British lunar lander, 1954

BIS lunar lander

The picture above shows a comparison between an Apollo-style lunar lander, on the right, and the more traditional idea of a “spaceship” on the left. More technically, the comparison is between the Lunar Orbit Rendezvous approach used by Apollo and the competing methods of Direct Ascent (going all the way from the Earth to the Moon with a single vehicle) and Earth Orbit Rendezvous (ditto, but with the vehicle first being constructed or refuelled in Earth orbit). You might guess the picture dates from circa 1962, when NASA surprised the world by selecting LOR over the (previously much more likely) other two options. Actually it comes from a book printed in 1954.

That’s the date on my copy of the book, which is the second edition of one originally published in 1952 (I don’t know if the same picture was in the first edition). It’s called Development of the Guided Missile, by Kenneth W. Gatland – a member of the British Interplanetary Society, which was the source of the lunar landing concept depicted here. In the text the lander is designated “Type B”, while the counterpart of the Apollo CSM is Type A: “The Types A and B operate together as a composite vehicle; the former acts as the propulsion component for the Type B and remains in the terminal orbit of the destination planet whilst the smaller rocket descends to the surface.”

The most famous member of the British Interplanetary Society was Arthur C. Clarke, and he touched on the same subject in his “science-fictional autobiography” Astounding Days:

We discussed many types of rendezvous and space-refuelling techniques, to break down the journey into manageable stages. One of those involved the use of a specialized “ferry” craft to make the actual lunar landing, while the main vehicle remained in orbit. This, of course, is the approach in the Apollo project – and I am a little tired of hearing it described as a new discovery. For that matter, I doubt if we thought of it first; it is more likely that the German or Russian theoreticians had worked it out years before.

Actually the concept in Gatland’s book is a mixture of Earth Orbit Rendezvous and Lunar Orbit Rendezvous, since the Type A spacecraft (which is powered by a nuclear-thermal rocket) is first constructed in Earth orbit, using smaller unmanned rockets (Type C) and a winged shuttle (Type D) to ferry the astronauts to and from Earth orbit. The whole ambitious concept is illustrated in the picture below – it strikes me as extraordinarily sophisticated for a book published in 1954!

British Interplanetary Spacecraft

The Telescopic Tourist’s Guide to the Moon

Telescopic Tourist Guide to the Moon
Hot on the heels of Destination Mars, here’s another book of mine that’s new out this month – The Telescopic Tourist’s Guide to the Moon, published by Springer. I actually wrote it several months after the Mars book, but Springer have a very fast system compared with more traditional publishers so it caught up!

This is the second book I’ve done with Springer, following Pseudoscience and Science Fiction last year. That one was in a series called Science and Fiction, and in fact there’s quite a lot of SF in this new one too (as you might guess from my earlier blog post about lunar research). However, this book actually belongs to a different series – the Patrick Moore Practical Astronomy Series. Here’s the blurb:

Have you ever been inspired by stunning images from the Hubble telescope, or the magic of sci-fi special effects, only to look through a small backyard telescope at the disappointing white dot of a planet or faint blur of a galaxy? Yet the Moon is different. Seen through even a relatively cheap telescope, it springs into life like a real place, with mountains and valleys and rugged craters. With a bit of imagination, you can even picture yourself as a sightseeing visitor there – which in a sense you are.

Whether you’re interested in visiting Apollo landing sites or the locations of classic sci-fi movies, this is the tourist guide for you! It tells you the best times to view the Moon, the most exciting sights to look out for, and the best equipment to use, allowing you to snap stunning photographs as well as view the sights with your own eyes.

It probably goes without saying, but The Telescopic Tourist’s Guide to the Moon is available from all good bookshops, as well as online retailers such as Amazon.com and Amazon UK.

Lunar Research

Moon books and films
About a year ago I did a couple of posts on my old blog (here and here) showing some of the books and DVDs I had the pleasure of “researching” for my Pseudoscience and Science Fiction book. Now I’m working on the follow-up. It’s not really a sequel, except that it’s for the same publisher and involves a similar mix of science fiction and real science (though no pseudoscience this time).

The general subject will be easy enough to guess from the “research” materials pictured above. My book is going to have a Unique Selling Point … but I don’t want to divulge that until its finished!

Photographing the Moon

Closeup of Vallis Alpes region

About six months ago I got interested in photographing the Moon, and I’ve been posting some of the results on Facebook. Mostly I’ve used a simple telescope webcam, which can produce high-resolution images of relatively localized areas such as the one above (showing the lunar north pole at the top and the Alpine Valley at the bottom, with the craters Aristoteles and Eudoxus to the east of it). Then a few days ago I posted a wider field of view using a DSLR on the same telescope, and Rhodri Evans asked how that compared with using the DSLR with its own lens.

That prompted me to try a few tests last night (with the Moon at first quarter). For anyone who may have just stumbled across this blog, I should stress that I know almost nothing about astrophotography, so please don’t take this as “best practice” advice. On the other hand, it does give an idea what a beginner can achieve with bottom-of-the-market equipment (I’ll give details of the hardware and software at the end of the post).

To start with, here is a picture of the Moon taken through the 75-300 mm lens that came with the camera. This uses the highest zoom (300 mm) at f/16, 1/250 second exposure, ISO-800 (settings visually optimized using Live View). It’s the sort of picture anyone with a DSLR could take.

Moon with DSLR

Now here’s a single frame taken with the same camera attached to the telescope (i.e. effectively using the telescope as a long telephoto lens). My telescope has a focal length of 600 mm, but I used a 2x Barlow lens as well, which doubled the focal length to 1200 mm (i.e. four times the camera’s own lens). The telescope aperture is 120 mm, which I guess makes it f/10, and again I used a 1/250 exposure and ISO-800.

Moon with DSLR and telescope

I also took a short movie (20 seconds, 500 frames) using the same settings, and stacked the result into a single image using Autostakkert. The result is a definite improvement (I tried the same trick with the camera-only shot, but in that case it made things worse).

Stacked image with DSLR and telescope

Here’s a side-by-side comparison of those three photos. The telescope is an improvement on the camera alone, but stacking is what really works the magic.

Comparison of Moon photos

As I said at the start, I normally use a small astronomical webcam to capture images, because it’s so easy to use. Optically this is identical to attaching the DSLR to the telescope (aperture 120 mm, focal length 1200mm with the 2x Barlow lens), but the field of view is much smaller because the sensor array is tiny (4.8 mm rather than 22.3 mm). For the same reason the image drifts across the screen more quickly (I don’t have a tracking mount), so I only have time to grab a 10-second video, or 300 frames at 30 fps. Nevertheless the results – such as the example at the top of this post – are impressive after stacking in Autostakkert.

Here is a side-by-side comparison of that picture with the same area seen in the single-frame DSLR+telescope and DSLR-alone images:

Comparison of Moon detail

For reference, my telescope is a Skywatcher Startravel-120 refractor on an equatorial mount, which cost me £389. There are plenty of other good telescopes available around this price. The webcam is a ZWO ASI120MC, which at around £170 is pretty much the cheapest astronomical camera on the market. Similarly my DSLR is from the bottom of the market – a Canon EOS 100D, which I got complete with two zoom lenses for just £379.

The ZWO camera came with two pieces of software – SharpCap for capturing videos and Autostakkert for stacking – but they’re both freely available online (here and here respectively). In the examples shown here, I used GIMP (also free) to crop, rotate and contrast-enhance the images.

Space-Age Nostalgia


Here are two items I bought in W. H. Smith’s recently. The first is a special (and very expensive) issue of the BBC Sky at Night magazine about the Apollo missions, and the second (a much better deal at the same price) is a repackaging of a 2008 Discovery Channel series about NASA spaceflights from Mercury to the Shuttle, together with another magazine. Presumably both items were put out for the Christmas gift market – mainly as a nostalgic treat for people of my generation, I guess, although it would be nice to think some youngsters are interested in the subject too.

I learned quite a lot from both items, particularly about the earlier and later missions. Although I was always interested in space, it was only in a vague, general way up until the Apollo 8 mission. That happened shortly after my 11th birthday, and it was the first one I really got drawn into – in the sense that I knew the astronauts’ names and avidly followed every little phase of the mission. This really intense awareness continued through Apollos 9, 10, 11, 12 and 13, but then started to get murky again after that point.

Not for the obvious reason, though. You might think, “well, of course, everyone lost interest in the later Apollo missions” – but that wasn’t it at all. I’ve got files of newspaper clippings I carefully cut out about Apollos 14 to 17, as well as Skylab and the Apollo-Soyuz test project. I’ve got some photos and fact sheets about Skylab that I sent off to NASA for (as well as another batch about Apollo from a few years earlier). But I never absorbed the huge amounts of information about those later missions that I did for Apollo 8-13 – for the simple reason that the information just wasn’t there to be absorbed.

In the early 70s Britain only had three TV channels, and they were all in the “general entertainment” category. There were no purely factual channels, no 24-hour news channels … and of course no internet. The TV gave blanket coverage to things like Apollo 8 and Apollo 11, but later missions had to compete for airtime with soap operas, sports, comedy shows and the like. Key space events were still covered – live – but they had a frustrating tendency to happen when you were at school, or otherwise indisposed. People didn’t have video recorders in those days.

So it’s an over-simplification to say that “everyone lost interest in the later Apollo missions”. It was the mainstream media that lost interest – and in the 1970s, that was the only kind of media there was. We’re so much luckier today!