AstroNotes 1983 August Vol: 22 issue 07

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Ottawa-1983-08

 

ASTRONOTES ISSN 0048-8682
The Newsletter Magazine of the Ottawa Centre of the RASC
Vol. 22, No. 7 $5.00 a year August 1983

Editor......Rolf Meier.....4-A Arnold Dr......820-5784
Addresses...Art Fraser.....11-860 Cahill Dr....737-4110
Circulation...Robin Molson....2029 Garfield Ave...225-3082

 

OBSERVER'S GROUP MEETING - JUNE 24 David Lauzon

Chairman Rolf Meier opened the meeting at 8:26 pm with 21 people in attendance. He made the following announcements.

August 6 is the Stellafane weekend and anyone wishing to enter the telescope maker's convention, do so! The star night held on June 17/18 was a success with 10 telescopes and 50 people. The moon and planets were the main attractions. The next star night is planned for August 12. The enclosure for the centre's 10-inch telescope for IRO is being planned and will be of the roll-off type. Rolf gave some insight into the visibility of the planets for the next month. He also reminded comet seekers that 5 comets have been visible over the past 5 months. They were Kopff, Tempel I, Tempel II, IRAS-Araki-Alcock, and Saguna-Saigusa-Fujikawa.

Vice-Chairman Gary Susick spoke on deep sky observations under varying sky conditions. Since most deep sky objects are faint, the conditions of the atmosphere play a critical role in their observation. Since this is true, a proper report in your log bode is important, because no two nights are the same. Aspects like light pollution, seeing conditions, and sky conditions should be noted. As scale of sky contrast should also be made.

Meteor coordinator David Lauzon talked about the upcoming meteor showers for the summer. Briefly, Dave says that this summer should be excellent for meteor observing. The only shower not favourable is the Northern Iota Aquarids, which peak on the night of the full moon. Many meteors are expected to be observed this summer. Dave also showed different ways of observing meteors. People are invited to try these ways out on the meteor night planned for July 9/10.
 
Gary Susick and Linda Warren finished the presentations with their own slides of the arrival of the Space Shuttle Enterprise as it flew over Ottawa on a 747. Linda also showed some observing slides, including some which showed a method of projecting the solar image.

Rolf closed the meeting at 9:50 pm and people were invited for refreshments.

* * *

GRAZE WORKERS WANTED - NO EXPERIENCE NECESSARY  Brian Burke

Openings are available for two graze expeditions in the near future. You must be willing to 1) work unusual hours, 2) explain your identity to the OPP, 3) detect nearby skunks, 4) know that dogs barking in the distance may in fact be right behind you, and 5) try to observe the right star. If you think this job is for you then you can participate in the following two expeditions:

Graze 1

date: August 3
time: 3:12 EDT
star: ZC 527
magnitude: 6.3
limb: north, dark
moon: 36% sunlit
type: favourable
location: about 15 km south of Alexandria, Ontario
 
Graze 2
date: September 3
time: 3:10 EDT
star: X 10836
magnitude: 8.3
limb: north, dark
moon: 20% sunlit  
type: marginal
location: 3 km east of North Gower, Ontario

The meeting place for graze 1 will be the St. Laurent Shopping Centre beside the bus stops near the Dominion Store. The time will be chosen when I know the driving time. Most of the driving will be on the 417.
 
We will meet at the Billings Bridge Shopping Centre outside Mr. Donut for graze 2. The time for this also has to be determined. The meeting time is determined so that we will arrive at the graze site about one hour before graze time so that peole will have time to set up their equipment, locate the star, and watch the clouds roll in.

The equipment required is a telescope, tape recorder, and a radio that can receive the CHU or WWV time signals. Since most people do not have all three, groups of two can be formed with one observing and one taking care of all the equipment. If you would like to participate in either of these expeditions, let me know at the meeting or give me a call at 521-8856.

* * *

THIS SUMMER'S METEOR SCENE    David Lauzon

Summer seems to be that time of year when people like to observe meteors. So to make things easier, here is a rundown of the summer meteors. Remember, if you don't go out to observe them, you will never see them.
 
Southern Delta Aquarids
duration: July 21 to August 29
peak: July 28 22:00 EDT
hourly rate: 20
moon: near last quarter
radiant: 17° below the celstial equator
speed of meteors: 41 km/sec
duration to 1/4 strength: 7 days

With the low radiant, this shower will be difficult to observe. So, face south to see the maximum number of meteors.
 
Northern Delta Aquarids
peak: July 12
hourly rate: 10
moon: first quarter
speed of meteors: 42 km/sec

This is a minor shower which will be hard to discern from the Southern Delta Aquarids.
 
Alpha Capricornids
duration: July 15 to August 10
peak: July 30
hourly rate: small
moon: last quarter
speed: 23 km/sec
 
This minor shower stream is associated with Comet 1954 III (Honda-Mrkos-Pajdusakava).
 
Southern Iota Aquarids
duration: July 15 to August 25
peak: August 5
hourly rate: 10
moon: last quarter
speed: 34 km/sec

This is a minor shower.

Northern Iota Aquarids
duration: July 15 to September 20
peak: August 20
hourly rate: small
moon: full
speed: 31 km/sec
 
With the full moon, this shower is too obscure this year to observe.
 
Perseids
duration: July 23 to August 23
peak: August 12 13:00 EDT
hourly rate: over 50
moon: first quarter
speed: 60 km/sec
duration to 1/4 strength: 4.6 days
 
This is possibly the most-observed shower of them all! The nights of August 11/12 and August 12/13 would be the best times to observe them. Perseid meteors have been seen from the beginning of the summer until the fall. Observing will be favourable this year as far as the moon is concerned. The comet associated with the Perseids is Swift-Tuttle 1862 III, which is expected in the inner part of the solar system, possibly giving rise to better hourly rates. This is the most important shower of the year, so observe it.

The basic information on visual meteor showers can be found on pages 122-123 of the Observer's Handbook. The chart provided below shows the reference stars to estimate the meteor magnitudes.

 

 

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