As mentioned on the main page, this wasn't a triple conjunction by my criterion and, even worse, it would only be visible in the early morning. I thus didn't give it much attention initially but it soon became well publicised, and promised to be quite photogenic, so I eventually persuaded myself I'd better try to capture it. Quite a bit of persuasion was needed though, due to the timing, so although Mars and Jupiter had been in conjunction on 18th October (1/3deg); there had been a nice almost-linear alignment on the 23rd, and Venus and Jupiter came into conjunction on 26th (1deg) I didn't start making concrete plans until the 28th. It also has to be said that the weather forecasts for these early mornings had not been very optimistic, giving me the ideal excuse not to set my alarm!
When I did finally grasp the nettle my first thought was to lessen the discomfort by getting up just before dawn, when the planets would be high in the sky and thus far enough away from the rising Sun to still be visible. However, this idea soon got torpedoed by yet another gloomy forecast and so I decided to simply look out of my bedroom window if I should wake during the night and see if anything was visible - it wasn't (not at 3am or 5am, anyway). And so we moved on to the 29th. I paid close attention to the forecast, which said that the early hours would be clear but potentially misty and that a cloud front would reach us around 5am. No dawn observations then! At the other end of the window, although the grouping would rise at 2:30am it would take until 4am for it to get to the respectable elevation of 13deg. My only sensible option was thus to get up around 4am and hope to take pictures until the cloud arrived. The upside of this plan was that the relatively low elevation would provide some foreground for my pictures: not an astronomical necessity but it does help provide scale.
And so it was. I took our eldest cat rather by surprise when I passed through the living-room togged up in two pairs of trousers, two jumpers and a fleece, plus woolly hat and gloves, but I was relieved to find on exiting the house that the forecast had been accurate - basically clear but misty. The "upside" had also come true - Venus and Jupiter were sitting nicely in the eastern sky just above the far hedge to our meadow. Mars was easily visible in binoculars, and also in a quick test shot I fired off - we were in business. The mist put a considerable halo round Venus though! Fortunately, conditions did improve thereafter - probably due to a change in atmospheric conditions rather than the grouping moving out of the mist band as it only rose by 3deg during the time I was taking pictures. It was another more dramatic change in conditions that brought photography to an end however, as around 4:30am the camera lens started to mist over very badly, and continued to do so almost as fast as I cleaned it. Interestingly, I had noticed exactly the same problem at the same time at the end of the lunar eclipse a month earlier (although it was 5:30am on that occasion, due to Summer Time!). The promised cloud bank had arrived by this time anyway, and as I had captured sufficient images by that time I was not too unhappy to be forced to give up and get back to bed for a few more hours sleep.
| Here we have the view on 29th October, with Mars just above centre; the brilliant Venus to its upper-right, and finally Jupiter further up. The separations are Mars-Venus 21/3 degrees; Venus-Jupiter 25/6 degrees and Mars-Jupiter 45/6 degrees. The star you can see at top-left is Denebola (mag.2.12), with Nu Virginis (mag.4.03 - left of centre), Sigma Leonis (mag.4.03 - upper-left of Venus) and Chi Leonis (mag.4.59 - just above Jupiter) completing the scene. And if you are thinking that this is quite a close grouping, so why I am saying it's not really a triple conjunction, I must quickly point out that this image is shown reduced by 4 times standard scale! Click or tap on it to see what the separation would look like at standard scale: this is in fact an image taken with a "longer lens" rather than a re-scaled version of the original, which is why the planetary discs are more obvious than in other conjunction images. You can now see that the separation is actually rather wide: click again to add a "reference disc" if you're not convinced. The single star visible is Sigma Leonis. |
The early-morning weather was then cloudy for a couple of days, often with light rain as well, making observations impossible. The morning of 1st November didn't sound much better, with fog forecast, but in fact a glance out of my bedroom window at 5am showed both Venus and Jupiter shining out of the murk. I thus donned the usual layers of warmth and headed out, to be greeted by a rather ghostly sight (very appropriate for the junction between Hallowe'en and All Saints Day!). Sitting in a pearly-white sky, the Moon was circled by not one but two haloes - an inner "rainbow coloured" one and an outer white band - while Venus had its own halo close to the eastern horizon. Jupiter was easily visible above, with Mars just discernible with care close by. A long exposure captured all three nicely though.
And here's what I saw. The separations are Mars-Venus 11/6 degrees; Venus-Jupiter 42/5 degrees and Mars-Jupiter 61/6 degrees. Denebola is again to top-left: the other stars noted above are also still just visible, but much less clearly due to the fog. The scale of the image is the same as for 29th October which is, I must remind you, 4 times standard scale. This does make the point about conjunctions and "groupings" rather well though, because of course in this image Venus and Mars really are in conjunction due to the decrease in distance over the 3-day interval. The 4x scale makes them look very close together.
The image is not just at the same scale as the previous one but is in fact aligned with it. Although it was taken an hour later and thus higher in the sky (hence the absence of much foreground) I have rotated it slightly to cancel this out. Click or tap on it to compare the two images: the first click shows you the previous image, the next one shows this image, and the third one overlays the two. The difference in apparent motion of the three planets is very noticeable. I say "apparent" because the motion is in fact a combination of the planets' true orbital motion and the effect of changing geometry: we see them from slightly different directions each day due to the Earth's orbital motion. In fact, it is this latter effect which is the main cause of groupings and conjunctions, which is why they occur much more frequently than any "natural" alignments of the planets would suggest.
Incidentally, given that Venus orbits the Sun closer in than does the Earth, and that all planets go round the Sun in an anti-clockwise manner (when considered from the Earth's northern hemisphere), the fact that Venus' motion in these images is "from right to left" (albeit at a rather steep angle!) tells us that it was heading towards the far side of the Sun from the Earth at the time. The same conclusion cannot be drawn in the case of Mars and Jupiter as, being further away from the Sun than the Earth, their apparent motion is (except for the time around opposition) always "right to left". I say more about this topic in my Theory Pages - see "The behaviour of the outer planets near opposition" and "Periodicities in the observed position of the planets". As it happens however, both Mars and Jupiter were, in fact, on the far side of the Sun also: their position to the west of the rising Sun shows us that this must be the case. Note also that if one were to draw lines between the "before" and "after" positions of each planet the lines would be close together and pretty-well parallel. This would suggest that they were all orbiting in nearly the same plane, which is indeed correct: with the exception of Mercury (7deg) and the dwarf planet Pluto (17deg), the orbital planes of all the planets in the Solar System are within 3.4 degrees of that of the Earth.
The weather then reverted to its previous "cloud & rain" status, meaning I could not capture Venus and Mars at their position of very closest approach (2/3deg) on the morning of 3rd November. This signalled the end of the grouping, as the planets rapidly separated thereafter. There was however a final "triple" of sorts when the thin crescent Moon joined Venus and Mars on 7th November. But guess what? Yep - rain! The last chance to catch anything remotely interesting was on the morning after, but of course it rained - right? Well no actually, just for once it didn't!
One couldn't call the early morning conditions "clear", but at least stars were easily visible overhead when I struggled out into the darkness at around 4:45am, a darkness which smelled distinctly of burning and gunpowder due to the local celebrations for Bonfire Night the previous evening. Conditions were much more misty near the horizon though, so the rising crescent Moon was glowing through light fog. Both Venus and Jupiter were in clearer skies so were shining brightly, meaning that the trio made really quite a dramatic sight extending up from the horizon in an almost straight line. Capturing it satisfactorily on camera proved to be an almost impossible task, however! The Moon is incredibly bright as compared to the planets and stars and so even as a thin crescent it outshone them considerably. The misty conditions gave Venus an extensive halo of its own and even Jupiter was a little "puffed up".
Consequently, when exposing for the stars the Moon and planets came out excessively bright - the only one appearing "normal" is Mars, the brighter of the two objects just above and slightly to the right of Venus. The other object is the star Zavijava, or Beta Virginis - mag.3.56. This image is to the same scale as those above but covers a much larger extent vertically due to the extended nature of the grouping, as the separations were by this time becoming very large - while Venus and Mars were "only" 21/3deg apart, Jupiter was 112/3deg away from Venus in one direction while the Moon was 8deg away in the other. To assist in orientation, the star centre-left at the top is again Denebola but Sigma Leonis is now adjacent to Jupiter rather than Venus (as it was on 29th October), showing just how far the planets have moved in 10 days. Nu Virginis, the other star mentioned originally, sits at the apex of the thin triangle of stars at upper right-centre.
Click or tap on the image three times to steadily reduce the exposure, in order to more correctly capture the Moon. The stars quickly disappear, and even Mars is barely visible in the last frame which (at just 1sec exposure) finally shows the Moon more-or-less "as seen" - note the Earthshine on the upper portion of its disc.
One last click/tap brings up a composite image constructed from the long and short-exposure views. It is not really representative of the scene "as viewed" though, as it considerably under-states the contribution of the Moon. This is because while the scale at which the Moon is shown here is an accurate representation of its true apparent size, the scale at which the planets and stars are shown in these sorts of image is a reflection of their brightness. The Moon is therefore much less bright here than it really was and the planets are much larger. Also, the visual effect was much more dramatic due to the eye's superior capability to accommodate brightness variation and the fact that the whole scene was spread out across the sky in front of me rather than being squeezed into a small picture. I felt it was worth doing the composite however, just to give some idea of the overall effect.
There were a number of clear morning skies after the separations had increased, of course, but that's just the usual frustration of astrophotography!
