AstroNotes 1980 November Vol: 19 issue 11



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A stronotes ISSN 0048-8682
The N ew sletter Magazine of the Ottawa Centre of the RASC
Vol. 19, No. 11 $5.00 a year November, 1980
E d ito r ... Rolf Meier..............4-A Arnold Dr.................... 820-5784
Addresses Jacqui Tapping...61 Oval D r., Aylmer....684-1186
C ir c u la tio n .. .Barry Matthews.. .2237 I r i s S t ...................... 225-6600
Renee Meyer and Mary Geekie
Chairman Robert Dick opened the meeting at 8:15 with
41 people in attendance, 6 of whom were non-members.
Art F raser commented th a t the Ottawa Centre display
a t the Civic Centre Hobby F a ir was a success.
Robin Molson informed the group th a t 3 members have
been added to the IRO Committee. Those members are Frank
Roy, Ted Bean, and Fred Lossing. Robin also displayed to
the group a new method of mirror grinding for which there
is no need to walk around while grinding.
P e te r Jedicke, of the London Centre, kindly delivered
a ta lk concerning h is astronomical excursions. H ighlights
o f h is talk included the London C entre's attempt to expose
young people to astronomy by means of the Regional
C h ild re n 's Museum and a portable planetarium, the
C e n tre 's plan to build a new observatory, holding public
s ta r n ig h ts a t pro v in cial parks, and the London C entre's
astronomy show, hosted by P e te r, on London cable te le ­
vision. P eter’s recent excursions include trip s to
P atterso n Air Force Base (Daytona), Neil Armstrong
Museum, the Michigan Space Centre, S te lla fa n e , Syracuse,
Boston, and Newfoundland.
Charles Fassel of the Niagara Centre displayed to
the group his interesting attempts at astrophotography.
Some o f these e x t r a t e r r e s t r i a l s lid e s were taken from
the Chipawa Conservation Area on down to the big lake
they c a l l Gitch-i-goomee, and some were taken from
Tuscon, Arizona. These s lid e s included a Tuscon sunset,
the moon a f t e r the 1979 e clip se of the sun, J u p ite r ,
Saturn, Lyra, Gemini, and so on.
Dave Fedos iewi ch proceeded with "Comme t s on Comets".Comets v is ib le in the f a l l sky are Stephan-Otema, with a
38-year period, T u ttle , with a period of 14 years, and
Encke, with a 3.3-year period, and ju st below the lev el
of naked-eye v is ib ility .
Brian Burke informed the group of the upcoming
grazing o c c u lta ti on of Regulus. The s ta r w ill be a t
magnitude 1.3, the graze w ill occur on the southern limb
of the moon, and is considered to be b e tte r than
favourable. The graze lin e runs through G racefield,
Frank Roy proceeded with the "C o n stellatio n Quiz".
C onstellations included were Bootes, Serpens Caput, Corona
B orealis, Aquila, Lyra, Cygnus, and the Ring Nebula.
Barry Matthews followed, and informed the group that
some C e le s tro n -8 's have been stolen from a Montreal
telescope sto re . So beware of cheap C elestrons, as a l l
s e ria l numbers have been recorded.
The e le c tio n s for coordinators w ill take place a t
the next meeting. Nominations are as follows:
Chairman - Brian Burke
Vice-Chairman - Dave Fedosiewich
Instrum entation - Ted Bean
O ccultations - Brian Burke
A steroids, Comets, and Novae - Dave Fedosiewich
Astrophotography - Rolf Meier
Deep Sky - Rolf Meier, Frank Roy
S olar, Aurora - Rob Dick
Meteors - s t i l l open
Variable Stars - s t i l l open
Lunar and P lanetary - Barry Matthews
Recorder - Dave Fedosiewich
Radio Astronomy - Frank Roy
Items for sale were announced as follows:
A 4½-inch Tasco r e f le c to r , asking $250, and 60-mm
r e fr a c to r , asking $80, c a ll Mike a t 749-9367.
And f in a lly , the announcement of the marriage of
two Ottawa s ta rfo lk , Noeline Butler and Dave Penchuk ,
who were married on October 25, 1980. Peace, liv e
long, and prosper.
Chairman Robt Dick adjourned the meeting at 9:51.FOR SALE: Meade 12½-inch f/4.9 Research Series Newtonian.
Less than one year old. As described in Meade ads, except
for factory addition of manual slow motion and custom
focal ra tio . Value in Canadian d o llars: $2750 (includes
$250 shipping co sts from C a lif o r n ia ) . P rice: $2100
firm. Call for futher d etails. Terence Dickinson,
Odessa, Ontario, 613-386-3747.
Brian Burke
On Monday, November 10, the a s te ro id (28) Bel lona
w ill occult the s ta r SAO 161869 and th is event may be
v is ib le in the Ottawa a re a . Some v i t a l information is
given below:
Time: 17:36 E ST
Duration: 4 seconds
S tar’s magnitude: 9.5
S t a r 's p o sitio n : RA 18h 46.6m Dec 19° 04' S
A stero id ’ s magnitude: 13
A telescope of a t le a s t 13 cm in diameter w ill be
needed to observe th is o c c u lta tio n . The s ta r w ill be in
the southwest at an a ltitu d e of 20°. At the time of the
event the sky w ill not be completely dark because i t w ill
be another 45 minutes u n til tw ilig h t ends. Although
Bellona w ill not be v isib le i t should be easy to locate
the s ta r with a medium-size telescope. The s t a r 's magnitude w ill decrease by 3.6 fo r a to ta l o c c u lta tio n . As
shown on the top diagram, the predicted path of t o t a l i t y
i s about 0.03” south of Ottawa and the angular diameter of
Bellona is 0.05". I f the prediction is in erro r such that
the path s h if t s south, i t would mean no o c c u lta tio n for
us, but a s lig h t northern s h if t could put the path of
t o t a l i t y through Ottawa! The bottom diagram is a s ta r
chart showing the p o sitio n of SAO 161869 and the motion of
Bellona. Both diagrams were supplied by IOTA.
Before observing the o cc u lta tio n find a lo catio n th at
provides a c le a r view of the south-west horizon a few days
in advance. Also, you should try to locate the sta r inadvance and make yourself fam iliar with the s ta r p a tte rn .
When observing the event use a tape recorder to record
your voice and the CHU time sig n a l. Pass your observatio n s to me a t the next meeting.
### ######OF METEORS AND SHOWERS Frank Roy
As the earth o r b its the sun i t sweeps up d eb ris in
i t s path, p a r tic le s ranging in size from a few molecules
to boulders. I f a p a rtic le is large enough i t w ill burn
up upon penetration of the upper atmosphere, a t about
95 km, and i f i t has s u ffic ie n t mass, i t w ill survive the
plunge through the atmosphere and co llid e with the earth
as a m eteorite. The l a t t e r is ra re , and most p a r tic le s
enterin g our atmosphere are only a few microns across.
The meteors we see usually never h i t the earth and few of
them ever come c lo se r than 70 km. Most meteors (or f a llin g
sta rs) are about the size of a grain of sand. The t r a i l
of lig h t we see is not the a c tu a l p a r tic le but the
ionized a ir as the meteor blazes through the upper atmosphere. I t is the frictio n of the meteor with the a ir that
causes the a i r to glow. Most meteors en ter the atmosphere
a t 10 to 30 km/sec (36,000 to 100,000 km/hour!).
More meteors are observed in the morning sky than in
the evening because in the evening the earth is rushing
away from them and in the morning the earth is smashing
into them. As a r e s u lt, meteors h i t our planet f a s te r and
become bright enough to be v is ib le .
Under good observing conditions, one observer may
expect to see 7 meteors per hour coming randomly from a l l
d ire c tio n s , but a t c e rta in times during the year many
meteors appear to be coming from one point in the sky.
This is called a meteor shower and the apparent position
from which they originate is called the rad ian t.
This f a l l there are two showers to watch fo r, the
Leonids and the Geminids. Although the Leonid radiant
r is e s about midnight, they are rated a t 15 per hour per
observer. The moon is f i r s t q u a rte r.
The Geminids are quite favourable th is year, being
overhead a t about 1 am EST. They are rated a t 50 meteors
per hour per observer. The maximum is December 13,
17:00 EST. This is a Saturday, and the f ir s t- q u a r te r
moon se ts a t 22:30 EST.
There w ill be a meteor session a t the Indian River
Observatory on Friday, December 12, and Saturday,
December 13. I f both nights are c le a r, there w ill be two
sessio n s. Refreshments w ill be provided and tra n sp o rta ­
tion made a v a ila b le .
I t is important to d ress warmly i f one is expected
to observe for more than an hour. Also, b rin g a lawn
c h a ir, the type you can lie on, and a sleeping bag.
This w ill be a great opportunity to observe thec o n ste lla tio n s and meteors. My number is 820-0874
Here are the meteor showers for the f a ll of 1980:
shower max date moon hourly rate
S. Taurids
Nov. 3
Nov. 16
Dec. 13
Dec. 22
Jan. 3, 1981
referenc: Meteor Science and Engineering, D.TA'.R. McKinley
The Quadrantids, named a f t e r the antique c o n s te lla tio n
Quadrans M uralis, i s perhaps the le a s t known of the strong
meteor showers. I t has been reported that this stream
sometimes reaches 100 meteors per hour per observer
(assuming the radiant is at the zenith). This is 1.7
meteors a minute. I t s normal duration to ¼ stren g th of
maximum is only 1.1 days. This means th a t the shower
must be observed a t or near the predicted maximum time.
According to the Observer’ s Handbook 1980, the hourly ra te
is 40 per single observer. The meteors are sometimes
reported blue with many f a in t members.
The 1981 Quadrantids w ill reach maximum a t 08:00 EST
on January 3. This i s a Friday night (Saturday morning),
and the moon is new. This is an ideal observing s itu a tio n .
I f sk ies are c le a r there w ill be an observing session
at eith er the Indian River Observatory or Springhi l l
Meteor Observatory. The session w ill be an a ll- n ig h t one,
so bring your sleeping bags and lawn c h a irs, and dress as
warmly as p o ssib le . Refreshments w ill be made av ailab le
(hot chocolate, coffee, e tc .).
A dditional information w ill be given a t the O bserver's
Group meetings, and through Astronotes. I f in te re ste d ,
please c a l l me a t 820-0874.
A rtic le s for the December issue of Astronotes are
due by November 21.