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Vesta "disk" resolved in 12" Newton

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#1 Bart Declercq

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Posted 20 February 2010 - 04:19 PM

Vesta at opposition is probably the smalles celestial body that is theoretically resolvable in a "small" telescope.

Since its major axis reaches about 0.6" at opposition, a 12" should have the resolving power necessary even in Red light.

To test this, I took pictures of both Vesta and a star of comparable brightness (SAO99128) that was very close to the asteroid.

I first processed the Red image, and it was very suggestive of resolution, the Green and Blue images are even more strong evidence, notice how the star's diffraction disk shrinks with decreasing wavelength, while Vesta stays the same size. Also notice how there appears to be elongation in Vesta's image, consistent across wavelengths but most obvious in blue light.

So I feel pretty safe to say that I not only resolved Vesta's disk, but am actually detecting the fact that Vesta is not a sphere, but an ellipsoid.

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#2 ZielkeNightsky

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Posted 20 February 2010 - 05:05 PM

Very nice work. This is really fascinating.

#3 Freddy WILLEMS

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Posted 20 February 2010 - 05:23 PM

Nice Bart.
How many frams did you capture and stacked ?

#4 Bart Declercq

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Posted 20 February 2010 - 05:33 PM

Nice Bart.
How many frams did you capture and stacked ?


Each image is a stack of the best 1000 frames of 3000, filmed at 15fps.

#5 DesertRat

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Posted 20 February 2010 - 05:49 PM

Bart very interesting but I remain sceptical. I've imaged stars to test optics and noted that the size of the central point highly dependent on magnitude. Was your seeing that good? Besides, is Vesta not pretty much spherical?

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#6 Bart Declercq

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Posted 20 February 2010 - 06:05 PM

Bart very interesting but I remain sceptical. I've imaged stars to test optics and noted that the size of the central point highly dependent on magnitude. Was your seeing that good? Besides, is Vesta not pretty much spherical?
Glenn


That's pretty much why I picked a star of a magnitude and color somewhat comparable to Vesta (it's a K-type star, so a bit more red than our sun, same as Vesta) and they're both mag. 6.1

It's more the consistency of the size that to me seals it, the star's diffraction disk clearly shrinks in line with the shorter wavelengths, while Vesta just as clearly doesn't.

And no, Vesta is not "pretty much spherical", check this Hubble image on Wikipedia.

#7 MvZ

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Posted 21 February 2010 - 04:03 PM

I hope you don't mind me posting this here Bart, but I took another look at my recordings of Vesta, and I also believe that Vesta looks less star-like than.. ehm.. a 'star' (in this case the double star Algieba)

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#8 azure1961p

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Posted 16 January 2013 - 06:34 PM

This is brilliant work. I didn't know we had folks doing this high end res I imaging. Inspiring.

So for the record, he didn't just resolve it but the hamburger shape too?

Pete

#9 Bart Declercq

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Posted 17 January 2013 - 06:59 AM

It's been a while, but yes, I believe I managed to resolve the shape - I want to have another go at it, but the weather circumstances have not been kind to us here...

#10 RedLionNJ

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Posted 17 January 2013 - 04:22 PM

As a measure of how successful (or not) resolution of one of the minor planets has been, I would suggest a more definitive test would be to take images of both the minor planet and a nearby star of identical magnitude, then subtract the star's image from the minor planet's. If the minor planet was "resolved", an annulus should be the result, even better if it's irregularly shaped.

I am not entirely sure how you would get a star of precisely-matching magnitude, though. If the minor planet is rotating, its magnitude will likely be changing over time.

I'll have to try this if we ever get excellent seeing again.

Grant

#11 Mirzam

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Posted 17 January 2013 - 04:38 PM

Might want to try Ceres as well. It is bigger at opposition.

JimC

#12 ToxMan

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Posted 18 January 2013 - 06:31 AM

Your data looks convincing, Bart. More so, I think, if you can repeat the results under similar conditions. Grant's suggestion sounds interesting, too. It is a lot more work than I would attempt. I'm only tracking Vesta and Ceres in a wide field format. Thanks for sharing some very interesting data.

Paul






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