Astrophotography - Beginners guide - Astroshack

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15 Νοε 2013 (πριν από 3 χρόνια και 11 μήνες)

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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