19th March 2018
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Stargazing: Natural summer light begins to recede

, by , in Features

The skies are darkening again; the natural light that covers the stars in summer is receding. Now we just have to contend with the light pollution we produce ourselves.

Astronomical darkness returned on the 20th August and the Sun moves below the celestial equator for the autumnal equinox on 22nd September at 10:18pm.

The full Moon is on the 4th and New Moon is on the 18th.

Evening – sunset to 1am

The Moon is out of the night sky from the 13th to the 25th.

After the Sun has set there is a bright star in the south-west. This is Arcturus, the main star of the constellation Bootes.
Low in the south-east and south by 1am is the giant planet Jupiter. While it is bright it is seen through a lot of the Earth’s atmosphere but the four Galilean Moons should be visible with binoculars. Those with access to a telescope might try to see the new dark spot on the planet. Something big has crashed into Jupiter and caused a “crater” in its clouds that shows up as a new feature.

Following Jupiter in the sky is the planet Neptune. Jupiter will be a good signpost to guide you to where Neptune is. So while last year you hopefully found the planet Uranus this year you may get to glimpse the outermost planet of the Solar System. Big binoculars or binoculars on a tripod will be needed to see this faint planet.

Far ahead of Jupiter in the night sky is Pluto for those with large telescopes or CCD imagers and following someway behind Jupiter is Uranus and hopefully you should be able to see this planet in binoculars before the end of the year with the aid of a map.

Morning – 1am to sunrise

The Moon is out of the night sky from the 17th to the 30th.

The other planet to join the sky as morning approaches is Mars around to the northeast. It will look like a reddish star and can be found between the constellations of Auriga and Gemini.

Getting ever lower in the sky over the month is the planet Venus. It is low down on the northeast horizon, below the altitude of Mars. At the end of the month it will act as a signpost to Mercury and Saturn. This will be start of a
three week session in which all the planets can be seen in one night – why not set yourself the challenge? The Solar System in one night.

The Perseid meteor show peaked in the middle of August. I had the good fortune to get a gap in the clouds that showed me three and I saw a reasonably bright one on a few evenings later in August. For September there are a few very
low meteor number showers but any clear night you should expect to see the occasional sporadic meteor.

September is the time to start getting any equipment together from the previous seasons night sky watching.

If you are just beginning astronomy then get down to The Shetland Times Bookshop where there are some useful beginners guides, and look at the event mentioned at the end of this article.

For those who do binocular observing you may want to purchase a star atlas, as they are easier to take outside than a computer. And if you are not too sure you need to have your own copy then have a look in the library. Remember also to try and find a red LED torch, you may need light to see things but not so much that you destroy what dark adaptation you have.

And if you do have outside lights now is the time to shield them so they shine neither in your eyes nor your neighbours’ eyes if they are out sky watching. In fact with the recent change in the law about artificial light as a nuisance it may be a good idea not to disturb your neighbour with your outside lights.

Over the summer a couple of astronomically related items came to my attention. The first was that the next solar cycle had started and some sunspots had been seen. This solar minimum appears to be a long one reminding us that our local star does have some variability. In fact after starting it appears to have stopped again! Internet users can keep an eye on what’s happening via Spaceweather.com

Unfortunately the more sunspots the more active is the Sun and the more frequent the cloud of solar particles sent out that hits our magnetic field and causes spectacular northern lights. For this winter it is unlikely there will be many displays or a chance of a really spectacular one. But keep looking.

The second very interesting fact that came to me was that the Scottish Government changed the law on environmental nuisance earlier this year. Most interestingly for lovers of the night sky is that artificial light became a nuisance, with very few exceptions. So as in the past I had somebody asking me if anything could be done about the lights from the golf driving range as they shone into their house on Bressay – the answer was then no, not really.

This change in the law allows a process, which if the two parties talking to each other cannot agree on a satisfactory resolution then the SIC’s environmental health department can be called to help. Hopefully that would help form a solution but if there was a persistent offender then sanctions in law may be a route of last resort.

Now do not go pestering the environmental health department too quickly. They have pointed out to me that this is a new law and as such takes time to bed in properly – but at the end of the day if somebody else’s artificial light is affecting your use of your property then there is now a mechanism to help resolve the problem.

Unfortunately I have not had word back from the SIC planning department as to how the new law will affect developments from the single dwelling house to the large scale industrial development.

I would wonder if at the planning stage you could ask for a limitation on the artificial light from the completed development, something similar to the type of roofing material that must be used or the type and quality of drainage from the development. It would certainly make the job of the environmental health department easier if a level of consent already existed on a new development.

Maybe the time has now come for interested parties to develop Shetland’s own lighting policy, as already exists for many councils around the UK.

Amateur astronomy can be run as a solo hobby but if you would like to meet like-minded people then the Shetland Astronomical Society has some events for in the next few months for this International Year of Astronomy.

Specifically this month, on the 21st, at the Asta Golf Clubhouse, there is an observing session be­tween 7pm and 10pm – remember to take your telescope or bin­oculars.

In the following months there are a couple of events at the Shetland Museum with invited speakers and lunar observing sessions so keep an eye out for those.

Let’s hope for clear skies.

Chris Brown