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

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Gap

Kir

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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