Astronomy's New Grail: The $1 Billion Telescope

The NY Times ^ | 123003 | DENNIS OVERBYE

[djf]

Is Saturn the very bright object in the east about 11 pm? I thought that was Jupiter, I know Jupiter was in that neck of the woods a few years back.

[Calvin Locke]

...my binos.

I saw an ad for a pair that might do. It was comprised of 2 6" reflectors.

[TomB]

I'm just trying to find a decent 80mm refractor for cheap so I can look at Saturn's rings ;-)

Astronomy in Scotland? Is that legal? (or just impractical?)

;-)

[longshadow]

Is Saturn the very bright object in the east about 11 pm? I thought that was Jupiter, I know Jupiter was in that neck of the woods a few years back.

Saturn is currently "north" of Orion; at 11pm, it would be closer to overhead than East.

Jupiter is just crawling over the eastern horizon around 11pm these days; it's MUCH brighter than Saturn, or almost anything else in the night sky, save for the moon, and perhaps Venus.

[Prodigal Son]

LOL, more to the impractical side ;-)

[RightWhale]

Saturn is yellowish compared to Jupiter. The hard naked-eye planet is Mercury. Generally one has to go outdoors with the deliberate and planned intent to observe Mercury or one will never see Mercury, not in a lifetime.

[Prodigal Son]

Is Saturn the very bright object in the east about 11 pm?

Right now, you're getting Saturn, Jupiter and Mars at night, with Venus early in the evening. I use this interactive chart (below)- it's pretty useful:

Night Sky Map

What you can do with it is set your latitude (I'm at about 55 degrees here in Scotland), set the date you wish to view and then increase the time by hours or minutes or days to see how the sky will look. It allows you to print a portion you're interested in. It's a pretty neat tool, in my opinion. Play with it a little bit (making sure you get the dates right). If the link doesn't work, let me know and I'll give you a different one.

Saturn is getting well up in the sky between 9PM and Midnight right now, rising in the east and tracking across the sky in the E- ESE- S and setting to westward. To find it, you'll need to be able to identify the constellation Orion

Once you've found Orion and as you stand facing it in the night sky, make an imaginary line from Orion's foot (in the diagram above Beta), straight through the center of his belt and carry on through Betelgeuse and off to the left. You will come to a bright yellow star- this is Saturn at present. Slightly to the left of Saturn you'll see two more bright stars, Castor and Pollox, which make up the heads of the twins in the constellation Gemini. Saturn is actually between the legs of the twins. But once you've identified Orion- which is a pretty distinct feature of the sky- finding Saturn should be easy.

Jupiter rises later in the evening- after midnight- and can be found near Leo and Virgo.

[Prodigal Son]

Actually, to correct myself- Jupiter is indeed rising at around 11PM. It gets higher after midnight.

[djf]

OK, thanks. I'll take a look. This is hugh. Not to mention Sirius! (Also, very prominent now!)

[djf]

I did that for one express purpose once, although not Mercury (which I have never spotted).
A few years back, Venus was totally stunning right after sunset. So I went each day to the same place, earlier each night, with some telephone poles and wires in the foreground. Finally, after about five days, it worked. I saw it in the sky, very faint. Before sunset.

[RightWhale]

You saw Mercury? Or Venus? Mercury is bright enough, but it is so close to the sun at best that there is still twilight when you see the planet. There are only a few minutes between when you can make out the planet in twilight and when it sets.

[djf]

Venus. During the day, before sunset. I had heard long ago it was possible. It's very, very faint, but if you know exactly where to look, you can see it.

[RightWhale]

Yes, Venus is possible in daylight if the sky is very clear. So is the moon, but I would bet that few have noticed the moon in daylight.

[desertcry]

Why not use the moon as a platform for a 100 or more meters telescope, where there is no atmospheric and very little gravitational and thermal( on the dark side) distortion effects. This of course assumes the colonization of the moon.

[djf]

Saw the moon one morning very close to sunrise in the dead of winter, it was within a day of the new moon. There was a ring around it, almost like an annular eclipse, and a ghostly glow. Very beautiful sight.

[RightWhale]

There was a ring around it

Very close to the new moon if you saw most or all of the ring. Interesting that the whole disk of the moon can be seen, darkly, at the last or first crescent by reflected earthlight. Here, in Dec., the moon doesn't rise or set depending on how the orbit shapes up. The full moon just goes around and around barely clearing the horizon, especially around 21 Dec. when the moon happens to be in a northward position of the ecliptic. Like the midnight sun, but opposite time of the year.

[Physicist]

Why not use the moon as a platform for a 100 or more meters telescope

Because you can do far better than that on the moon, without building a behemoth. You can use a bunch of telescopes thousands of kilometers distant from each other, and use interferometry to make an optical telescope with an effective aperture that is thousands of kilometers wide. You can't do that on Earth because the uncorrelated atmospheric distortions destroy the relative phase information if the telescopes are too far apart. The limit for optical interferometry on Earth (I'm told) is a couple of hundred meters.

The two Keck telescopes (which were designed to work in concert this way) are optimally far apart, given the Earth's atmosphere. On the moon, the optimal solution would be to put the telescopes as far apart as possible.

[Prodigal Son]

to make an optical telescope with an effective aperture that is thousands of kilometers wide.

At this point, Tim Allen from Home Improvement makes the ape noise 'Augh, augh, augh!'.

Now that's a manly telescope ;-)

[longshadow]

You can't do that on Earth because the uncorrelated atmospheric distortions destroy the relative phase information if the telescopes are too far apart. The limit for optical interferometry on Earth (I'm told) is a couple of hundred meters.

Ah; that explains the mystery (to me) regarding why they don't just buy 25,000 Celestron C8's, link their GOTO controls to a common computer, digitize the output and timestamp it with an atomic reference clock, and ship the data off to some big-assed data base where a computer can leisurely number crunch to get everything in phase....

It would surely be cheaper than one of these behemoths....

[desertcry]

..... without building a behemoth. But the light gathering power of a telescope increases with the square of the diameter, does it not? Although using interferometry in conjunction with widely separated multiple telescopes does result in a great increase in resolution, it may not result in a large gain in the ability to observe extremely dim objects, like that of the infant universe or very small extra solar planets.