Society for Popular Astronomy

The cluster looks very pretty in the 25X70 binoculars. It's an old favourite. Thanks Ian for calling it the Owl and not the ET cluster. The colours are well shown in your image. Cassiopeia is rich in binocular star fields and clusters.

In 1953 at the age of twelve, I entered the school library and saw a little astronomy book on the shelf with the enchanting title of "The Star Spangled Sky". The book was authored by a vicar and for the general reader. The book had a number of black and white plates and one of them turned me on to a...

It looks like the discovery turns out to be that there's more water on the moon than was previously thought. This is according to a news item on the BBC TV this afternoon. Apparently, the discovery will make it easier to establish a base on the moon and also provide a source of hydrogen as rocket fu...

Oops, you're right Brian, Sorry about that!

Maximillian used his 355mm Newtonian and Baader RGB filters AS1290mm to make his visual discovery of the streak Nigel. Seeing was 6-7/10.

A dark streak has appeared near Arsia Mons and is telescopically visible. See today's www.spaceweather.com

The trio in their Soyuz-M16 capsule landed on the steppe in Kazakhstan yesterday. A couple of years ago, Tim Peake's Soyuz capsule was on display at Manchester's Museum of Science and Industry. The capsule was badly displayed. It stood vertically, so the public could only seen a little of the inner ...

Just to say Nigel, that you could go down a couple more notches in magnification on the 4-incher. From the sources I've read, the lowest magnification with a scope is 4D. That's to say four times the diameter of the aperture in inches. This would be 16X for a 4-incher.

To the delight of NASA controllers, it's asteroid probe to asteroid Bennu, launched in 2018, has landed on the stony body and attempted to take a surface sample of 60g.. If the first sampling is too small, there's enough fuel to make two more attempts.

Dammit Cliff, I missed today's prom. I was tempted to look through the PST this afternoon, but at the last minute decided not to. It was one of those days where the Sun popped in and out of passing cloud. I almost always find on days like today that by the time I get to the eyepiece, the Sun disappe...

Yes Nigel, a 4-inch/f.5 refractor makes a good richest field 'scope. Ideal for the Orion Nebula the Perseus double-cluster and M31 in Andromeda, etc.

You might like to consider Phillips Colour Star Atlas. The maps are very attractive and give the physical types of many stars. There's also plenty of interesting text for an atlas. I wouldn't like to part with mine.

How's your 4-inch/f.5 refractor for chromatism Nigel? I have the same spec, but a Celestron. The chromatism is pretty strong on higher powers. I bought a Baader semi-apo filter to deal with it, but I reckon that it's only about 30 per cent effective. It also reduces some of the incoming light, in co...

A thousand apologies Ian for mistaking your image for a Smerral one!

A recent theory of how the ice age began challenges the theory of Milankovitch cycles, by saying that gases released by volcanic activity, dissolving rocks in mountain sutures, cooled the atmosphere. Now, a new theory complements the first by explaining how the last ice age ended. It's been known fo...