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Thread: The Observational Astronomy Thread

  1. #16
    Senior Member Strange Magic's Avatar
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    Quote Originally Posted by mikeh375 View Post
    Adaptive optics are a brilliant way to counter atmospheric turbulence for ground base observing and one wonders what Halley would have made of that. Re AI, you might find this interesting StrangeM.....

    https://www.theverge.com/2017/11/15/...ploration-data
    I did indeed! Excellent article.

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    Senior Member Room2201974's Avatar
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    Quote Originally Posted by Strange Magic View Post
    I did indeed! Excellent article.
    I concur. Thanks mikeh375
    "One man's symphony is another man's earworm." ~ riffing on a R.A.H quote.

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    Senior Member mikeh375's Avatar
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    Have any of you guys ever seen something you couldn't explain whilst observing?

  6. #19
    Senior Member Luchesi's Avatar
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    Quote Originally Posted by mikeh375 View Post
    Have any of you guys ever seen something you couldn't explain whilst observing?
    This star is one of the oldest in the universe! And it’s only190 ly away in Libra. It probably formed in what would be the galactic halo before our galaxy had grown much and it later got a very big push in our direction.

    HD 140283 is an extremely metal-deficient and high-velocity subgiant in the solar neighborhood, having a location in the HR diagram where absolute magnitude is most sensitive to stellar age. Because it is bright, nearby, unreddened, and has a well-determined chemical composition, this star avoids most of the issues involved in age determinations for globular clusters. Using the Fine Guidance Sensors on the Hubble Space Telescope, we have measured a trigonometric parallax of 17.15 +/- 0.14 mas for HD 140283, with an error one-fifth of that determined by the Hipparcos mission. Employing modern theoretical isochrones, which include effects of helium diffusion, revised nuclear reaction rates, and enhanced oxygen abundance, we use the precise distance to infer an age of 14.46 +/- 0.31 Gyr. The quoted error includes only the uncertainty in the parallax, and is for adopted surface oxygen and iron abundances of [O/H] = -1.67 and [Fe/H] = -2.40. Uncertainties in the stellar parameters and chemical composition, especially the oxygen content, now contribute more to the error budget for the age of HD 140283 than does its distance, increasing the total uncertainty to about +/-0.8 Gyr. Within the errors, the age of HD 140283 does not conflict with the age of the Universe, 13.77 +/- 0.06 Gyr, based on the microwave background and Hubble constant, but it must have formed soon after the big bang.

    http://arxiv.org/abs/1302.3180
    Tradition is not the worship of ashes - but the preservation of fire!
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    Senior Member Strange Magic's Avatar
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    Quote Originally Posted by mikeh375 View Post
    Have any of you guys ever seen something you couldn't explain whilst observing?
    I have not had any close encounters.....

  8. #21
    Senior Member Luchesi's Avatar
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    KenOC hasn't posted in a week(?) while his daily average is over six posts a day.

    I hope he's okay.
    Last edited by Luchesi; Dec-13-2019 at 22:40.
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

  9. #22
    Senior Member KenOC's Avatar
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    Quote Originally Posted by Luchesi View Post
    KenOC hasn't posted in a week(?) while his daily average is over six posts a day.

    I hope he's okay.
    Im ok, thanks, traveling.

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  11. #23
    Senior Member Strange Magic's Avatar
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    My dream optics, if I could afford them: About 25 years ago, Fujinon offered--for $11,000--a pair of monster binoculars that were actually twin 150-mm refractors with ED glass objective lenses. One could use paired regular 1.25-inch eyepieces--whatever one wanted. I don't remember whether the price included the necessarily massive mount, but part of my brain thinks the mount was separate at $3,000 additional. I recently scoured through several sites including Fujinon itself to see whether this dream bino still was made and offered, and found only smaller and far less expensive "big binos", most without the monster bino's prisms in the light path that allowed for head-down viewing like a regular refractor (though offering correct-image viewing). It must have been fantastic looking at the night sky through such optics; Fujinon had, and still has, I presume, great optics--crisp, clear. My best kayaking binoculars were a pair of waterproof 6X30 Fujinon individual-focus binos, which, like an idiot, I left behind one day at the launch site and made someone else very happy.

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  13. #24
    Senior Member mikeh375's Avatar
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    Quote Originally Posted by Strange Magic View Post
    My dream optics, if I could afford them: About 25 years ago, Fujinon offered--for $11,000--a pair of monster binoculars that were actually twin 150-mm refractors with ED glass objective lenses. One could use paired regular 1.25-inch eyepieces--whatever one wanted. I don't remember whether the price included the necessarily massive mount, but part of my brain thinks the mount was separate at $3,000 additional. I recently scoured through several sites including Fujinon itself to see whether this dream bino still was made and offered, and found only smaller and far less expensive "big binos", most without the monster bino's prisms in the light path that allowed for head-down viewing like a regular refractor (though offering correct-image viewing). It must have been fantastic looking at the night sky through such optics; Fujinon had, and still has, I presume, great optics--crisp, clear. My best kayaking binoculars were a pair of waterproof 6X30 Fujinon individual-focus binos, which, like an idiot, I left behind one day at the launch site and made someone else very happy.
    Those Binos sound amazing, you would certainly need an equatorial or better for them, or perhaps one of those mounts that allow you to lie on a sunbed , relax and just look up through them. My dream would have been to build a shed complete with roll-off roof. Inside I'd have a computer driven scope with a 4K screen for viewing. When it was really cold, I'd just control the scope from inside the house with a glass of St. Emilion... I'm still hankering after a solar scope too, something like these beauties......

    https://www.meade.com/solar/solar-scopes.html

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    Senior Member Strange Magic's Avatar
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    Those Meade/Coronado solar scopes are impressive! Such views of prominences, flares, granulation--brings home the reality that the sun is a star!. Carl Sagan said that was what blew his mind as a kid and set him to astronomy. Other astronomers often credit seeing Saturn through a scope in somebody's back yard.

    If one had unlimited funds, setting up both the Fujinon monster binos and a comfy, heated viewing chair together on a giant GoTo mount, probably best alt-az, would be the ultimate for me. Without having to get out of the seat or otherwise shift yourself, you would just be swung into position to see anything you wanted, just by tapping a few keys. A boy can dream......

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    Senior Member mikeh375's Avatar
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    It's quite depressing to realise that a lot of people don't know our sun is a star. Coincidently, last night we where watching a quiz called Mastermind (English tv) and a question came up on this..."At 96 million miles from Earth, what is the name of our nearest star?"...answer..."Sirius". The quiz is a highbrow one and that answer was from a doctor!!!
    I think I've read everything Sagan ever published and his Cosmos series was a big influence on me. Speaking of Sirius, I once read of a tribe called the Dogon in Africa who for centuries believed that visitors had come from Sirius, which they say also has a companion star. This was long before we found out it is indeed a double star....spooky or flukey or hookey? All three I bet.

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    Senior Member Strange Magic's Avatar
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    Watching the transit of Mercury on November 11 again reminded me that the vast machinery of the cosmos grinds on completely oblivious to our own thoughts and strivings here on our fantastic museum planet that almost everyone takes for granted and shows little concern for its proper maintenance. Do people ponder the rotation of the Earth as they sense the sun moving through the sky overhead? The circling and cycles of the moon? Very few people today are even conscious of the objects in the night sky, and light pollution makes it yearly harder to even see those objects. And how many know why we have seasons? How many can guess why we can't see Venus or Mercury in the middle of the night, but we can see Mars, Jupiter, Saturn at times then?

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  21. #28
    Senior Member mikeh375's Avatar
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    Indeed and these things aren't that hard to grasp are they. I'm proud to say that my wife now understands why we have seasons, my demo with toffee apple on a stick orbiting a tennis ball did the trick... the stick was useful as it helped her grasp the tilt in the Earth's axis. Encouraged, I tried to tell her about precession as a bonus bit of info, but she gave me that glazed over look and gave me permission to go to the pub with a mate who is as nuts about this stuff as I am...yay.

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  23. #29
    Senior Member Luchesi's Avatar
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    Quote Originally Posted by mikeh375 View Post
    Indeed and these things aren't that hard to grasp are they. I'm proud to say that my wife now understands why we have seasons, my demo with toffee apple on a stick orbiting a tennis ball did the trick... the stick was useful as it helped her grasp the tilt in the Earth's axis. Encouraged, I tried to tell her about precession as a bonus bit of info, but she gave me that glazed over look and gave me permission to go to the pub with a mate who is as nuts about this stuff as I am...yay.
    For insomniacs, recite and try to visualize these our zodiacal windows below, with your head on the pillow.


    CAPAT GC LVL SOS


    Think about where the sun is each month and it reminds us what's overhead at midnight for stargazing, which is always the exact opposite direction (and in these letters) from the sun.


    Our Supercluster of more than 10,000 galaxies is in V for Virgo.


    Our spiral arm is in G for Gemini, just above Orion.


    Our sister galaxy Andromeda is above P for Pisces (you’ll be looking below the plane of our galaxy to see it, but since our orbit takes us downward in the autumn - therefore Andromeda appears quite high in our sky, even though it’s below our galaxy if Polaris is up direction).


    Our galactic center is in the 2nd S for Sagittarius.

    So these are the 4 important directions in the local universe, on a diagram 3 o’clock (Spring), 6 o’clock (Winter), 9 o’clock (Autumn) and 12 o’clock (Summer). It’s relaxing to ponder, and within a month you’ll be an expert. Sweet dreams.
    Last edited by Luchesi; Dec-14-2019 at 18:01.
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

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  25. #30
    Senior Member Luchesi's Avatar
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    The Maya noticed the darkest part of the elongated rift extending through the center of the brightest section of the Milky Way as they looked up in the Sagittarius direction. We know now that it's a series of overlapping dust and molecular gas clouds that are positioned between our solar system and the spiral arm whose outer edge is visible (if you know where to look) about 10,000 LYs away in that direction. We're located at the inner edge of a spur of stars and dust, so that when we look in that direction (inward toward the galactic center) there's less obstructions (between us and that spiral arm). But also there's these dirty gas clouds only a few thousand LYs in between there too. These clouds cause it to appear as if the Milky Way is divided into two roughly equal sections above and below them.
    I assume the Maya were afraid that the dark rift would capture or attack or weaken the Sun when it got too close. If you have good records of the Sun's apparent position in the sky back then you can calculate where it will be in the future.

    The sun is still crossing the middle of the Dark Rift again this year on the December solstice. Keep your fingers crossed.
    Tradition is not the worship of ashes - but the preservation of fire!
    Gustav Mahler

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