Wednesday 3rd January 2018
This evening was our welcome back social after the Christmas and New Year break.
Wednesday 10th January 2018
Andrew said that next week we have an update on Observing Highlights from Peter.
He introduced Dave Smith for his talk: A to Z of Astronomy
Andromeda Galaxy was first with a super image taken by Dave. He explained how to find it with a finder chart. The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy 2.5 million light-years from Earth, and the nearest major galaxy to the Milky Way. Its name stems from the area of the sky in which it appears, the constellation of Andromeda.
The 2006 observations by the Spitzer Space Telescope revealed that it contains approximately one trillion stars, more than twice the number of the Milky Way´s estimated 200-400 billion stars. The Andromeda Galaxy, spanning approximately 220,000 light years, is the largest galaxy in our Local Group. Its mass is estimated to be 1.5×1012 solar masses, whereas the Milky Way´s mass is estimated to be 8.5×1011 solar masses.
The Milky Way and Andromeda galaxies are expected to collide in ~4.5 billion years, merging to form a giant elliptical galaxy. With an apparent magnitude of 3.4, the Andromeda Galaxy is among the brightest of the Messier objects - making it visible to the naked eye on moonless nights, even when viewed from areas with moderate light pollution.
Binary Stars were next - a binary star is a star system consisting of two stars orbiting around their common barycentre. The term double star is often used synonymously with binary star; however, double star can also mean optical double star. Optical doubles are so called because the two stars appear close together in the sky as seen from the Earth; they are almost on the same line of sight. Nevertheless, ‘their’ doubleness depends only on this optical effect. The stars themselves are distant from one another and share no physical connection. A double star can be revealed as optical by means of differences in their parallax measurements, proper motions, or radial velocities. Most known double stars have not been studied sufficiently closely to determine whether they are optical doubles or they are doubles physically bound through gravitation into a multiple star system. Dave added that some binaries orbit each other in only 13 hours.
Clark (Stuart Clark) was next. Stuart Clark is an astronomy journalist and author of several books about space, both non-fiction and fiction, including The Sky´s Dark Labyrinth trilogy. Dave has copies of these with him and said they were available for any of us to read.
Dumbbell Nebula which is also known as Apple Core Nebula, Messier 27, M27, or NGC 6853) is a planetary nebula in the constellation Vulpecula, at a distance of about 1,360 light-years. This object was the first planetary nebula to be discovered; by Charles Messier in 1764. We saw super pics and a finder chart showing location.
The Eagle Nebula (catalogued as Messier 16 or M16, and as NGC 6611, and also known as the Star Queen Nebula and The Spire) is a young open cluster of stars in the constellation Serpens, discovered by Jean-Philippe de Chéseaux in 1745–46. Both the ‘Eagle’ and the ‘Star Queen’ refer to visual impressions of the dark silhouette near the centre of the nebula, an area made famous as the ‘Pillars of Creation’ photographed by the Hubble Space Telescope. Dave showed the superb Hubble photo and a finder chart.
Filters - they work simply by blocking some of the object´s light to enhance the contrast. Neutral density filters are mainly used in traditional photography, but are used in astronomy to enhance lunar and planetary observations.
A Galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust and dark matter. The word galaxy is derived from the Greek galaxias, literally ‘milky’, a reference to the Milky Way. Galaxies range in size from dwarfs with just a few hundred million stars to giants with one hundred trillion.
Dave showed us his image of the Markarian´s Chain is a stretch of galaxies that forms part of the Virgo Cluster. When viewed from Earth, the galaxies lie along a smoothly curved line. Charles Messier first discovered two of the galaxies, M84 and M86, in 1781. We also saw M81 & M82 - a classic.
A Hydrogen-Alpha filter is an optical filter designed to transmit a narrow bandwidth of light generally centred on the H-Alpha wavelength. They are characterized by a bandpass width that measures the width of the wavelength band that is transmitted.
The Iris Nebula, NGC 7023 and Caldwell 4, is a bright reflection nebula and Caldwell object in the constellation Cepheus. NGC 7023 is actually the cluster within the nebula, LBN 487, and the nebula is lit by a magnitude +7 star.
Julian dates (abbreviated JD) are simply a continuous count of days and fractions since noon Universal Time on January 1, 4713 BC (on the Julian calendar). Almost 2.5 million days have transpired since this date. Julian dates are widely used as time variables within astronomical software.
Comet Kohoutek, formally designated C/1973 E1, 1973 XII, and 1973f, was first sighted on 7 March 1973 by Czech astronomer Luboš Kohoutek. It attained perihelion on 28 December that same year. Comet Kohoutek is a long-period comet; its previous apparition was about 150,000 years ago, and its next apparition will be in about 75000 years. We saw a nice NASA image of it, but Dave said he found it disappointing.
Libration is manifested as a slow rocking back and forth of the Moon as viewed from Earth, permitting an observer to see slightly different halves of the surface at different times. There are three types of lunar liberation: Libration in longitude results from the eccentricity of the Moon´s orbit around Earth. We saw a delightful video clip of the moon rocking from side to side.
William Optics Megrez 90 APO is Dave´s current scope – Megrez is the name of one of the stars in the Plough.
The Needle Galaxy NGC 4565 is an edge-on spiral galaxy about 30 to 50 million light-years away in the constellation Coma Berenices. It lies close to the North Galactic Pole and has a visual magnitude of approximately 10. It is known as the Needle Galaxy for its narrow profile. First recorded in 1785 by William Herschel. We saw a brilliant image and a finder chart.
Omega Centauri NGC 5139 is a globular cluster in the constellation of Centaurus that was first identified as a non-stellar object by Edmond Halley in 1677. Located at a distance of 15,800 light-years, it is the largest globular cluster in the Milky Way at a diameter of roughly 150 light-years. It is estimated to contain approximately 10 million stars and a total mass equivalent to 4 million solar masses. Dave said it was bigger than a full Moon.
The Pipe Nebula is a dark nebula in the Ophiuchus constellation and a part of the Dark Horse Nebula. It is a large but readily apparent pipe shaped dust lane that obscures the Milky Way star clouds behind it. Clearly visible to the naked eye in the Southern United States under clear dark skies, but it is best viewed with 7 binoculars.
Pickett´s Bell is a strange bell shaped dark nebula surrounding Betelgeuse.
A Quark is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Due to a phenomenon known as colour confinement, quarks are never directly observed or found in isolation; they can be found only within hadrons, such as baryons (of which protons and neutrons are examples) and mesons. For this reason much of what is known about quarks has been drawn from observations of the hadrons themselves.
Reflection Nebulae are clouds of interstellar dust which might reflect the light of a nearby star or stars. The energy from the nearby stars is insufficient to ionize the gas of the nebula to create an emission nebula but is enough to give sufficient scattering to make the dust visible. Dave said a fine example was the Pleiades.
The Schmidt-Cassegraine telescope (SCT) uses a combination of mirrors and lenses (Catadioptric optics) to fold the optics and form an image. The light is folded to make a greater focal length. These catadioptrics are the most popular type of instrument with the most modern design, marketed throughout the world in 3.5 in and larger apertures. Dave said he found them rather heavy.
Sharpless 101 (Sh2-101) is an H II region emission nebula located in the constellation Cygnus. It is sometimes also called the Tulip Nebula because it appears to resemble the outline of a tulip when imaged photographically. It was catalogued by astronomer Stewart Sharpless in his 1959 catalogue of nebulae. It lies at a distance of about 6,000 light-years.
The Teapot asterism in the constellation Sagittarius is easy to spot in a dark sky. Look this way, and you´re looking toward the centre of our Milky Way galaxy. The Teapot is an asterism, not a constellation, but a recognizable pattern of stars. Dave showed us a shot of the Milky Way with the asterism drawn in. It’s bigger than you think.
Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. Uranus is similar in composition to Neptune, and both have different bulk chemical composition from that of the larger gas giants Jupiter and Saturn. For this reason scientists often often classify Uranus and Neptune as ‘ice giants’ to distinguish them from the gas giants.
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It has the longest rotation period (243 days) of any planet in the Solar System and rotates in the opposite direction to most other planets. It has no natural satellites. It is named after the Roman goddess of love and beauty. It is the second-brightest natural object in the night sky after the Moon, reaching an apparent magnitude of -4.6, bright enough to cast shadows at night and sometimes visible to the naked eye in broad daylight. Dave showed his own brilliant sequence of images displayed as one with the Sun in the middle.
The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop a large but relatively faint supernova remnant. The source supernova exploded circa 3,000 BC to 6,000 BC the remnants have since expanded to cover a large area.
The Whirlpool Galaxy, also known as Messier 51a, M51a, and NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy. Its distance is estimated to be between 15 and 35 million light-years.
X-ray Emission The study of the x-ray emission of normal galaxies is a very recent part of astronomy. This work has been made possible by the sensitive x-ray imaging observations of the Einstein (HEAO 2) satellite, launched by NASA in November 1978. Material falling into a black hole may emit X-rays, but the black hole itself does not. The energy source for the X-ray emission is gravity. Infalling gas and dust is heated by the strong gravitational fields of these and other celestial objects. Many thousands of X-ray sources are known. Dave showed an image of M51 again but this time in X-ray.
Zodiacal light is a faint, diffuse, and roughly triangular white glow visible in the night sky that appears to extend from the vicinity of the Sun along the ecliptic or zodiac. Sunlight scattered by interplanetary dust in the zodiacal cloud causes this phenomenon. Dave added that Brain May did his thesis on Zodiacal Light.
Wednesday 17th January 2018
Mike said that next week we have himself talking about ‘The Curious Moon’ unless of course it´s clear when we will be observing - so please bring your scopes. Plus he has been in discussion with EWT to hold an observing session at their Thameside Reserve sometime in the future.
Ted said that the he had gained permission from the church for Ed´s ‘after meeting’ observing sessions to go ahead.
Andrew said that there was a box of CDs about astro stuff which had been left for us – not sure by whom – but please help yourselves.
Mike said that club fund raising would be more important at future Open Nights.
MikeB said that Haw Wood Farm have 18 pitches booked for us on 14th to 21st March at £12 per night – talk to him to reserve your places.
Mike introduced Peter for his talk:
Observing Highlights February 2018
He started with the news that the club Geminid Meteor watch had started very badly weather wise but had cleared and they saw 170 of them.
He added that his friend Denis in Scotland was snowed in!
He showed us a star chart for 11th Feb at 06.00 with Saturn, Moon, Mars and Jupiter in the East. He said that Jupiter does not look like a star it has a disc and 4 visible moons – he showed a video clip of the moons moving. He pointed out the two prominent bands.
He said that Mars has Antares below it – the name means rival to Mars – they are of similar mag. In July Mars will be at its closest and be 24secs across.
Saturn is only 150 high so not at its best but still wonderful.
He said the Moon was waning.
ATLAS is an asteroid impact early warning system being developed by the University of Hawaii and funded by NASA. It consists of two telescopes, 100 miles apart, which automatically scan the whole sky several times every night looking for moving objects. It consisted of two 500mm scopes on adjacent Hawaiian Islands. It can also find comets - we saw an image of a comet that Peter had taken.
He recommended that we visit Heavens Above site re ISS Visible passes there are quite a batch coming up on consecutive nights.
He also mentioned a Grazing Lunar Occultations. This is where a star skims past the moon and the mountains cause it to flash. There’s one on 27th Jan at 18.20. There are due to be loads in 2018. He will put a summary on the email group.
Mike introduced Jane for her occasional:
A mission is planned to send a probe up 50 miles to study X-ray emissions.
Mission Gold is set to examine the area around Earth.
InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) is a NASA Discovery Program mission that will place a single geophysical lander on Mars to study its deep interior. But InSight is more than a Mars mission - it is a terrestrial planet explorer that will address one of the most fundamental issues of planetary and solar system science - understanding the processes that shaped the rocky planets of the inner solar system (including Earth) more than four billion years ago.
Parker Solar Probe Plus will be an extraordinary and historic mission, exploring what is arguably the last region of the solar system to be visited by a spacecraft, the Sun´s outer atmosphere or corona as it extends out into space. Solar Probe Plus will repeatedly sample the near-Sun environment, revolutionizing our knowledge and understanding of coronal heating and of the origin and evolution of the solar wind and answering critical questions in heliophysics that have been ranked as top priorities for decades. Moreover making direct, in-situ, measurements of the region where some of the most hazardous solar energetic particles are energized.
The Transiting Exoplanet Survey Satellite (TESS) is a two year survey mission that will focus on the discovery of Exoplanets in orbit around the brightest stars in the sky. This first-ever all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances.
Hayabusa2 will target a C-type asteroid ‘Ryugu’ to study the origin and evolution of the solar system as well as materials for life by leveraging the experience acquired from the Hayabusa mission. To learn more about the origin and evolution of the solar system, it is important to investigate typical types of asteroids.
Solar Orbiter, a spacecraft geared to study the powerful influence of the sun. Solar Orbiter will be an ESA-led mission, with strong NASA contributions managed from Goddard Space. Space Flight Centre in Greenbelt.
The goal of the Space Weather and Atmosphere team is to understand how solar variations affect the Earth´s space radiation environment, upper atmosphere and continue providing expert advice to the Cabinet Office and UK Government departments through our membership of the Space Environment Impacts Expert.
BepiColombo is Europe´s first mission to Mercury. It will set off in 2018 on a journey to the smallest and least explored terrestrial planet in our Solar System. When it arrives at Mercury in late 2025, it will endure temperatures in excess of 350°C and gather data during its 1 year nominal mission, with a possible 1year extension.
The New Horizons mission is helping us understand worlds at the edge of our solar system by making the first reconnaissance of the dwarf planet Pluto and by venturing deeper into the distant, mysterious Kuiper Belt – a relic of solar system formation.
Jane showed us a chart indicating where the various probes from Voyager, Pioneer and New Horizons are in space.
Helen Sharman, Operations Manager for the Department of Chemistry and the first Briton in space, has been made a Companion of the Order of St Michael and St George for her outreach work.
Professor Michele Dougherty has been awarded a CBE.
Mike introduced Ed for some Stuff.
Ed began by giving us an update on Florrie´s Ken who is sadly still poorly in hospital.
Ed showed us a sketch of two double stars and with the aid of one of his homemade double star models and a diagram he explained how 67 Cygni worked.
The other was Mintaka, the RH star in Orion’s belt. It´s actually a double star too. Another interesting star is Eridanus 40 which is a triple. We saw a comparison chart showing that the components compared to the Sun. A is a Yellow Dwarf smaller than the Sun, B is a tiny White Dwarf they are very dense with the size of the Earth but the mass of the Sun and C is a Red Dwarf these are very common a less dense than a white but still more than half a solar mass.
Mike himself was on next with his ‘Me and My Scope ’ talk on:
My new SkyWatcher Star Adventurer
It provides an excellent route into astrophotography for those using DSLR cameras with wide-field and medium focal length DSLR lenses. Its ease of use and aircraft-friendly size will also appeal to those wanting to travel to dark-sky locations. The user-friendly Sky-Watcher can attach to any standard tripod via its ¼” or 3/8” adapters. The latitude can be set by either adjusting the tilt of your tripod head to match your latitude or more accurately by purchasing the optional Equatorial Wedge. To fit a camera to the Star Adventurer, either a tripod Ball Head is required (not supplied) or the optional Dovetail L-Bracket. The optional Dovetail L-Bracket used in conjunction with the optional counterweight shaft/counterweight also allows small telescopes to be used. A small telescope and camera (using a ball head, not supplied) can be mounted simultaneously on the Dovetail L-bracket. Using just the dovetail bar from the optional Dovetail L-Bracket, two cameras can be mounted at the same time using two tripod ball heads (not supplied). It has various drive speeds to track all standard objects and contains its own batteries.
He said it had a built in polar scope which was not ideal as you had to remove the camera mount to use it.
However at £269 it was very affordable.
We saw an excellent image of Cygnus and M31.
Well what a lot we got!
Wednesday 24th January 2018
Ted said that last Friday he plus Ed and Mike helped the local Beaver group gain their Astronomy badges.
Peter said that a variable star with an 11 month period was at its brightest in Cetus.
As it was cloudy for the planned observing evening Mike was giving his talk:
The Curious Moon
With a nice image displayed he pointed out the ‘Rabbit’ that folk have seen on the Moon for years – it is of course a pattern formed by the ‘seas’, but he said our eyes were good at seeing patterns.
There´s also a Frog, Witch, Crab, Stag Beetle, a Victorian Lady reading a book and apparently a basketball player.
Mike said that in the past there was a theory that the Moon was a mirror reflecting the Earth. Some were arguing against this as it would change as it moved over different parts of Earth.
Thomas Harriot an English astronomer, mathematician, ethnographer, and translator who has made advances within the scientific field. He is sometimes credited with the introduction of the potato to the British Isles. Harriot was the first person to make a drawing of the Moon through a telescope on 26 July 1609, over four months before Galileo.
Galileo Galilei made his drawings in September 1609. We saw several of the sketches.
Johannes Hevelius was a councillor and mayor of Danzig, then part of the Polish-Lithuanian Commonwealth. As an astronomer he gained a reputation as ‘the founder of lunar topography’, and described ten new constellations, seven of which are still recognized by astronomers. He used a 46m long telescope and made very complex drawings of the Moon in 1642.
Christiaan Huygens used a 63m long scope of a very strange design. It had an objective lens in a mount attached to a tall pole and Hyghens held a cord attached to the eyepiece taught and looked through it tracking objects at the same time. He found several interesting features on the Moon including the Straight Wall.
William Herschel thought he saw trees growing on the seas and saw towns the Lunarians had built.
He also saw a bright spot on the dark part of the Moon and assumed it to be an erupting volcano. However he had just seen Aristarchus the brightest feature on the Moon.
Baron Franz von Paula Gruithuisen (March 19, 1774 – June 21, 1852) was a Bavarian physician and astronomer. He taught medical students before becoming a professor of astronomy at the University of Munich in 1826.
Like others before and since his time, Gruithuisen believed that the Earth´s Moon was habitable. He made multiple observations of the lunar surface that supported his beliefs, including his announcement of the discovery of a city in the rough terrain to the north of Schroter crater he named the Wallwerk. This region contains a series of somewhat linear ridges that have a fishbone-like pattern, and, with the small refracting telescope he was using, could be perceived as resembling buildings complete with streets. He published his observations in 1824, but they were greeted with much scepticism by other astronomers of the time. His claims were readily refuted using more powerful instruments.
He thought he could see faint extensions to the ‘horns’ of the crescent Moon and assumed this to be proof of an atmosphere. However he also considered that the lunar craters were caused by impacts!
John Herschel, son of William, was a prominent astronomer in his own right. Unfortunately the New York Sun newspaper published an extraordinary story with pictures of bat-like creatures living on the Moon and incorrectly attributed to John.
The Rev, T W Webb saw changes on the lunar surface.
Julius Schmidt also saw lunar changes – he was an obsessive observer – he looked at 85,000 variable stars in the last 2 years of his life.
William Pickering and his brother Edward were sent to Peru with a 13inch scope to study spectra – they managed to see a grazing occultation of Jupiter.
Mike finished by talking about the Apollo missions and the fact that there are still some who doubt that the Americans ever went to the Moon.
Wednesday 31st January 2018
Ed announced that he was going to do his Extra Observing after tonight´s event.
Gord had two old astro books to give away.
Ted said that we have enough funds now to cover our rent to the church – hooray - which he has just paid.
Mike said that next week we have Dave H with a talk on Extreme Stars.
Then he introduced our very own Andy T for the next part of his trilogy on:
HR Diagram Part 3
He spoke briefly about the earlier parts explaining that it was a way of charting the colour/temperature of stars against their brightness.
Andy explained that it was used as an Illustrative Tool.
It was made up of the plots of 23,000 of the stars that are our nearest neighbours.
He said that stars had four phases – we do not see the first as this is star formation as in the Pillars of Creation – we saw a Hubble image of this superb object.
Phase Two is the Main Sequence of the Hertzsprung-Russell diagram the various stages of stellar evolution. The main sequence stretches from the upper left (hot, luminous stars) to the bottom right (cool, faint stars) dominating the HR diagram. It is here that stars spend about 90% of their lives burning hydrogen into helium in their cores.
The Sun is near the centre of the diagram at present and will stay there for a long time. A star like the Sun will leave the Main Sequence after 10.4 billion years.
Phase Three is the red giant period, red giant and supergiant stars occupy the region above the main sequence. They have low surface temperatures and high luminosities which, according to the Stefan-Boltzmann law, means they also have large radii. Stars enter this evolutionary stage once they have exhausted the hydrogen fuel in their cores and have started to burn helium and other heavier elements.
Stars in this phase can be truly enormous perhaps as big as the Earth´s orbit in diameter.
Phase Four - white dwarf stars are the final evolutionary stage of low to intermediate mass stars and are found in the bottom left of the HR diagram. These stars are very hot but have low luminosities due to their small size. A sun like star will shed its outer layers and reduce in size to something like the Earth´s size but still have most of its original mass. This phase lasts a very long time.
Andy explored the case of imaginary stars with their theoretical track through the diagram.
At one point as the nuclear core has used most of its Hydrogen whilst in the outer layer the radiation zone which still has Hydrogen and this gets used suddenly creating more Helium.
At the end of this process the star becomes a White Dwarf and moves rapidly down and to the left in the diagram.
Andy showed a super image of the Cat´s Eye Planetary Nebula with its shells of gas surrounding a white dwarf. We also saw an image of the Crab Nebula which is another example.
Andy said the diagram was also a useful tool for estimating the age of groups of stars.
Constructing a plot of the stars in the cluster scientists can determine the mass of the stars that are just ending this phase and moving on to the next phase of their life, the red giant phase. Computer models allow us to predict how old a star of that mass must be to be at that juncture of its life and hence to estimate the age of the cluster. Recently, this procedure has come under close scrutiny because that age it gives for the oldest star clusters in our Milky Way seems to be older than the age of the universe derived from the most recent Hubble Space Telescope data!
We saw the technique applied to M37 and the Double Cluster.
He also showed M67 and NGC188 where the clusters are much older than expected possibly because they are in the outer fringes of the Milky Way.
Andy said the HR Diagram is drawn by comparing the absolute mag to the colour index. Basically it is the difference between the observed mag and the absolute brightness using the Inverse Square Law.
It’s as simple as that!