Many of us have been impressed by the images made by Stefan Seip, an
astro-photographer based in Stuttgart Germany. His shots of Comet Machholz
against the Pleiades and Venus at inferior conjunction framed by wispy
clouds are stunning examples of what digital imaging technology can produce
when directed by a discerning eye.
(View his work at: http://www.photomeeting.de/astromeeting/_index.htm)
So, even though I'm a committed visual observer, when Seip's "Digital
Astrophotography: A Guide to Capturing the Universe" became available (It
was first published in German under the title "Astrofotografie digital") I
thought what better photographer to acquaint me with what's become such a
huge part of the astronomy hobby. And I was right. As an intro, it's superb.
His book is an attractive soft cover volume, profusely illustrated in color
and printed on a heavy weight glossy paper with lots of open margins for
notes. It enjoys two clear advantages over some other digital
astrophotography texts. First, it does not limit itself to one particular
type of digital tool/photography and two, being published this year, its
camera and software references should be up to date.
A short introductory chapter, "Before You Start" addresses some basics and
presents some terms and concepts which will figure in later discussions.
Then comes the heart of the book: four chapters, each treating a type of
camera available to today's digital astro-imager:
- Compact Digital Cameras
- Webcams
- Digital Single Lens Reflex Cameras (DSLR)
- Charged Coupled Device Cameras (CCD)
Within each chapter, Seip
- explains the characteristics of the specific camera type and
mentions its advantages and disadvantages
- mentions the types of photographs suited to it, e.g., only
webcams are recommended for planetary imaging while CCD cameras
are unsurpassed for deep sky objects.
- gives tips on purchasing, e.g., webcams with a CCD sensor are
better than those with a CMOS sensor for astrophotography
- recommends accessories, e.g., his chapter on CCD cameras
mentions software, autoguider connections, filter wheels, focal
reducers, portable power supplies, etc.
- takes the reader, step by step, through the process of capturing
an image and processing it. Understandably, to do this, Seip
necessarily uses specific equipment and software in his
explanations, e.g., his webcam chapter is geared to the Celestron
NexImage camera and Registax software. The CCD chapter utilizes
MSB's Astroart software. Adobe Photoshop is used throughout the book.
As Seip progresses from simpler to more complex cameras, the discussion of
digital imaging itself becomes more sophisticated and the reader's grasp of
the whole topic becomes deeper. Later chapters discuss topics that
definitely would be of concern to intermediate level imagers, e.g., thermal
noise, spectral sensitivity, format conversion, field flatteners, coma
correctors, etc.
I was impressed that the book was able to educate me about a seemingly
complicated subject in a painless way. Plus, I kept thinking should I ever
decide to take the plunge into digital imaging, I'll have what amounts to a
"cookbook" reference.
The book has an internet tie-in to Stefan Seip's web site. The actual images
used to illustrate software photo processing techniques can be downloaded,
so the reader can duplicate the steps shown in the book. Also three
documents, one on how to treat dust and pixel defects, another telling how
to remove a satellite trail from an image and the last listing selection
criteria for a CCD camera are available as PDF's.
There is an appendix containing some useful information, a glossary (which
comes in handy for a visual observer when a term such as "resolution", for
example, takes on a definition which differs from the one that applies to
telescope optics alone), a list of resources and reading suggestions and
last, but not least, entries giving the exposure info and equipment used for
each of the images used to illustrate the book.
John Cheng
Pittsburgh PA
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