Ring Geometry

Saturn's Ring System at Opposition as imaged from the Jodrell Plank Observatory 2012 - 2017

"Saturn takes about 29½ years to orbit the Sun and over time we view the rings from different angles.  In 2017, the ring system is  wide open as seen from Earth and Saturn's Northern hemisphere is tipped in our direction. The angle of Saturn's rings as imaged from the Earth varies year on year depending upon the specific orbital geometry of the two planets.

The last time the rings were wide open was in 2002-3, when Saturn's Southern hemisphere was tipped in our direction. The rings then began to close, showing an increasingly narrow aspect, with Saturn becoming rather dimmer at each successive opposition (ie when Saturn is at its closest point to the Earth). The rings last appeared edge-on in September 2009, when the Earth passed through the plane of Saturn's Rings. I can well remember the rather odd image visible in 2009, as I saw the rings edge on for the first time through an eyepiece and the 127mm Meade Refractor. The Northern face of the rings came into view during the latter part of 2009, as they slowly began to provide a less oblique view as seen from Earth. 

In the year 2025, the rings will again appear edge-on as seen from Earth.  After that, we’ll begin to see the south side of Saturn’s rings, which will increase to a maximum inclination of 27 degrees by May, 2032.  I hoped to be alive and well enough to see this once again!

The above image is a composite  of six images taken at opposition each year from 2012. The quality- clarity of each image varies from year to year depending upon - 

•  Sky transparency and air quality
•  Light pollution
•  The height of Saturn above the horizon - 'Declination'
•  Improvements in technology (telescope- camera - imaging software)
•  Improvements in digital imagery manipulation.

To paraphase the late and great Fred Zwicky - Saturn is a 360 degree Beauty - A beauty which ever way you look at it! "
  Kurt Thrust - current Director of the Jodrell Plank Observatory

The inauguration of the OpenScience Observatories Open University - Coast and Pirate Telescopes - Mount Teide, Teneriffe - Canary Islands

Image grab from the Inauguration video presentation - Inauguration Presentation from the clamshell dome of the COAST Telescope - Credit Open University

 More information on the Inauguration Event

George and Anita Roberts, friends and financial sponsors of the Jodrell Plank Observatory, have, at this time, internet access to the Robotic Telescopes on the extinct volcano Mount Teide -Teneriffe - Canary Isles.

" George has agreed to allow the Jodrell Plank Observatory to use data obtained from these fantastic remote observatories at high altitude under pristine skies. Wherever such information is used by our Imaging Team Leader' -  Pipp Stakkert, the Observatory will credit the data aquisition from telescope.org- Open University." Kurt Thrust -current Director of the Jodrell Plank Observatory.

'Clamshells' containing the PIRATE and COAST Robotic Telescopes - Credit: telescope.org- Open University

 

PIRATE Telescope - Credit: telescope.org- Open University

 "Image data collected by the PIRATE Telescope this week. Sulphur, Hydrogen Alpha and Oxygen filters were used and pasted into the Red, Green and Blue channels of this image respectively.  Pipp Stakkert, the Jodrell Plank Observatory Visualisation Team Leader, has made a good attempt at this target made famous by the iconic Hubble Space Telescope image 'The Pillars of Creation'." Kurt Thrust- current Director of the Jodrell Plank Observatory.

Comparison between an enlargement from the PIRATE Telescope image of M16 on the left and The Hubble Space Telescope on the right

The Saturnian System

Saturn with 5 of its larger moons on the 25th May 2017 - Composite of two images taken with a DSLR and a high speed planetary video camera whch were later merged together using specialist software.

"The Cassini Spacecraft is somewhere in this image but far too small and dim to see through any telescope. The Cassini Spacecraft was launched in 1997 and has been exploring  the Saturnian System since 2004. It has been an immensely successful scientific project gaining unknown insights into its moons, rings and atmosphere.

 Cassini Top Ten Scientific Highlights

 Science Overview

Cassini in orbit around Saturn - Graphic credit : NASA-JPL

Cassini is travelling currently at a speed of 19,000 mph relative to Saturn and as it runs out of fuel for adjusting its orbit after 19 years in space, it has commenced a series of planned orbits that take it inside the rings and close over the cloud tops of Saturn itself.  Its orbit will decay and in September of this year, Cassini will disappear within the clouds to be crushed out of existence by Saturn's atmospheric pressure.  Every inch of the way, the Cassini Spacecraft's instruments will be recording new information and beaming it back to Earth.

For me Cassini's greatest discovery was the subterranean sea on the moon Enceladus." Credit Kurt Thrust - current Director of the Jodrell Plank Observatory 

Enceladus Subsurface Ocean 

 'Enceladus is ripe for life. In one final pass through the icy moon’s liquid plumes, NASA’s Cassini spacecraft found molecular hydrogen, which indicates favourable conditions for life in Enceladus’s subsurface sea.' Credit: New Scientist

Saturn with its retinue of moons tiny amongst the starfield in the Constellation Sagittarius - Image taken with the 127mm. Meade Apo- Refractor from the Jodrell Plank Observatory.

 " The Cassini project is a NASA ESA joint scientific exploration of the Saturnian System. It is a wonderful example of cooperation between scientists and intellectuals in the United States of America and Europe. We do it not because its easy but because we choose to.  Curiosity, brains, cooperation, compassion and the pioneering can do spirit define our species. So lets keep doing great stuff together and turn our backs on ignorance, xenophobia, pseudo-science, bullshit and hatred." Credit: Kurt Thrust - current Director of the Jodrell Plank Observatory.

Satellites

A satellite, possibly a Russian electronic surveillance satellite, flaring reflected sunlight .

"The night sky teems with satellites and bits of old rockets, so much so that its almost impossible to take a sequence of photographic images without one of them showing the tell-tale streak of low orbit astro-debris.  Every now and again sunlight bounces of a tumbling satellite creating a bright flare in the night sky.
 
The bright star in the right corner of the image is Alpha Bootes or Arcturus.  Arcturus is the fourth brightest star in the night sky and the brightest in the Northern hemisphere sky.  Its apparent brightness is a function of its absolute luminosity - approximately 170 times that of the Sun, its large diameter - approximately 25 times that of the Sun and its relative proximity at 36.7 light years.  Arcturus has been shining for the best part of 7 billion years or for about half the life of the Universe. Arcturus has used up its hydrogen, left the 'main sequence' and is a 'red giant'.

Just below and to the right of the flaring satellite, is a 'C' ring of stars known as the 'Northern Crown' or Corona Borealis.  The white and brightest of the stars in Corona Borealis - Alphecca  is an eclipsing binary star".  Kurt Thrust -current Director of the Jodrell Plank Observatory.

Jupiter and the Galileans

Composite image of Jupiter and the 4 Galilean Moons on the 25th May 2017. Taken with the Meade 127mm Apo Refractor, x3 Televue Barlow lens and the QHY5-11 Planetary Camera

"The four largest moons of Jupiter are known as the Galilean Moons as they were first seen and recognized for what they are, satellites of Jupiter, in 1610 by Galileo Galilei. Galileo was living in Florence when he used his refracting telescope to investigate the Solar System's largest planet - Jupiter.

We have just returned from Florence and whilst there were able to locate the house from which these observations were believed to have been made". Kurt Thrust current Director of the Jodrell Plank Observatory.

Galileo's House in Florence

Galileo on the Wall -"with a smile that says it all, as he sees the rise and fall of every soldier passing".

Wall plaque commemorating the observation of the Galilean Moons or Medicei Satellites (or Medicei stars) as they were than known

" The night of the 25th of May 2017 was clear and still over our sleepy town of Lowestoft. Kurt was out in the Observatory until 5.00 am the following morning. When he awoke, around about lunch time, I had aleady been hard at work for several hours in the imaging studio, manipulating the Jupiter data set obtained the night before. I am quite pleased with the image which shows a number of cloud top features." Pipp Stakkert Imaging Team Leader at the Jodrell Plank Observatory.

The planet Jupiter on the 25th May 2017. Taken with the Meade 127mm Apo Refractor, x3 Televue Barlow lens and the QHY5-11 Planetary Camera

Two nights in May 2017

The planet Saturn in the constellation Ophiucus taken on the 26th May 2017 from the Jodrell Plank Observatory using the Meade 127mm. Apo refractor plus 3x Televue Barlow lens and the QHY5-11 colour planetary camera.

" The ringed planet Saturn will be at opposition, ie. at its nearest point to the earth in their respective orbits around the Sun, on the 15th. June 2017. Unfortunately and for the next few years, Saturn will be very low in the sky as viewed from Lowestoft. Indeed the above image was aquired when Saturn was only 15 degrees above the horizon.  As the Jodrell Plank Observatory does not benefit from a mountain top location, capturing a clear picture was logistically difficult. We tracked the planet as it appeared and disappeared from view between adjoining buildings and the branches of trees. Thankfully our Imaging Team Leader' -  Pipp Stakkert was able to assemble the threads of data to obtain a coherent and relatively sharp image.  Saturn is angled to show its northern hemisphere in 2017, and its rings are inclined at an angle of 26° to our line of sight, which is almost the maximum inclination they can have. The above image shows the outer A ring and inner B ring separated by the dark Cassini Division. A closer inspection reveals a hint of the C ring inside the B ring".
Kurt Thrust - the current Director of the Jodrell Plank Observatory.

 

Comet C/2015 V2(Johnson) in the Constellation Bootes on the 27th May 2017. 127mm. Meade Apo Refractor - Altair Astro 0.8x Field Flattener and Focal Reducer - Canon 600d DSLR - guided exposures using the QHY5-11 camera. 5x4minute exposures at ISO 1600 stacked.

"The comet is moving at approximately 28 kilometres a second getting ever closer to the Earth  and the Sun. It is also decreasing in declination heading towards perehelion on the 12th of June 2017. The tail always points away from the Sun and does not indicate its direction of motion - as can be seen in the time lapse animated image below"  Archie Mendes - Astrophysicist Reydon University.

Comet C/2015 V2(Johnson) - showing real motion over approximately one hour.

Comet C2015 V2 (Johnson)

Just after midnight 30 April 2017.Composite stacked image using the 127mm Refractor with 0.8x focal reducer and field flattener and Canon 600d DSLR. The image is a section of a wider-field and is the composite of stacked 10x 1 minute exposures taken at ISOs 1600, 3200 and 6400.

Comet C2015 V2 (Johnson) was discovered in 2015 by Jess Johnson (Catalina Sky Survey) and will leave the Solar System on a hyperbolic orbit. - credit Wikipedia.

" A comet is a minor member of the Solar System which travels around the Sun in an orbit that is generally more eccentric than the orbits of the planets. Comets typically have three parts : The 'nucleus', the 'coma' and the cometary 'tails'. 

The nucleus is the solid portion of the comet. The size of cometary nucleii vary. Most are less than a kilometer in diameter but some of the more spectacular comets are larger.  Hale Bopp, probably the best comet seen from the UK in the last 200 years was estimated to have a diameter between 40 and 80 kilometers. The cometary nucleus, described by the astronomer Fred L Whipple in 1951 as a 'Dirty Snowball" is thought to be made up from dust and frozen; water ice, carbon monoxide, carbon dioxide, methane and ammonia.

The  coma is the most obvious part of the comet when it is close to the Sun. The coma is a diffuse luminous nebulous cloud of gas and dust that surrounds and hides the cometary nucleus from sight. It is formed by the sublimation of ices and the ejection of dust particles from the nucleus. The coma is densest closer to the nucleus where the material being released is at its highest. The sublimation is driven by the warming of the nucleus by sunlight and so the size of the coma varies with distance from the Sun. The luminosity of the coma is mainly produced by fluorescence from a variety of carbon, nitrogen,hydrogen and oxygen ions and the reflection of sunlight by dust particles. The coma is extremely rarefied and consequently even faint stars may be seen shining through it. Comas may be circular or fan -shaped.

The cometary tails. If there are tails of gas and dust, they point away from the nucleus in a direction opposite to the Sun.  The tails are only readily apparent when the comet is near to the Sun and usually within two astronomical units (x2 the average distance between the Sun and the Earth). Not all comets have visible tails, but when present, their luminosity is due to both molecular and atomic emission and to the reflection of sunlight. The dust and the gas is forced away from the nucleus by the radiative pressure of the Sun and solar wind interactions. There are two very different types of cometary tail; the plasma or ion tail which is often straight and bluish, consisting of ionized molecules moving at speed and the more strongly curved dust tail. The dust tail shines simply because it is made from billions of tiny solid particles which reflect sunlight.

Comet 2015 V2 Johnson was 152.72 million kilometers from Earth and 259.82 million kilometers from the Sun when it was imaged  just after midnight on the 30th April from the Jodrell Plank Observatory.  The comet was at Magnitude 7.64 and was located at RA 15 degrees 53 minutes 43 seconds and Dec 43 degrees 56 minutes 14 seconds N."

 Kurt Thrust - Director of the Jodrell Plank Observatory

 

Positive and negative images taken from the Observatory showing details of the diffuse fan- shaped coma

 "Most comets move in elliptical orbits (some like Halley's Comet being retrograde). They fall into two distinct classes; 'long period' comets and 'short period' comets. The former are the great majority and have orbital eccentricities very close to unity (1.000 - almost parabolic). The much smaller group of short period comets are regular returnees to our skies following elliptical orbits with the Sun at one focus of the ellipse and at all inclinations to the ecliptic. Most comets reach perehelion (closest point to the Sun) at one or two Astronomical Units (AU) and move within a sphere centred on the Sun. The aphelia (greatest distance from the Sun) of long period comets may extend as far as 50,000 AU with orbital periods as long as a million years or even more. In some cases planetary gravtational effects may make a cometary orbit hyperbolic (ie. where orbital eccentricity is greater than unity), while in others the orbit may be changed into a small ellipse. C2015 V2 (Johnson) will leave our Solar System on a hyperbolic orbit never to be seen again - so when its gone its gone! With every perehelion event, a comet loses material as a result of the intense solar heating and gravitational tidal forces. So eventually short period comets, like the Cheshire Cat, just evaporate away". 

 Archie Mendes - visiting theoretical astronomer at the Jodrell Plank Observatory - Reydon University - 'School of Computer Modelling and Difficult Sums' - author of "Quantity Surveying and Standard Methods of Measurement in Curved Space Time" or "When the Socks come off!"