Credit- NASA

Astrophotography

Astrophotography

Copyright © Dave McDonald 2006

AgendaAgenda

What is astrophotography?

Basic conceptsImagersTechniquesGuiding

Advanced concepts

What is astrophotography?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…A typical session…

Choose your subjectChoose your techniqueTake the image(s)Process the image(s)Display your results

Techniques vary from very basic to highly technical

Why do it?Why do it?

Recording events (conjunctions, phases, solar activity, Deep Impact)

Advancing personal knowledgeShare your experiencesReal science

‘A picture paints a thousand words’

Before you take the plunge…

Before you take the plunge…

Decide what you want to do and set clear goalsShort, medium and long-term

Where will you be living in 5 years?What are you prepared to spend?Research, research, research

How…How…

Types of imager

Basic techniques

FilmFilm

Take a snapshot of the projected sunUse an SLR (similar techniques to Digital

Cameras – next)Film is chosen based on the subjectCan get very technical (hypered-film etc)Is diminishing in popularity with the advent of

digital techniques

Digital cameras - Webcams

Digital cameras - Webcams

Cheap, easy to use, lots of free software for capturing and processing images

Stunning planetary imagesVery popular

Digital cameras – integral lens

Digital cameras – integral lens

Dual purpose – astrophotography and holiday snaps

PopularComing down in price

Digital cameras – SLR’sDigital cameras – SLR’s

Dual purposeVery sensitiveExpensiveCan purchase variety of lenses for

different applications

Astronomical CCD imagersAstronomical CCD imagers

Purpose designed Very sensitive$300 to $40,000Can be used for scienceSuperb deep sky images

Basic Techniques Basic Techniques

Point and clickEyepiece projectionPrime focusTo guide or not to guide…

Point and clickPoint and click

Hold your camera and click!Works with webcams and digital/film camerasDoesn’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 projectionEyepiece 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 focusPrime focus

Your OTA becomes the lensWebcams, DSLR’s, CCD’s

GuidingGuiding

The sky moves…If you take an image, trailing increases with

exposure length (can be an advantage!)Can use a camera guiding systemCan use your mount’s guiding system

(piggy-back, projection or prime-focus)

Advanced ConceptsAdvanced Concepts

CCD and OTA matchingCollimationOrthogonalityPolar aligningGuiding

PEC, mount trainingIntegrated CCD guidingDual CCD guiding

Cooling

FocusingFiltersImage reduction (darks,

bias, flat-field)Software/hardwareAdvanced processingPhotometry/astrometryNova searches

Q&AQ&A