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/)

Processing steps: Choose align-points Align, limit, stack Sharpen with wavelets Gamma/RGB adjustment

More examples. (mine )

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.