July | 2015 | WATCH THIS SPACE(MAN)

As a visual and photographic spectacle, in my opinion Jupiter comes a close second to Saturn among the planets. The so-called ‘King of the Planets’, Jupiter is more than twice as massive as all the others combined. Notwithstanding its size, Jupiter has the shortest ‘day’ of any planet, rotating fully in just 9-hours and 50 minutes – as a result creating a significant equatorial bulge that measures 88,760 miles in diameter and 83,082 miles from pole-to-pole. However, as a gas giant the planet does not rotate en masse, with the outer regions moving slower than the equatorial region leading to a series of distinctive belts and zones, most notable of which is the Great Red Spot – a massive storm on the edge of the South Equatorial Belt.

Partly because of its vast size and resulting gravitational field, Jupiter is thought to have played a dominant role in shaping the present Solar System. The planet we see today is not alone, with 67 moons so far identified, the four largest discovered by Galileo 400 years ago being easily visible from Earth. In order of distance from Jupiter the moons of Io, Europa, Ganymede and Callisto are extremely diverse in nature – ranging from the highly volcanic Io to the frozen world of Europa, whilst Ganymede and Callisto may have sub-surface oceans and are bigger than the planet Mercury.

Despite being by far the largest planet in the Solar System and the fourth brightest object after the Sun, Moon and Venus, my attempts to image Jupiter and its Jovian neighbours have so far met with only mixed success.

Most people’s first view of Jupiter is likely to be through binoculars or a basic telescope, which will show the very bright planet accompanied by a number of its Gallilean moons, depending on their orbital position i.e. when located behind the planet they will, of course, not be visible. Having viewed Jupiter a few times like this, my first attempt to image the planet and its moons was just such a view simply using the William Optics 81mm refractor, a x2 Barlow and my Canon 700D DSLR. Compared to Jupiter the moons are not as bright and to capture their presence it is necessary to boost either the ISO or exposure time, which then overexposes the bright planet resulting in loss of detail – in this case the distinctive coloured gas bands. Conversely, with a lower ISO or exposure this detail once again becomes apparent but some or all of the moons are then lost in the image. The way round is to combine two sets of images taken at different camera settings, thus obtaining the best of both worlds, literally. For the moment however this remains work in progress.

January 2014, Jupiter – overexposed but shows all four Gallilean moons | 1 sec @ ISO 400

Jupiter – lower exposure shows the gas belts but the moons, though there, are now very difficult to see. 1/3rd sec @ ISO 800

Personally I like the wider view of Jupiter and its moons but inevitably the holy grail has to be a close-up image showing details of the planet’s characteristic gas belts, which requires the use of a CCD video, in my case a ZWO ASI 120MC camera. Having mostly concentrated on DSO photography to-date using a DSLR, my use of the ZWO camera is limited and with mixed success. Using this camera and the Skywatcher 150PL reflector telescope I have previously managed images of Saturn, Mars and the Moon but this time I used the William Optics refractor instead.

CCD imaging is a very different technique to DSLR and it’s fair to say that I still have much to learn. Notwithstanding, using Registax for processing I obtained some reasonable first-time Jupiter images but will need more practice to improve the detail; the quality might also be improved using WinJUPOS software during processing, which applies a de-rotational programme to the fast moving planet thus reducing blur – however, I have yet to understand let alone master this software. Also, whilst the quality of the William Optics telescope is far superior to the Skywatcher 150PL, it is obvious that its relatively short focal length is not really adequate for good planetary imaging.

21st February 2015. Jupiter up close
WO 81GT81 | ZWO 120 MC

So far this year Jupiter had already provided a number of different opportunities for imaging. Between February and April the planet moved across the southern sky in all its glory, whilst more recently it moved into close conjunction with Venus at the end of June and there’s more to come.

On 26^th August from our vantage point on the Earth, Jupiter will appear very close to the Sun in the sky as it passes around the far side of the solar system from the Earth. At closest approach, Jupiter and the Sun will appear at a separation of only 0°52′, making Jupiter totally unobservable for several weeks while it is lost in the Sun’s glare. At around the same time, Jupiter will also be at its most distant from the Earth – receding to a distance of 6.40 AU – since the two planets will lie on opposite sides of the solar system. Over following weeks and months, Jupiter will re-emerge to the west of the Sun, gradually becoming visible for ever-longer periods in the pre-dawn sky. After around six months, it will reach opposition, when it will be visible for virtually the whole night, by which time I have hopefully mastered some new techniques for imaging this Jovian King of the Planets.

This time of the year is something of a fallow period for astronomers: short nights combined by with the complete absence of astronomical darkness and fewer DSOs. I have personally found this year more difficult than usual as since April 25^th, following an operation to replace my left knee, I have been physically unable to set-up Fairvale Observatory and undertake astronomy of any sort. Notwithstanding, once over the initial few weeks of pain, I have tried to use the extra time afforded me usefully.

I have been reading Arthur Koestler’s excellent book The Sleepwalkers, which charts the history of man’s understanding of the universe and astronomy. Speaking of fallow periods, in the book I’m just past the very long period of inactivity and general superstition regarding the cosmos that occurred during the Middle Ages, which followed the more enlightened thinking of the Greeks, particularly Pythagoras; taking account of the Greek’s progress in understanding the Universe, our astronomical knowledge might have been 1,500 years more advanced today were it not for this prolonged medieval hiatus! Fortunately Copernicus (his better known Latin name) finally initiated what has become today’s heliocentric model of the Solar System, although his seminal work On the Revolutions of the Heavenly Spheres was only published just a few hours before his death after a delay of 30-years, such was his reluctance to put forwards such thoughts at that time.

Next, I have just completed the 6-week AstroTech MOOC course organised by Edinburgh University, which covered the scientific logic behind astronomical discoveries and the technology that lies behind them. This was my third astronomy MOOC and provided some interesting insight into telescope and imaging technology, as well as filling time during my recovery.

Finally, as my (limited) mobility has slowly started to improve, the night sky has recently provided a fascinating show of its own that did not require the observatory’s paraphernalia and, furthermore, beautifully demonstrated the principles originally outlined by Copernicus in 1543.

During the latter part of June Venus and Jupiter moved inexorably towards very close conjunction by the end of the month. Reaching just under ¾ of a degree separation on 30^th June and 1^st July this is a rare event, which with a clear sky could be easily viewed with the naked eye. Better still, I set out to photograph the two planet’s journey during the preceding 12 days, thus illustrating Copernicus’ revolutions around the sun of these two heavenly spheres. Whilst any school child will today understand this process, it is a frightening thought that belief in such a mechanism could once have led to the death penalty!

Obscured from view at Fairvale Observatory as Venus was just 17 ½^o above the western horizon, I had to travel to a nearby location which provided a clearer westerly viewpoint of both planets at their low attitude. In order to obtain a series of comparable images and thus show the real spatial changes occurring up to conjunction, all pictures were taken from exactly the same location. With my Canon EOS 700D fixed on a photographic tripod I shot a series of images over a 50 minute period using either the 18mm or 55mm telephoto settings, playing with ISO and speed settings as darkness progressed; this was roughly the time the two planets took to disappear below the Earth’s horizon after achieving Civil Darkness.

The resulting photographs show Jupiter apparently advancing on Venus before at conjunction ‘passing’ close by on the aforementioned days. Whilst Jupiter is the third brightest object in the night sky (after the Moon & Venus) and nearly 12 times the size of Venus or 1,400 times by volume, the planet looks very small by comparison to Venus. This of course is the effect of perspective, with Jupiter currently some 565 million miles distance from Earth, whereas Venus is only 48 million miles; furthermore although at -1.8 the apparent magnitude (brightness) of Jupiter is high, at -4.4 Venus is much brighter.

18th June 2015: Jupiter left, Venus right – trees on the horizon provide a reference scale as the planets move towards each other during the month in subsequent photographs.

25th June 2015 + 7-days

30th June 2015 + 5 days. Nothing – dark thunder clouds completely obscure the western sky during conjunction!!!

1st July 2015. Bingo = conjunction; though one day later Jupiter has now moved to the right of Venus.

1st July 2015. Close-up of the conjunction using 55mm telephoto setting and ISO 400 - Venus now left & Jupiter right.

1st July 2015. Conjunction close-up using 55mm telephoto setting and ISO 400 – Venus now left & Jupiter right.

Unfortunately I am expecting it will be at least another month before I have recovered sufficiently to consider setting-up Fairvale Observatory again, by which time Astronomical Darkness will thankfully be slowly returning. In the meantime I’m looking forwards to the next section of The Sleepwalkers which covers Kepler and Galileo and hopefully exciting developments from the New Horizon Pluto fly-by and more from the Rosetta Mission and the re-awakening of its Philea lander. Given clear skies there should also still be plenty to see without the observatory: The Perseids, Saturn and of course at the centre of our Solar System as determined by Copernicus, the Sun, which will be at aphelion on 6^th July – though you wouldn’t think so judging by the high temperatures currently prevailing in the UK and Europe!