Cotswold Astronomical Society

Professor Chris Lintott will be delivering a lecture, available to view free online, on Wed 13th September 2023. The title is

Island Universes: Discovering Galaxies Beyond the Milky Way

Details are available about how to register for the event on the Gresham College website at

https://www.gresham.ac.uk/whats-on/galaxies-beyond

By James Weightman

Took advantage of (rare!) early evening to take picture of Venus with handheld camera. Care taken to stand in shadow of sun, it was then relatively easy to find Venus (surprisingly conspicuous) using coordinates from computer program, and then with steady hands to zoom in. Further details on image.

The nights are drawing in and observations should be getting easier.

Planets:

Mercury:  Mercury reaches greatest eastern elongation of 27^° but is low and difficult to find.  It is worth having a go if you have a clear western horizon.  

Venus:  Venus is lost in the evening twilight early in the month and passes through Inferior Conjunction on the 13^th of the month.  It will be a morning object by the end of August.

Mars is still visible in the evening sky, but is an increasingly difficult object.  The disc size drops to 3.8 arc seconds this month and it is low in the western sky by the time it gets dark. 

Jupiter is now rising before midnight and becoming more easily observed for those willing to stay up into the early hours.

Saturn reaches opposition on the 27^th and is visible all night.  It is low in the sky, but is well worth viewing.  The rings are at a shallow angle.

Uranus and Neptune are still morning objects.  They will be better placed in the autumn.

The Sun

Solar activity is still increasing and solar observations are a good idea.  Take great care to never look directly at the Sun, or directly through an optical instrument.

Ensure a proper filter is in place or project the image onto card.

Meteor Showers:  The Perseid meteor shower continues, lasting from 17^th July until 24^th August.  These can be quite prolific and it’s well worth waiting up for them.  The full Moon will be a problem at the start of the month. 

Moon

1^st and 31st August:  Full Moon.          8^th August:  Moon is at last quarter.

16^th August:  New Moon.                               24^th August:  Moon is at First Quarter.

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I have recently undertaken a detailed survey of light pollution in south Gloucestershire, including a region around the A417. This was commissioned by the Cotswold Conservation Board in Northleach and funded by the Highways Agency. Highways wanted to know the current state of light pollution within 20km of the A417 with a view to minimizing the impact of the proposed changes to that road. Prior to Covid, I had been on a committee with the Conservation Board in an effort to get some form of Dark Sky Status for parts of the Area of Outstanding Natural Beauty (AONB) of the Cotswolds. I was one of two astronomers asked to sit on the committee, the other being from the Chipping Norton Astronomical Group.

As amateur astronomers we are very much aware that dark skies are needed for many of our night time observations and that light pollution seriously impacts our ability to see and image fainter objects. It is only when viewing the Moon and planets that light pollution is not a major problem, but for all other objects the ever-increasing glare in our night skies is a great nuisance to us.

It is estimated that the extent of light pollution has increased by around 10% each year, thereby doubling within 8 years. Apart from the negative impacts on both amateur and professional astronomy, light pollution has many other detrimental effects.

The switch to LED lighting has not reduced light pollution, quite the opposite. Moreover, it has increased the amount of light in the blue part of the spectrum, which is even more damaging to wildlife. Light pollution seriously affects the predator/prey relationship for nocturnal creatures. The extra light gives an undue advantage to the predator, such as bats, owls and foxes. This then leads to a crash in prey numbers, with a knock-on effect on the predator. Prey that does survive may move to darker places and thus there is loss of habitat for the prey. The impact on insect populations has been dramatic and, remember, we depend upon insects for the entire food chain.

Evolution is a slow process, and none of us, insects, animals or humans evolved to live in permanent light. It affects all our circadian rhythms, disrupts sleep patterns, and leads to additional stress.

It is not often realised how far reaching light pollution can be. Many of us will have seen badly directed security lamps, those wretched 500W things, that dazzle us when we merely pass nearby on the road. These are completely unnecessary on a typical house and can be a major nuisance to those around. They are often badly directed and are frequently tripped by a passing cat or fox, and stay on for a while. The tripping does not alert neighbours to think anything untoward is happening, as it happens so frequently, and so they are ignored. Even if you did look to see what was happening, you would be unlikely to see any detail against the dazzling light. As a security tool on a house, they are worse than useless as they are costly to run, annoy the neighbours, and cause serious light pollution. One some distance from my house has often disrupted astrophotography in my back garden.

Lights from towns can spread a long way from the town itself, as my research clearly showed.

Below is a fisheye lens view of the sky near Daglingworth about 5 km from Cirencester

Notice how far up from the horizon the glow has spread. This was one of the darker sites for which I took readings. Even Stroud, at 13km distant is still producing some sky glow, while the glow from Stratton and Cirencester almost a third the way to zenith.

The photo below is of Rendcomb, which lies some 8km north of Cirencester.

The photo was taken above the village on a lane near to the White Way. Although it is clear that Rendcomb was below me in altitude, the lights from the College’s Astroturf, more than 1 km away, are dazzling, despite using the trees to block the direct glare. It is clear that these lights are poorly directed, as they are clearly pointing upwards at some angle! The light pollution is dreadful. Moreover, this was after 8.30 pm and the pitch was not in use. I could clearly read all the camera settings from the lights of Rendcomb. This emphasises how far-reaching light pollution can be.

One last photo here emphasises the impact of major towns and roads:

This is taken from Crickley Hill Country Park that allowed me in after sunset. The lights of Gloucester are to the left, with the A417 coming out towards you. The M5 crosses in front of Chosen Hill and Cheltenham to the right. Note that the lights of moving traffic are more separated and therefore cause less light pollution. See if you can spot the Plough in the sky above and to the left of Cheltenham.

So, what can we do? Well, we need to be more aware of any unnecessary light pollution we cause ourselves. Do we need that outside light on all the time, that security light or the curtains left open? Check that any external lighting is directed downwards and not outwards.

The Highways Agency are doing their bit, as they have decreed that the new section of the A417 will not be lit. I have supported this decision. After all, the section it joins is currently not lit either. Despite the local council requesting lighting, I am pleased that Highways are holding out on energy and environmental grounds.

We can campaign for street lighting to be reduced, or at least dimmed, with future lighting and bulbs to be better directed and using less white LEDs, but more environmentally sympathetic colour temperatures. Less lighting does not mean less security. There is growing evidence that crime rates actually fall when lighting is reduced. Criminals want to be able to see what they’re doing!
If we do not take action soon, we will lose the night skies, reduce wildlife and impact our own health. Unlike other types of pollution, light pollution is reversible, could save energy and let many more people enjoy the wonders of truly dark skies.

As a society we need to see what action we can take to prevent the loss of dark skies. Perhaps some of you feel strongly enough to form a small focus group that could recommend a way forward. Please email your Coordinator Neil at coord@cotswoldas.org.uk if you could take part.

Furthermore, in the meantime, we could all get behind a petition to Parliament to pass a Dark Sky Law. If enough people sign it, Government will have to give it consideration.

Details can be found at https://petition.parliament.uk/petitions/632558

 

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Neil Havard

CAS Coordinator

The light evenings persist throughout most of the month, although it will be getting dark noticeably earlier by the end of the month.

Planets: 

Mercury:  Mercury is not well placed, but might be picked up in the evening sky in the second half of the month.  It has an elongation of 25^° at the end of July, but sets barely an hour after the Sun.  It will be difficult to pick up, unfortunately.

Venus:  Venus is now racing in towards inferior conjunction early next month.  It is still a prominent object after sunset, with an elongation of 40^° at the start of the month, but dropping to 22^° by the end of July.  The phase decreases from a crescent of 33% at the start, dropping to a thin crescent of less than 10% by the end of the month.  The angular size does increase rapidly from 33 arc secs to 52 arc secs in the same period.  This will be your last chance to see it in the evening sky for a while.

 Mars is still visible in the evening sky, but is a difficult object now.  The disc size drops to 4 arc seconds this month and it is very low in the western sky by the time it gets dark.  It moves into Leo and passes very close to Regulus in the first week of the month.  It might be worth looking out for this.

Jupiter is now a prominent object in the morning sky, rising around 1 a.m. by the end of the month.

 Saturn is still just a morning object in Aquarius, but rises well before midnight.  It is low in the sky, but is now worth staying up for.  It reaches opposition next month.

 Uranus  and Neptune are still morning objects.  They will be better placed in the autumn.

Pluto reaches opposition on the 22^nd at RA 20h 06.1m  Dec  -23^° 1.5’ with a magnitude of 14.9.  Good luck!!

The Sun

Solar activity is still increasing and solar observations are a good idea.  Take great care to never look directly at the Sun, or directly through an optical instrument.

Ensure a proper filter is in place or project the image onto card.

Meteor Showers:  The Perseid meteor shower lasts from 17^th July until 24^th August.  These can be quite prolific and it’s well worth waiting up for them.  The Moon won’t be a problem near the end of the month. 

Moon

3^rd   July:  Full Moon.                     10^th July:  Moon is at last quarter.

17^th July:  New Moon.                   25^th July:  Moon is at First Quarter.

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June is never a great month for amateur astronomers, apart from observing the Sun.  Astronomical twilight lasts throughout the night, especially later in the month.

Planets:

Mercury:  Mercury is not well placed, but might be picked up in the morning sky in the first half of the month.  It has an elongation of 24° at the start of June, which is your best time to pick it up. 

Venus:  Venus reaches greatest eastern elongation on the 6^th June and is 45° east of the Sun.  It also reaches its brightest, with a magnitude of -4.7°.  The apparent diameter is rapidly increasing from 23° at the start of the month to 33° by the end of June.  The phase drops from 50% at the start of the month, to a crescent of 35% by the end.

 Mars is still visible in the evening sky in Cancer.  During the month it passes south of the Beehive Cluster (M44), but by the time it’s dark enough to make out the cluster, they will have set. The disc size drops to 4.5 arc seconds this month and it is very low in the western sky by the time it gets dark. It is a difficult object now.

Jupiter is now a prominent object in the morning sky, but you’ll need to be up by 3 a.m. to see it properly!

 Saturn is also a morning object in Aquarius, but is still low in the sky this month, rising around 1 a.m. (BST).

 Uranus  and Neptune are morning objects, but very poorly placed this month.

The Sun

Solar activity is still increasing and solar observations are a good idea.  Take great care to never look directly at the Sun, or directly through an optical instrument.

Ensure a proper filter is in place or project the image onto card.

As I am writing this, I am aware of a couple of sizeable sunspot groups visible.

 Meteor Showers:  There are no favourable meteor showers this month.

Aurora: The increased solar activity should raise the possibility of seeing the aurora borealis, although the lack of darkness means this is unlikely before the Autumn.  Download an App that warns you of auroral activity in readiness for the darker nights.

Moon

4^th   June:  Full Moon                     10^th June:  Moon is at last quarter

18^th June:  New Moon                   26^th June:  Moon is at First Quarter

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May will not be a great month for observing planets, but I advise you take advantage of the nights getting dark at a reasonable time to do some observing of deep sky objects, such as clusters or galaxies.  By next month the skies will never get truly dark all night.

Planets:

Mercury:  Mercury reaches greatest Western elongation on the 29^th and is moderately well placed for observing in the morning sky.  The end of the month and the start of June is your best time to pick it up, when it is around 17 degrees from the Sun and has a fairly northerly declination.  However, it is not very bright until the start of June and may be tricky to find. Use binoculars to hunt for it as this gives a better chance of finding it. 

Venus:  This is now a very prominent evening object and becoming much brighter and higher in the sky.  The apparent diameter is rapidly increasing as the phase drops to about 50% by the end of the month.

 Mars is still visible in the evening sky in Taurus.  The disc size drops to less than 5 arc seconds this month and it is getting low in the western sky by the time it gets dark. It is a difficult object now.

Jupiter is now becoming a morning object.

Saturn is also a morning object, but very poorly placed this month, rising at around 3 a.m.

Uranus and Neptune are morning objects, but very poorly placed this month.

The Sun

Solar activity is still increasing and solar observations are a good idea.  Take great care to never look directly at the Sun, or directly through an optical instrument.

Ensure a proper filter is in place or project the image onto card.

Aurora: The increased solar activity raises the possibility of seeing the aurora borealis even at our southerly latitudes, as has happened recently.  Keep alert and look online, or maybe download an App that warns you of auroral activity.

Moon

There will be a penumbral eclipse of the Moon on the 5^th May, but it will not be visible in the UK as it occurs during daytime.

Another challenge is the occultation of Jupiter on the 17^th May at 13.40 BST.  The occultation is only visible in Scotland, but it will be a grazing pass here.  As it is in the day, you will need to use a telescope to see this, but as Jupiter is bright and the Moon easy to find, it’s worth a try.

5^th May:  Full Moon.                      12^th May:  Moon is at last quarter.

19^th May:  New Moon.                  27^th May:  Moon is at First Quarter.

 

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The CAS 2023 AGM report is available for members to view online in the member’s area.

(https://cotswoldas.org.uk/members).

31 members attended, plus 3 guests.

Subscription rates are unchanged, full membership £20, concessions £10, family £30, family concessions £15.

Although the present committee were willing to continue for another year, it is vital for the continuation of the society that the positions are rotated on a regular basis. It would also be appreciated if members would volunteer for co-opted roles, possibly as an assistant to any of the current committee members.

The committee post currently vacant is that of Events Organiser. Despite the title, this does not involve organising “events”, but primarily arranging visiting speakers for the majority of our Saturday meetings. (Club meetings are held on the Second Saturday of every month). In 2022 for example, there were just 5 external speakers. There would only ever be a maximum of 10 but we always have at least 2 or 3 speakers from within the club. For the Events Organiser it is an opportunity to personally sometimes meet professional speakers, such as Chris Lintott, for example.

Please support your club and volunteer to help.

The 2023 annual CAS Treasurer’s report is available for members to view online in the member’s area. (https://cotswoldas.org.uk/members).

The 2023 annual Coordinator’s report is available for members to view online in the member’s area. (https://cotswoldas.org.uk/members).

If you would prefer to see a printed copy, please attend the AGM on Saturday 8th April and email the Coordinator by the latest Thursday 6th so a copy can be prepared for you.