These are the slides accompanying the 28th of March 2013 Cambridge Darkroom meetup: http://www.meetup.com/CambridgeDarkroom/events/106902682/ James Billings, a photographer with a penchant for all things starry, guided us through three different types of Astro Photography: - Wide field with just a camera - Planetary images with a webcam - Deep-sky images with a DSLR With plenty of examples included.
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Astrophotography(A non-scary introduction, hopefully) James
Billings, March 2013
Why bother?Why not just look through a telescope and
appreciatethe beauty of the heavens? Why do you need tophotograph
it?! Its all Hubbles fault
What Hubble sees
What you see
I dont have a telescope! OK, I bought a telescope. Using your
DSLR Using a webcam
I dont have a telescope!No problem, as long as you have atripod
and shutter release, exposuretimes are normally quite long... Some
examples
Make the sky part of the picture16mm f/3.5, 30s @ISO-400
Use brighter night-sky objects18mm f/4.5, 8s @ISO-400
Zoom in!300mm f/11, 1/4s @ISO-200
Try capturing satellites30mm f/4, 25s @ISO-400
Rare events35mm f/6.3, 25s @ISO-400
Try to capture the Milky Way16mm f/3.5, 30s @ISO-1600
OK, I bought a telescope Using a DSLR on a telescopeChallenges:
Light pollution The moon Long exposures Accuracy of mount Wind
Pesky Satellites! 80s @ISO6400
Easy (ish) the moon1000mm f/1, 1/1000s @ISO-200
Harder - fainter objectsGalaxies Nebula Star Clusters
ProblemsPlanet earth rotates. This is NOT helpful. We use an
Equatorial Mount to counteract the rotation of the earth. Even
then, were limited: Alignment Worm error Stability
A single photograph1000mm f/1, 69s @ISO-1600 But we want
this:
Traditional processingMore detail, but horrible noise. We need
to increase signal > noise.Multiple exposures help as noise is
random, subject is consistent.
Time for a demo
End resultAdjust luminance and RGB levels.Beautify in
photoshop/lightroom/gimp etc.
Some more examples
What about the planets? Planets are small, details are tiny, so
we need to increase our S/N even more (100s of shots) Our shiny
DSLR is no use- the planet is too small in the image We need a
smaller sensor = we use a webcam and record a movie!
Recorded videoLow resolution sample, up-scaled. Consumer cam
(10-80)Avi courtesy Jim Prior
(http://www.flickr.com/photos/70350201@N03/ )
Time for a demo
With an astro-specific cameraBetter quality CMOS sensor for
less noise, ~240(.avi courtesy Keith Townsend:
http://www.flickr.com/photos/keith-t/)
The End jowlymonster JamesBillings jmbillingsRegistax (for
planets): http://www.astronomie.be/registax/Deep Sky Stacker
(deepsky objects):
http://deepskystacker.free.fr/english/index.htmlStartrails (stack
to make trails): http://startrails.de/Heavens-above (satellite
timings): http://www.heavens-above.com/Thanks to Keith and Jim for
the planet .avi files.