Celestial line up on the 24th August

Saturn, Mars and Antares all line up on the evening of the 24th August.  The graphic below is for 20:45BST from Abingdon.

3 in a line

The day before Mars will be slightly to the West of the Saturn/Antares line and the day after it will be slightly to the East. Should be a nice photo opportunity and nice naked eye sight.

Clear skies,

The Tidore Total Solar Eclipse

Number one on the bucket list – total solar eclipse.

EclipseFullSizeRenderCredit: BBC

Whatever people say, there is a clear winner in the bucket list stakes. People may say ‘oh yeah, solar eclipse; I’ve seen one of them and it was good…’ But no, if you’ve ever seen a total one, you’d never be so blasé about it.

And beware, they are very addictive.

My first one was in June 1983 in Java, Indonesia. It seemed a bit of a long way to go and it was a rather expensive holiday. But I’m glad the umbraphiles in Liverpool AS worked on me and I gave in. At least I could say I’d seen one and I’d be satisfied….
So, 8 eclipse trips later, two failures (Hawaii 1991, Cornwall 1999) I ended up back in eastern Indonesia, Manado, North Sulawesi, and flew over to Ternate, North Maluku on 8th March, 2016. Ternate, and Tidore and famous for their spices, especially cloves, and are typical tropical volcanic bumps sticking out of the Maluku Sea. They were constantly capped by thick clouds on the summit. Ternate was on the centre line and many umbraphiles congregated at the Bela International Hotel there. There’s a rather special kind of relief when you arrive within the centre line. But, the more intrepid and energetic members of our tour group chose to venture out by boat early on eclipse day (9th March) so we could get to the south of Tidore and get about 20 seconds more of totality. We set out while it was still dark but it quickly began to get light as we clambered over other moored boats to get onto ours so we could make the quick trip across. There were taxis waiting for us to go down to the south of the island. Quite a hairy trip indeed, as they zapped past local traffic that had no lights. Lots of hooting and zipping down the middle of the road. (They do drive on the left side of the road normally.)

Tidore is a Muslim island, and eclipse day was a special calendar day for them too. They had also been preparing for our invasion for three years. We were quite nervous about seeing it as most of our mornings had been clear but we often had cloud come in later and the night before the eclipse there was a downpour. We had hoped it would stay clear long enough for us to see the eclipse but there was quite a lot of cloud to the south from where we finally stopped. If you saw my slides at the AGM you will see that it was a wonderful site. Incredibly clear water. One small island out to the east, which made for a picturesque view, and helped me to keep the eclipse in focus when I ran my camera on video during totality.

The locals had set up on the beach behind us and had collected loads of plastic chairs (?where from?) and had set up a large awning. They provided drinks and snacks, part funded by our hotel. They also organised a few dances, but really we just wanted to get on with it. They also wanted to take pictures of themselves with us, ‘selfies’ as they called them. They seemed to have a lot of smartphones for a place so isolated.

The clouds were threatening, and we just got first contact. You never really believe it will happen until you see that tiny bite out of the Sun. Then the bite gets bigger very quickly but by the time the Moon has covered about a third of the Sun nothing much really happens for ages, so it seems. Time seems to slow down. We’d been ready for ages. A sunspot became visible near the centre of the disc as our eyes dark adapted. Odd. You never realise the light levels dropping until something like that happens. The Sun was rising straight up, as we were just slightly north of the equator. Someone saw Venus above but it took me ages before i could see it. Mercury was also supposed to be visible but I was otherwise occupied.

As the crescent becomes slimmer in the final 15 minutes or so the sky takes on a metallic quality, but there were some high clouds and it didn’t seem so obvious this time. You can also get odd effects when you look at the shadows of leaves. You can get a pinhole effect which produces lots of crescent images of the eclipse. You also notice that shadows become blurry along one side and sharp on the other. In the final ten minutes the light levels dropped rapidly. At this point you usually get a sharp wind picking up, because of the temperature drop. It didn’t seem to happen much here in the tropical heat. My little compact camera was fixed to one of the plastic chairs with a gorilla pod. The tide was also going out in front of me, so I decided I would be able to jump down on the sand and not be bothered by the locals who were surrounding us and putting me on edge.

The locals were totally fascinated by this invasion of mainly tall, pale people with lots of gadgets. I still couldn’t believe how many had smartphones. Normally the final phases before third contact seem to go quite quickly but my body seemed to be on high alert and the last five minutes lasted a lot longer than usual.

You have to protect your eyes when looking at the Sun, even in those final minutes. Iwas using mysmall binoculars with astro-solar filters on them and my 15×70 binoculars were ready for viewing totality. So i was able to watch the crescent dwindle. In my first eclipse the crescent broke into three very distinct Baily’s beads before totality, but this time the light must have come across a more bland area on the Moon’s profile as the crescent just got lumpy in its final stages.

Then suddenly… I have videoed three eclipses now, so that I can just admire the view through my eyeballs and my binoculars, so I started the camera running before totality and stood in front of it to protect it. Wham, and the Sun imploded. So difficult to describe those few seconds as the light drops and this wonderful apparition appears, the Moon just seems to slot itself quickly over the Sun and trembles there. I had never got such an impression of the light falling into a hole and the Moon acting as a plug. Maybe it was because this eclipse was so high, 49 degrees up. China 2009 was much higher but there was a film of cloud. The Moon became very 3d, maybe because my dark adapted eyes were seeing some Earthshine. Our atmosphere means there is a constant sort of trembling. I jumped down onto the sand in front of the camera, and there is a special feeling I cannot describe. The eclipse lasted just over three minutes, and the whole body seemed to tingle and boil all over. You have to be there. I looked through the binoculars and there was a very impressive coronal streamer out at 5 o’clock on the disc and a bright pink and long prominence at 8 o’clock, near where the final crescent disappeared. The horizon around me seemed to stay very light, which surprised me, but the video shows that there was a lot more high cloud than I realised, so this would have kept the light levels up. There is usually a blackening and reddening effect where you can see the edges of the Moon’s shadow around us but not this time. The clouds also prevented us from seeing shadow bands, an effect of light refraction in the atmosphere in the very final seconds before second contact.

I was grabbed by a local while I looked through my binoculars and elbowed him away, as you see in the video. The video shows some of the locals photographing us, backs to the Sun! The locals are probably still afraid of eclipses. As in Java ‘83 there was lots of banging as the locals tried to scare the demon away that was trying to eat the Sun. You hear the racket on the video but I was oblivious to it at the time. Of course, all this hoohah worked, and the demon spat the Sun out. (t works every time.) Someone shouted it was finishing and within a second a bright diamond ring came up at 12 o clock. It seemed long and wide and the sky seemed to light up all over at the same time. That seemed odd to me, but then I noticed the high cloud all around it. I have overused the word ‘gawp’ in describing eclipses, but the brain just focuses all attention on visual input, and excludes everything else. The video shows me wiping my eyes. I am usually pouring my eyes out by the time the eclipse ends, but am not aware of it at the time.

So, forgive me if I get silly when I talk about my eclipse trips, but there is something about them that makes me feel real. Go get one for your bucket list and you’ll see what I mean. How about August 21 next year, central USA, or for a really good one, Gibraltar/Egypt, August 2nd 2027? That is part of the same saros as Hawaii 1991 and China 2009, which has given us two of the longest eclipses in these two centuries.


The 2016 transit of Mercury

On the 9th of May a rare event will be visible from the UK. Mercury will be crossing the face of the Sun and the whole event will be visible from the UK, assuming the skies are clear. The transit starts at 12:12BST and ends at 19:41BST. Although the whole event last 7.5 hours, the most interesting parts are the 3 minutes when Mercury starts the transit and the 3 minutes at the end when it leaves the disk of the Sun. For those with H-alpha scopes you might get a few extra minutes if the tiny planet should happen to cross a prominence on its way in or out.

Mercury transits occur around May or November, about 13 or 14 times a century. So although more common than a Venus transit, they still unusual. And given the weather in the UK, this one is the best one you’re going to get for quite sometime. The last one visible from the UK was back in May 2003. In November 2019 and November 2032 we will get to see partial transits (weather permitting, which is unlikely given the typical winter weather for the UK). The next full one won’t be until November 2039 and it only lasts 3 hours.

On May 9th first contact, when the disk of Mercury first encroaches on the Sun’s disk occurs around 12:12BST, as shown in the diagram below:

Mercury transit 1st Contact

Second contact, when the trailing edge of Mercury’s disk comes onto the Sun’s disk, occurs about 3 minutes later at 12:15BST. Third contact is when the leading edge of the planets disk starts to leave the Sun’s disk and it occurs at 19:39BST as shown below:

Mercury transit 3rd contact

Fourth contact is when the disk of Mercury leaves the Sun’s disk completely at 19:41BST.

It is worth starting to observe these events a few minutes before these times as they can vary be a minute or two depending on where you are in the UK. You will need some sort of optical aid to see this as Mercury is too small to be seen with the naked eye. Do NOT look as the Sun using a telescope or binoculars, without using appropriate filters. The safest method is to project an image of the Sun through a telescope of binocular lens onto some card. Abingdon Astronomical Society will be holding a public observing event, see here for details. Do come and join us if you get the chance.

Clear skies,