at a distance of about 100 yards
is equipped with a second microphone which records the appropriate
voice signal of "ON" or "OUT".
This method would allow us to obtain information on lag
time for different observers and observing conditions. The
relative merits of tape recorder and stop watch for recording
occultations could also be studied. The cost for such a
device is negligible since the parts are available or can
easily be scrounged.
* * * * * * * * * *

Thanks to Les MacDonald for this very careful and
thoughtful analysis. The experts do not agree on the best
methods for occultation timing as shown by the following

Gordon E. Taylor (HMNAO): "Many experienced observers
prefer the eye-and-ear method whereby the observer listens
to a signal giving seconds beats, counts from the minute
beat and estimates the fraction of a second when the occultation
occurs....The author has found his ’lag time' to be
about 0.3 sec for disappearances and 0.5 sec for reappearances."
Tom Van Flandern (USNO): "Every stopwatch has different
and peculiar problems...Most behave badly in cold weather...
Each needs corrections determined under actual observing
conditions...for every observing session."

"There is no better way to treat personal equation than
to eliminate it...One technique comes close for those willing
to practice a great deal...When you are confident that you
can estimate the precise length of one second mentally,
force yourself to delay exactly one second after an occultation
before..." saying "OUT".


Steve Craig

At the last Observers Group meeting I held up a rather
substantial pile of papers; they were approximately one half
of all the observations which have passed through my hands
in the past year, and would seem to be quite impressive when
compared with the Solar observations produced before 1968.
It will take all the time I have to get these two
pounds of observations into a form which can be presented
at the General Assembly, so I will not have time to beg for
observations. But this doesn't mean that I don't want any
more observations; I could use more than twice as many
observations as I had last year.

So I am asking every member of the Group who can
observe the sun to go out and observe it at every opportunity.
The type of observations I went were outlined in the December
issue of Astronotes, and you can get useful results with
almost any type of equipment.
* * * * * * * * * *
Confucius Say:
"Best Finisher is Self-Starter."
* * * * * * * * * *

THIS MONTH'S PROBLEM... last month's boob. It is a numerical error on
page 10 of the February issue.
Can you find it? And if so, what is the correct
* * * * * * * * * *


Space in the last two issues was too much at a premium
to acknowledge the exceptionally interesting talk on "The
Fine Structure of the Solar Atmosphere" given by Dr. Vic
Gaizauskas to the Centre on Dec 18. It was copiously illustrated
with excellent slides and a most interesting timelapse
movie of a small spot area which showed snaky emissions
of darker material from the spot, and the growth and decay
of convection cells.

Dr. Gaizauskas has found that a site on the Ottawa
river almost surrounded with water gives far better daytime
seeing than land sites around Ottawa and on Mount
Kobau. In relation to his equipment, his pictures are
outstandingly good.