Solar Scopes and Filters
Presented by Tim Milligan
Below is an outline of the topics that Tim covered:
Hydrogen Alpha Filter
By isolating and passing the Hydrogen Alpha wavelength of 656.3 nm., this
filter permits viewing features of the chromosphere just above the
photosphere,
including flares, prominences, filaments, spiculae and sunspots.
The device consists of a 2 stage filtering scheme with a narrow front band
filter:
Fabry Perot interferometer which allows 10 A pass band and a secondary
blocking filter (energy rejection filter) to prevent infra red wavelengths
(heat) from entering the telescope.
White Light Filters
Observe sunspots and solar granualtion in the sun’s photosphere (blocks
99.99% of suns light).
(1) Glass triple coated stainless steel fits snugly over objective
lens.
(2) Aluminum Coated Mylar Least expensive and better image that
glass.
(3) Herschel Wedge a wedge of unsilvered glass which transmits
about 5% of incoming light to eyepiece with remainder going through a hole
in the rear of the unit.
Southern Hemisphere “The Tools”
Presented by James Morgan
Christine Kronberg of Munich Germany has defined constellations as belonging
to “families” and the “Tools” belong to the La Caille Family because they
were
invented by the astronomer, Abbé Nicolas Louis de Lacaille (1713-1762).
Of the fourteen “Tools, James presented six : NORMA
(The Level), CIRCINUS (Compass), TELESCOPIUM (Telescope), MICROSCOPIUM
(Microscope), SCULPTOR (Sculptor’s Studio), and FORNAX (Furnace) .
Norma is another of those relatively insignificant constellations
in the Southern Hemisphere. Invented by Nicolas Louis de Lacaille in the
mid-eighteenth century, the constellation represents a scientific instrument,
"the level". The original name was "Norma et Regula" (the level and the
square). Since Lacaille's time, the principle stars of
Norma have been redistributed, leaving it with fewer Bayer stars.
Circinus, The Compass, is a Southern Hemisphere constellation
introduced by Nicolas Louis de Lacaille in the mid-eighteenth century.
Only seven Bayer stars are brighter than sixth magnitude. The
one deep space object it holds is a recently discovered (25 years ago) galaxy
called “The Circinus Galaxy”.
In Telescopium, it is a shame that the most important instrument
for astronomers should be associated with
such a tiny portion of the sky, practically devoid of telescopic interest.
Lacaille devised the constellation in the mid-eighteenth century.
Microscopium, The Microscope is one of Nicolas de Lacaille's creations,
celebrating yet another scientific instrument. Like so many of Lacaille's
constellations, there isn't much of interest here. The asterism gives a vague
suggestion of its subject. There are only a handful of Bayer stars,
mostly fourth and fifth magnitude.
Sculptor is one of those obscure constellations invented by Nicolas
Louis de Lacaille to help fill in part of the southern sky. The full name
was "L'Atelier du
Sculpteur", the Sculptor's Studio. Its stars are generally fourth
and fifth magnitude. The constellation has two binaries with very long orbits,
a couple of
nice variables, and several spiral galaxies.
Fornax was the most notable as it is seen from our latitude and
contains "The Fornax Galaxy Cluster". Eighteen galaxies make up the
cluster. The brightest is
NGC 1316 (which is also a radio source called Fornax A). NGC 1399 is nearly
as bright; the third brightest, NGC 1365, is a splendid barred spiral seen
face on, with open spiral arms. NGC 1316 is 2º SW of chi3 For;
NGC 1365 is 1º ESE of chi3 For; NGC 1399 is 2º E of chi2
For.
Lacaille studied over 10,000 Southern Hemisphere stars from the Cape of
Good Hope using a 1/2 inch refractor.
The remaining 8 tools constellations, are listed below :
Antlia (The Airpump), Caelum (The Sculptor’s Chisel), Horologium(The
Pendulum Clock), Mensa (The Table Mountain), Octans (The Octant)
Pictor (The Painters Easel), Pyxsis ( The MagneticCompass), Reticulum
(The Net)
Lunar Eclipses
Presented by Michael Borgia
Eclipses in general
Eclipses occur when the sun, moon and earth are in a near direct line
causing the moon or earth to cast its shadow on the other. Because
the moon’s orbit is inclined
5 degrees to the earth’s, an eclipse can only occur when the moon is within
15-18 degrees of an ascending or descending node.
When the moon casts its shadow on earth, a solar eclipse occurs.
Solar eclipses must occur at least twice each year.and may occur as many
as 5 times a year.
When the earth casts its shadow on the moon. a lunar eclipse occurs. Lunar
eclipses can occur no more than 3 times a year and indeed do not have
to occur at
all in a given year.
After the basics, Borgia went on to discuss
The Saros cycles
These are important in determining the recurrence and periodicity of eclipses.
Every 18 years, 10.3 days, the moon reaches nearly the same position with
respect
to perogee, node and phase. e.g. The eclipse of 11-09-2003 (Saros 126
#45) which is virtually identical to the eclipse of 10-31-1985 and
to the eclipse coming in 11-19-2021.
With each such cycle, the eclipse shifts 120 degrees aoround the globe.
After 3 such cycles (54 years 1 month), the eclipse will returm to the same
longitude on
earth but shifted about 600 miles south. This period, called an
“exeligmos” will cause the next solar eclipse on 04-08-2024 (Saros
139 #30) to be virtually
identical to the eclipse 03-07-870 ( #27) but 60 miles farther south.
Astronomy Software Update
Starry Night Pro 4.5
Tom Pomponio demostrated the planetarium program Starry Night.
Visually it is arguably the best planetarium program around, and a steal
at $149.95. It has the complete Hipparcos and Tycho stellar databases
from the ESA and will incorporate main sequence stars into its
HR plug in.
It will incorporate user images including a 360 degree image of the user’s
observing area.
From the President’s Desk.....
November 11, 2003
Have you noticed the improvement in content, presentation, and overall
interest in our monthly meetings? I have. I have noticed the
changes and I like them. There is an increased enthusiasm and a willingness
to shoulder the responsibilities of gathering and presenting meeting
materials. The net result is more people involved
in our meetings and a fostering of the Learn-Teach-Learn principle that
is basic to the quality of amateur astronomy. Not one of us knows
all there is to know about
our avocation but as a group where members accept and embrace opportunities
to improve and share we will certainly improve as a group. Stay tuned
for continuing improvements in coming meetings.
Our hobby is doing well on Delmarva. We enjoy relatively good observing
conditions (I did say relatively). We have excellent monthly meetings,
enjoy our
successes, accept responsibility, look for opportunity, and Mother Nature
presents us with a varied menu of observing events. We have a
nice, well-mannered
group of members and we are financially sound…we are fortunate.
The Mother Nature part is beyond our control or influence but the people
part is for us to
manage, challenge status quo, and hopefully improve over time. Just
as surely as we enjoy the good times our hobby and club provide, we must
remember it is our
responsibility to monitor the pulse of the group and adjust as necessary
for success.
Did you see the Lunar Eclipse? I hope you did because it was a dandy
one. Several Star Gazers met at Woodland Beach on the Delaware River
east of Smyrna to watch the moon rise above the River and slide into the
shadow of Earth. We were not disappointed. The sun set in a clear
sky, and the moon rose in a clear sky. The wind was blowing briskly
out of the north – straight down the River. So we circled the wagons
to form a windbreak which provided some relief from Ol North Wind. We
watched as the shadow crept slowly across the moon’s face. Several of
us had cameras, scopes, binos, etc. to aid in the viewing. Our
next meeting should have a plethora of pics to share. Folks, it was
cold! But the cold could not prevent the Cosmic Geometry show.
In spite of the wind, tides, and native Woodland Beachers’ Saturday night
cruising the shadow of Earth continued creeping across the moon’s face.
I thought about how disturbing this event could have been to our ancestors
if they had viewed what we were experiencing. What kind of explanation
would they have for the “FULL” moon disappearing in such a short period?
And if they were brave enough to stick around how would they explain it’s
return? This was the first time I have ever seen an eclipse without
buildings, trees, and other familiar objects in the picture. It was
easy to imagine our ancestors alone on the riverbank watching this type
of event and conjuring up all types of explanations for it that included
evil spirits, monsters, interferences by the “gods”…
The best view of the eclipse was produced by the 25 X 100 Chinese binocular
I mounted on an anvil-grade tripod salvaged from Jim Acker’s photo studio.
I cannot say enough praises for this combination tripod/binocular.
It is probably the best addition to my observing equipment since the 25”
Obsession. Two eyes are great for viewing the heavens and heavenly
events.
I witnessed another beautiful event on Monday morning, Nov 10, about 6:30
– 6:45.The morning was very cold, the atmosphere was clear, we had the heaviest
frost of the season (about a 2”er), the moon was one day past full and was
hanging about 25 degrees above the western horizon as the sun was trying
to rise in the east. I was driving due north so I had a great
view of the western sky. The overhead was brilliantly blue with the
light of late dawn; next came a solid band of pink (the Belt of Venus) that
supported an unusually bright moon, and then came the dark gray/black band
of night that was disappearing below the western horizon as the sun rose on
the eastern side of Earth. All of this was placed above the frosty white
surface of Earth. Now if I only had a camera with a 90 degree
fov lens…
Our Christmas party will take place at the Church on Saturday, December
6, from 1:00 to 5:00 PM. All Gazers and their families are invited.
Please talk to Kathy
Sheldon for details other than: bring a side dish/chips/dips/dessert
(select one), a white lephant gift for the “exchange of gifts” ( we have
had some REAL white elephants), the club will supply turkey/ham, drinks,
& dinnerware. That’s all I know – I will be at the Church about
12:30. If you have a special party game or astro event please share
them with the group. If the skies cooperate we will have the prom scope
and white light scope for observing Ol Sol.
We are progressing rapidly on the 22” mirror. Currently it is polished
out and has a nice parabolic surface taking shape; I estimate we are 50-75%
of the way from
spherical to “on the numbers parabolic”. That means the center needs
to be deepened a tiny bit which will cause the 70% zone to “rise” and then
we will
probably have to knock down the 95% zone a bit. Complicated?
Naw…it’s just fun making a big piece of glass perform.
Keith Lohmeyer is our chief of telescope building and will head the team
to construct the 22”. Please contact him if you would like to be part
of the effort.
So what is on your short list for Astro Santa this Christmas? Warm
clothes, arctic boots, lights, sky atlases, digital observing aids, scopes,
eyepieces,
filters, software, binoculars, ??? Now is the time to write Astro
Santa and let him know your wants, wishes and needs.Enuf – See you at the
Church for the next meeting, the Christmas Party on the 6th, or at Tuckahoe.
Stay safe and look up!
Don…
Knowing full well I'd be busy enough looking at it visually through my
own scope, and many friends telescopes as well, I nevertheless set up that
bulky Linhof
tripod, a fancy equatorial mounting and an ETX-90 telescope; all to capture
the moments of totality on film; 35mm film in this case. Do you remember
that format? I managed to expose four rolls of ISO 400 & ISO 800
Fuji film during the duration of the eclipse, and bracketed many different
exposures. Just moments ago the
processed film was ready for me to pick up. So, how were the pictures?
They were (I'm saying this almost yawning) fine, yeah they looked OK.
What's my point? My point is, no matter how many pictures one examines
of an eclipse, the event is just too awe inspiring to capture on film.
It's nice for me to
look at the pictures, but when I do so, it's usually to remind me of the
feelings I felt while viewing the eclipse, the total human experience, if
you will.
When I lecture about photographing solar eclipses on some of the eclipse
expeditions I've been on it's usually the layperson attending those expeditions.
I
always stress not wasting time taking pictures with their point-and-shoot
cameras. Don't miss the event fiddling with your cameras! Believe me, I
tell them, a
year from now, you won'teven know where those pictures are. But 30 years
from now you'll remember every explicit detail of experiencing and viewing
the eclipse.
However, every solar eclipse morning there you'll find Kent Blackwell
setting up gobs of equipment to photograph the event. Will I ever learn?
Thanks for listening to yet another editorial!
Kent Blackwell
38.98°N 75.93°W 5hrW Standard Time Astronomical Twilight
Sun Moon
Date Twi. Rise Transit Set Twi. Rise Transit Set %
12/1/2003 5:29a 7:03a 11:53a 4:42p 6:17p 1:24p 7:08p ***** 60
12/2/2003 5:29a 7:04a 11:53a 4:42p 6:17p 1:47p 7:50p 1:02a 70
12/3/2003 5:30a 7:05a 11:53a 4:42p 6:16p 2:08p 8:30p 2:03a 78
12/4/2003 5:31a 7:06a 11:54a 4:41p 6:16p 2:31p 9:11p 3:02a 85
12/5/2003 5:32a 7:07a 11:54a 4:41p 6:16p 2:54p 9:53p 4:01a 91
12/6/2003 5:33a 7:08a 11:55a 4:41p 6:17p 3:21p 10:37p 5:01a 96
12/7/2003 5:33a 7:09a 11:55a 4:41p 6:17p 3:51p 11:23p 6:02a 99
12/8/2003 5:34a 7:10a 11:56a 4:41p 6:17p 4:28p ***** 7:02a 100
12/9/2003 5:35a 7:11a 11:56a 4:41p 6:17p 5:11p 12:12a 8:01a 99
12/10/2003 5:36a 7:11a 11:56a 4:41p 6:17p 6:01p 1:03a 8:56a 97
12/11/2003 5:36a 7:12a 11:57a 4:41p 6:17p 6:58p 1:54a 9:45a 93
12/12/2003 5:37a 7:13a 11:57a 4:42p 6:17p 7:59p 2:46a 10:28a 87
12/13/2003 5:38a 7:14a 11:58a 4:42p 6:18p 9:04p 3:36a 11:04a 79
12/14/2003 5:39a 7:14a 11:58a 4:42p 6:18p 10:09p 4:25a 11:36a 71
12/15/2003 5:39a 7:15a 11:59a 4:42p 6:18p 11:15p 5:12a 12:04p 61
12/16/2003 5:40a 7:16a 11:59a 4:43p 6:19p ***** 5:58a 12:29p 50
12/17/2003 5:40a 7:16a 12:00p 4:43p 6:19p 12:22a 6:43a 12:54p 39
12/18/2003 5:41a 7:17a 12:00p 4:43p 6:19p 1:30a 7:31a 1:20p 29
12/19/2003 5:42a 7:18a 12:01p 4:44p 6:20p 2:42a 8:20a 1:49p 19
12/20/2003 5:42a 7:18a 12:01p 4:44p 6:20p 3:57a 9:14a 2:22p 11
12/21/2003 5:43a 7:19a 12:02p 4:45p 6:21p 5:16a 10:13a 3:03p 4
12/22/2003 5:43a 7:19a 12:02p 4:45p 6:21p 6:35a 11:17a 3:54p 1
12/23/2003 5:44a 7:20a 12:03p 4:46p 6:22p 7:49a 12:23p 4:56p 0
12/24/2003 5:44a 7:20a 12:03p 4:46p 6:22p 8:53a 1:29p 6:07p 3
12/25/2003 5:45a 7:21a 12:04p 4:47p 6:23p 9:45a 2:30p 7:22p 8
12/26/2003 5:45a 7:21a 12:04p 4:47p 6:24p 10:26a 3:27p 8:35p 15
12/27/2003 5:45a 7:21a 12:05p 4:48p 6:24p 10:59a 4:17p 9:45p 23
12/28/2003 5:46a 7:22a 12:05p 4:49p 6:25p 11:26a 5:04p 10:51p 33
12/29/2003 5:46a 7:22a 12:06p 4:50p 6:25p 11:50a 5:47p 11:53p 43
12/30/2003 5:46a 7:22a 12:06p 4:50p 6:26p 12:12p 6:28p ***** 53
12/31/2003 5:47a 7:22a 12:07p 4:51p 6:27p 12:35p 7:09p 12:54a 62
