Credit- NASA

Astrophotography Copyright © Dave McDonald 2006

Agenda  What is astrophotography?  Basic concepts  Imagers  Techniques  Guiding  Advanced concepts

What is astrophotography?  Taking images of the sky (celestial objects or phenomena)  Can be done any time of the day or night

A typical session…  Choose your subject  Choose your technique  Take the image(s)  Process the image(s)  Display your results  Techniques vary from very basic to highly technical

Why do it?  Recording events (conjunctions, phases, solar activity, Deep Impact)  Advancing personal knowledge  Share your experiences  Real science ‘ A picture paints a thousand words’

Before you take the plunge…  Decide what you want to do and set clear goals  Short, medium and long-term  Where will you be living in 5 years?  What are you prepared to spend?  Research, research, research

How…  Types of imager  Basic techniques

Film  Take a snapshot of the projected sun  Use an SLR (similar techniques to Digital Cameras – next)  Film is chosen based on the subject  Can get very technical (hypered-film etc)  Is diminishing in popularity with the advent of digital techniques

Digital cameras - Webcams  Cheap, easy to use, lots of free software for capturing and processing images  Stunning planetary images  Very popular

Digital cameras – integral lens  Dual purpose – astrophotography and holiday snaps  Popular  Coming down in price

Digital cameras – SLR’s  Dual purpose  Very sensitive  Expensive  Can purchase variety of lenses for different applications

Astronomical CCD imagers  Purpose designed  Very sensitive  $300 to $40,000  Can be used for science  Superb deep sky images

Basic Techniques  Point and click  Eyepiece projection  Prime focus  To guide or not to guide…

Point and click  Hold your camera and click!  Works with webcams and digital/film cameras  Doesn’t work with CCD’s (no lens)  Can piggy-back your camera on your OTA or use a guiding system to take longer exposures (more on guiding later)

Eyepiece projection  Hold your camera to the eyepiece and take an image  Can purchase t-adapters and rings to get the camera lens as close to the eyepiece as possible (to avoid vignetting)

Prime focus  Your OTA becomes the lens  Webcams, DSLR’s, CCD’s

Guiding  The sky moves…  If you take an image, trailing increases with exposure length (can be an advantage!)  Can use a camera guiding system  Can use your mount’s guiding system (piggy-back, projection or prime-focus)

Advanced Concepts  CCD and OTA matching  Collimation  Orthogonality  Polar aligning  Guiding  PEC, mount training  Integrated CCD guiding  Dual CCD guiding  Cooling  Focusing  Filters  Image reduction (darks, bias, flat-field)  Software/hardware  Advanced processing  Photometry/astrometry  Nova searches

Q&A