Stefan Seip (Rocky Nook, Inc. 2008) 155 pages. $29.95 (less at Amazon) ISB: 978-1-933952-16-1
What astronomer hasnât wished to record the splendor of the night sky to review later? It is natural to want to be able to recall those glorious evenings that are so few and far between, like looking at a family album. Astrophotography is a way to do that but as anyone who has tried it can tell you, that can be daunting.
In Digital Astrophotography: A Guide to Capturing the Cosmos, Stefan Seip provides a solid introduction to several digital techniques for recording the visible universe. After a first âBefore You Startâ? chapter describing the basics of resolution, focal length and ratio, Seip breaks the remainder of the book into four main categories of digital astrophotography: the Digital Compact Camera (DCC), the Webcam (WC), the Digital SLR (DLSR), and the dedicated Astronomical Camera (AC).
The ubiquitous Digital Compact Camera is inexpensive and most everyone already has one so getting started takes little or no money. They are self contained so no computer is required to acquire the images. On the downside, they are often not very flexible in use, mounting to a telescope may be difficult, and some simply donât have the needed features such as long exposure. The book provides tips for connecting the camera to the telescope for either through the optical tube assembly for high power imaging or piggy back for low power. The author then covers after the fact image processing with popular software.
The Webcam, introduced first for live images over the Internet, has had an enormous impact on planetary imaging in the last decade. Like the DCC, many people already have one and they are inexpensive if not. Also like the DCC, some webcams are better suited to astrophotography than others. Unlike the DCC, they do require an attached computer and typically they are used for through the telescope imaging only. Seip provides tips for purchasing the webcam and accessories for attaching it to the telescope. He goes into detail on setting up the software, the critical focusing, tips for acquiring the images, and processing with the popular (and free) Registax application.
Next, Seip covers the Digital SLR which has the advantages of the DCC but far fewer of the disadvantages so as a fixed lens and limited functionality. Of course, DSLRs are a big step up price wise from the previous two camera types but that price is coming down. Since DSLRs have removable lens, you can switch focal length very easily and also shoot through the telescope much more easily. They also usually have much larger chips making for larger fields of view and more sophisticated software than their DCC cousins. They do tend to be prone to electronic noise and tend to run through batteries so you need to take measures to overcome both issues.
Finally, Seip discusses dedicated Astronomical Cameras which tend to be more sensitive, cooled to reduce electronic noise, and more dynamic range than any of the previous camera types discussed. Of course, they cannot be used for normal photography and must be controlled by a computer. The author covers the details of these cameras, what accessories you might want, as well as the software you might use to acquire and process your images.
Digital Astrophotography: A Guide to Capturing the Cosmos provides a solid introduction to the art for the beginning astrophotographer. If you follow his tips and techniques you should be soon producing good images of night sky objects. However, if you are not new to the subject you may find the book of limited value.
Review by Jim Dixon