Skip to main content

DSLR Observing Manual

The AAVSO DSLR Observing Manual

Download Version 1.4 Here

Sponsored by the AAVSO & NSF award DRL-0840188



This manual is a basic introduction and guide to using a DSLR camera to make variable star observations. The target audience is first-time beginner to intermediate level DSLR observers, although many advanced observers may find the content contained herein useful.

The AAVSO DSLR Observing Manual was inspired by the great interest in DSLR photometry witnessed during the AAVSO’s Citizen Sky program. Consumer-grade imaging devices are rapidly evolving, so we have elected to write this manual to be as general as possible and move the software and camera-specific topics to the AAVSO DSLR forums. If you find an area where this document could use improvement, please let us know.  Please send any feedback or suggestions to

Most of the content for these chapters was written during the third Citizen Sky workshop during March 22-24, 2013 at the AAVSO. The persons responsible for creation of most of the content in the chapters are:

Chapter 1 (Introduction): Colin Littlefield, Paul Norris, Richard (Doc) Kinne, Matthew Templeton
Chapter 2 (Equipment overview): Roger Pieri, Rebecca Jackson, Michael Brewster, Matthew Templeton
Chapter 3 (Software overview): Mark Blackford, Heinz-Bernd Eggenstein, Martin Connors, Ian Doktor
Chapters 4 & 5 (Image acquisition and processing): Robert Buchheim, Donald Collins, Tim Hager, Bob Manske,
                                                                           Matthew Templeton
Chapter 6 (Transformation): Brian Kloppenborg, Arne Henden
Chapter 7 (Observing program): Des Loughney, Mike Simonsen, Todd Brown
Various figures: Paul Valleli

The current version retains much of this material but has been revised and extended. Many thanks go to Arne Henden, Rebecca Turner, Brian Kloppenborg, Matthew Templeton, and Elizabeth Waagen for their editorial and other contributions to the first edition of this Manual.

Clear skies, and Good Observing!
Mark Blackford
AAVSO Member, Observer, and Volunteer

American Association of Variable Star Observers
Cambridge, Massachusetts
March 2016


1.    Introduction

1.1.    Prologue
1.2.    Target audience
1.3.    The what, why, and how of DSLR photometry
1.4.    Visual vs. DSLR vs. CCD observing
1.5.    Are you ready? (Prerequisites)
1.6.    Expectations

2.    Equipment Overview

2.1.    What is a DSLR?
2.2.    Lenses and telescopes
2.3.    Tripods and mounts
2.4.    Camera settings

3.    Software Overview

3.1.    Minimum requirements for DSLR photometry software
3.2.    Useful software features
3.3.    Software capability comparison chart
3.4.    Other useful software

4.    Image Acquisition

4.1.    Acquisition overview
4.2.    Preparatory work
4.3.    Noise sources and systematic biases
4.4.    Calibration frames (bias, darks, and flats)
4.5.    ISO and exposure times
4.6.    Finding and framing the field
4.7.    Acquiring science data and tricks of the trade

5.    Image Assessment, Image Processing, and Aperture Photometry

5.1.    Overview
5.2.    Processing preliminaries and image assessment
5.3.    Application of calibration frames, stacking, and binning
5.4.    RGB color separation (extraction)
5.5.    Post-calibration assessment

6.    Photometry – from measurement to magnitude

6.1.    Aperture photometry
6.2.    Instrumental, differential and standardized magnitudes
6.3.    Comparison and check stars
6.4.    Spectral response of DSLR color channels
6.5.    Traditional extinction correction and transformation
6.6.    Alternative extinction correction and transformation 
6.7.    Submitting your results

7.    Developing a DSLR Observing Program

7.1.    Recommended Beginner Target Lists
7.2.    Deciding what to observe
7.3.    Time to get started

Appendix A:  DSLR Camera Testing
Appendix B:  Testing Flats for Uniform Illumination
Appendix C:  Illustration of Primary, Secondary and Differential Atmospheric Extinction
Appendix D:  Star Images Inside and Outside of Focus
Appendix E:  Linearity Testing

Supplementary Material

In addition to the Manual itself, Mark Blackford has created some supplementary material which we hope you find useful:

Photometry Software Calibration and Photometry Tutorials (V 1.0) (4.3MB)

Data Reduction Spreadsheet (V 2.6) and Instructions



In an effort to make the DSLR Observing Manual more useful to our members and observers world-wide, we have undertaken a project to translate the manual into different languages:

Greek (Version 1.3) - translated by Stelios Kleidis

Spanish (Version 1.1) - translated by Sebastian Otero



AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484