Preface

There are at least two avenues to CCD photometry. First is for someone who knows precisely what they want and digs into learning how to achieve their goal. If they have experience with single channel photometry the learning curve is much easier. Another avenue to CCD photometry is with the astronomer who starts with visual observing, moves to astro photography and then CCD imaging. After taking many pretty pictures this person decides there must be something more that can be done with the equipment. Since the basis of CCD photometry requires images being taken, this person has a jump start on learning CCD photometry. There is still a great deal to learn in order to produce usable photometric data from the images, however.

Many people are under the impression that a very expensive CCD camera is needed. Certainly some of the upper-end CCD cameras designed specifically for CCD photometry are excellent, however, their cost can be well out of sight of most astronomers. Many people think you need a high altitude dark sky location to do useful photometry. This is not true. Unlike imaging faint deep sky objects, most CCD photometry can be done within an urban light polluted area. While it is true the darker the location the fainter the stars you will be able to image, there are many lifetimes worth of objects much brighter just begging to be observed.

Having done single channel photometry for many years we decided to try CCD photometry without having to mortgage our houses in order to buy a high-end CCD camera. When Meade came out with the monochrome Deep Sky Imager (DSI) Pro for under $400 we decided that would be an ideal CCD camera to work with. The price is well within the budget of most astronomers and the specifications for the camera looked more than sufficient to experiment with CCD photometry. In order to do BVRI color photometry we added a filter wheel and standard BVRI photometric filters.

When purchasing the DSI Pro a copy of the AutoStar Suite software is included at no additional cost. While there are other CCD photometry software packages on the market, we decided to see just how useful the AutoStar software would be. Because of less than perfect documentation that comes with the AutoStar software, first impressions were that we should probably look to other software. But since the AutoStar software required no further investment we decided to go ahead and investigate and experiment with the included software. It turns out that the AutoStar Suite software is excellent and will do most anything and much more than other CCD photometry software.

Because the Phoenix, Arizona area tends to be very warm to extremely hot, even at mid-night, during the warmer months an uncooled camera produced high dark counts. A simple and inexpensive modification to add a thermoelectric cooler was tried that proved excellent not only reducing the dark counts, but also increasing the camera's sensitivity.

After mentioning our success with the modifications and AutoStar software we received many requests for more information. A web site was created with some of the basic details of what we had learned. This included a step-by-step procedure for using AutoStar to produce photometric data. We thought about this we decided we needed to expand the information and create a book. This book is a result of that expansion.

It is hoped this book will help and inspire others to do CCD photometry. While the primary aim is with a DSI Pro camera and AutoStar software, much of the information applies to any CCD camera and associated software. Once set up the observations and resulting data can be very rewarding. Indeed, you may even see your name and data in some articles in professional journals.

 

Present Page Version as of 27 April 2007

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