This piece was originally broadcast on Radio Scilly in May 2019.
Hello again from the Observatory on St Martin’s! I’m sat here in our warm room, which is the astronomer’s way of saying 'posh shed'. In short, it’s the space here at the observatory where we keep all the computer equipment and our telescopes when we’re not using them in the domes. It’s also where we come together to plan what we’re going to look at in the night sky at our stargazing sessions. We’ve got wall charts with the moon phases, maps of the sky and a big calendar for major events coming up. If you’ve visited us already, you’ve certainly been in here; if you haven’t, what are you waiting for? We’re open Tuesday evenings and Friday afternoons.
Many people have asked why we’re open during the day. Well, it’s a myth that astronomy only happens at night. Fridays are dedicated to solar-gazing. The Sun – our nearest and most important star – is all too easily forgotten as an object of astronomical interest! It can offer some of the most visually rewarding observations in astronomy. It’s also never been more popular.
On St Martin’s, we have a powerful solar telescope, with which we can observe the sun in detail with our very own eyes.
Now, before you fear for your eyesight I should say that solar telescopes like ours are sophisticated bits of kit, with the crucial bit being a very strong hydrogen-alpha filter which blocks out harmful wavelengths of light. This means you can look at the Sun directly. (Something you should absolutely never, ever do with the naked eye!)
So what can you see? Looking through the solar scope on a clear sunny day, the Sun appears as a red disc in the eyepiece. You can make out a dynamic, shifting surface, almost whirling before your eyes. If you’re lucky and there’s a period of high solar activity, you could easily find a sun spot or a solar prominence – shards of gas, shooting from the edge of the sun’s disc. All this activity has the potential to impact life on earth, which is why it’s a growing area of interest. Whether you spot any or not, it’s pretty exciting to look at our Sun, up close and personal. Where would we be without it?
To the night sky. We’re approaching the longest day of the year, and it doesn’t get truly dark here on Scilly until gone 11pm. A little too late for many of us – myself included – on a school night. That said, anytime after 10pm, on a clear night, I do enjoy looking up at the twilight sky as the first stars pop out, like distant lights, twinkling on.
The first you’ll probably see will be Arcturus, biggest star in constellation Bootes ('Booties' is the wrong pronunciation by the way – it should be Boe-OH-teez, from the ancient Greek for ox herder, but I always feel a little silly saying it that way, so I’m happy to be wrong). Arcturus is an orange giant, appearing dazzlingly pinky-orange in the southern sky. It’s about 170 times brighter than our little Sun and more than 36 light years away.
Look further East and you’ll spot Vega, in constellation Lyra, the harp. This one’s a mere 25 light years away. In 10,000 years, Vega will replace Polaris as the pole star! In the meantime, enjoy it where it is as part of our lovely – if not completely dark – Summer sky.
This piece was originally broadcast on Radio Scilly in May 2019.
A post on our COSMOS Facebook group from a London-based friend of mine prompted me this week to turn my attention, once again, to the Moon. Our last astronomy talk on St Martin’s looked at the Earth’s cultural relationship with the Moon, from dragons to werewolves, many of which mythical. And yet there are many cultures around the world for which the Moon has a very real influence.
My friend was requesting help to spot the new crescent Moon, on the evening of 5 May. As a Muslim and a keen amateur astronomer, he – and his group of friends based at the Royal Observatory in Greenwich – always look for the new crescent, to begin Islamic months.
The Moon plays a significant role in Islam, because Muslims follow a lunar calendar. Specifically they use the first appearance of the new crescent moon (after the non-visible New Moon) to determine the start of each month. The moon is thought to be a sign of God, and indeed is mentioned directly no less than 28 times in the Koran. In fact, the importance of getting the start of months correct and spotting that new Crescent, was one of the drivers for the study of astronomy across the Islamic world. And we have a LOT to thank for it! Numerous stars carry names given to them during the golden age of Islamic astronomy. Most of those in the plough, for a start (Alkaid, Megrez, Merak, Dubhe), plus Aldebaran, Deneb, Rigel, Saiph…. I could go on.
This month’s moon gazing was particularly significant, because the sighting of the new crescent determines the start of Ramadan, the most holy of Muslim months, during which followers fast from dawn to dusk.
While we don’t have a sizeable Muslim population on the islands, we are well placed to contribute scientifically to this important cultural area of astronomy; with both our dark skies and low, even horizons, chances are we’d be some of the first to spot a new crescent (far better than my friend in London, as I know from experience!). Sadly, however, the clouds didn’t play ball for us, so we had to leave crescent spotting to moon lovers in other climes. Indeed, the new crescent was not spotted anywhere in the UK, or Western Europe.
Believe it or not, particularly where Ramadan is concerned, the spotting of the new crescent can be a rather political issue in the Muslim world. Not all Islamic countries use the first sighting of the crescent Moon to signal the start of the month. Saudi Arabia (which has few official astronomers) has been accused of fixing the start of each month and has been criticised for its perceived ‘control’ of the Muslim calendar.
Many Muslim countries now follow the lead of the Saudis to set their dates, having veered away from raw astronomy into political allegiance. Those following the local moon in the UK started Ramadan on Tuesday 7 May, whereas those Muslims who follow the Saudi-led calendar started a day earlier, as the Saudi determined Ramadan to begin on 6 May. Bring back the astronomers, some say.
The Moon will be growing in size as the crescent waxes towards Full Moon on 18 May. Now is a good chance to grab those binoculars and cast your eyes up onto that celestial body that continues to have a hold over us earthlings.