Your humble servant is going up to Kitt Peak next week for some imaging.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Hey Cool, Have fun!

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If this writing is blue you're going too fast!

Thanks, I am sure I will.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Break a mirror, George!

Injoy!!!

Thanks. It's time I stand on the shoulder of giants, though I'll probably just end up on their toes. They reportedly have no tar or feathers to abuse amateur heliochromoligsts.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Ok, I'm back from the mountain. What a great time! All night at Kitt Peak is an amazing experience. Great folks up there, too.

They now have three observatories for their AOP (Advanced Observation Program) to allow small groups to observe all night with either a 16" or 20" scope.

Roy Lorenz was my operational tech. He worked hard all night. We never took our meal break, we just kept going. He handled, essentially, everything.

My goal was to get some respectable color images of some of the solar twins. The Canon EOS Rebel is reportedly pretty good at capturing "true" color. Fortunately, I assumed, it was not modified (filter change) which might have produced more reds than a hyper sensitive eye should behold.

Anyway... Here are just a few solar twins. Keep in mind these are color images. They have not been processed by any improving software, yet.




[The lower right star is the solar twin.]





The technique comes from an image I stumbled into from Stefan Seip. He used progressive focusing to produce a beautiful image of the southern cross. The colors become much more apparent using this method.

The more interesting images are too large for Image Shack, regrettably.

We did obtain a yellow image of 18 Sco which is perplexing. Also, there seemed to be too much loss of red as many stars seem more yellow than red. Antares was included to emphasize this issue. Maybe someone can explain this. I believe we were in auto for white balance on the Rebel. [Added: Reportedly, the Canon 300D Rebel does not have manual color temp. settings.]


It was a great time for this amateur and a great lesson on how important it is to document everything, as I have had to struggle to nail down which image was which.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

For the sunny heliochromologists...





I wish I could claim the color is accurate, though there is a chance it is.

Hopefully, some of you with experience might want to try this technique on the solar twins to see what color you get. [Unfortunately, the modified Rebel and the 20Da are red biased from natural color.]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

18 Sco is well-placed for viewing now. Funny you'd mention this now, as I was thinking about looking for it with binocs this week. I'm afraid the waxing Moon may wash out colors, though, so I might have to wait a couple of weeks.

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Phil Plait
The Bad Astronomer
http://www.badastronomy.com
badastro@badastronomy.com

what am i looking it (if you don't mind me asking)? is what is the deal with the "conical" shape i'm seeing? where these photos taken over time? obviously, i don't know enough about astronomy and/or photography to answer these questions on my own. :-) interesting photos.

Great, BH (Bad Heliochromologist)!

This might assist all those interested in gandering at what could easily be seen as the true color of the sun....



[Added: Oops, the 8" stated in the image was suppose to say 8 degrees.]

Most binoculars have a field of view close to 8 degrees, hence the circle. The little dipper is not the Little Dipper, so call it the Micro Dipper or something.

The Moon will sure mess it up for a few days, however.

Your binocular coatings could alter its color, so I already have an excuse if I don't like someone's color determination.

Yes. To get the trailing effect, we had to slow the tracking rate, but with a 16" scope used as a prime focus, we could not simply turn off the rate (as it would disappear quickly). Forunately, we could simply dial-in the rate we wanted (as a percentage of full rate). We used two, sometimes three, different rates to allow for greater intensity when the image was enlarged. This enlargement came by simply defocusing at a, somewhat, constant rate during the entire 3 minute exposure.

The star 18 Sco is known as the closest twin to our sun. It's size, age, composition, mass, etc., and...its color matches closely to that of our sun. Therefore, if it is green, blue, white, peachy-pink, or some other color, then that will tell us, likely, the color of our sun.

Keep in mind, however, that our atmosphere "bleaches" ("extinctions" I think is the proper term) some of the blues, up to half at lower altitudes, and, to a lesser extent, some of the other colors. Therefore, if it [18 Sco] is seen as a white star when observed from the ground, it could still be a bluish-white star if viewed from space. [The sun is too bright to see. ]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

There are six, possibly more, "solar twins" with 18 Sco still being the closest twin. The prior posts show one in Bootes and another in Serpens. There are two more in Serpens and another in Ursa Major. These vary, IIRC, from 7.2 mag to about 8 mag. since they are so deep into outer space - about 180 light years.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

George,

Congrats on your successful imaging run.

FYI, the field of view of a typical binocular is about 6 degrees. It can be as small as 2.3 degrees.

http://www.excelsis.com/1.0/section.php?sectionid=21

Dave Mitsky

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Chance favors the prepared mind.
De gustibus non est disputandum.
Never attribute to malice that which can be adequately explained by stupidity.

Thanks Dave,

What a great list of binoculars there.

I googled to a site that favors the larger field of view binoculars, unfortunately. They were actually about 7.5 deg. but the circle diameter was too small to allow the stars to fit nicely, so I went to 8 (should have gone to 7 ).

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Thanks to Roy Lorenz at Kitt Peak Observatory, we have a color image of the sun as seen at the world's largest solar telescope (McMath-Pierce).


[Credit: George Cooper/Roy Lorenz/NOAO/AURA/NSF]

The red, green, and blue objects, of course, are for color reference. This white "color" is how I recall seeing it during the McMath-Pierce control room tour.

I doubt this surprises anyone here, but it does provide visual evidence to help support the claim that the Sun is not yellow and is likely white of bluish-white.

As stated in other threads, due to atmospheric effects, the color that is missing is primarily a little blue and little less green. [This is obvious when comparing the spectral irradiance of the sun as seen from space with its s.i. as seen down here.] If we were to add these colors back into this white image, as the SPACC has attempted, we might get a little hint of the sun's true color. It might still be bluish-white, slightly. It won't be yellow, however.

So is it white or bluish-white?

So onward as we continue the prodigious...
Quest for the Color of the Sun!

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.