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ragasssd
2014-Jan-28, 04:02 PM
I mean is it possible to resolve a star's diameter with a telescope (besides the sun)? Does any telescope have that much power? Or is it that no matter how hard we try, a star will always appear as a single point of light on our ccds? I've wondered this for a long time, and I think I remember seeing some pics online suggesting that yes we can. I would equate this with being able to 'see' another star, in its true form.

thx

Solfe
2014-Jan-28, 04:08 PM
A few (http://en.wikipedia.org/wiki/List_of_stars_with_resolved_images): Altair, Betelgeuse, Mira, Regulus and so on.

R.A.F.
2014-Jan-28, 04:27 PM
I think I remember seeing some pics online suggesting that yes we can.

Here (http://en.wikipedia.org/wiki/File:ESO-Betelgeuse.jpg) is an image of Betelgeuse.

ragasssd
2014-Jan-28, 04:30 PM
Ah yes! Silly question. But that photo of Betelgeuse is incredible. I find it incredible to look at a star's diameter, not sure why.

John Mendenhall
2014-Jan-28, 04:50 PM
Ah yes! Silly question. But that photo of Betelgeuse is incredible. I find it incredible to look at a star's diameter, not sure why.

It's like being that close. Yes, awe inspiring.

antoniseb
2014-Jan-28, 05:04 PM
It will be interesting to see if the appearance is any more dramatic after the 30 and 40 meter telescopes start showing us stuff early next decade.
Having several times the resolution might make a big difference.

ngc3314
2014-Jan-28, 07:38 PM
Something that made the Betelgeuse image seem more incredible to me - using UV spectra with HST (http://adsabs.harvard.edu/abs/1998AJ....116.2501U), it was possible to get the differential Doppler shifts from one side of the star to the other, so that we know that the big bright spot is roughly at its north pole! Its rotation period is ~17 years, which seems like a lot until I realize that the orbital period at its surface is not so many times faster.

ShinAce
2014-Jan-29, 03:38 AM
It turns out there's a wiki page for resolved stars:
http://en.wikipedia.org/wiki/List_of_stars_with_resolved_images

Cool stuff!

mapguy
2014-Jan-29, 02:36 PM
...that photo of Betelgeuse is incredible. I find it incredible to look at a star's diameter, not sure why.

I agree... and not just any star, but one believed to be at least 500 LY distant!
(Although, if I'm correctly understanding the Wiki article, a lot of what we're seeing are shells of ejected stellar mass that are very hot, but also less dense than the air we're breathing.)

thoth II
2014-Jan-29, 04:50 PM
I like the one of R Doradus which is the second largest apparent diameter star (after sun)
http://en.wikipedia.org/wiki/R_Doradus

John Mendenhall
2014-Jan-29, 05:25 PM
It turns out there's a wiki page for resolved stars:
http://en.wikipedia.org/wiki/List_of_stars_with_resolved_images


Cool stuff!

Yes but department: it's a list of the stars, not the resolved images. The ones I tried to find feature not so good sites. I'm at work and can't dig for them. Thanks for the Betelgeuse pic, anyhow.

ragasssd
2014-Jan-31, 03:32 AM
Something that made the Betelgeuse image seem more incredible to me - using UV spectra with HST (http://adsabs.harvard.edu/abs/1998AJ....116.2501U), it was possible to get the differential Doppler shifts from one side of the star to the other, so that we know that the big bright spot is roughly at its north pole! Its rotation period is ~17 years, which seems like a lot until I realize that the orbital period at its surface is not so many times faster.

Amazing.. knowing the star's orientation in the night sky, will never see Betelgeuse the same way again, thanks.