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Spring 2012 Astronomy Course
Mississippi Valley Night Sky Conservation
The Sky Around Us
Program developed by
Mississippi Valley
Conservation Authority
Royal Astronomical Society
of Canada
Ottawa Astronomy Friends
Instructors:
Pat Browne
Stephen Collie
Rick Scholes
Earth Centered Universe
software for illustrations –
courtesy David Lane
III Star Clusters in and around our Galaxy
WHERE
Locating Star Clusters
WHEN
Are they Visible?
WHAT
Types of star clusters
Open Clusters
WHO
Pioneers in star cluster analysis
Helen Sawyer Hogg
(Canadian Astronomer)
Introduction to Star Cluster Observing
What’s up ? Is the Moon up?
Where’s our meridian?
What can we see when the
Moon is up…
For clusters of stars, or special
nebulous stellar bodies, or
galaxies, the moon , like light
pollution obscures the photons
emitted from these objects.
Where’s our meridian?
Galaxies galore coming up close to
our local meridian…
Open Clusters setting in the West…
Globular Clusters in the East
Open Clusters looking West (setting)
( Spring time Northern Hemisphere)
WHAT:
Open clusters:
Widely-spaced groupings
of easily resolvable stars
Also called Galactic Clusters
because they lie i
Observing Spring Open
Clusters
Monoceros: M46, M47
Cancer : M44, M67
Auriga: Clusters,M38,M36,
M37 (West)
M44 – ‘Beehive’
Modest neighbour
M67
Auriga
cluster
M38,
M36,M37
Meridian
Monoceros
Cluster M46,
M47
Winter (west) Milky Way
From a true, dark sky,
nothing can compare to a
naked eye view of the Milky
Way. During the winter
months in the Northern
Hemisphere, we face away
from the furiously busy core
of our home galaxy and look
outward, through its more
tenuous periphery.
Despite being more delicate,
this slice of the Milky Way is
still rich with structure.
http://www.perezmedia.net/b
eltofvenus/archives/0
01397.html
Open Clusters and Nebulous
Regions in Constellation Auriga
Auriga
Auriga contains an nteresting variety:
many open clusters and nebulous
regions simply because the
Milky Way runs through it.
3 Open clusters in/out of
pentagon of Constellation
Auriga south of Capella.
M37 the richest cluster containing over
500 stars spread across 20
arcminutes and is the brightest of
the three with an apparent magnitude +5.6.
M36 - 60 stars with an angular width of 12
arcminutes.M38 100stars and is the
dimmest of the three at magnitude+6.4.
All three of these clusters, 4000 light-years
away, can be seen with a small telescope.
Courtesy - Dave Garner teaches astronomy at
Conestoga
Observing Log Book
Suggesteed Recording Format
(Do what’s comfortable for you)
Header:
Observation Number
Observation Date and Time
Observing Instrument
Telescope/EyePiece Combination
Observing Conditions – Temperature, Wind, moon
phase
References – Books, Sky Charts,etc
Body:
Guests or observing companions
Each object – Designations commonly include those
found in in the RASC Observers Handbook : Messier
NGC
David Levy Gems
Methodology for Finding the Object
Impressions of the object
This log book won the RASC Ottawa Center Observer of the Year
Award 2004 . Lack of neatness is forgiven in favour of
persistence in recording (even after a long night).
When the Moon is UP!
First Quarter Moon in the
West – Waxing Crescent –
sets after midnight!
Night Sky Conservation – Impact of Lighting Up the Night Sky
Accessibility to darkness of the night sky
Milky way only visible wth moderately dark skies
Faint objects like clusters of stars, ane even galaxies an be
naked
eye objects with very dark skies not even visible in a
telescope from moderately dark skies
When we are in the phase of the moon from First Quarter to Full
moon, we can see how much light (even natural light) can
obscure
the fainter celestial objects
Fred Lossing Observatory
Operated in the area by the Royal Astronomical Society of
Canada (RASC) 16” telescope with research grade optics
produced
by NRC The only observatory in Canada to boast the
discovery of 5 Comets
Good Neighbour Lighting
Shielded lighting directing light towards buildings and ground
Reduced glare means more effective security
Light goes where it is needed reducing electricity by
30% for the same results
Mississippi Mills By-law for Outdoor Illumination
Light pollution abatement Conservation of the night sky
This is a video on the need to reduce light ing up
the night. You can download this:
http://www.millstonenews.com/2012/03/themississippi-valley-conservation-authority-willonce-again-be-offering-its-astronomy-course-atthe-mill-of-kintail-on-fri.html
Sky measuring: Brightness and Size of objects
:
Given a dark location reasonably free of unshielded
lighting (referred to as "light pollution"), this
scale describes what is shown when you query ECU
about Magnitudes:
http://www.mpas.asn.au/MembersInfo/viewing/smohr/ApparentMag/ApparentMag.htm
Magnitudes on a Sky Chart
and in the sky…
So that when we see Mars is at
magnitude -0.2 with an
angular width of 10.7”
we know, it’s bright, and
can be seenin binoculars ,
but better yet in a telescope.
Observing naked eye
and with optical aids…
Compare the size and
magnitude of the
Beehive cluster vs. the
other Open
Cluster in Cancer:
M67 (much smaller,
fainter, and one
of the oldest star
clusters known…
Beehive Cluster – Praesepe –
size 95’ (> deg) Magnitude 3.1
M67: size 29 ‘ (1/3 deg)
Magnitude 6.9
Now go do the
OpenCluster exercise!