AstroNotes September 1969

EDITORIAL . A TRIBUTE TO MISS NORTHCOTT . TWO AMATEUR MEETINGS IN VERMONT . DARK SKY OBSERVATIONS . SOME ELUSIVE NEBULAE IN CYGNUS . EXCELLENT PROGRESS ON THE SIXTEEN-INCH MIRROR . REDUCTION OF OUR PLEIADES TIMINGS

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ASTRONOTES     Vol. 8, No. 7     September, 1969

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

EDITORIAL

The summer was a momentous one in the history of
astronomy, with the fantastic success of Appollo 11 in
achieving the landing and safe return of two men on the
moon. Of even more importance scientifically is the
deployment of a laser reflector and a lunar seismometer,
and the collection and return of a useful quantity of the
lunar surface materials, part of which will shortly be
arriving in Ottawa for study.

The laser reflector will permit measurement of the
earth-moon distance within a matter of inches. Clearly
this will permit a very much closer check on the theory of
the moon’s motion than has been available up to now.
Also, since the earth-based lasers can be set up anywhere,
it will be possible to check the figure of the earth to
similar accuracy and within a few years to establish for
sure whether continental drift is still occurring on the
earth.

The lunar seismometer, aside from recording the impact
of cosmic objects on the moon, is likely to be able to tell
us a great deal about the internal structure of the moon -
by techniques similar to those used in the analysis of
terrestrial seismometric data. In particular, it should
show whether the moon has a liquid core and, if so, its
size. Also, it should be possible to pick up evidence of
any volcanic activity there may be on the moon.

The lunar rock and soil samples are already providing
puzzles to mineralogists and there is no doubt whatever
that more will appear as analysis progresses. The samples
are of course related to a Mare area, with perhaps a few
pieces of ejecta from distant craters, and the next piece
of the puzzle will require samples from highland and other
types of lunar terrain.

The behaviour of the core sampler, as described by the
astronauts, was very strange, for although it encountered
considerable resistance as it was hammered in, the ground
around it failed to support it against toppling.
One of the least-known questions facing the astronauts
was how bad would the dust be in obscuring their
vision as they neared the surface? Neil Armstrong said
that it blew away over the horizon in an almost horizontal
direction, somewhat interfering with his appreciation of
spacecraft velocity but transparent enough for seeing the
larger rocks on the surface. Yet the crater under the
rocket nozzle was only a few inches deep, and the astronauts'
footprints all around the area proved that by no
means all of the surface dust was blown away. In the
vacuum of the moon's atmosphere, it must take an actual
collision of a molecule or more of the exhaust gas to set
a particle of the fine lunar dust in motion. On earth,
a great deal of dust would be lifted by the motion of its
surrounding air.

For us spectators, the whole episode was very nearly
as thrilling as it must have been to the astronauts
themselves. As each critical point was reached we held
our breaths, and sighed with relief as it came off
flawlessly.

Our congratulations go out not only to the three
astronauts equally, but to the vast and complex organization
behind them for achieving the goal set by President
Kennedy and carried faithfully through by his successors.
Truly, the study of the moon has entered a new era.
The study of Mars also took a step forward with the
two successful Mariner flybys. The pictures had a good
deal more detail than the previous efforts and the
coverage of the polar cap was new and especially
interesting. One scientist announced that unexpectedly
deep drifts of ’snow' were discernible, and the full
details will surely provide much food for thought when
they are published. Mars is peppered with craters as
densely as the moon, yet its thin atmosphere and polar
'snows' indicate processes of erosion available to change
its topology in the long term. It is to be hoped that
closeups of Deimos and Phobos will be attempted before
very long, perhaps by the Mars Orbiter which is planned
for the near future.

We are still a long way from unlocking the secrets
of the Solar System - let alone the Universe - but who
does not feel privileged to live in this age of discovery?

A TRIBUTE TO MISS NORTHCOTT

Ian Halliday

The Royal Astronomical Society of Canada lost a
devoted servant while many members of the Society lost a
close personal friend in the death of Miss Ruth J. Northcott
in Toronto on July 29, 1969. As Editor of the Society's
publications she had been responsible for the regular
publication of both the Journal and the Observers' Handbook
since 1957 and previously had been the Assistant Editor
for Dr. C. A. Chant during the last five of his fifty
years as Editor. As in other areas of her life Miss
Northcott's editorial work was characterized by a meticulous
care for detail and accuracy. Under her direction
the Society's publications maintained the high standards
which had been set by Dr. Chant and both the Journal and
Handbook attained increased recognition within and outside
Canada.

Miss Northcott's service to the R.A.S.C. was not
limited to her editorial work. From 1962 to 1964 she
served as National President of the Society and many
members of the Ottawa Centre will recall her address to
our Centre in October 1963 as well as her retiring
presidential address delivered at the General Assembly
in Ottawa during May, 1964. Her activities included
membership on numerous committees of the Society and her
many contributions were recognized by the award of the
Society's Service Award in 1967.

As an Associate Professor in the Department of
Astronomy at the University of Toronto Miss Northcott took
a personal interest in the progress of all her students.
She maintained an active research program in stellar
astronomy at the David Dunlap Observatory where she was
one of the earliest staff members. Her intense love of
nature found expression in her accomplishments as a
talented painter and a skilful photographer.
Ruth Northcott will indeed be missed by her many
friends as well as by the entire astronomical community
in Canada.
* * * * * * * * * * *

TWO AMATEUR MEETINGS IN VERMONT

Ken Hewitt-White

The Stellafane, 1969 meeting at Springfield, Vermont
was an enjoyable get-together of about 700 amateurs and
telescope makers. Rain spoiled Friday evening viewing but
Saturday broke sunny and warm. The afternoon displays
were varied and well done; the Saturday night viewing was
splendid until about midnight when scattered clouds came
over. New friends were met, ideas exchanged, and several
traditional stories handed down the line. For the six
Ottawa members and four friends who attended it was a
thoroughly appreciated experience despite the sky's incapacity
to keep all the rain to itself. For three people it
was especially enjoyable; Sidney Sundell of the Montreal
Centre invited Barry Matthews down to the Montreal Deep Sky
night in northern Vermont for the following weekend. Thus
Barry, myself and Frances found ourselves trekking down to
Vermont the next Saturday. There we found Walter Scott
Houston browsing over a moon atlas and the Sundells sipping
appreciatively at a bottle of the local 'mountain dew'. A
former Montrealer but now living in Boston came and later
the secretary of the Montreal Centre followed. At midnight
our good friend Constantine Papacosmas and company drove in
fresh from a two hour drive in the rain. Being a one shot
affair, just the Saturday night, mother nature deemed it
necessary again that we all take a bath and thoroughly
drenched the northern Vermont hills with an almost all
night rain. But if it was cold and wet on the outside, it
was warm and comfortable on the inside thanks to the wonderful
hospitality of the Sundells and the equally lively
warmth of our second host Andy Anderson, whose summer house
on the mountainside we used for our 'scopes.

Both Stellafane and the Deep Sky night had more than
their share of inclement weather and yet for these Ottawa
observers at least both were more than compensated for by
the meeting of so many new, wonderful and diversified
people. It has something to do with common grounds that
these affairs work so well and the people get along perfectly
together, rain or shine. And Mr. Houston said it
so well when he autographed my Skalnate Pleso atlas:
"Drink deep to common grounds", he wrote.
We did and everybody had a wonderful time. Perhaps this
is what our torn world needs more of today, don't you think?

DARK SKY OBSERVATIONS

Fred Lossing

The sky at my cottage at Howdenvale on the Lake Huron
shore of the Bruce Peninsula appears at its best much darker
than conditions allow in the Ottawa area. An apparent
reason is the large ratio of water surface to land surface,
and the correspondingly low levels of dust and haze. Naked
eye and binocular observations are startlingly better than
under the best conditions here. In view of this it is
surprising and disappointing to find that the performance
of my 6" f/4.5 reflector under such conditions was not all
that much better than it is in the more opaque Ottawa skies.
For example I can see more locally with a f/4.5 8" than I
could up there with the 6" in spite of the apparent difference
in sky clarity. Why should the difference be less
evident at larger aperture? Has anyone else noticed this
effect, and is there an explanation? The only one I can
come up with is that the visible and evident difference is
not real, but an optical effect resulting from greater
dark adaptation of the eye in the complete absence of
diffuse light from nearby towns etc. Whatever the cause,
views of the sky with 10 x 50 binoculars under such
conditions are spectacular. Using a comfortable deck-chair
and lots of mosquito repellant, I spent some hours with
10 x 50 binoculars on several clear nights in early July,
and made some notes as follows.

1. The North America nebula in Cygnus was clearly seen
as a bright area surrounded by several dark patches,
the darkest forming the "Gulf of Mexico". The whole
object covers several square degrees.

2. Part of the Veil nebula in Cygnus was easily seen,
consisting of the part making up NGC 6992; a C-shaped
light ring at RA 20:55, Dec + 31°00. The concave
face is toward the west and south. It is easily
found by coming out from the central star of the
Northern Cross to the star forming the eastern arm
(Epsilon) and continuing along this line a further
1/3 of this distance. This seems to be brighter than
the part of the Veil (NGC 6960) which passes through
the 4th magnitude star 52 Cygnus. This part is
barely visible in an 8", but not seen with the
binoculars.

3. The Dumbbell nebula (M27) in Vulpecula was easily
found and appeared as a very bright fuzzy patch,
rather small at 10x.

4. The Ring nebula (M57) in Lyra looked like an out-offocus
star. A solid rest for the Binoculars was
needed to see the difference between it and neighboring
stars.

5. Several Ursa Major galaxies were picked up without
difficulty: M81 and 82 were very bright, M51 was
seen as an apparently single fuzzy spot, M101 appeared
as a large faint diffuse spot.

6. M31 was of course easily visible to the naked eye, but
a careful search showed the satellite galaxy M32 as a
small diffuse area, faint but unmistakable.

7. Many well-known globular clusters were surprisingly
easy objects: M4 in Sagittarius was faint, but M22
in Scorpius was extremely bright. Other Milky Way
objects were nearly as well seen as in a 6" reflector,
allowing for the effect of lower magnification.
* * * * * * * * * * *

SOME ELUSIVE NEBULAE IN CYGNUS

Ken Hewitt-White

There are many dark and diffuse nebulae scattered
throughout the summer Milky Way but perhaps the finest
occupy the borders of northern Cygnus. Here lies the
North America nebula, the Pelican and the two Veil nebulae.
These are tremendous sights in photographs but are
very tenuous articles to perceive visually. A richest
field ’scope is almost a necessity and the very best of
nights is mandatory for the amateur to challenge these
objects.

The night of August 19 provided the above-mentioned
conditions for a small party of observers at Springhill.
Fred Lossing had his 8-inch f/4.5 on hand for this occasion
along with my 8-inch 'Big Bertha' and Ted Bean's
6-inch Newtonian. The night was cool and crisp, the
seeing rather unsteady, but the sky coal black. Time
was short so attempts were made only with the RFT and
binoculars.

The Veil is a two-fold deal, lying a few degrees
south of Epsilon Cygni. Oddly enough one of the filaments
has two NGC numbers but only one object could be seen.
This one arm was Cuba-shaped and very finely grained into
long thin filaments. The section was quite reasonably
bright and well defined. The other section, a few
degrees westward, was more flatly bright and not filamentlike
at all. This meteor-trail-like wisp passes almost
right through a 4.5 magnitude star and then we perceived
curves on several angles when viewed closely. These were
the finest views the writer has seen of the Veil Twosome.
The North America is a much larger nebula situated
three degrees north-east of Deneb. On not a few nights I
have identified the 'Gulf of Mexico' in binoculars but
never very much more. On this night several persons
identified not only the gulf, but also the entire 'continent'
plainly visible and well defined. In the ’scope, the
gulf was seen well but there was little contrast between
the rest of the nebula and the stellar background.
The Pelican object is a touchy subject. I have
thought to have seen it at various times under good
conditions but this time it stood viewing well. The
pelican 'beak' was lost but the general shape was faintly
visible as a hazy whitish mass. It was not attempted in
the 8-inch.

All four objects provide a respectable challenge to
the experienced observer and I would be interested in
hearing other reports of sure sightings.
* * * * * * * * * * *

EXCELLENT PROGRESS ON THE SIXTEEN-INCH MIRROR

First, the 16-inch telescope Committee would like to
acknowledge a number of helpful contributions. Thanks are
due:
To Rick Salmon, for donating a beautiful eyepiece
focusing mount.

To Maurice Couture, for making a wood pattern for the
grinding and polishing tools.

To Butch Cairns, for grinding an edge groove on the
mirror, and for much useful advice.

To Frank Fanning, for radiusing the mirror on the
diamond wheel, for setting glass blocks on the grinding
tool, and for radiusing the blocks to match the mirror.

To Tom Tothill, for donating the grinding and polishing
tool castings, and boring them.

To Fred Lossing, for setting up the grinding machine
and for several hours of work on the mirror.

To Ted Bean, for his assistance on the mirror grinding
The mirror is now in the stages of fine-grinding,
thanks in large part to the use of the diamond wheel as
mentioned above, which in a few hours of work obviated
any necessity for coarse grinding work.

By the greatest good fortune, we were able to locate
a mirror grinding machine which was in process of being
declared surplus and disposed of for scrap. This saved us
all the trouble and expense of constructing a machine for
the job. The machine is good for mirrors up to 25" diameter
and works well. It contains two large variablespeed
motors and is complete with water spray and drainage
facilities.

Our work started with #280 carborundum with which
the mirror and tool were brought into mutual fit. Work
is now proceeding down through the emerys.
We made a separate tool for polishing so that if it
becomes necessary to go back to grinding at any time we
can do so.

Progress is so unexpectedly far advanced that we are
going to have to start work on the ball mount pretty soon.
This is going to entail some cash outlays for fibreglass
and resin, styrofoam for the mould, aluminum for the tube,
and a few sundries. Anyone who would like to contribute
is requested to contact any member of the Committee, i.e.
Fred Lossing
Bill Dey
Tom Tothill
Rick Lavery
* * * * * * * * * * *

REDUCTION OF OUR PLEIADES TIMINGS

Tom Tothill

I've had a couple of letters from Mrs. Flora McBain
Sadler of HMNAO thanking us for our March 22 Pleiades
occultations and sending preliminary reductions for the
ZC (Zodiacal Catalogue) stars. We also timed quite a few
non-ZC stars from the USNO list which included fainter
stars.

The Ottawa observers in alphabetical order were
Jon Buchanan, Steve Craig, Ken Hewitt-White, Jacques
Labrecque, Rick Lavery, Fred Lossing, Les MacDonald,
Allen Miller, Tom Tothill, and E. G. Woolsey. Spread
across Ottawa at their home locations, their timings on
any particular star delineated not merely one point on
the lunar limb but a stretch of 10 to 15 miles. In some
cases all ten of us got the same star. Some useful
preliminary cross-checking was possible because by very
good luck our home locations formed four very nearly
straight lines on the map and one could plot time intervals
against distance intervals along these lines; the plotted
points should form a smooth line, almost straight, with a
different slope for different PAs (Position Angles).
Each observation is treated individually by the
HMNAO computer and results in a slip of paper like this:
PHASE is just a code for disappearance, reappearance,
at dark limb or bright. POSN. ANGLE is the calculated PA
for the observation. PROFILE CORRECTION is from Watts'
charts of the lunar limb at the appropriate lunar librations
indicating Watts' determination of the position of the
actual limb inside or outside the circle defining the mean
limb.

My interpretation of the last three lines is that
Jon Buchanan saw the star disappear 0.80" inside the mean
limb. The Watts limb is 1.37" inside at that point,
requiring a positive correction of 0.57" to bring it out
to match Jon's observation. Jon was definitely not wrong,
for the rest of us agreed with him very nicely.
Mrs. Sadler says: "We expect most of the corrected
distances to lie between +1.5" and -1.5"..." indicating,
if my interpretation is correct, that rather substantial
corrections to Watts' charts are needed, in many places.
The diagrams opposite show all our observations on
ZC stars. The base line is the mean limb, with PA (from
north through east) going right to left. The Watts limb
is marked W and the Ottawa limb is marked T (for true!).

Apart from a few obvious errors, we hang together quite well
Buchanan

STN/TEL/OBS
DATE
TIME(U.T.)
Z.C. NO.
PHASE
POSN. ANGLE
DISTANCE OF STAR
FROM MEAN LIMB.
PROFILE CORRECTION
CORRECTED DISTANCE
-0.80 (arcsec)
+1.37 "
+0.57
800/87/87
690323
1 13 35.50
536 (P 044)
1
36.0 (deg.)