Bulletin – June 2018

Society News

Most of the behind the scenes activity in May was related to the issue of relocating the observatory. We have a number of sites to which we may be able to move, none of which ticks all our boxes. Negotiations with the owner of our first choice are imminent. There will be an update in the July Bulletin.

We should like to express many thanks to Martin Whipp for his work with YAS in various roles over many years. Martin recently resigned as Chairman, but will continue as an active member of YAS

The committee recently met and agreed to continue without a Chairman for the time being.

Last month’s Society Events – May
May 4th (Friday)

Priory Street meeting. Brian Jones from Bradford AS gave an enjoyable talk entitled “The Astronomical Scrapbook”. Taking his cue from the book The Astronomical Scrapbook, Brian took us through a number of vignettes ranging from the correct pronunciation of Halley (which does not rhyme with ballet or daily but does rhyme with sorely), through the names and history of some old constellations (e.g. Argo Navis and Robur Carolinum), issues of astronomical stamps, and where our space probes have got to. See Voyager 1.

May 6th (Sunday)

Observatory clear-out day at Rufforth. We made a start on sorting out items we want to keep, and those we wanted to throw out or sell.

May 18th (Friday)

Priory Street meeting. This was an EGM at which members were informed about the sites to which we may move the observatory. There was an initial discussion regarding whether we really had to vacate our current site, then the facts that were known about each alternative site were presented. As the known facts indicate at the moment, we do have to move, and the recommended destination site was Beetle Bank Farm. At the end, those present were asked to indicate their preference, and there was overwhelming support for Beetle Bank. Although there was no motion and no binding vote, the strong indication of preference must guide the trustees, who ultimately have the authority to decide. Whichever site we go to, it will only happen if and when we can negotiate a satisfactory agreement with the owner.

Society Events Coming Up in June

June 1st (Friday)

Priory Street meeting. Mike Terzza of our society will give a talk entitled “A Journey into Astrophotography”. After buying his first telescope at the end of 2014, Mike has been hooked on taking photos of space and the night sky. Join us to learn about the journey he’s taken striving to learn the craft of Astrophotography.

June 9th (Saturday)

Working party at the observatory. We will be dismantling equipment and beginning the task of readying the containers for relocation. Any help you can give will be much appreciated. Please bring tools and contact the project manager, Mike, via observatory@yorkastro.org.uk in advance.

June 15th (Friday)

Priory Street meeting. Informal night, where members give short talks and practical hints on different astronomical topics.

June 29th (Friday)

Committee/Trustee meeting at the observatory. This should result in more news about the move.

In the Sky in June

Not exactly the best month for astronomy, as at least from York, the sky doesn’t get astronomically dark (sun 18° or more below horizon) at all during the month. Nautical twilight is when the sun is 12° below the horizon, and this is from 2343 to 0224 BST on the 1st and only lasts for 84 minutes centred on about 1 am at the summer solstice on the 21st.

However, there is still something worth observing this month that’s easy to see from 40 minutes after sunset onwards, and that’s Jupiter.

Jupiter was at opposition on 9th May and is still close and conveniently observable for the whole of June. It is due south and highest in the sky at 2315 at the beginning of the month, 2215 on the 15th, and 2115 at the end of the month. Throughout the month, it only reaches 21° altitude so viewing may suffer from imperfect seeing, but nevertheless, apart from the Moon, Jupiter is the easiest and most satisfying object to observe. Even a reasonable pair of binoculars will show its four Galilean satellites, and a half decent telescope will reveal its cloud belts. Higher resolution instruments will show the shadows of the moons as they transit the planet’s surface. Here are some of the most convenient transits to look out for.

In all cases, the moon in question will be seen very close to the limb of Jupiter 10-20 minutes before “Moon transit starts”. It will then move in front of the planet’s surface where in all but the very highest resolution telescopes, it will disappear. The moon’s shadow will then begin to transit the planet’s surface at the time stated. Please note all dates are June and all times are approximate ( 5 mins).

Moon Moon transit starts Shadow transit starts
Io 1st @ 2205 1st @ 2235
Europa 6th @ 2130 6th @ 2250
Io 8th @ 2350 9th @ 0030
Europa 13th @2350 14th @ 0130
Io 24th @ 2150 24th @ 2250

The other conspicuous object to observe is of course Venus. This brilliant (magnitude -4.0) planet can be seen from shortly after sunset in the west to north-west. Venus is still on the far side of the sun, so through a telescope will show a gibbous phase. Its angular diameter is 13.2 arc seconds on the 1st, increasing to 15.7 arc seconds on the 30th. We will have to wait until mid August to see it as a 24.4 arc second diameter “quarter moon”. There will be a nice pairing of Venus and the Moon on the 16th. In case you haven’t kept up with the discoveries about Venus (e.g. its surface temperature is hotter than Mercury’s), the Wikipedia Venus entry is well worth a read.

Click here for SEASKY astronomy events

Click here for BAA Bi-monthly Sky notes