AstroNotes 1970 February Vol: 9 issue 02

LUNAR . PURKINJE EFFECT - CURSE OF THE VARIABLE STAR OBSERVER . ECLIPSE NEWS . COMET TAGO-SATO-KOSAKA (1969g) . VARIABLE STAR AWARD WINNER . OBSERVER OF THE YEAR . TELESCOPE FUND . BLITZ ON THE MIRROR . OBSERVERS GROUP MEETING - JAN 3

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Volume  ASTRONOTES  Vol. 9, No. 2

Editor:
Addresses:
Circulation:
February, 1970
Tom Tothill
Howard Harris
Ted Bean
22 Delong Drive, Ottawa 9
620 Keenan Ave, Ottawa 13
399 McLeod St, Ottawa 4

LUNAR

Barry Matthews

After Chris Martin reported a sliver of silver in the
western sky, I decided that as one of the coordinators I had
better investigate, and lo and behold, even I found it, just
as Chris had described it over the phone.
It appeared as an approximate -10 magnitude crescent
relatively low in the western sky. Also showing was a com­
paratively large dark area in a very red face, and I would
now like to correctly identify this object as "Mare Crisium".
I am sure without any more ado that you all realize I am
talking about a three day old moon. If, however, you did
not figure it out or did not realize Mare Crisium is easily
resolved with the naked eye, I would like to recommend a
book by Ernest H. Cherrington Jr. called "Exploring the Moon
through Binoculars".

To quote from the book ...
"The moon is yours, and Ernest H. Cherrington Jr., a
noted astronomer, invites you to stake your claim now. A
do-it-yourself space program, this month-long guided tour
enables you to have, from the outset, a more detailed look
at the moon than either Copernicus or Galileo ever had!
All you need is a small telescope or a pair of binoc­
ulars, access to the sky, and the capacity to be thrilled.
Because, as this exciting new book proves, it is simply not
true that you need high-powered, high-priced equipment in
order to observe the moon in full and fascinating detail.
Beginning a day or two after the new moon and contin­
uing night by night until the day before the next moon, Dr.
Cherrington presents the most arresting features of the
moonscape. He focuses his binoculars on the high contrast
strip along the terminator which separates the bright sec­
tion of the moon from the dark portion. This unique method
enables you to find the objects discussed (from gigantic
lunar seas to crater rills) quickly and easily, and assures
you of seeing them under optimum conditions."

At the next meeting I will have a prepared list of
objects to find at your own convenience. Also I'd like to
get up a list of scopes and binoculars owned by members.


PURKINJE EFFECT - CURSE OF THE VARIABLE STAR OBSERVER

Rick Lavery

"Generally speaking,it may be said that with experience, two independent observers will agree to within 0.1
or 0.2 magnitude in their estimates on any particular night for white or yellow-white variables (e.g. the U Gem
or RV Tau variables), but for red stars the difference in
estimates may be as much as one or two magnitudes." So
says John Glasby on p. 320 of his book Variable Stars.
It is experimentally well known that if two point
sources of light, one red and the other white and of
equal intensity are brightened by the same amount, it is
observed that the red light is now the brighter. The
reason for this is that the fovea of the eye, when light-
adapted becomes relatively more sensitive to red light
than white. This effect is called the Purkinje Effect.

To minimize this effect one must either use filters
or not let the red light fall on the outer part of the
retina. For amateurs, the first method is probably expensive, but also there would be a great loss of light
involved using ordinary filters. The second method, although more practical, also has its drawbacks. The outer
parts of the retina are relatively insensitive to red
light making a red star appear fainter than it should.
J.Glasby suggests that the best method to use when red
stars are particularly bright is to stop down the instru
ment or use a smaller telescope.

Unfortunately, those involved in the Variable Star
program of the Ottawa Centre are using the smallest instrument available - binoculars, and it is impossible to
see most of the variable stars we are interested in using
the naked eye (in the City). The best solution for us
seems to be a quick glance method. If one compares the
variable and a comparison star with one glance, one should
use their first impression as to whether the variable was
brighter or dimmer than the comparison star and approximately by how much. Another comparison star should then
be chosen that is nearer to the estimated brightness of
the star and the glance method used again to make a more
accurate estimation of the magnitude.

Observers will find that this method works very well
with g Herc, RX Lepr, R Sctm, UU Aur and TX Piscm. The
other stars do not seem to cause too much problem,

Judging by the agreements in estimates being received.


ECLIPSE NEWS

Tom Tothill

Since our own plans towards the eclipse of March 7th
did not reach any definite point on a group basis, here
are some of the options open to members of the Ottawa
Centre.

For those who are thinking of driving down to Florida,
we have a kind invitation from Ken Chilton, President of
the Hamilton Centre:

"Anyone from Ottawa is welcome to share our site which
we have reserved near the junction of US 41 and Fla 6 just
north of Jasper, Florida. Just look for our sign!"
I would suggest that anyone who is planning to go
there should write to Ken Chilton at 93 Currie St, Hamilton
57, Ont. They have an excellent team program and might
like to know what equipment you have. And naturally, the
sooner the better.

For those who do not own the doubtful blessings of
transportation, there is still a chance that they may be
able to get on the Montreal Centre's bus. Through the
kindness of Mr. Good of the Montreal Centre, four places
for Ottawa members have been reserved on the bus and we
know that three of them are filled already. The bus will
leave Montreal on Thursday evening, March 5th, arriving
at a site in North Carolina on Friday afternoon. The bus
will leave for Montreal again on Saturday evening, arriving
on Sunday afternoon, March 8th. Thus two nights will be
spent on the bus, and the total cost of transportation and
overnight accommodation will be kept down to below $60 per
person. Of course you will have to pay your own meals for
three days as well. Contact Rick Lavery immediately for
further details.

A third possibility arises through Jacques Labrecque
of the Dominion Observatory. He plans to drive down to
the Carolinas with several telescopes and a program of
observations. He is looking for a reliable person to help
him. The transportation would be free but the person must
pay for his own accommodation and meals, of course.
For those who will be observing the partial eclipse
from Ottawa, local radio hams are looking for optical
observers who will cooperate with them by timing the
eclipse of sunspot groups for correlation with their meas­
urements of ionization changes. Contact Gordy Grant for
further details.We hear of one brave soul who is going down to
Halifax by train for the eclipse. Murphy's Law of Eclipses
is probably the most rigorous of all his laws: "After you
have read what all the pundits say about weather prospects,
climate, sites, accommodation, etc, head for the most
unlikely place!"

Anyone for Newfoundland?
* * * * * * * * * * *


COMET TAGO-SATO-KOSAKA (1969g)

Four or five members had spotted the comet low in the
southwest before Jan 17th. It is right on the predicted
track but about a magnitude fainter than predicted.
On Feb 1st it will be at RA 1h 55m, Dec +19.4°, about
6th mag, moving northeast at about 6 degrees a day, and
not far from Hamal (Alpha Arietis).
* * * * * * * * * * *


VARIABLE STAR AWARD WINNER

Rick Lavery

Ken Hewitt-White was the winner of the Variable Star
Award for 1969. He has been making variable star estimates
all year (except for a few months in the summer) but his
contest total given below is for the months April to Decem­
ber. The final totals for the contest were:
Jon Buchanan    145
Ken Hewitt-White 151
Rick Lavery (for info, only)131
Chris Martin  43
Barry Matthews 18
Allen Miller  80
                            568

It is hoped that monthly totals can be printed in
Astronotes if observers will bring their observation sheet
to each meeting. Barry Matthews has drawn up new observing
forms and I have drawn up a corrected chart for the summer
variables.

Reminders: 1. Try making magnitude estimates of the comet. Failing that, note its exact position on charts available from me.

2. Try estimating the magnitude of the minor planet Hebe as it passes opposition (was on Jan 10; use U Mon chart for magnitude
estimates.)


OBSERVER OF THE YEAR

Tom Tothill

The Award Committee this year had an unusually simple
task in selecting the Observer of 1969. Ken Hewitt-White,
our continuing Vice-Chairman and perennial observer in all
fields, got the nod without any argument. As he also won
the new Variable Star Award donated to the Centre by Rick
Lavery, there is talk of a conspiracy to keep Ken locked
up in a basement somewhere for 1970 so that others can get
ahead of him. This may not be effective because he is sure
to find some way of peeking out.
* * * * * * * * * * *


TELESCOPE FUND

Rick Lavery

The Observers Group meeting of January 3rd, 1970 will
go down in Astronomical History as the day the chairman of
the Telescope Fund was able to declare that the minimum
goal of $400 was reached as a result of many generous
donations at the meeting and since the last one. The
Telescope Committee immediately agreed to meet before the
February meeting so that some final decisions could be made
concerning the mount design for presentation at that time.
Naturally, the fund must still remain open for further
contributions, for we must still look ahead to the question
of housing the telescope in a satisfactory way - it can't
be simply left to rust in some farmer's field. Hopefully
the telescope will have a drive which will involve the need
for a power hookup.

So we have set an additional goal of $200 to cover
that aspect of the problem, hoping that those who have not
yet contributed will see the need and take the opportunity
to be associated with this worthwhile project.

Please help to provide a good home for YOUR telescope!


BLITZ ON THE MIRROR

January was a terrific month for the mirror workers. An all-day session on the 10th got rid of the last pits and parabolizing commenced. This continued on the 11th, 17th,
22nd, and 24th, bringing the hours of polishing up to 39.
Then the 16-inch mirror was given a temporary coat of silver so that it could be put on display at the Annual Meeting and Dinner of the Centre on the 27th. The Telescope
Committee cordially thanks all concerned with this effort.


OBSERVERS GROUP MEETING - JAN 3

Sylvia Wake

The first meeting of the decade had approximately 36
people attending, with Dr. Lossing in the chair.
Mr. Tothill announced the selection of Ken Hewitt-
white as Observer of the Year.

The successful observation of the Quadrantid meteor
shower was described by Ken and Chris Martin, and Chris
gave a short talk on how to become a meteor observer (ask
him).

Doug Beaton talked on planetary observations, emphasizing that if one is out on the occasional really good
night one can see a lot with quite modest telescopes. Mars
is still fairly good, Saturn very good, and Jupiter in the
morning sky.

Barry Matthews spoke about the "lune" and gave a plug
for same. Then he gave a talk on drawing the moon and
reporting it.

Next Allen Miller explained his new Deep Sky program
with some ever-appreciated humour.

Rick Lavery announced the results of the Variable Star
competition and Dr. Lossing presented the Award to none
other than Ken Hewitt-White, alias "Observer of the Year"!
The main talk of the evening, by Peter MacKinnon, was
on computerized analysis of the 1968-69 Perseid meteor
shower results. The program also produced histograms for
the individual observers and their ratings and a discussion
developed around this.

After summing up and handing over to the new Chairman
Rick Lavery, Dr. Lossing explained the Foucault and Ronchi
tests which were demonstrated on the 16-inch mirror after
the meeting.


LAST MONTH’S PROBLEM

Walter Turner

The cover of Astronotes shows the sky at 9 pm on April 30th if you are looking south, or October 30th if you are looking north.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

THE MARCH MEETING OF THE OBSERVERS GROUP WILL BE HELD ONE |
WEEK LATE - ON MARCH 14th - TO AVOID THE ECLIPSE.