Creatures of the Night

Last Saturday we were invited to take telescopes along to Grafham Water where the Huntingdon Area Group of the Wildlife Trusts was holding a barbeque and showing visitors how to detect and identify bats, how to catch and identify moths, and how to dissect and interpret owl pellets.

The barbeque was excellent and we all learned a lot from the wildlife experts. It had been cloudy all day so we were pleasently surprised when the cloud began to break up and clear. Initially we could only show people the Moon but as it got darker and clearer we showed them Saturn and Mars in the same field of view. Jupiter was visible later and despite being very low in the sky showed lots of detail. Other favourites such as the Ring Nebula and Andromeda were also seen.

We took several telescopes including the Equinox 80 from SkyWatcher. Mounted on a Vixen Portamount and fitted with a Baader 8-24mm zoom this proved very popular and we decided we liked it a lot. As a 'grab and go' combination it is very quick to set up and easy to use. If you are looking for a qood quality small refractor we can recommend the Equinox 80.

It was interesting to note that the bat expert was using the Batbox Duet that we sell. Although he could tell which bats were around by the noise from the detector, he took recordings of the frequency-divided signal for analysis at home in case there were any rare ones around. We now sell BatScan analysis software designed for the Duet for those of you who are getting seriously interested in bats.

TeleVue Eyepieces

TeleVue continue to make some of the world's best eyepieces and thanks to the weakness of the dollar and a recent price reduction at TeleVue they really are good value now. Even the most exotic, like the new 8mm Ethos, are becoming more affordable. So why not treat yourself in time for the new observing season.

Celestron Spring Offer

The offer on Celestron Nexstar SEs and SLTs must end on 31st July. We are told there are no more Nexsatr 6 SEs until the end of September but all other models in the two ranges are still available.

Latest News from Mars

Although it is more than 330 million km away, we can still see Mars as a small disc in modest telescopes. As I implied above, it is quite close to Saturn and the two make an interesting site at low power. For a closer look we can refer to NASA's Mars Reconnaissance Orbiter which is sending back pictures that scientists believe show that the Red Planet once hosted vast lakes, flowing rivers and a variety of other wet environments that had the potential to support life.

Not only is there evidence of substantial clay deposits which can only form in the presence of water, it seems that water existed on the planet for a very substantial period. Meanwhile, the Phoenix Lander is still digging away, looking for ice-rich soil to analyse.

The Summer Triangle

Some star formations are like old friends and the Summer Triangle is one of my favourites. It only consists of three stars but in the summer sky it stands out against the twilight making it easy to find a wide range objects. It was one of the starting points I used when first finding my way around the sky. It immediately identifies three constellations, Cygnus, Lyra and Aquila, with several smaller ones dotted around them.

Binary stars such as Albireo, nebulae such as the Ring and the Dumbell, asterisms such as the Coathanger make it a great area of the sky to explore with binoculars or telescope. And it's around when it's relatively warm.

It's very easy to dismiss summertime observing because 'it never gets properly dark' but there is still plenty to see and it's much more comfortable sorting out your equipment and techniques in preparation for the dark winter nights.

What can you see on the Moon?

We often get asked this question by new astronomers who are thinking about buying a telescope. Sometimes they add 'I don't suppose we'll be able to see the flag left behind by the lunar astronauts?' They are right of course but the way they ask the question shows they aren't really sure whether they should be able to see it or not.

The smallest detail you are likely to see on the Moon is limited by the Earth's atmosphere and is around 1 km. Lunar orbiters can see a lot more detail and the Japanese Selene spacecraft has imaged a bright area believed the be the mark left behind by Apollo 15's engine exhaust. This is the first time in the almost 40 years since the Moon landings that any signs of the landings have been detected by a subsequent mission.

Looking South at 11 pm from Cambridge, UK

The nearby Moon will make it difficult to see all but the brightest objects tonight but as it moves away in subsequent nights you can look for some of the things I mention. You will probably have noticed Jupiter looking like a very bright star low in the south-east. Tonight it is close to the Moon and you may be able to get it and the Moon in the same binocular view, depending on the binoculars.

The Milky Way starts on our southern horizon and extends upwards and a little to the left running up the left-hand side of the Summer Triangle. Close to the horizon and to the left and right of our meridian respectively we find Sagittarius and Scorpius. Astronomy books often have an American bias and describe these constellations as though they are easy to see. In the UK they are much lower in the sky and so not so obvious. But they are worth looking at when you get the chance.

Look for Antares, the rival of Mars, a bright reddish star in Scorpius. You may be able to see it and Mars on the same night and compare their appearance.

About 20 degrees above the horizon you would be able to see Pluto if it were dark and clear enough. However, you would need a fair-sized telescope as its magnitude is around 13.9.

Continuing up we encounter Ophiuchus, the serpent bearer.  Although the Sun's path, the Ecliptic, passes through Ophiuchus it isn't regarded as one of the astrological signs. A supernova exploded in Ophiuchus in 1604 and was subsequently named Kepler's Supernova because of the amount of effort he put into studying it. Galileo used it to argue that the heavens were not unchangeable.

The brightest star in Ophiuchus is called Rasalhague and it is very close to our meridian. Stretching from Rasalhague to our overhead lies Hercules. Its distinctive 'keystone' shape is to the right of our meridian. One of the best globular clusters, M13, is located along the right-hand edge of the keystone. Try looking at it in binoculars and different sized telescopes to see how the view varies.

Globular clusters occur in the halo above and below the galactic plane, and contain some of the oldest stars in the galaxy. They are low in metal content (astronomers call anything other than hydrogen and helium a metal in this context) which indicates they were formed before the interstellar medium was contaminated with metals produced by the first stars to die.

Goodbye to Wendy

Wendy is leaving us in early August but tomorrow is her last day at work because of holidays. We shall be sorry to see her go as she has been a key part of Green Witch for over seven years. We wish her all the best in the future.

Ralph is also leaving although we expect him to appear at Green Witch from time to time. He will still be available to collimate telescopes, offer training and give talks to societies. Please contact Green Witch if you want to use any of his services.

And finally...

The SOHO spacecraft was designed to study the Sun and is providing stunning images and data that you can find on the web. One of the spin-offs from its observations is the discovery of comets and it has now notched up over 1500, more than all the other comet hunters put together.

Clear Skies and Best Wishes

Neil

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