Post AItCDcQbofy9JAF9Jw by dpthorngren@mastodon.online
(DIR) More posts by dpthorngren@mastodon.online
(DIR) Post #AItCDcQbofy9JAF9Jw by dpthorngren@mastodon.online
2022-04-27T21:57:24Z
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If you weren't aware, astronomers don't have a great relationship with Musk. A big issue for us is the Starlink satellites, which due to their low altitude and high number, already regularly interfere with ground-based observations. #starlinked on Twitter has endless examples.We get told it's the "price of progress" and that SpaceX will make space telescopes cheap anyway. But that's BS: development of advanced space tech is much more expensive than the launch.https://www.vox.com/science-and-health/22396388/space-x-elon-musk-starlink-too-bright-astronomy-stars-pollution
(DIR) Post #AItCDd51OQINKV9QJM by publius@mastodon.sdf.org
2022-04-27T23:06:35Z
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@dpthorngren This is a side point, but : I think you're confusing two things.Because launch opportunities have been rare as well as costly, for a while now the emphasis in space science missions, such as space telescopes, has been to take decades developing unique, highly capable, extremely costly and sophisticated, instruments.With frequent cheap launches, you don't have to do that. You can build a lot of small, modest capability instruments, a lot faster ― and you can iterate.
(DIR) Post #AItCDeVI6Eu1kGRutc by dpthorngren@mastodon.online
2022-04-27T22:00:18Z
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Maybe people will consider the tradeoff worthwhile, I couldn't say. But it seems like the whole Starlink project went forward without even considering the effect on ground-based astronomy or how people will feel about a night sky crawling with satellites.https://www.deepskywatch.com/Articles/Starlink-sky-simulation.html
(DIR) Post #AItD1lWSHIxVzbtDZQ by takloufer@fosstodon.org
2022-04-27T23:15:39Z
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@publius @dpthorngren I'm really confused; why would you want only modest instruments that 'iterate fast' in astronomy of all places? You physically need a huge photon bucket to observe dim targets no? AND you need a large apeture to resolve small things as well?
(DIR) Post #AItD6PmMXyoA0LXzLk by takloufer@fosstodon.org
2022-04-27T23:16:31Z
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@publius @dpthorngren I'm really confused; why would you want only modest instruments that 'iterate fast' in astronomy of all places? You physically need a huge photon bucket to observe dim targets no? AND you need a large aperture to resolve small things as well?
(DIR) Post #AItDLK1YE5ywV1lAJ6 by publius@mastodon.sdf.org
2022-04-27T23:19:13Z
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@takloufer @dpthorngren Firstly, not everything you want to observe and gain data about has those characteristics. If you're trying to gather light curves of a large number of variable stars, for instance, you don't need either large aperture or a "huge photon bucket". You just need many telescopes which can be held on target for extended periods. For doing synoptic surveys, enumerating Solar System objects, you need a huge field of view, probably best attained with lots of instruments.
(DIR) Post #AItDXC5ZYSW7MdIll2 by publius@mastodon.sdf.org
2022-04-27T23:21:21Z
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@takloufer @dpthorngren For resolving exoplanets, sure, you need a really large aperture… in which case an interferometer built up of numerous smaller telescopes, with high-precision relative position measurement, might be your best bet.And if launch mass is fairly cheap, you may be able to afford big mirrors for your modest instruments. Besides which, the atmosphere attenuates and distorts so much that a square centimeter of mirror is usually worth MUCH more in space than on Earth.
(DIR) Post #AItE17XN2fxfw1Zf7o by publius@mastodon.sdf.org
2022-04-27T23:26:46Z
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@takloufer @dpthorngren As for why you might want to "iterate fast", well, the original Orbiting Astronomical Observatory, or the Hubble as-launched, to give two quite different examples, should suggest something to you. Sometimes you launch your "I've been working on this my whole career" instrument and it DIES on you in short order, or it fails to work at all.
(DIR) Post #AItE1fLVLIfin4HfLk by takloufer@fosstodon.org
2022-04-27T23:26:50Z
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@publius @dpthorngren well, sure: there is science to be done with more modest instruments too. I wouldn't however expect that putting most resources on instruments very far from the tech frontier is a very fruitful allocation in terms of sci impact. Same w synoptic surveys: why scale CCDs by putting an entire telecope around just small chunks, and then even add satellite systems around that too?
(DIR) Post #AItEESAxcUQNi0RwVk by publius@mastodon.sdf.org
2022-04-27T23:29:10Z
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@takloufer @dpthorngren For generations most comet discoveries have been made by amateur astronomers with modest instruments, operating "far from the tech frontier". But I think you're missing an important point here : the resource commitments involved are modest. The effort involved in one JWST could reasonably produce a thousand instruments over the same time-frame in this new environment.
(DIR) Post #AItEPEC7wSGtX48J4S by publius@mastodon.sdf.org
2022-04-27T23:31:07Z
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@takloufer @dpthorngren Basically, the question is this : is instrument capability, or instrument availability, the limiting factor in what you're trying to study?For cases in which it's availability, we are well on our way to being able to discard that problem as trivial. Not as far as if we had a lunar base with mirror-manufacturing facilities, but pretty far nonetheless.
(DIR) Post #AItEPN4IwuMV3PXgcy by takloufer@fosstodon.org
2022-04-27T23:31:06Z
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@publius @dpthorngren if they have big mirrors we're not talking about a modest instrument per def, so that's a different ballgame. There's nothing modest about stng like JWST. and sure, its concievable a complex interferometric swarm could do what is needed, w lots of extra complexity ofc. Honestly, better just put one's decently sized instruments on the Moon (and prob no less futuristic).
(DIR) Post #AItEYF0mH2LCfk7dUO by dpthorngren@mastodon.online
2022-04-27T23:32:42Z
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@publius @takloufer There is definitely value in getting more small instruments into orbit. I'm really just objecting to a certain genre of Musk-ite who declares ground-based observing obsolete (it is *definitely* not).Space-based interferometric telescopes would be super cool, but for a good SNR for dim objects you still need a large collecting area. Right now the SNR is our focus because of how out-of-reach resolving exoplanets is for now.
(DIR) Post #AItEZxqt2l0U23JkQa by takloufer@fosstodon.org
2022-04-27T23:33:03Z
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@publius @dpthorngren I also don't see how one puts carefully callibrated ginormous instruments like the ESPRESSO spectrograph anywhere near a rocket.
(DIR) Post #AItEmLNhO7zWTvZHYe by publius@mastodon.sdf.org
2022-04-27T23:35:17Z
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@takloufer @dpthorngren Payload fairings today typically come in 5 meter diameter, because of the needs of comsats.Hence it appears feasible that the "modest" instrument I mention could have a 2.5 meter main mirror. That's a Palomar telescope, but with substantially better performance just in the visual, PLUS the ability to look at bands such as the far-UV which the Earth's atmosphere doesn't pass at all. Of course it means a modest use of adaptive optics to keep the mirror cost down.
(DIR) Post #AItF3TPAoEC0I2QSIa by publius@mastodon.sdf.org
2022-04-27T23:38:23Z
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@takloufer @dpthorngren One of the important arguments for a real space station, as envisioned from the beginning, is to avoid having to design everything that goes into space around five minutes of its lifetime during which it will be subjected to 10 Gs acceleration ±4 G vibration. But you'd be shocked the kind of delicate calibrated instruments that have been launched. And sometimes you find an alternative which accomplishes the same job a different way.
(DIR) Post #AItFDYHJXsGoIeYVJw by takloufer@fosstodon.org
2022-04-27T23:40:12Z
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@publius @dpthorngren I just think the resource comitments involved are at best in proportion with the likely contribution. One is no more likely to find answers we can currently seek in say cosmology or planetery science w a bunch of small instruments than one is to find say Higgs with a buch of small particle accelerators.
(DIR) Post #AItFKM5tFDsQXQSL6O by dpthorngren@mastodon.online
2022-04-27T23:41:24Z
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@publius @takloufer Astronomers are certainly aware of the usefulness of both large and small programs. TESS is an example of a small program where the cost was ~1/3 launch. JWST is the opposite end of the spectrum, launch cost about 2%. JWST was expensive both for the large area and extremely fine temperature control. You really can't do infrared observations of this quality from the ground or on the cheap.
(DIR) Post #AItG4IOpJTFwOtDg1I by takloufer@fosstodon.org
2022-04-27T23:49:44Z
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@publius @dpthorngren well, sure, from a long enough view, in a future where we finally get a cislunar economy, mining and manufacturing capabilities etc, hard to see why one couldn't do everything we're doing on the ground in space. Then we can build room scale instruments connected to a telescope and the like in space too. I sincerely hope I'll live to see it and celebrate that future.
(DIR) Post #AItG90yjVjTlooGTWi by publius@mastodon.sdf.org
2022-04-27T23:50:36Z
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@takloufer @dpthorngren I can't quite discern your point.The number of stars and other bodies there are to be observed is, pardon the expression, astronomical. You get entirely different kinds of information from looking at lots of them than you do from extremely intensive study of a single one with a powerful instrument.
(DIR) Post #AItHED5rziYInLe02K by dpthorngren@mastodon.online
2022-04-28T00:02:39Z
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@publius @takloufer I mean that while small space telescopes are useful, the big flagship telescopes provide essential capabilities you can't get otherwise.Example: TESS can find the best targets for atmospheric observations, but you need a Hubble or JWST to do atmospheric spectroscopy, even for the most favorable targets in the sky. It's just that hard to get a usable SNR.
(DIR) Post #AIxKJUYRa07wtL3jOa by yes@social.handholding.io
2022-04-29T22:56:10.203107Z
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solution: out the telescopes in orbit :^)