Finding Stuff
How to Look for objects in the Solar System
Old Style
• In the old days – 1800’s, and even up to now for some amateur astronomers, the technique used to discover comets, asteroids and planets was basic.– 1 – Memorize a part of the sky you are interested in –
each star, galaxy, nebula and its position.– 2 – go out every night and look for things that “aren’t
supposed to be there”. – 3 – if you see one, make a sketch map, and go out
the next night and see where it’s moved to. If it has moved, you’ve discovered something!
Now
• Now you don’t have to memorize as much
• Go out, take an image of an area.
• 15-30 minutes later, take a second image of the same area
• Put them in a blink comparator!
What’s a Blink Comparator
• Take the two images (of the same part of the sky)
• Align them up carefully – Match the Stars
• Blink back and forth – watch for changes in the stars – (watch out for cosmic rays strikes that pretend to be stars if you are
using a CCD camera)
• The “star” that changes it’s position – is not a star.
• It could be: Asteroid – Comet – Spacecraft – a couple of cosmic ray strikes – (that’s part of why you need 3 or more images to “prove” your discovery
as well as calculate an orbit)
Lets try! – find the asteroid
Lets try! – find the asteroid
Quaoar
• Here, they’ve put together three images to show the movement of a KBO
Even Newer
• There is a cool technique being used now – modified from the earlier electronic blink comparator system.
• Take an image every 3-4 minutes – through a different colored filter – ROYGBV
• Electronically combine them – and if you see a small colored line – you’ve found a comet/asteroid!!!
• Look for the rainbow caterpillar – That’s the asteroid (or comet)
Cool extra
• It turns out – you can then analyze the color of the asteroid by comparing it’s brightness at different colors. This lets you find out what “family” of asteroids it’s in.
• And may eventually let us figure out which asteroid gave us which meteorites.
www.astro.washington.edu/ivezic/sdssmoc/a_sini_prop4c.jpg
Vesta
Eos
Themis
Koronis
Kir
kwo
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Gap
Kir
kwo
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Gap AA
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DisclaimerAloha
I put together these power points for use in my science classes.You may use them in your classes.
Some images are public domain, some are used under the fair-use provisions of the copyright law, some are mine. Copyright is retained by the owners!
Ted Brattstrom