kkokkolis

Παράλλαξη, Copperleaf Studios, 2010 Όλα τα χαρακτικά σε μπρούτζο και τσίγκο.

Σελήνη, Copperleaf Studios, 2010

Luna, Copperleaf Studios, 2010

Βαρύτητα, Copperleaf Studios, 2010

Έκλειψη, Copperleaf Studios, 2010

Πτολεμαϊκό Σύστημα, Copperleaf Studios, 2010

De Motis Stelle Martis, Copperleaf Studios, 2010

Αστρονομική Συσκευή, Copperleaf Studios, 2010

Voyager 2, Copperleaf Studios, 2010

Αστρονομικά Όργανα, Copperleaf Studios, 2010

Ουράνια Σφαίρα, Copperleaf Studios, 2010

This too shall pass, psnt.net (positive science | negative theology), Paul Wallace, Jun 07 2010 During my last few years as an astronomy professor, I started off the first day by walking to the front of the class and writing the following on the board: ASTRONOMY IS A WASTE OF TIME. I then ask: Why might this be true? The idea is to short-circuit some of their inevitable concerns up front, to adjust their expectations, and to motivate them. Once they see that I’m serious the students relax a little and the conversation begins to flow. A common answer is: Astronomy is useless. This is true. Not that it is not wholly without use; our understanding of the Sun’s workings and of the orbits of near-Earth asteroids may one day be most helpful. Astronomy was once very useful for navigation, hence trade. Also for calendry and for certain religious purposes like setting the date for Easter. Routine uses of astronomy today tend to be highly specialized and have to do largely with ultra-precise reckoning of time. So it has its utility. But only a fraction of astronomy is concerned with the Sun or the orbital dynamics of bodies housed within the inner Solar System, and even within that fence much is clearly impractical. Astronomical science is almost wholly occupied with stuff that has no pragmatic bearing whatsoever: Saturn’s auroras, galactic evolution, quasars, cosmology. Arguments like No one foresaw the uses of the laser are familiar. And it is true that we cannot know now what we will need to know in the future. But if one were to order the sciences using any conceivable measure of usefulness, astronomy would come in at the bottom with plenty of daylight between it and the rest of the pack. There have been other predictable answers, such as: Astronomy is expensive. This is also true. American astronomy is funded through two pipes: NASA and the NSF. For a good time, browse the 2011 NASA Science Mission Directorate and 2010 NSF astronomy budgets. You’ll get the idea. These two answers were expected. But there was another popular answer that I was wholly unprepared for: Astronomy is depressing. Usually what the student had in mind is that we’re small compared to the cosmos. This is true. To say that the Earth is a drop in the ocean of space is so frantically understated as to be laughable. We would need to compare a single drop of water to 10^30 Pacific Oceans to get a decent comparison. (The number 10^30 is the same as the number 1 followed by 30 zeros.) And this takes into account only the visible universe. We have good reasons to suspect that there’s much more of it that we can’t see, that we will never be able to see. What students are generally less aware of is that things appear to be winding down. The Sun is not immortal. It will die in a few billion years, and when it does the Earth will be cooked, its life extinguished and its oceans vaporized. Who knows where we will be by then. It seems unlikely that we will make it that far, because we have a lot more to cope with than ourselves and our toxic combination of violent tendencies and nightmarish weapons. Catastrophic meteorite impacts await us in the next million years, to say nothing of the next billion. Also dramatic climate changes. If we make it through and leave the Solar System behind before the Sun’s final gasp, we will no longer appear human by today’s standard. The pressures of evolution and biotechnology will see to that. But even if we make it we won’t make it, because the universe itself is dying. Currently astronomers think it’s headed for the ultimate freezeout. In this scenario the entire cosmos will continue in its current expansion into an infinite future, its ambient temperature on a one-way descent toward absolute zero, its dynamism lost in a total washout of physical structure. There are other possibilities, but all of them lead to a single conclusion: Humanity will not prevail against nature. Thus I concede, at least partially. Astronomy can be depressing. But you know what? It’s just a reminder of what everyone already knows but doesn’t want to know: This too shall pass. This fact of life occurred to me first when I was about twelve. Carl Sagan‘s Cosmos had just been published and Dad had a copy. In it was a series of four paintings of a single locale. The first one was edenic: A bright array of living things grew alongside an expanse of incandescent blue water. The scene was lit by a perfectly yellow sun. As the series progressed the sun became orange and bloated enormously. Life disappeared and the ocean with it. In the end the blooming prospect was reduced to a wasteland ruled over by a hideous red orb. Here is the caption. I read it over and over. The death of the Earth and Sun. Several billion years from now, there will be a last perfect day. Then, over a period of millions of years, the Sun will swell, the Earth will heat, many lifeforms will be extinguished, and the shoreline will retreat. The oceans will rapidly evaporate and the atmosphere will escape to space. As the Sun evolves toward a red giant, the Earth will become dry, barren, and airless. Eventually the Sun will fill most of the sky, and may engulf the Earth. Clearly death awaited the world. A last perfect day. The words alarmed me. But I also felt the pull of a strange curiosity. Billions of years. No one I knew would be alive. But I looked around and tried to set the particulars of my environment into relation with the coming apocalypse. Even then the interstate freeways around Atlanta were crowded with cars, and I wondered when and under what circumstances those roads would be emptied. At the time the seventy-two-story Westin Peachtree Plaza was the city’s tallest building. To me it was monumental. I had watched it rise. When would it fall? Would it stand until the Sun melted it? One day it occurred to me with supreme force that, as a fact, my family’s house would crumble eventually. I stood outside with my nose three inches from the wall and wondered when the bricks, those bricks right there, would be separated from one another. Because, as a fact, they would be. On what exact calendar date? What would the weather be like on that day? Would there be clouds? If so, what would their configuration be at the precise moment of separation? Heavy thoughts for a 12-year-old, maybe, but it’s real and we spend a lot of time avoiding the fact that things — all things — fall apart. Pragmatists ever, the Buddhists are keenly aware of this and even have a special word — anicca — to express this fact of life. It is one of the three interrelated marks of existence, the other two being dukkha and anatta. Dukkha refers to suffering. Indeed, suffering is a fact. I don’t think I need to convince anyone of this. Anatta, or “not-self,” refers to the idea that there there is no permanent self, that all phenomena — the earth, the sun, trees, ourselves — possess no true, everlasting essence. It is for that reason that we should not cling to anything: not material goods, not status, not nature, not education, not even life itself. My New Testament professor, Luke Timothy Johnson, once said that of all major religions he preferred Christainity and Buddhism because only these two displayed an appropriate level of cynicism regarding our human station. I laughed when he said that but I wrote it down in the margin of my notes, thinking: I need to remember this. What happens when one really embraces one’s impermanence? Does one commit suicide? Does one come to understand Jesus? Does one wake up? Or does one, to paraphrase Walker Percy, live happily ever after precisely because one does not have to?

Artes Liberales, Astronomia et Ptolemaeus, 15ος αιώνας Unibibliotek Salzburg

Leica Aspheric Zoom 25x-50x, 18-9mm, 60-80 degree

Leica Zoom APO Televid WW ASPH Eyepiece 25-50x82mm

A Soliloquy of the Full Moon, She Being in a Mad Passion, Samuel Taylor Coleridge, 1800 Now as Heaven is my Lot, they're the Pests of the Nation ! Wherever they can come With clankum and blankum 'Tis all Botheration, & Hell & Damnation, With fun, jeering Conjuring Sky-staring, Loungering, And still to the tune of Transmogrification -- Those muttering Spluttering Ventriloquogusty Poets With no Hats Or Hats that are rusty. They're my Torment and Curse And harass me worse And bait me and bay me, far sorer I vow Than the Screech of the Owl Or the witch-wolf's long howl, Or sheep-killing Butcher-dog's inward Bow wow For me they all spite -- an unfortunate Wight. And the very first moment that I came to Light A Rascal call'd Voss the more to his scandal, Turn'd me into a sickle with never a handle. A Night or two after a worse Rogue there came, The head of the Gang, one Wordsworth by name -- `Ho! What's in the wind ?' 'Tis the voice of a Wizzard ! I saw him look at me most terribly blue ! He was hunting for witch-rhymes from great A to Izzard, And soon as he'd found them made no more ado But chang'd me at once to a little Canoe. From this strange Enchantment uncharm'd by degrees I began to take courage & hop'd for some Ease, When one Coleridge, a Raff of the self-same Banditti Past by--& intending no doubt to be witty, Because I'd th' ill-fortune his taste to displease, He turn'd up his nose, And in pitiful Prose Made me into the half of a small Cheshire Cheese. Well, a night or two past -- it was wind, rain & hail -- And I ventur'd abroad in a thick Cloak & veil -- But the very first Evening he saw me again The last mentioned Ruffian popp'd out of his Den -- I was resting a moment on the bare edge of Naddle I fancy the sight of me turn'd his Brains addle -- For what was I now ? A complete Barley-mow And when I climb'd higher he made a long leg, And chang'd me at once to an Ostrich's Egg -- But now Heaven be praised in contempt of the Loon, I am I myself I, the jolly full Moon. Yet my heart is still fluttering -- For I heard the Rogue muttering -- He was hulking and skulking at the skirt of a Wood When lightly & brightly on tip-toe I stood On the long level Line of a motionless Cloud And ho! what a Skittle-ground! quoth he aloud And wish'd from his heart nine Nine-pins to see In brightness & size just proportion'd to me. So I fear'd from my soul, That he'd make me a Bowl, But in spite of his spite This was more than his might And still Heaven be prais'd! in contempt of the Loon I am I myself I, the jolly full Moon.

Uranus set fra Ariel, Rolf Wahl Olsen, 2001

Arch, Rolf Wahl Olsen, 1999

SuperNova, Rolf Wahl Olsen, 1998

Galactic Center, Rolf Wahl Olsen, 1998

Ocean, Rolf Wahl Olsen, 1998

Quasar, Rolf Wahl Olsen, 1998

Omega Centauri, Rolf Olsen, 1999

A Beautiful Trifid, R Jay Gabany, 2011

Είναι το ο πιο ευέλικτος φακός που θα μπορούσες να πάρεις. Με ένα Barlow φθάνεις τα 300x (αν και συχνότερα θα στοχεύσεις τα 200x με 12mmx2 και 1mm exit pupil) και ναι, δουλεύει καλά με Barlow. Θα προτιμούσα έναν κοντύτερο, όπως τον Celestron Ultima (είναι πιο λειτουργικός με τον Orion Shorty Plus 2x από ότι με τον ψηλό Televue Powermate 2.5x). Αλλά φυσικά θα δουλεύει καλά με όλους τους Barlow. Εγώ τον ξεκινώ από τα 20mm καθώς το πεδίο είναι στενό και το field stop θολό στα 24mm (ο MkII είναι ο δικός μου). Μεταξύ 16mm και 8mm είναι υπέροχος. Στο Dob 8 η ιδανική ρύθμιση είναι 12mm +/- 4mm, δηλαδή ακριβώς στο παράθυρο βέλτιστης λειτουργίας του (στα SCT και MCT είναι λιγότερο ευτυχής η συγκατοίκηση, καθώς τα 24 και 20mm είναι στενά όπως σου είπα). Εντέλει ίσως χρειαστείς και έναν φακό ευρέως πεδίου >24mm, όπως τον Hyperion Aspheric 36mm ή τον φθηνότερο Skywatcher 38mm για να ξεπεράσεις την στενότητα του πεδίου στα 24-20mm του zoom. Με τρία μόνο κομμάτια μπορείς να κάνεις πολλά λοιπόν. Πολλοί θα έλεγαν να πάρεις 3 σταθερούς φακούς υψηλής ποιότητας και μεγάλου πεδίου. Δεν θα διαφωνήσω, αντιθέτως. Ο Zoom όμως θα σου δώσει τον χρόνο που χρειάζεσαι για να αποφασίσεις ποιά εστιακά μεγέθη έχεις ανάγκη και να μαζέψεις τα χρήματα ή να ενεδρεύσεις για τις κατάλληλες ευκαιρίες. Και ίσως με έκπληξη δεις πως δεν έχουν αρκετοί από τους σταθερούς φακούς καλύτερη ποιότητα από τον Baader Zoom. Εγώ πάντως τον κράτησα και ας έχω πια αρκετούς καλούς σταθερούς φακούς και αυτό νομίζω κάνουν οι περισσότεροι καθώς δεν πουλιέται συχνά ως μεταχειρισμένος, αν και είναι από τα μεγαλύτερα Best Seller και υπάρχει μάλλον σε πολλά σπίτια. Και αν τελικά δεν τον χρειάζεσαι άλλο θα πωληθεί σαν ζεστό ψωμάκι.