Canon 200mm 2.8 lens for widefield imaging

I have been trying out widefield imaging with the Geoptik adaptor and my Atik 460 mono camera using a relatively cheap Canon 75-300mm zoom lens. I have found that you need to step down the focal length to a more reasonable f6 or f7 to get some nice round star shapes. But really you want to me imaging at about f4 or f5. This means purchasing a more expensive camera lens like the Canon 200mm f2.8 or Canon 100mm f2.8.

I began looking at the beige Canon zoom lenses. I was interested in the 70-200mm 2.8 lens. Expensive new, but they can go for about £500-£600 used. I had been looking at the second hand market for a while. But what put me off is that I imaged in Ha and OIII at 100mm on my zoom lens and as you have to take apart the imaging train in order to change filters I found it impossible to not move the zoom when doing so.

This meant that the Ha images may have had a different Field of View compared to the OIII images. That’s usually not a problem you have with telescopes which are fixed. So a fixed prime lens did make more sense, plus it may be sharper.

As most of the widefield images I have taken are between 100mm and 200mm. I thought that a 200mm prime lens and a 100mm prime lens would do the trick. So I then started looking at the Canon 200mm f2.8 lens. I was trying to discount it as I had purchased the smaller version of the Telefokus to help me focus and the maximum diameter on those rings are around 78mm. I was worried that the rings would not fit around the barrel of the 200mm lens, but it turns out they do fit.

How I know is that I ended up buying a used Mk 1 version of the Canon 200mm prime f2.8 lens. I can’t see much difference between the Mk1 and Mk2, although the Mk1 does have an in-built lens hood.

The Canon 200mm f2.8 lens is a bit heavier – maybe more glass elements and a larger diameter is the reason.

I am yet to give the lens a go yet as it has been cloudy every night for the last week, but I’ll post some feedback and some images once I have used it.

Viewing and Imaging the Solar System Book Review

Viewing and Imaging the Solar System from Jane Clark is an easy to read beginners guide to viewing and imaging the Solar system. It explains in some detail the principles of the telescopes and the in’s and out of star maps, which are best to use in the garden on a cold dark night and which are best used indoors. One item I found interesting was the explanation of what to wear and why, which you don’t often see in Astronomy books.

‘Viewing and Imaging the Solar System’ goes on to explain telescope mounts, the different types and the advantages of Altitude – Azimuth such as a Dobsonian and Equatorial Mounts. There’s an explanation of how to carry out alignment of the Equatorial mount using polar scope.

The next chapter titled ‘Telescopes Binoculars and Light’ explains the principles of light. It covers the different types of lenses, convex and concave and it covers Eyepieces, Barlow Lenses, Binoculars and filters. The different types of telescope are described and the advantages of each type. The next chapter introduces the reader to photographing the solar system, explaining the hardware, the importance of focusing using a Hartmann and Bahtinov masks.

Photographing the Moon and planet is explained by outlining the different types of cameras such as a DSLR and Web cams. The pros and cons of each type are discussed as well. Then comes the processing of the images with the help of computer screen shots of software K3CCD and RegiStax. There is a great section on using Dark frames to remove the thermal noise on the CCD chip during processing.

The next few chapters’ deal with what you can realistically expect to see with the naked eye and a camera. The superior planets are covered in detail with the aid of the author images and explanations. Jupiter sections outlines how best to view the four moons through a telescope and observe the moons rotation of the planet with a number of detailed drawings. I will say that some of the accompanying photos were a little dark which made the surface detail hard to see clearly.

Chapter 8 completes the solar system with observing the Sun using different types of solar scope at the different wavelengths of the light. This section included white light, hydrogen alpha and details on solar spectra. The book finishes its tour of the solar system with Asteroids and Comets and observing the solar system from your armchair.

This book is quite strange as it covers a lot of different areas of astronomy. I do feel that this book is very much for the beginner. A beginner will get a lot out of reading this book, but I would prefer books that deal with specific in-depth topics.

The book an interesting read for the beginner but I feel its let down by the authors photographs.

Reviewed by Mick Jenkins

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Lessons from the Masters Book Review

Lessons from the Masters is an astrophotography book from Springer. Each chapter is written by different well known astrophotographers. It is good to have individual chapters, as it makes it nice to pick up the book and just read one chapter at a time.

There really is something for everyone in this book, whether you are into solar imaging, lunar photography, widefield SLR imaging, planetary imaging or deep sky imaging.

It took me a while to read the book cover to cover, but I did begin reading the chapters I found most interesting first. I then seemed to randomly pick chapters one at a time and read them.

I began with Damian Peach’s chapter about planetary imaging. Now I think his images are amazing, and I am sure there is something he does, that he is not telling us. Unfortunately I thought he could have told us some more about what he does exactly when he images. I felt the chapter was a little bit too much of an overview.

‘Lessons from the Masters’ begins with a great chapter on the theory of astronomical imaging which includes lots of equations and graphs discussing signal to noise ratio, full width at half maximum, quantum efficiency, sampling and calibration etc.

Then there are a number of chapters covering different areas of astro imaging from authors that include Tony Hallas, Don Goldman, Ken Crawford, Damian Peach and Robert Gendler.

Lessons from the masters chapters:

• High Dynamic Range Processing
• Intensifying Colour
• Revealing small scale details
• Bringing out faint large scale structure
• Narrowband imaging
• Widefield imaging
• Noise reduction techniques
• Deep Sky Imaging workflow
• High resolution lunar and planetary imaging
• Secrets to successful earth and sky photography
• Imaging and processing images of the solar corona
• Catching sunlight
• Aesthetics and composition in deep sky imaging
• Hybrid images: A strategy for optimising impact in astronomical images

It’s nice to see colour images throughout the book. Some of the chapters you can just read through and others are chapters that you will need to sit at your computer and work through in programs like Photoshop.

There are some great tips throughout ‘Lessons from the Masters’, I think everybody will get something out of it. It is nice that ‘Lessons from the Masters’ is a new book (published in 2013), and not an imaging book that is 10 years old. I think your astro imaging will improve after reading this book.

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Observer’s Guide to Star Clusters Book Review

Observer’s Guide to Star Clusters by Mike Inglis

This book is part of the Patrick Moore Practical Astronomy Series, and it is a book which is organised by constellation. This is actually a good way to organise a book as it allows you to locate the positions of important star clusters in the 88 constellations from anywhere on Earth.

The constellation maps in the book are in black and white, this may not sound so great, but it does allow you to read the maps by the light of a red LED torch or reading light. The clusters themselves and their names or numbers are printed in bold black, against a ‘greyed-out’ background of stars and constellation figures.

The Observer’s Guide to Star Clusters book begins with an introduction to star clusters, which includes how they star clusters are classified, how to record your observations, a full list of the constellations and which constellations will be on show at certain times of the year.

A typical page of the Observer’s Guide to Star Clusters gives you fast facts about the constellation such as its abbreviation, genitive name, it’s translation e.g. Andromedae means Princess of Ethiopia, its visible latitudes, and it’s culmination date.

Then within that constellation the book lists the star clusters in turn providing the reader with the catalogue name that the star cluster is listed in, RA and Dec co-ordinates, the visual magnitude, the approximate number of stars in the cluster, the concentration class and finally the level of difficulty to finding it. There is then a small description about the cluster by the author.

The index at the rear of the book lists each star cluster by its catalogue name, so for example by its NGC or Messier number.

When I first flicked through the book, I felt a bit let down by the endless lists and black and white constellation map drawings, but I can see how this book will help out the astronomer who wants to locate both easy and hard to find star clusters – a lot of which are NGC numbers. It is very handy to have the book ordered by constellation – that I love, the only thing that could be improved here are the star maps. Overall, the Observer’s Guide to Star Clusters is a useful astronomy title.

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Lunar Rover Users Manual Book Review

The Haynes Lunar Rover Owners’ Workshop Manual contains a foreword by Apollo 15 Commander David R Scott.

This Haynes Lunar Rover users manual covers the Lunar Rover from 1971-1972 and tells the complete story of the lunar vehicle that cost over $38 million to manufacture. It begins with early drawings, all the way to the Rover in use on the Apollo missions.

The Lunar Rover, the most expensive car in history.

This book really does bring together a great number of images never really seen before in one place. This is such an interesting book, which contains some early science fiction drawings and actual early NASA drawings of what the lunar rover could have looked like. There are even details on a lunar motorbike that was also developed at the same time as the lunar rover.

The Lunar Rover made the most of the EVAs, by taking the astronauts further than they had ever been before across the lunar landscape. The book includes the maps of where the LRVs went and what occurred.

The nice thing about the lunar rover users manual book is that you will also find a good range of lunar images with the rover in the background. The 3 rovers are still on the lunar surface 40 years later.

The book contains some really good cross sectional diagrams of certain areas of the lunar rover, as well as early test shots of the rover in action.

If you are interested in the Moon and the lunar landings, then get this Haynes book on the lunar rovers, you will not regret it.

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