Sunderland Astronomical Society

From David Hughes, Houghton-le-Spring, Tyne and Wear

Former Chairman Graham Darke sent us some images of the Ethiopia Telescope Mirror, which he's been grinding into shape for the last couple of months.

Graham says that fine grinding has now been completed and, subject to a successful test in the capable hands of local expert mirror maker, John Nichol later this month, will proceed to the next stage which is polishing followed by figuring.

Pictured above is assistant mirror maker Master Isaac Darke.

Another batch of four lenses with matching eyepieces was dispatched to Woldiya, Ethiopia last week, which should arrive in about three weeks.

From David Kidd, Woldiya, Ethiopia

Thought you might like to see the prototype school telescope made from the binocular lenses. I've put some pictures on my flikr stream for you to look at. It's made from a cardboard box and with a 50mm lens has a magnification of about 11. The telescope is easy to use, quite robust and it looks good which is important here. I've tried it out over a few nights now and its easy to find even quite faint objects like the Orion Nebula and the Andromeda Galaxy with it and it gives good views of the craters of the Moon and the moons of Jupiter. When I put some out to schools I'll get some pictures of children using them but I wanted to test them round the college first to make sure they were durable.

David Kidd, 14th March 2012, Woldiya, Ethiopia

From David Kidd, Woldiya, Ethiopia

The first package of lenses and eyepieces donated by members of Sunderland Astronomical Society has finally touched down at Woldiya in Ethiopia.

They arrived on Tuesday! There was nothing to pay at this end so the system works. I have made four telescopes so far and they all perform well. The best is the 50mm lens with a 20mm eyepiece which gives a magnification of about 12 on a field of view of about 5 degrees - enough to show large craters on the Moon and the moons of Jupiter.

David Kidd, 2nd March 2012, Woldiya, Ethiopia

From David Hughes, Sunderland, Tyne and Wear

The first batch of lenses and eyepieces are ready to ship to Ethiopia.

A total of six pairs of binoculars were stripped down to their components and checked to make sure that they were suitable. The best examples were then put to one side and given a quick clean, essentially to make sure that the surfaces were free from cracks and scratches. Only one pair failed this test.

A couple of prisms were also included in the package as they're useful teaching aids.

The remaining aluminium bodies will be recycled for scrap and the money raised used for postage and packing.

From David Kidd, Woldiya, Ethiopia

Measuring the distance of the Sun is a good practical activity.

The procedure is simple: the ratio of the size of the sun's image to the telescopes focal length is the same as the ratio of the Sun's diameter to its distance from Earth. In this case the diameter of the image was 5mm and the focal length 55cm.

Taking the sun's diameter as 1.39 million kilometers gives the distance as 152.9 million km, around 6% greater than the actual value.

The same technique can also be used to find the Sun's diameter given its distance.

David Kidd, 10th February 2012, Woldiya, Ethiopia

From David Kidd, Woldiya, Ethiopia

I've been training teachers how to observe the Sun by projection.

I do it this way with the telescope on the shoulder because we don't have proper mounts and I like to have everyone everyone looking away from the Sun not staring at it.It's easy to aim the telescope using the shadow and it's safe even for quite young children to use.

I hope to have telescopes in all local schools for the eclipse November 2013 and I want to teach them to use this method as it works well with small groups and will stop children damaging their eyes by staring at the Sun. The eclipse will be in the evening just before sunset so the angles are just right.

Human "tripods" work well at night too with the telescope on the shoulder of one child and another looking through it. They like to work together and I like to encourage them to talk about what they can see.

The telescope is my old Ross watch keeper telescope. It was made by Ross when they were owned by Charles Parsons so I like to think of it as a link with Grubb Parsons even though it was made in London.

David Kidd, 27th January 2012, Woldiya, Ethiopia