Observing: so many ways!

January 2015
Observing: so many ways!
The skies present us with a myriad of sights, both simple and complex, both hard-to-see and obvious,
both to the bare senses and only to our technology. This means that a great many people from different
backgrounds, with different abilities and wildly-different interests, can find ways to enjoy themselves.
Enjoyment - the key to observing the sky and its inhabitants.
This article of the Focus newsletter is all about OBSERVING, and its many manifestations.
Observing the skies began as soon as people became aware of their surroundings. For example,
thinking “those small lights at night stay in the same place” might save lives, by guiding them home.
Star patterns spring readily to mind. Olaf Lutz describes the best-known of these (in the Northern
skies): the Big Dipper.
As observers became more adept at interpreting the skies, devices were constructed to help predict the
future. The rings of stones found at Stonehenge and so many other sites would have predicted things like
eclipses, until came the time they failed to do so.
Chris Purton describes a very simple measurement device on Munson Mountain near Penticton: Pen
Henge.
A few of us have begun “looking” at the sky through the “eyes” of radio technology. Hugh Pett
mentions a couple of problems (and solutions) recently encountered in developing the radio telescope at the
Okanagan Observatory.
Our members concentrate on observing the night sky, and set themselves goals to mark their efforts.
These Challenges present lists of objects with various appearances, and of varying achievement difficulties.
In this issue Dave Gamble introduces a new Challenge list, the Bedford Catalogue.
For all of us, a simple glance upwards may bring a moment of surprise, of enjoyment, of puzzlement.
Observing is all around us, always available, even if the result is only “Drat! Cloudy AGAIN!”
Observing Reports
Name
total required
Terry Adrian
Zoli Boda
Greg Dean
Jim Failes
Jim Fisher
Dave Gamble
Stewart Hill
John Karlsson
Guy Mackie
James McRae
Daniel Martin
Colleen O'Hare
Grant Rice
Ron Sherer
Wendell Shuster
Mikkel Steine
Jim Tisdale
Alan Whitman
ETU
55
55
IOL
30
Messier
110
28
108
94
55
110
110
110
110
110
110
56
72
45
105
110
110
94
110
110
27
30
ASNF
159
129
93
159
NGC
110
DSC
45
H400
400
27
1
29
45
400
580
45
400
1833
4
19
52
53
267
45
400
10
37
15
110
24
110
28
7
110
19
79
60
110
H2500
2500
DN
38
ARP Caldw'l
100
109
81
63
64
17
1112
38
109
* totals in bold blue recognize completion of the list
Messier/NGC/Challenge Certificate Requirements
The ETU list may be found on-line at: http://www.rasc.ca/sites/default/files/exploretheuniverse2.pdf
The Okanagan Centre is a Local Certification Centre for the ETU list. Guy Mackie is the contact person
([email protected]).
Reference maps for the OC – Introductory Observing List (IOL) may be found on-line at:
http://www.ocrasc.ca/introlist.pdf
Reference Lists for Messier, NGC, Dark Nebula (DN), DSC objects, and other objects may be found in the
2013 Observers Handbook starting on page 314.
The All Splendors, No Fuzzies (ASNF) list is on the RASC Okanagan Centre website:
http://www.ocrasc.ca/All%20Splendor.html
Reference maps from the RASC website:
Messier http://www.rasc.ca/observing/messier-certificate
Finest NGC http://www.rasc.ca/observing/finest-ngc-observing-certificate
Dark Nebula http://www.rasc.ca/sites/default/files/darknebula.pdf
DSC objects http://www.rasc.ca/observing/deep-sky-challenge-observing-program
The H400 list may be found on-line at: http://www.astroleague.org/al/obsclubs/herschel/hers400.html
The H2500 list is given at: http://messier.seds.org/xtra/similar/herschel.html
The ARP list may be found on-line at http://www.astroleague.org/al/obsclubs/arppec/arppec.html
The Caldwell Catalogue (Caldw'l) is found at http://www.astroleague.org/al/obsclubs/caldwell/cldwlist.html
AN ADDITION TO OUR CHALLENGE LISTS
As most of you know, Dave Gamble has been working on The Bedford Catalogue, compiled by
Admiral William H. Smyth in 1844. Considering he did this with an English polar mounted 6" refractor, a lot
smaller than most Okanagan Centre members have available, this could provide a different perspective on the
night sky, using the larger ‘scopes you have.
On December 14 Dave sent out an email on astrookanagan about his pursuit of a few of the Bedfords look it up in your email files (or ask Dave to send it to you: [email protected] ). Dave starts his email
with this description of the Catalogue:
“... comprises 850 objects made up of mainly double stars, but also multiple stars, nebulae and galaxies
observed with a 6" refractor and compiled by Admiral Wm. Smythe in 1844. The catalogue book is done
in a quaint style with colourful descriptions of the objects, and it is a great observing reference which takes
one into some fascinating corners of the sky.”
Dave comments: “I would be pleased to resend the observer report, as well as provide help for others
interested in the list.”
Thank you, Dave!
The Bedford Object List can be found online at: http://messier.seds.org/xtra/similar/smyth_c.html
The actual Bedford Catalogue with descriptions of the objects is a book available from Willman-Bell at:
www.willbell.com/handbook/HAND1.htm
NOTE: member tallies towards various observing lists are available on the website at:
http://www.ocrasc.ca/obclubtallies.html
Please send your Observing Reports to Hugh Pett, Editor, Focus Newsletter, ([email protected])
for the January and June issues of the Focus newsletter.
FEATURE ARTICLES
ASTERISM: The Big Dipper and Polaris
by Olaf Lutz
For the sake of this discussion I will
refer to star patterns as asterisms and leave the
term Constellation to mean large, arbitrarily
defined areas of the
sky.
Nearly everyone that ever looked at the
Northern night sky recognizes the Big Dipper
but it might come as a surprise that it has been
acknowledged in some form for at least 12,000
years. In our Greek derived western star-lore
this asterism is part of a larger one, The Great
Bear, that corresponds to The Greater Bear in
Arabic culture. We take for granted that most of
the named stars have Arabic names and that the
Arabs were instrumental in preserving much of
classical learning through the middle ages but there
are enough differences between Greek and Arabic
star-lore to point to an earlier common origin,
presumably Mesopotamian, rather than just an
Arab adoption of the Greek stories.
In England this asterism is commonly
referred to as the Plough and less commonly as the
Wain (wagon) or Carl's Wain. There is a tradition
that the name Carl's Wain is in commemoration of
Charles the Great (Charlemagne) but I think it
unlikely that any self-respecting band of AngloSaxons would show that much respect for a
Frankish king. It's a pretty safe bet that the name
comes from the Norse Karlswogen or Karlsvagn
reflecting the North Germanic heritage of AngloSaxon Briton. Further to the east, in Indian
tradition, these seven stars are sometimes called the
Seven Sages and further still in the Far East they
are again a dipper or a ladle.
Meanwhile, back in North America, this
asterism is usually described in animal terms. For
the Migmaw of eastern Canada it is three hunters
tracking a bear, one of the hunters, Mizar, is
carrying a stew pot, Alcor, in anticipation of a
successful hunt. Further west in some Iroquois
traditions the story is he same but Alcor becomes a
hunting dog. For the Anishinaabe people it is a
Fisher (the weasel kind). The Wasco people from
the Columbia River basin have a fun story that
involves one of my favourite characters, Coyote,
and it goes like this:
“Once there were five wolves who would
share meat with Coyote. One night the wolves were
staring at the sky. "What are you looking at?"
asked Coyote. "There are two animals up there."
they told him. "But we can't get to them." "That is
easy." said Coyote. He took his bow and shot an
arrow into the sky where it stuck. He shot another
arrow which stuck into the first. Then he shot
another and another until the chain of arrows
reached the ground and they all climbed the arrows
into the sky. The oldest wolf took along his dog.
When they reached the sky they could see that the
animals were grizzly bears. The wolves went near
the bears and sat there looking at them and the
bears looked back. Coyote thought they looked
good sitting there so he left them and removed his
arrow ladder. The three stars of the handle of the
Big Dipper and the two stars of the bowl nearest
the handle are the wolves. The two stars on the
front of the bowl are the bears. The tiny star by the
wolf in the middle of the handle is the dog.”
In Inuit tradition the Big Dipper is a
Caribou or sometimes a herd of them. A distinct
deviation from the animal theme is the Revolving
Man of the Navajo people. This asterism re-aligns
the stars of Ursa Major into the figure of a man that
revolves around the pole opposite the Revolving
Woman which combines Cassiopeia with parts of
Perseus and Cepheus.
Through-out history Astronomy has been
about time keeping and navigation but the Big
Dipper does little for us in either case. It's
orientation as it circles the pole tells us the seasons
but chances are we already new that anyway. It's
contribution to navigation is limited to it's two
“pointer” stars, the grizzly bears, showing the way
to the pole star. Polaris though is a multi-tasker, it
was the go-to reference for any kind of navigation
until the magnetic compass replaced it in the 9th
century in China and the 12th century in Europe.
Just as important, the angle of Polaris above the
horizon is the same as the latitude of the observer
and as such is vital to knowing where in the world
you are. It's interesting to look at old maps and
compare the North-South relationships of places to
the East-West relationships. The latitudes that these
ancient navigators and cartographers recorded were
not that far off the mark, it was with longitude
where they fell down because that requires an
accurate chronometer, which was not invented until
1737 and is another story.
Summer Solstice at Pen Henge
by Chris Purton
Summer Solstice was a great event at Pen Henge, and the fact we could actually see the Sun on that occasion,
at least for a short time just before it set, was a huge advantage.
The picture of the setting Sun was taken by Ryan Ransom the day before, with the summer solstice
stone graced by his daughter Olivia, adorned with her customary halo. My interest, to be looked after the
following day, was in ferreting out details of the horizon, in particular its
elevation and slope at the point where the Sun sets. Knowing those two
things permits calculation of virtually any aspect of the setting Sun that
you might care to know about.
On the day of solstice, in the midst of a
crowd that had gathered at Pen Henge to celebrate
the event, Jim Shaver set up his spotting 'scope to
project an image of the setting Sun on to a crude
screen that I'd cobbled together. Sandra Purton
Sunset as seen from Pen Henge
took a series of pictures of the projected image.
June 20, 2014. Olivia stands on the One of those, taken about half way through the
projected image of
summer solstice stone, with the
setting process, is duplicated here and shows a
Sun setting as seen
heel stone in the foreground.
jagged horizon of tree tops (inverted) bisecting the from Pen Henge on
Photo by Ryan Ransom.
Sun. Armed with those pictures - there were seven June 21, 2014. Photo
of them altogether - and the time at which each
by Sandra Purton,
was taken, I was able to get the information I wanted.
taken at 8:48:10 pm,
The answers are: 1) the elevation of the horizon at the sunset point is 2.13deg, PDT.
so sunset occurs earlier by 18.7 minutes than for the `standard' case (of a horizon
90deg from the zenith) that is used to calculate published sunset times, and 2) it slopes upward to the north by
2.67deg, so the time between first and second contact is shorter than for the standard case by 26 seconds.
The images could also be used to get accurate times of sunset. Second contact, the instant when the
Sun's upper limb touches the horizon and the official moment of sunset, was at 8:50:12 pm, PDT. First contact,
when the lower limb of the Sun first touches the horizon, was at 8:46:30. The time between those, about 3-3/4
minutes, is the active period, the interval in which you can see something happening.
(for a more detailed description of the process see Page 9.)
The Joys of Making a New Telescope Work Right by Hugh Pett
On November 11, 2014, the radio telescope at the Okanagan Observatory made its first observations of
Galactic hydrogen emissions.
Right away, something was obviously not working properly: the signal was much weaker than it should
have been. This is not surprising, since a radio telescope must be adjusted in much the same way as an optical
one must be collimated. I had no time or inclination to spend hours in the freezing temperatures trying to coax
more signal from the antenna. IT WAS WORKING! Leave it alone! was my only thought.
But over the next few days, a further problem became clearer: there was MUCH more random variation
in signal strength, laid on top of the expected changes as the Milky Way passed across the field of view.
Discussions with my mentors Ken Tapping and Marcus Leech suggested one source of the variability
and weak signal, caused by the way I had connected various parts, or, more correctly, how I had NOT
connected one point.
On a subsequent trip, with help from Grant Rice, I made the extra
connection, and checked on a wild surmise I had had: the antenna might be
pointing at the ground! This is classed as a “BAD THING”, both for optical
and radio astronomy.
Sure enough, on checking the alignment of the dish carefully, it was
(now!) obvious that half the field of view was the treeline to the South of the
Observatory. This means that the desired signal is buried under a lot of
ground-generated radio noise.
After some adjustment in the dish supports, and with the dish pointing
only a couple more degrees skyward, the quick trek into the Support Building
to the computer plotting the results confirmed the signal was stronger.
The first full day of observations was enough to show a drastic
reduction in the variability that had been plaguing the observations.
This is only the beginning of the commissioning phase of making the
radio telescope fully operational. As Dave Gamble has found with the 25", this
can go on for quite a while, but the challenge of getting it RIGHT is part of the
enjoyment of a fascinating hobby. (right Dave?)
Outreach events by Colleen O'Hare
Now you can follow the Okanagan Observatory on Twitter! @okobservatory
Find out about upcoming Astronomical events and Kelowna Outreach events.
Kelowna Outreach
Each month on the 2nd Tuesday, we visit the Cancer Rotary Lodge with our Tour of the Universe
presentation starting at 6:30 pm. If the weather is clear, we also set up telescopes to allow views of celestial
wonders. Please consider joining us for this very rewarding event. The next visit is Feb 10.
I have started an Outreach Calendar on our AstroOkanagan Google email discussion site. If you would like
access to this to keep up with events, please let me know.
Clothing, New Items, Styles and Colours!
Check out the Zenfolio pictures of the Okanagan Observatory’s new line of clothes! T-shirts ($20), Polos
($40), Hats ($15) and anything else you like from the catalogue. To find the pictures go to
http://rascoc.zenfolio.com/p246016613.
Let me know if you would like to order anything. ([email protected])
Meetings Schedule
Meetings held in Penticton on Thursdays (First Thursday of the month in 2014/15)
Okanagan College – Penticton Campus, Sunoka building, Room C02. See map.
February 5, 2015
7:15 at OC
March 5, 2015 7:15 at OC
April 2, 2015 7:15 at OC
May 7, 2015
7:15 at OC
May 23, 2015 Gala Dinner/Auction/Speaker; Kelowna 5:00pm
(Fourth Thursday of the month in 2015/16)
September 24, 2015
7:15 at OC
*October 27, 2015
7:15 at OC Kelowna (Tuesday)
November 26, 2015
7:15 at OC
December 17, 2015
7:15 at OC
January 28, 2016
7:15 at OC
February 25, 2016
7:15 at OC
March 24, 2016 7:15 at OC
April 28, 2016 7:15 at OC
**May 28, 2016 Gala Dinner (Kelowna 5PM)
June 23, 2016 7:15 at OC
Meetings held in Vernon on Wednesdays (Last Wednesday of the month)
OSC - Okanagan Science Centre , 2704 Hwy 6, Vernon See map.
January 28, 2015
7:15 at OSC
February 25, 2015
7:15 at OSC
March 25, 2015 7:15 at OSC
April 29, 2015 7:15 at OSC
May 23, 2015 Gala Dinner/Auction/Speaker; Kelowna 5:00pm
June 24, 2015 7:15 at OSC
September 30, 2015
7:15 at OSC
*October 27, 2015
7:15 at OSC
Kelowna (Tuesday)
November 25, 2015
7:15 at OC
December 30, 2015
7:15 at OSC
January 27, 2016
7:15 at OSC
February 24, 2016
7:15 at OSC
March 30, 2016 7:15 at OSC
April 27, 2016 7:15 at OSC
**May 28, 2016 Gala Dinner (Kelowna 5PM)
June 29, 2016 7:15 at OSC
Meetings held in Kelowna on Tuesdays (First Tuesday of the month in 2014/15)
Okanagan College Science building at Okanagan College KLO Road, Kelowna. See map.
February 3, 2015
7:30 at OC
March 3, 2015 7:30 at OC
April 7, 2015 7:30 at OC
May 5, 2015
7:30 at OC
May 23, 2015 Gala Dinner/Auction/Speaker; Kelowna 5:00pm
(Fourth Tuesday of the month in 2015 /16)
September 22, 2015
7:30 at OC
*October 27, 2015
7:15 at OC Kelowna (Tuesday)
November 24, 2015
7:30 at OC
December 22, 2015
7:30 at OC
January 26, 2016
7:30 at OC
February 23, 2016
7:30 at OC
March 22, 2016 7:30 at OC
April 26, 2016 7:30 at OC
**May 28, 2016 Gala Dinner (Kelowna 5PM)
June 28, 2016 7:30 at OC
* denotes the Annual General Meeting held at 7:15 at the Okanagan College Kelowna
** denotes a combined meeting between the Kelowna, Penticton and Vernon Chapters
Kelowna Meeting
February 3, 2015, 7:30 at Okanagan College, K.L.O. Campus, Kelowna
Presentation: This month's main presentation is entitled " Predicting Steady Astronomical Seeing and Finding
Clear Eclipse Weather" and will be presented by Alan Whitman. Alan will explain how to interpret weather
charts and related data in order to predict those really great nights. Please be advised that this presentation will
be at the beginning of the meeting and business will be conducted after the break.
COTM: The Constellation of the Month will be dispensed with this month to allow Dennis Krause extra time
to present the annual budget.
The following Kelowna Meeting of the OC RASC will be held on Tuesday, March 3, 2015 at 7:30 PM at the
O.C. Kelowna Campus, KLO Rd., Lab Building, Room C368.
Pen Henge - Decoded by Chris Purton
How the relevant information is extracted from the images and timings might be of interest to those
contemplating doing something similar.
First, on each image a circle was drawn around the circumference of the Sun, and a jagged line along the
horizon. Circle and line from each were then transferred to one composite image, duplicated here, carefully
laying the horizon lines one on top of the other so they matched. The size of the Sun on each image was used
to establish the angular scale, and each image was adjusted to make the Sun circles all the same size on the
composite. A `best straight line' was fit to the composite horizon, to be used as an idealised representation of
the real one.
Then an azimuth-elevation grid was drawn up, and the position of the Sun (its centre) plotted on it for each of
the image times. In calculating those positions the effects of refraction in the Earth's atmosphere had to be
included. A set of solar positions ignoring that effect was also plotted. Just for fun. The copy of the az-el plot
duplicated here shows both sets. A straight line fit to the positions of the Sun (the set which included
refraction) represents the path of the setting Sun on the sky, as it would be seen.
The composite image was then placed on the az-el grid (mathematically) after being un-inverted, rotated and
shifted by the correct amount so the observed positions of the Sun from the composite image coincided, on
average, with the calculated positions. The idealised horizon line was dragged along in this process, resulting
in a plot of the western horizon, or at least a small section of it, on the az-el grid. And thus the slope of the
horizon in that part of the sky is known.
For both first and second contact, the position of the Sun on the az-el grid was found by requiring its centre to
be on the path of the setting Sun, and its circumference tangent to the horizon line. This gives the elevation of
the horizon at the sunset point, that being the tangent point for second contact.
The elevation of the Sun at first and second contact, found from the plot, was converted to PDT by going
backwards through the process that was used to get az-el of the Sun from times of the images. And thus the
times of first and second contact were known. There is a small dip in the horizon which sits between the first
and second contact points, as shown on the plot (in an idealised way), but this dip had no effect on the results.
An important part of a process like this, for me, is presenting preliminary results to the Penticton Group,
because of the helpful comments that come back . . . things I just didn't think of. For example, uncertainty in
the times the images were taken is a major source of error, and Dave Whalley suggested using a camera that
stamped each picture with an accurate time. Also, the angular size of the Sun is a bit of information used to
scale all the
images, and Alan
Whitman pointed
out that it varies
through the year,
but an accurate
value for any date
can be found in the
Observer's
Handbook. And
Maureen Foucault
pointed out that the
amount of
Composite of the individual
refraction depends
images with circles (and
on atmospheric
associated times) representing
conditions so
the Sun, together with jagged
azimuth-elevation plot showing positions (of various
relying on some
lines representing the horizon,
kinds) of the Sun, relative to the observed horizon.
`standard value',
from each.
which I'd done,
skews the calculations.
That last comment inspired a proper error analysis, which was useful. The formal errors came out as +/0.015deg for the angles, and +/-8 seconds in the times, coming mainly from uncertainty in timing and in
processing the images. Next biggest source of error was the `fuzziness' in the real horizon, which is a jagged
line of tree tops. The contribution coming from refraction unknowns came way down the list, but the
difference in refraction between centre and limb, which gives the Sun its flattened appearance when it's
setting, turned out to have a major effect. The angular size of the Sun, which is used to find out where it is at
first and second contact, is smaller, and what's worse, it depends on elevation, and the elevation isn't known
before doing the calculations ! So this effect was ignored to get a rough idea of the elevation, and that was
used to revise the angular size of the Sun, from which a better calculation of the elevation (and times of
contact) could be found. This kind of calculation could go 'round and 'round for ever, getting better and better
answers, but once around proved to be quite adequate . . . and thank Heaven for that.
Figure caption 3: Composite of the individual images with circles (and associated times) representing the Sun,
together with jagged lines representing the horizon, from each.
Figure caption 4: azimuth-elevation plot showing positions (of various kinds) of the Sun, relative to the
observed horizon.
Elected Officers
President David Player
1st VP Vernon Jerry Thompson
2nd VP Penticton Dave Whalley
3rd VP Kelowna Olaf Lutz
Treasurer Dennis Krause
Secretary Dennis Krause
Observatory Director Guy Mackie
Librarian Colleen O’Hare
National Representative Richard Christie
Directors
1
Jim Failles
2
Rafael Scotto Sachianca
3
Wes Quist
4
Grant Thompson
5
6
Past President Colleen O’Hare
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250-485-0010
250-863-0187
250-763-2677
250-763-2677
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250-762-5445 x4484
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778-436-9441
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Appointed Positions
Focus Editor Hugh Pett
Webmasters
Andrew Bennett
Dave Gamble
Membership Secretary David Hawkins
RASC merchandise David Hawkins
Outreach Coordinators
Vernon
Raffaele Scotto Sachianca
James Kanester
Kelowna Colleen O’Hare
Penticton Al Fishler
Picture of the Month
Mark Force
Sharon Carter
Zenfolio Manager Dave Gamble
What's Up Contributor Dave Gamble
The Focus newsletter of the RASC Okanagan Centre is published on the 15th of each month, September
to June. Deadline for submitting material to the Editor, Hugh Pett ([email protected]), is the 8th of
the month.