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Phobos
Contents
1) Meetings.
2) Society News.
3) Guest Speaker,
4) Sky Diary.
7) Gemini.
12) Camelopardalis.
14) Samuel Smiles.
15) Quiz.
16) Keeping Abreast.
19) Brightest Stars.
20) Answers.
Volume 33
Number 12
March 2007
Ken Willoughby
Ken Willoughby.
Doctor Joe Foster.
Derek Hufton.
Ken Willoughby.
Ken Willoughby.
Ray Emery.
Ivan Harden.
Clive Down.
Meetings
March Meetings
1st. (Thursday.)
Committee Meeting.
5th.
Visit: 6:00pm-7:15pm.
6th.
The LHC At CERN. Building The World's Microscope.
Doctor Joe Foster.
University of Manchester.
8th.
Visit: 6:00pm-8:00pm.
13th.
Open Night. 7:30pm-10:00pm.
16th. (Friday.)
Open Night. 7:30pm-10:00pm.
20th.
Oh Those Яussians!
Ken Willoughby.
27th.
Telescope Training.
Jim Boulton & Kevin Read.
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SOCIETY NEWS.
KEN WILLOUGHBY.
Annual General Meeting, Tuesday February 27th 2007.
The following were elected as officials and committee members for 2007/2008.
Chairman:
Secretary:
Treasurer:
Ken Willoughby.
Jim Boulton.
Kevin Read.
Committee:
Emma Barton. Dave Cooke. Andrew Farr.
Jenny Hutchinson. Debi Knight. Michael Wilde..
Member of the Year: 2006.
Steve Stern.
Best Article: Howard Thomas.
Best Photo: Brian Joynes.
The membership over the last 12 months has been the best for a long time with the social side
really taking off. This is a very important part of any society. Membership of any society isn't
about just turning at meetings, listening to a talk then going home, it is also about organising
outings, the occasional meal, meteor watches etc. We also have the added advantage of Dave
Cooke with his 'Battlefield' outings which everyone found extremely interesting, more are
planned for later in 2007.
We have a lot to look forward to over the next 12 months. The car park has been re-surfaced
with 20mm washed limestone (no more puddles.) The new projector screen will be installed in
March and we await the results of two grant applications.
Please Note: 'Triple' Nickel will now be talking on THURSDAY the 26th of April at
Carleton Community High School, 7:30pm-9:00pm) admission £5. More about this in the
April issue of Phobos.
Free lecture by Dr. Alexander Martynov and Cosmonaut Alexander Volkov.
Thursday March 15th @ Manchester Metropolitan University, Oxford Street (opposite the
BBC) Manchester. 16:15 - 21:00. For details contact Ms Anderson :
[email protected] or tele: 0161 247 2158.
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I grew up in California, interested in everything scientific. I took a degree in Physics at
Amherst College in Massachussetts, and then taught in Nigeria for two years with the US
Peace Corps. I came to England in 1967, married, and have lived here ever since. I taught at a
large comprehensive (Foxwood School)in Leeds at first, then did a PhD in Cosmic Ray
Physics at Leeds University. Since 1982 I have worked as a researcher in Particle Physics, first
in the European Muon Colloboration and WA69 experiments at CERN in Geneva, then in the
H1 experiment at DESY, in Hamburg. From 1996 I have been part of the ATLAS
collaboration at CERN, helping to ensure that the Semiconductor Central Tracker works as it
should when the Large Hadron Collider switches on in November. For most of this time I have
been employed by the University of Manchester. My areas of specialism have been in testing
detectors, writing software to extract and analyse the data, and in Quality Assurance, which is
proving very important at the LHC.
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Sky Diary: March 2007.
Derek Hufton.
Monthly Highlights: The first total eclipse of the Moon since 2004 occurs on the night of
March 3rd-4th. Also, several bright planets are favourably placed for viewing this month. At
dusk Venus is fairly high in the west and Saturn in the east-southeast. Jupiter doesn’t rise until
the middle of the night and is highest in the south at dawn. Mercury reaches greatest elongation
in the morning sky this month, but is better viewed from the southern hemisphere.
Dates & Time: Thursday 1st March is the 60th day of the year and it is also number 2454160 in
the Julian Calendar.
The Sun: Rotations number 2054 and 2055 of Carrington’s series begin on March 4.18 and
31.49 respectively. During the month the Sun’s axis of rotation is tilted to the west of the
vertical some 21.4o at the start of the month and by month end it will be 26.1o to the west. The
Sun’s disk is also tilted towards us by 7.2o at the start of the month ending the month tilting
towards us by 6.6o – crucial data for you sunspot plotters!
The Sun reaches the March (Vernal) Equinox at 0.07h Universal Time on the 21st as it makes
a welcome move across the celestial equator, heading north.
The Moon: In the Farmers Almanac, the March Full Moon is called the Crust Moon. In other
places it is also referred to as the Chaste, Death, Sap, Crow and Lenten Moon. The Moon is
less than one degree from Saturn on the 1st (actually occulting it for observers in Scandinavia
and eastern Europe). On the morning of the 11th the Moon is about 2o lower left of Antares and
about 8o below Jupiter on the next morning. A very thin waning crescent Moon is well lower
left of Mars on the 16th and Mercury the next morning. On the evening of the 21st the slender
waxing lunar crescent appears quite far above Venus and on the night of the 28th the waxing
gibbous Moon passes very close to Saturn.
A Total Lunar Eclipse, of magnitude 1.229, occurs on March 3rd. The appropriate contact
times (UT) are as follows:
Moon enters Penumbra
20:19 Moon enters Umbra
21:31
Start of Totality
22:24 Eclipse maximum
23:20
End of Totality
23:56 Moon exits Umbra
01:10
Moon exits Penumbra
02:22
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The Moon's Phases are:
New
Full
19d 02h 43m
03d 23h 17m
1st Qtr 25d 18h 16m
Last Qtr 12d 03h 54m
The Moon is at Perigee (closest approach to the Earth) on March 19th at 19h. Its apparent
diameter will be 33’ 23”. Apogee (furthest approach) occurs on March 7th at 03h with
apparent diameter of 29' 27".
The maximum Libration points of the Moon’s ‘wobble’ occur on March 12th and 25th, the
main extra tilt being visible at Position Angles 48o and 227o respectively. This means that you
get a chance to ‘peep round the edge’ of the lunar limb even more on these dates. Remember
that Position Angle is measured from North through East on the face of the Moon (North=0o,
East=90o, South=180o, West=270o) and it tells you where to concentrate your telescope.
Mercury: pulls out to its greatest western elongation of 27.7o from the Sun (about the
maximum ever possible) on the 22nd. This makes for a superb apparition for observers at midsouthern latitudes, but in our location, the +0.1 magnitude planet climbs just 5o high about 30
minutes before sunrise and will probably require binoculars to glimpse. Mercury’s disk is 7.4”
wide and 53% illuminated at the time of the elongation.
Venus: continues its steady climb during March. After sunset it can be glimpsed at magnitude
–3.9 about 27o high in the west-southwest as the month begins; its altitude increasing to 34o by
month end. Telescopes will reveal the planet’s relatively small, gibbous disk, which will be
just less than 13” wide around mid-month.
Mars: races across Capricorn this March but remains mired low in morning twilight for
viewers at mid-northern latitudes. It rises only about 100 minutes prior to the Sun throughout
the month. The red planet shines at magnitude +1.2 when it passes 1o south of Neptune on the
morning of the 25th, although the latter may be too dim to detect low in the bright sky.
Jupiter: starts coming up around midnight during March, shining at magnitude –2. As
morning twilight begins, the planet stands well to the upper left of Antares. On the 9th Jupiter
reaches western quadrature (90o west of the Sun). This is when Jupiter’s shadow is cast farthest
west, facilitating observations of the planet’s eclipses of its four bright satellites.
Saturn: shines prominently in the east-southeast as night falls, drifting farther west from
Regulus as the month progresses. The planet’s brightness decreases slightly from last
February’s peak at magnitude 0.0, but telescopes will show its rings getting a little more open
during the month. Saturn remains high for much of the night and this is a prime month for
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enjoying Saturn and its rings as well as the six or seven of its brightest moons that are
accessible in medium-sized telescopes.
Uranus and Neptune: Uranus is in conjunction with the Sun on the 5th and therefore will not
be visible this month. Neptune is also still close to the Sun in the dawn sky and difficult to
locate.
Meteor Showers: Meteor Showers: Again, there are no major meteor showers this month, but
as usual, look out for the 4 or 5 sporadic meteors you can expect to see every hour under good
observing conditions.
Night Sky looking South at Midnight on March 15th.
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GEMINI
THE TWINS
Mythology and History
Uranus and Pluto were discovered in Gemini. Uranus was found near h Geminorum and Pluto
near q Geminorum.
In Greek mythology, Castor & Pollux were twin heroes. The two were born from an egg laid
by Leda after she was seduced by Zeus in the disguise of a swan. Yet it was said that Pollux
was the son of Zeus, and Castor was the son of Tyndareus. The two brothers were good
companions and became gods, patrons of athletes and protectors of sailors at sea. Castor &
Pollux had power over the winds and waves. Castor became famous as a rider of horses while
his brother Pollux became equally skilled at boxing and fighting battles.
The twins were raised by the centaur Chiron (now the constellation Sagittarius) and later
joined Jason and the Argonauts in search of the Golden Fleece. Eventually they decided to take
wives and selected the two beautiful daughters of the king of Sparta.
Now it happened that the two women were already married to Idas and Lynceus, cousins of the
twins. But this seems to have made little difference to the Twins. They simply carried to girls
off and settled down with them. The two cousins were not bothered by this. A few years later,
the cousins, in friendly company of the Twins, made a joint raid on some cattle. It is said that
trouble between the two pairs of thieves began when they tried to divide the cattle among
themselves. Idas had the solution. He hacked one of the cows into four equal pieces and said
that whichever two individuals completely finished eating their quarters first would divide the
spoils.
This took the Twins off guard and they watched helplessly as their two cousins wolfed down
their quarters of the cow. Idas and Lynceus then drove off the entire heard. Tricked, Castor
and Pollux vowed to get even with their cousins. Within a few days they set out after the two
cousins to recover their share of the cattle. During the fight that followed, Idas killed Castor
with a spear.
Infuriated over the loss of his twin brother, Pollux chased his cousins and killed Lynceus with
a single blow. Just as Idas was about to hurl a tombstone at Pollux, Zeus came to Pollux's aid
and hurled a thunderbolt at Idas, killing him on the spot. Pollux, the immortal son of Zeus,
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begged to die so that he would not be separated from his brother. Not even the mighty Zeus
could do such a thing so he placed them together in the sky as the constellation
The Constellation
The constellation of Gemini is one of the oldest recorded. As with so many others we inherited
it from Ptolemy in his work called the ‘Algamest’ (C.151 BCE.) He in turn took it from the
poetic work of Aratos called ‘The Phaenomena’ (275 BCE.) The information for his work was
taken from the list of Eudoxus of Knidos (403 to 350 BC). Where it originated from is
anyone’s guess, but it is certainly ancient.
This particular constellation forms part of a number of asterisms namely: ‘The Heavenly G’,
‘The Winter Octagon’ and ‘The Winter Oval’. It is the 26th brightest constellation and ranks
30th by size. It takes up 513.76 square degrees of sky (1.245%) and reaches its highest point in
the sky on 5th January each year. The whole of the constellation is visible from anywhere north
of –55 degrees but is invisible from anywhere south of –80 degrees. It commands a position on
the edge of the winter Milky Way and with a very large telescope no fewer than 5 faint
galaxies can be found within 1 degree of the main star, Castor. One of its claims to fame is that
2 planets have been discovered within this constellation.
W. Herschel in 1781 discovered Uranus and Pluto was discovered by Clyde Tombaugh in
February 1930.
Bright stars
There are 47 stars recorded in this constellation as being brighter than +5.5 magnitude (naked
eye visibility).
Alpha Geminorum (RA: 07.34.4, DEC: +31.53.08)
This star is the famous Castor, the horseman. There is some idea that either this star or Pollux
has changed in brightness over the past few hundred years because Castor is no longer the
brighter of the two. Instead it is now ranked as the 23rd brightest star in the sky or perhaps we
should say brightest stars. The reality is that this ‘star’ is in fact a congregation of 3 double
stars, making a total of 6. It is one of the most complex systems in the sky and theory says that
such a system is inherently unstable and should separate.
To the eye Castor appears diamond white in colour and it was not until 1678 that G.D. Cassini
resolved it into a double star. Indeed it was the first ‘binary star’ to be recognised. We have to
remember that in those days people had difficulty in coming to terms with the Earth going
around the Sun let alone other stars orbiting one another.
In time the orbit of what appeared to be the ‘A’ and ‘B’ stars was established as being between
380 and 511 years. Their separation distance is believed to be about 90 astronomical units or
8.4 billion miles (a little more than the diameter of the Solar System). Observations revealed
their widest separation to occur in 1880 and by 1965 it had closed to its smallest separation of
55 astronomical units. The whole system is receding away from us at the rate of 3 miles per
second. Some time later Castor ‘C’ was discovered at magnitude +9.1 with an orbital period of
10,000 years. Not only that but also all three were discovered by spectroscopy to be binary
systems in their own right.
Castor ‘A’ is magnitude +1.58. The two stars are in an eccentric elliptical orbit of 9.2.28 days
and are 4 million miles apart. Both are main sequence stars and are almost identical.
They are about twice the diameter of our Sun, 47.3 times the luminosity and a total of 3.2 times
the mass. They are 51.6 light-years distant. Castor ‘B’ has a magnitude of +2.85 and the two
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stars are in an almost circular orbit lasting 2.9283 days. 3 million miles separate them and both
have an A5 spectrum. They are 1.5 times the diameter of the Sun, 6 times its luminosity and
the total mass is 2.3 times that of the Sun. Castor ‘C’ (also known as yy Geminorum) consists
of a pair of red dwarf stars. They reside 100 billion miles from Castor ‘A’ and ‘B’ (over 1,000
astronomical units) and their orbit last for an estimated 10,000 years or more. They both have a
dK6 spectrum and they follow an orbit that eclipses one another. Their orbital period is 19.5
hours and they are separated by 1.67 million miles, which they cover at 70 miles per second.
They have almost identical magnitudes of +9.1 and +9.6.
Beta Geminorum (RA: 07.45.23, DEC: +28.1.22)
This star is called Pollux, the pugilist or boxer. The name originates from the Greek word
Polydeuces, which has the same meaning. It is the 17th brightest star in the sky with an
apparent magnitude of +1.16, the absolute magnitude being 0.2. It will be seen that this star,
although classified as the ‘beta’ star, is in fact brighter than Castor, the ‘alpha’ star. Its
spectrum is K0 111var, which makes it a yellow star with a surface temperature of about 4,500
degrees Kelvin. It is quite a large star with a diameter 11 times that of the Sun and 29.8 times
the luminosity. Although from its distance of 33.7 light-years it appears to be receding from us
at 1.9 miles per second its real motion through space has been calculated at 19 miles per
second.
It could be, that one of the stars, Castor or Pollux, has changed magnitude over the years.
Records show that Ptolemy in 150, Al-Sufi in 960 and Ulugh Beigh in 1430 and Tycho Brahe
in 1590 each had both stars ranked at +2 magnitude. It was not until 1700 that Flamsteed’s list
showed Castor as +1 and Pollux as +2. It is only in the last 200 years that agreement has been
reached that Pollux is the brighter.
Gamma Geminorum (RA: 06.37.46, DEC: +16.23.50)
This is the 43rd brightest star in the sky and is known by two names, Alhena and Almeisam. It
shines at an apparent magnitude of +1.93 (-0.7 absolute) and has an A01v spectrum. It is 105
light-years distant and is 141 times as luminous as he Sun. It is approaching us at 7.7 miles per
second.
Delta Geminorum (RA: 07.20.11, DEC: +21.58.46)
This star is called Wasat and has an apparent magnitude of +3.51. It has an F01v spectrum and
is 58.8 light-years away. It is 10.5 times more luminous than the Sun. In 1829 Mr Struve
discovered that it was a binary system with the ‘B’ companion being a K6 dwarf star. The stars
are separated by 95 astronomical units and take 1,200 years to orbit one another. It was close to
this star system that Pluto was discovered in 1930.
Epsilon Geminorum (RA: 06.44.00,DEC: +25.7.45)
This star is the 161st brightest in the sky and is called Mebsuta. It shines at an apparent
magnitude of +3.06 and has an A3mA6-A9 spectrum. For some reason it is known as a supergiant ‘G’ star, which is 903 light-years distant and 3,714 times the luminosity of the Sun. Its
absolute magnitude is –4.6, it has strong emission and absorption line of helium and is part of
the Pleiades Group.
Eta Geminorum (RA: 06.14.56, DEC: +22.30.20)
This +3.31 magnitude star is called Propus and also Tajat Prior. It has an M3 111 spectrum and
can be seen to be a double star in a telescope of 12-inches or over. The ‘A’ star is known to be
a red giant, which varies in magnitude over a period of 233 days. The variability is believed to
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be due to an unseen companion. The distance is recorded as 349 light-years and the luminosity
as 441 times that of the Sun.
MESSIER OBJECT / OPEN CLUSTERS
M35 (NGC2168) (RA: 6.09, DEC: +24.21)
This open cluster of stars has an overall magnitude of
+5.1. It is 2,800 light-years distant and 20 light-years
across. It can be found close to the left foot of Castor. It is
thought that Philippe Loys de Chescaux may have
discovered the cluster in 1745. Charles Messier observed it
on 30.8.1764 and plotted it on his chart for the comet of
1770.
Even binoculars will reveal this cluster to be very large,
rich in stars and fairly compressed. The stars within it
range from +9 to +16 magnitude so not all of them will be
resolved even in a medium sized telescope. To the naked eye it appears as a mottled patch of
hazy light, nearly the same size as the full moon. Magnification will show a more rectangular
shape with a lighter arc or ridge where the stars are brighter.
A good telescope and good seeing will show that the outlying members of the cluster fill a 1.5degree field (3 times the size of the full moon). They are best seen with a wide field telescope
but it must be borne in mind that the whole cluster is prone to interference from light pollution.
Estimates as to the number of stars vary but the general theme seems to be in the region of 300,
a figure derived by the Earl of Ross.
NGC2158 (RA:06.7.5, DEC: +24.06)
This open cluster of stars can be found in the same field of view as M35. It looks much smaller
and fainter, at magnitude +8.6, than M35 but in reality it is about the same size. The reason
that it looks smaller is that it is 6 times further away (around 16,000 light-years). Close
examination at times of good seeing reveals a dark lane between two halves of the cluster.
NGC2174 / 5 (RA: 06.9.7, DEC: +20.30)
This open cluster, surrounded by a circular nebula, is to be found on the Gemini / Orion
border. I have read that it is easy to see in a 12-inch telescope with a nebula filter and that it
may be visible in telescopes as small as 6-inch. The use of a filter is said to be essential. It
appears like a planetary nebula to the untrained eye as a bright central star dominates the
cluster.
Planetary Nebula
NGC2392 (The Eskimo Nebula)
(RA: 07.29.2, DEC: +20.55)
The Hubble Space Telescope took a fabulous image of the
Eskimo Nebula, after its servicing mission in December 1999,
over the 10th and 11th of January 2,000 (image number PR00-07).
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This glowing remnant of a dying Sun like star was first recorded in 1787 by William Herschel.
The origin of its name is plain to see through the telescope. The image seen is of a face with a
fur parka hood around it. The fur of the ‘parka hood’ is in fact a disk of material embellished
with a ring of comet-shaped objects with their tails streaming away from the central, dying,
star. Scientists are still puzzled about their origin.
The ‘face’ of the Eskimo has also been seen to hold fascinating detail. The central region
resembles a ball of twine, although we know it is a bubble of material being expelled at high
speed.
This +9.2 magnitude planetary nebula began to form about 10,000 years ago as two lobes of
material were ejected from the star. We see only one lobe; the other is hidden behind this at the
opposite side of the star from our line of sight.
When the star was in its red-giant stage it ejected a dense band of material around its equator,
which plods along at 72,000 miles (115,000 km) per hour. This belt of material prevented the
high-speed winds from developing in that region. Instead the 900,000 miles per hour (1.5
million km) winds fan out into the lobes at either side of the star at 90 degrees to the equatorial
belt. The resulting bubbles of material are not smooth as they have filaments of denser material
within them. Each bubble is about 1 light-year long and about half a light-year wide.
The nebula is about 5,000 light-years distant from Earth and the image from Hubble revealed
an abundance of nitrogen, hydrogen, oxygen and helium in the structures observed.
Sir Patrick Moore also records this object as number 39 in the Caldwell Catalogue. It appears
as a blob in a 4-inch telescope and a 20-inch telescope will reveal more detail of the parka fur.
Detail of the disk should be visible in 8 to 10-inch telescopes on good nights.
Abell 21 (RA: 07.29.0, DEC: +13.15)
This planetary nebula is a challenge even for large telescopes. The Americans refer to it as a
showpiece object and in theory it should be visible through a 12-inch telescope or larger. A 14inch telescope view is reportedly good but through a 16-inch it is said to be ‘stunning’. All you
apparently need is a dark site and an oxygen 111 filter to see it clearly.
SUPERNOVA REMNANT
IC443 (RA: 06.16.9, DEC: +22.47)
Found between Eta and Mu Geminorum is a little spoken of supernova remnant, IC443. With
anything smaller than a 10-inch telescope it is very difficult to see visually. Even with a
suitably sized instrument it still requires a nebula filter and moments of good seeing to pick out
the band of light that is to be seen. Despite this it is the 3rd brightest confirmed supernova
remnant in the northern sky.
It apparently makes a good photograph by a CCD image system will require a wide field lens
or telescope to image it properly. If you have a radio dish you might even pick up the radio
emissions.
METEOR SHOWERS
The Geminids
The Geminid showers actually occur twice in the year, 19th October and between the 7th and
the 15th December. The latter display is frequently the best of the year although it is equally
frequently blotted out by cloud in these regions. Professional interest in the December shower
stems from the rapid evolution of the stream, which has only been active, according to records
since the 19th century. According to the professionals this shower may move away from Earth
altogether in the next 100 years so make the most of it while you can.
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The shower is unusual in that it has a much higher density than most at 2g/cm cubed. This was
accounted for, maybe, by the discovery in 1983 of an asteroid called Phaethon (by the IRAS
satellite), which shares the same orbit as the Geminid stream. On a clear night one can expect
to see somewhere between 80 and 90 per hour following a slow build up to a sharp peak in
activity about 1am.
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Camelopardalis , Latin: giraffe):
Camelopardalis is found between Polaris and Capella and is the name of a large but faint northern
constellation first recorded by Jakob Bartsch in 1624, but probably created earlier by Petrus
Plancius.
Although Camelopardalis is the 18th largest constellation, it is not a particularly bright
constellation, as the brightest stars are only of fourth magnitude.
β Camelopardalis is the brightest star, at apparent magnitude 4.03. This star is a double star, with
components of magnitudes 4.0 and 7.4. The second brightest is CS Camelopardalis, which has
neither a Bayer or Flamsteed designation. It is of magnitude 4.21 and is slightly variable.
In some astronomical reference books, one will often see an alternate spelling of this constellation
as Camelopardis. In approximately 40,000 years Voyager 1 probe will pass within 1.6 light years
the star AC+793888, which is located in Camelopardalis.
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Camelopardalis has no mythology associated with its stars, as it is a modern constellation, first
recorded by Jakob Bartsch. The faintness of the constellation, and that of the nearby constellation
Lynx, lead to the early Greeks considering this area of the sky to be empty, and thus a desert.
However, as a desert, together with other features in the Zodiac sign of Gemini (i.e. the Milky Way,
and the constellations Gemini, Orion, Auriga, and Canis Major), this may be the origin of the myth
of the cattle of Geryon, which forms one of The Twelve Labours of Herakles. Camelopardalis, in
order to show a Giraffe. The giraffe's body consists of the quadrangle of stars α Cam, β Cam, BE
Cam, and γ Cam: α Cam and β Cam being of the fourth magnitude. The stars HD 42818 (HD 2209)
and M Cam form the head of the Giraffe, and the stars M Cam and α Cam form the giraffe's long
neck. Stars β Cam and 7 Cam form the giraffe's front leg, and variable stars BE Cam and CS Cam
form the giraffe's hind leg.
Notable deep sky objects
NGC 2403 is a spiral galaxy approximately 11 million light years distant. It is of magnitude 8.4.
NGC 1502 is a magnitude 6.0 open cluster about 6,800 light years distant.
Kemble's Cascade.
Located in the constellation Camelopardalis, is an asterism - a pattern
created by unrelated stars. It is an apparent straight line of more than 20
colorful fifth to 10th magnitude stars over a distance of approximately
five moon diameters, and the open cluster NGC 1502 can be found at one
end.
It was named by Walter Scott Houston in honor of Father Lucian J.
Kemble (1922 - 1999), a Franciscan Friar and amateur astronomer who
wrote a letter to Walter about the asterism describing it as "a beautiful
cascade of faint stars tumbling from the northwest down to the open
cluster NGC 1502" that he had discovered while sweeping the sky with a
pair of 7x35 binoculars.
Walter was so impressed that he wrote an article on the asterism that appeared in his "Deep Sky
Wonders" column in the astronomy magazine "Sky & Telescope" 1980 naming the asterism
Kemble's Cascade, its a good target for binocular observing.
NGC 2403:
Is an intermediate spiral galaxy in the
Camelopardalis constellation. It was discovered
by William Herschel in 1788. NGC 2403 is an
outlying member of the M81 Group, and is
approximately 8 million light-years distant. The
northern spiral arm connects to NGC 2404. It
may be easily seen using 10 × 50 binoculars
Supernovae:
As of late 2004, there had been two reported
supernovae in the galaxy: SN 1954J and SN
2004dj.
Allan Sandage detected Cepheid variables in
NGC 2403 using the Hale telescope, making it
the first galaxy beyond our local group to have
Cepheids found in it. He derived a distance of a
mere 8 kly. Today, it is thought to be a a
thousand times further away at about 8 Mly.
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Samuel Smiles and the Railway Astronomer.
Ray Emery.
Samuel Smiles – onetime newspaper reporter in the fair city of Leeds – is chiefly remembered these
days as the doyen of biographers of self-made men in the Victorian era. His numerous works, with
telling titles such as “Self Help” and “Thrift”, extol the virtues of pulling oneself up by one’s own
bootlaces, and conquering all in the face of adversity, ignorance, and the sheer apathy of one’s
fellows on this earth. In this sense, his books are more by way of modern day hagiographies, echoes
of the “lives of the saints” of earlier times, in their essentially uncritical depiction of the inventions
and struggles of their subjects. Nonetheless they are still an entertaining read, and their significance
is denoted by the fact that many of them are still in print – and those which are not can usually be
obtained on the second-hand market.
In his 1883 work “Men of Invention and Industry”, Smiles denotes his final chapter to “astronomers
in humble life”. One of these persons is described as a railway porter, working at the station of
Blairgowrie in Scotland: John Robertson. I leave those interested to search out the details for
themselves, but there are two elements of Robertson’s story which I wish to bring to your attention
here. The first relates to an “anonymous New York poet”, who (Smiles tells us) penned a ditty in
praise of our astronomer hero. The second stanza goes as follows:
John’s watchful eye becomes more bright
And takes another glow’r aye
Thro’ yon blue dome of sparkling stars
Where Venus Bright and ruddy Mars
Shine down upon Blairgowrie.
He kens each jinkin’ comet’s track,
And when he’s likely to come back,
When they have tails, and when they lack –
In heaven the waggish power aye;
When Jupiter’s belt buckle hings,
And the Pyx mark on Saturn’s rings,
He sees from near Blairgowrie.
Now, what is all this talk of “Jupiter’s belt buckle” and the “Pyx mark on Saturn’s rings”? Alas, a
search on the web brought little joy. One might suppose that the Great Red Spot might stand in for a
belt buckle on Jupiter, although it is not an equatorial or “midriff” feature. As for “pyx”, this is
listed in the Concise Oxford English Dictionary as either a kind of chalice in which consecrated
communion wafers are held, or a box in which gold or silver coins were kept prior to testing at the
Royal Mint! How either of these relates to the ringed planet I have been unable to discover. Can
anyone enlighten us? (“Pyx” is also the abbreviation for the southern constellation Pyxis, the
Mariner’s Compass, but that does not seem appropriate in this case.) Smiles goes on to tell us of
how John Robertson was fortunate enough to be tied into the astronomical alert circulars system
even then in operation. He gives the following as Robertson’s own account:
“ I have also taken up the observation of variable stars in a limited portion of the heavens, That, and
‘hunting for comets’ is about all the real astronomical work that an amateur can do nowadays in
our climate, with a three-inch telescope. I am greatly indebted to the Earl of Crawford and
Balcarres, who regularly sends me circulars of all astronomical discoveries, both in this and foreign
countries. I will give an instance of the usefulness of these circulars. On the morning of 4 th October,
1880, a comet was discovered by Hartwig, of Strasbourg, in the constellation of Corona. He
telegraphed it to Dunecht Observatory, fifteen miles from Aberdeen.
15
The circulars announcing the discovery were printed and despatched by post to various
astronomers. My circular reached my by 7 p.m., and, the night being favourable, I directed my
telescope upon the part of the heavens indicated, and found the comet almost at once – that is,
within fifteen hours of the date of its discovery at Strasbourg.”
Now, how’s that for the days of pre-Internet, steam-and-gaslight astronomy?
Copies of this and others of Smiles’ opus are available for those who might wish to seek them out –
Amazon is always a good place to start. However, for those (like myself) of a truly Yorkshire
persuasion, it is possible to download some of them for free – including the book from which the
above extracts have been taken. Several websites provide this service, but Project Gutenberg is a
good place to start your hunt for smiley Smiles freebies – Google etc. will doubtless oblige!
Quiz .
The easy one.
1. Which is the third planet from the Sun?
2. What is the biggest Planet?
3. How many Satellites orbit Mars?
4. What are their names?
5. Where would you find "The Sea of Tranquility"?
6. Where would you find the mountain called Olympus Mons?
7. Who was the first man to land on the Moon?
8. Who was the first person in Space?
9. What do the letters ISS stand for?
10. Where would you find the Hubble Space Telescope?
11. What do the letters ESA stand for?
12. What do the letters STS stand for?
13. How long does it take for light to reach us from the Sun?
14. Where is the so called Asteroid Belt?
15. Which is the nearest star to the Solar System?
16. How long does it take the Earth to orbit the Sun?
17. What are the stars of Orion's 'Belt' called.?
18. Where would you find Io?
19. What is the second Full Moon in the same month called?
20. Where would you see the "Great Red Spot"?
21. The constellation Ursa Major is commonly called what?
22. The constellation 'Crux' is also known as what?
23. What is the brightest star in the Northern Hemisphere?
24. The Moon Titan orbits which planet.
25. In which constellation would you find the star, Betelgeuse?
The hard one.
1)
An observer at Bristol, latitude 51º27'-N. Longitude 2º 33' -W., finds that the star Altair, RA
19h. 48m. Dec. +08-44', is at transit at 22h. 20m GMT. Find:
a)
The Altitude of Altair at upper transit?
b)
The Greenwich sidereal time of the time of transit at Bristol?
c)
The GMT. of the transit of Altair as seen from Bristol one week later?
16
KEEPING ABREAST.
CLIVE DOWN.
PLUTO PROBE OBSERVES JUPITER
New Scientist
The 'New Horizons' spacecraft, bound for Pluto and possibly other objects in the outer Solar
System, is making a fly-by of Jupiter to gain speed and test its instruments. It will make its closest
approach on February 28, passing 2.3 million kilometres from Jupiter's centre, but it took the first of
700 planned observations of the planet on January 8. In the first 10 days of its observations of
Jupiter, New Horizons found that an area northwest of the Great Red Spot was unexpectedly
tranquil. Pictures from the Cassini spacecraft in 2000 showed significant turbulence there. Now
the area looks more as it did when Voyager flew by in 1979. Scientists are hoping also to
observe a little red spot that formed fairly recently through the merger of three smaller storms. New
Horizons has already taken a distant picture of that area, and will get more images when it is
closer. Scientists look forward to measurements to be made in Jupiter's so-called magneto tail, a
region of sulphur and oxygen ions originating from the volcanic moon Io. The charged particles
get trapped in Jupiter's magnetic field, then blown by the solar wind into a tail that stretches
hundreds of millions of kilometres behind Jupiter -- practically to Saturn's orbit. After its closest
approach, New Horizons will keep making measurements of the magneto tail until June. Mission
managers estimate that it could fly one-quarter of the length of the tail. In addition, it will make a
detailed search for satellites around Jupiter with its telephoto camera. It will also get a nearlyedge-on view of the tenuous ring system, which it will map in 3D; scientists hope to determine
which of Jupiter's dozens of moonlets create the rings. The main point offlying past Jupiter,
however, is to get a boost in speed. By a clever use of Jupiter's gravity, theprobe's speed will be
increased by 4 km/s, reducing by three years its travel time to Pluto. So far, New Horizons has
remained quite close to its intended trajectory, and has not needed to call on the 25 kilograms of
fuel (out of its initial total of 77 kg) reserved to correct any deviations. Now, that extra propellant
promises to be available to take it, after Pluto, to other objects in the ring of trans-Neptunian
bodies known as the Kuiper Belt.
DISC OF MATERIAL ENCIRCLES MIRA B
California Institute of Technology
It has been reported that material from the well-known evolving star Mira is being captured into
a disc around Mira B, its companion. Located 350 light-years away in the constellation Cetus, Mira
made history 400 years ago upon the discovery of its variations in brightness. Visible to the naked
eye for a month or two at a time, it becomes 100 times fainter and disappears from view, only to
reappear again, on an 11-month cycle. Although Mira was once a star somewhat like the Sun, it is
now in a late stage of its evolution as a giant star and is expelling its outer layers at a rate of one
Earth-mass every seven years. If Mira were a single star, all that material would dissipate into
space. Mira, however, has a companion star in an orbit with a period of about 1,000 years, and the
companion, Mira B, has a gravitational field that catches nearly 1% of the material lost from Mira
A. By using specialized high-contrast techniques at the 10-m Keck I telescope in Hawaii and the 8m Gemini South telescope in Chile, observers discovered heat radiation coming not only from Mira
B itself but also from a location offset from Mira B by a distance equivalent to the radius of
Saturn's orbit. The intense radiation from Mira A, 5,000 times brighter than the Sun, heats the edge
of the disc to about the Earth's temperature and causes it to glow in the infrared.
The researchers found that the material was indeed the edge of a disc and not just a local
condensation in the wind from Mira A. By modelling the way in which the outflow from Mira A is
captured, the researchers were also able to confirm that Mira B is simply an ordinary star like the
Sun, although only about half as massive. Eventually Mira A will have expelled all of its tenuous
outer layers, and what is left will appear as a white dwarf about one million years from now.
17
NEW DISTANCE ESTIMATE FOR ORION NEBULA
Topix.net
The distance to the Orion Nebula was previously estimated at about 1,500 or 1,600 light-years,
but now astronomers at Keele University say that it is actually closer than that. They studied 34
stars formed in the nebula, and compared their rotational velocities with their periods of rotation to
deduce their size. It was then possible to derive their intrinsic magnitudes and compare them with
the apparent magnitudes to show that the true distance of the Orion Nebula is 'only' 1,300 lightyears. The new distance increases the estimated age of the Nebula's stars to 1.5 million years -- still
very young.
DISTANT STAR CLUSTERS FOUND BEHIND NEARBY ONE
University of California
Astronomers have discovered the most distant population of star clusters so far identified,
hidden behind one of the nearest such clusters to Earth. At a distance of more than a billion lightyears, the newly discovered star clusters probably exemplify what similar systems in our own
Galaxy once looked like. However, because a billion years is hardly a tenth of the ages that
globular clusters are supposed to have, it is not to be expected that there have been significant
changes in their characters or appearance in that time. The study began as an investigation of a
globular star cluster known as NGC 6397; at about 8500 light-years it is one of the closest such
clusters. The Hubble telescope was used to image a small field within the cluster. In the
background, however, was a population of stars and galaxies which included a large elliptical
galaxy that contains several hundred globular clusters. Although each of the clusters probably
contains hundreds of thousands of stars, they are so far away that each cluster appears as a single
faint point of light in the Hubble image. In fact, a single giant star in NGC 6397 appears 10
million times brighter than one of the distant globular clusters. The distance of the elliptical galaxy
hosting the globular clusters was estimated from its red-shift, and showed that the globular clusters
are the most distant so far identified.
UNDERGROUND WATER RESERVOIRS ON MARS?
New Scientist
Apparent dried-up rive-beds and other evidence have been held to imply that Mars once had
enough water to fill a global ocean more than 600 metres deep, together with a thick atmosphere of
carbon dioxide that kept the planet warm enough for the water to be liquid. Now, however,
Mars is very dry and has a thin atmosphere. Some scientists have proposed that Mars lost its water
and CO2 to space as the solar wind stripped molecules from the top of the atmosphere.
Measurements by Russia's Phobos-2 probe in 1989 hinted that the loss was quite rapid, but now the
Mars Express spacecraft has indicated a rate of loss that is much lower. Its measurements suggest
that the whole planet loses only about 20 grams per second of oxygen and CO2 to space, only about
1% of the rate inferred from Phobos-2 data. If the same rate has been maintained throughout Mars'
history, it would have removed only a few centimetres' depth of water and a thousandth of the
original CO2. Either some other process removed the water and CO2 or they are still present and
hidden somewhere on Mars, presumably in underground reservoirs.
Pictures from the now-lost Mars Global Surveyor suggested that liquid from sub-surface sources
had gushed down slopes on Mars in recent years, so it seems possible that there is some water
existing in liquid form even now. However, the researchers point out that other mechanisms, such
as asteroid and comet impacts, might have removed water and CO2 from Mars, or the solar wind
might have blown off whole chunks of atmosphere rather than individual molecules.
18
ROSETTA OBSERVES ASTEROID PREMATURELY
The Register
The spacecraft 'Rosetta' is primarily intended to observe Comet 67P Churyumov-Gerasimenko,
which it will not reach until 2014. Before then, it will pass close to two asteroids -- a small one,
2867 Steins, at a distance of only 1700 km on 2008 September 5, and a 100-km one, 21 Lutetia, at
3000 km on 2010 July 10; much sooner, on the 27th of this month, it will pass by Mars, but not so
much to observe Mars as to obtain additional speed by utilising the planet's gravity. Asteroids, like
comets, are supposed to offer clues as to conditions in the early Solar System, so observations of
them promise to add to the scientific return of the Rosetta mission. Rosetta has started observing
Lutetia already; it cannot resolve any surface detail but is only monitoring its apparent magnitude,
with the intention of determining the orientation of its rotational pole. Its rotation period is already
known -- it was discovered to be 8.172 hours by Russian scientists observing from the ground years
ago.
NEW STAR DISCOVERED IN SOUTHERN CROSS
Science Daily
A research team at Swarthmore College discovered a previously unknown companion to the
bright star Beta Crucis in the Southern Cross. The companion star was discovered accidentally
while the research team was using the orbiting Chandra X-ray Observatory to study the X-rays
emitted by Beta Crucis itself. The astronomers were surprised to see two strong X-ray sources
where only one had been expected.
HUBBLE'S MAIN CAMERA BROKEN
The Register
Hubble's main camera, the Advanced Camera for Surveys (ACFS), has shut down after an
electrical failure. The camera went offline last year after a problem with its power supply. That
was eventually resolved, but this time most of the damage appears permanent: NASA says that
only one of the ACFS's three sub-cameras is likely to be restored. The ACFS was installed during
the 2002 servicing mission. Its three cameras observed in the ultraviolet, visible and infrared
wavelength regions, and its installation effectively doubled Hubble's field of view. The camera's
three channels took in wide-field and high-resolution pictures, as well as a dedicated channel for
observing our own Solar System. NASA speculates that it will be able to reboot that last-named
channel -- the solar blind -- but says that the wide-field and high-resolution channels are almost
certain to remain offline. Since its installation, the camera has sent back some truly remarkable
images and has made a great contribution to science. It has been the most frequently demanded
instrument on the observatory. Hubble is long overdue for its next service, and is scheduled to be
attended by astronauts in 2008 September. NASA had hoped that that mission would be able to
repair the ACFS properly, but that looks unlikely now. Instead, the mission will carry out its other
objectives -- installing the new wide-field camera and the 'Cosmic Origins' spectrograph, as well as
new batteries and gyroscopes.
19
Brightest Stars
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Common
Name
Sirius
Canopus
Alpha
Centauri
Arcturus
Vega
Capella
Rigel
Procyon
Achernar
Betelgeux
Agena
Altair
Acrux
Aldebaran
Antares
Spica
Pollux
Canis Major
Carina
Apparent Spectral Luminosity Distance
Absolute
Mag.
Type
(Sun = 1) (Light Years) Mag.
-1.46
A1
26
8.7
+1.4
-0.72
F0
200,000
1,200
-2.5
Centaurus
-0.04
G2
1.7
4.3
+4.1
0.00
0.03
0.08
0.12
0.38
0.46
0.0 - 0.9
0.61
0.77
0.83
0.85
0.96
0.98
1.14
K2
A0
G8 F0
B8
F5
B5
M2
B1
A7
B1
K5
M1
B1
K0
115
52
90 70
60,000
7
400
15,000 v
10,000
10
3,200
120
7,500
2,100
60
36
25
43
910
11.4
85
310
460
16.6
360
68
330
260
36
+0.2
+0.6
+0.4
-8.1
+2.6
-1.3
-7.2
-4.4
+2.3
-4.6
-0.3
-5.2
-3.2
+0.7
1.16
A3
13
22
+2.0
1.25
1.25
A2
B0
70,000
8,200
1,800
425
-7.2
-4.7
Constellation
Boötis
Lyra
Auriga
Orion
Canis Minor
Eridanus
Orion
Centaurus
Aquila
Crux Australis
Taurus
Scorpius
Virgo
Gemini
Piscis
Fomalhaut
Australis
Deneb
Cygnus
Crux Australis
Becrux
Apparent Magnitude tells how bright the star is as seen from the Earth. The magnitude
scale was devised by the Ancient Greeks. The brightest stars were called First Magnitude,
the next brightest were called Second Magnitude, etc. In modern times, the scale has
been defined mathematically. A star of magnitude 1 is about 2.5 times brighter than a star
of magnitude 2 which in turn is 2.5 times brighter than a star of magnitude 3. The brighter
a star, the smaller its magnitude. Many stars are brighter than first magnitude. Some stars
are so bright they have negative magnitudes. The magnitude of the Sun is -26.72 but is
only 150 million kilometres away (0.000 016 light years.) Placed at 10 parsecs (32.6 light
years) which is the standard distance for measuring absolute magnitude, the Sun would
have a magnitude of +4.8.
20
Answers to quiz.
The easy one.
1. Earth
2. Jupiter
3. 2.
4. Phobos & Deimos.
5. On the Moon.
6. On Mars.
7. Neil Armstrong
8. Yuri Gagarin
9. International Space Station
10. Orbiting the earth, in outer space
11. European Space Agency
12. Space Transportation System.
13. 8.3 minutes.
14. Asteroids orbit mainly between Mars and Jupiter
15 Proxima Centauri which is 4.24 light years away from Earth
16. 365.25 days approximately
17. Alnitak, Alnilam, Mintaka.
18. It is a Satellite of Jupiter
19. Blue Moon..
20. On Jupiter
21. "The Great Bear" part of which is "The Plough"
22. The Southern Cross.
23. Arcturus.
24. Saturn.
25. Orion.
The hard one.
a)
You need to find the co-latitude of Bristol, i.e. it's latitude subtracted from 90º.
90º - 51º 27' = 38º 33'. To this you must add the declination of Altair, which is
North of the Equator. 38º 33' + 8º 44' = 47º 17', which is therefore the meridian
altitude of Altair.
b)
The local sidereal time = the RA of the star = 19h. 48m.
21
L.S.T. of transit
=
Allow for longitude of Bristol =
GST of transit
c)
=
h.
19
m. s.
48 00
10 12
___________
19 58 12
The difference is 3m 56s per day, so in 7days this amounts to 27m 32s. Taking
this from 22h 20m, you obtain 21h 52m 28s, which will be the time of the
transit of Altair one week later.
22