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MESSAGE OF THE MONTH
Under darker skies
I recently went on an astro camping trip along with the Northolt Branch Observatories Facebook group. It was my first time camping and the first taking my full deep-sky object setup away from home. We picked a campsite away from London towards Hastings, in a Bortle 4 location [the Bortle scale being a measurement of dark skies]. The weather wasn’t perfect, but in the clear spells between the hazy clouds there were spectacular skies. I saw the Andromeda Galaxy, M31, with the naked eye for the first time and you could see its entire width.
During the night I managed to get one single shot of M31 before the clouds rolled back.
I was shocked and amazed to see the result, compared to the results back home. It looked like the single RAW image was the same as a stacked 2–3 hours, stretched image from home. When I got back I decided to compare the two. The top is under Bortle 4 skies and the bottom under Bortle 8 at home. Both were taken with the same camera and settings. I am somewhat shocked by the result! Darshna Ladva, London
What a valuable insight, Darsha. The comparison really illustrates what light pollution does to our view of the night sky, and the value of escaping to a dark-sky location if you don’t live in one. Sadly it’s an experience many of us will be all too familiar with. – Ed.
This month’s top prize: two Philip’s titles
The ‘Message of the Month’ writer will receive a bundle of two top titles courtesy of astronomy publisher Philip’s: Heather Couper and Nigel Henbest’s 2021 Stargazing and Robin Scagell’s Guide to the Northern Constellations
Winner’s details will be passed on to Octopus Publishing to fulfil the prize
Harvest delight
While looking after a smallholding for some friends, my wife Myra and I had one of the most enjoyable nights of observing ever.
Two nights before the full Harvest Moon, armed with my Bresser 15×70 astronomical binoculars and a smartphone, we were thrilled when we observed the waxing gibbous Harvest Moon, Jupiter, Cassiopeia, and many other wonders of the night sky. We were also joined by Bob and Balderick, the two resident cats, who brought home to us that while observing, we have the opportunity to bond with nature, as other readers of Sky at Night Magazine have commented on previously.
Bobby Ayre, via email
How high the Moon
Something about the Moon has been on my mind for months. To illustrate, here are two photos; I took the first back at 8:04pm on 25 April and the other at 8:05pm on 26 April, 24 hours later. The thing that has puzzled me ever since is why the Moon was so much higher in the sky on the 25th than it was on the 26th, and what causes such a difference in such a short space of time? Sorry to trouble you with what may seem a simple thing, but I’m very intrigued.
Geoff Stainer, via email
Great question, Geoff! The thing that causes the Moon to be in a different part of the sky at the same time each night is that at the same time as Earth is rotating on its axis every 24 hours, the Moon is also moving more slowly in orbit around Earth, which it takes 27.3 days to complete. – Ed.
In a spin
I was lucky enough to ask the question, “Do black holes spin?” on The Sky at Night’s ‘Question Time’ episode, filmed in Chelmsford. Chris Lintott answered yes, and explained about the way that the gravitational effect of the spinning black hole caused the matter being captured to rotate around it as it nears the event horizon (in my words, like water going round a plug hole, before reaching the point of no return and going down the drain). After the show I thought further… if the theory is true that every galaxy has a black hole at its centre driving the dynamics of the matter it captures in its gravitational field, why are all galaxies not spiral in formation? So, if a black hole was static would matter still spin around it, or is it the spin of a black hole that produces this effect?
Consequently, if a black hole doesn’t spin, does this account for non-spiral galaxies or are there other contributing factors?
Stephen Piper, via email
Heading to space
I loved your online story about women in space (www.skyatnightmagazine.com/space-missions/women-astronauts). Well, a NASA study does reveal that we’re better suited for space travel! Now that space travel is becoming more accessible, I got inspired to build a tool to help you prepare for your own expedition. I teamed up with a fellow PhD candidate in physics, and we built the Space Travel Calculator (www.omnicalculator.com/physics/space-travel). It lets you calculate how much time and fuel it will take to travel to a certain astronomical destination. It includes Solar System and interstellar destinations, plus some from Star Trek! I hope this will get other readers exploring the wonders of space from home.
Purnima Singh, via email
Society In Focus
Weymouth Astronomy Club meets on the South Coast on the second Friday of the month (except August). We are a friendly bunch with a wide range of astronomical interests. Some prefer practical observing and astrophotography, while others get stuck into the theoretical aspects of the night sky. Overall, however, the club has a good pedigree of helping those just beginning their astronomical journey and guiding them through what there is to discover in the heavens above.
We have a varied programme and our visiting speakers always bring expertise to our meetings, enabling members to deepen their knowledge of astronomy. Besides our monthly meetings, we hold viewing nights timed to coincide with special astronomical events, and arrange visits to places of interest like Sidmouth’s Norman Lockyer Observatory. We have also held public viewing events in association with the Sandsfoot Castle and Rodwell Trail Trust, which have been well attended by people from across the area interested to learn more about observing the night sky. Throughout the COVID-19 pandemic Weymouth Astronomy Club has remained active, using online technology to deliver our monthly meetings. We expect to use both face to face and online meetings to deliver our programme for the future.
To find out more about Weymouth Astronomy Club, come along to one of our meetings at St Aldhelm’s Church, Spa Rd, Weymouth, or visit our website. John MacDonald, Chair, Weymouth Astronomy Club www.weymouthastronomy.co.uk
On Twitter
Joanna @Joeynoble • Sep 23
A bit of stargazing this evening, while doing a bit of research. I can’t help but love the colours of our night sky, even in the massively light-polluted Black Country! @OlympusUK #startrail #livecomp #BlackCountry #NightSky @skyatnightmag #Kingswinford @WeAreBCR
On Facebook
WE ASKED: What are your favourite astronomy jokes?
Tony Healey A galaxy walks into a bar and orders a drink. The bartender says ‘sorry I can’t serve you, you’re barred’.
David Greensmith Because of all the sniggering from tonight’s planet watch participants, instead of looking at Uranus we’re going to have a peek at Mars.
Gemma Brown “Orion’s Belt is a big waist of space.” Terrible joke – only three stars.
Lucas Borkowski A joke from the Cold War period: the USSR painted the Moon red to show its dominance in space, and then the Americans wrote Coca-Cola on it with white paint.
Martin Coule I went to a pub on the Moon. It was okay, but it had no atmosphere.
Carol Miller How did the Moon know it had had enough to eat? It was full.
Kriss Jupiter What do aliens listen to? Neptunes.
Colin Ackerley What do you do if you see a space man? Park in it man.
On Instagram
sloopjohnd82 • 13 September
I lost count of all the times I had driven past the Lovell Telescope and promised myself to get a picture next time. Finally, it happened! Anyway, I think I much prefer it in colour to black and white. #cheshire #telescope #jodrellbank #jodrellbankobservatory #astronomy #lovelltelescope @bbcskyatnightmag @jodrellbank @visitchesterandcheshire @visitengland
Scope Doctor
Our equipment specialist, Steve Richards, cures your optical ailments and technical maladies
Email your queries to scopedoctor@skyatnightmagazine.com
I’m turning my 10-inch Dobsonian into a Go-To scope and thinking of using an HEQ5 Pro mount, but what mount would you recommend? DEAN COATES
A 10-inch Dobsonian reflector would make an excellent telescope for conversion to equatorial Go-To use, for both observing and imaging. However, assuming that your telescope is of a standard metal construction, it will weigh around 11kg without accessories like a finderscope and eyepieces for observing, or a camera and guidescope for imaging, so it will require a substantial mount to support it properly.
The HEQ5 Pro would be operating above its recommended limit for astrophotography and a couple of kilograms under its maximum for observing. Taking into account additional external influences like the effect of shaking by the wind, the time it takes for vibrations to dampen down after focusing and so on, so this would not be the best mount choice for this scope.
A Sky-Watcher NEQ6 Pro or EQ6-R Pro would be a more suitable mount as they have a higher payload allowance, and alternatives like the iOptron CEM 40 should also be on your shortlist. Don’t forget to factor in the cost of a pair of suitable tube rings and a dovetail bar when pricing up your investment.
Steve’s top tip
What is a diagonal for?
When you observe through a refractor or Cassegrain telescope the eyepiece gets lower and lower as you increase the altitude at which you are observing, until it becomes very uncomfortable to view straight through the telescope.
However, you can use a diagonal to change the viewing angle. A diagonal is a triangular attachment with a small mirror set at 45°, which fits in the focuser and bends the light collected by the telescope through 90° to project it into the eyepiece.
This simple attachment makes it easier to observe through the scope as you can view down into it rather than up into it.