Near IR telescope

[alfchemist]

Hello UT members! How do you beat local weather condition like ours here in the Philippines where at least 21 typhoons visit us every year and most of the time, it's cloudy. We don't have the capability nor the resources to launch space-based telescope. Do we go for radiotelescope? Is there a near IR telescope? I reviewed the atmospheric window and found out that visible and radiowaves are the only EM radiations not blocked or absorbed by the atmosphere though I noticed that a small region in the near IR frequencies are also allowed to pass thru the atmosphere. I'm open to suggestions. Assume I have the backing of our local meteorological agency with an R&D section in astronomy so we might have some limited resources. Thanks in advance!

[Erimus]

I don't think a near IR telescope would be a good choice for the Philippines for two reasons:

1.) In the past, IR observations even on the ground required some kind of cryogenic coolant (like liquid nitrogen, or the like) to increase the sensitivity of the instruments.

link:
http://pegasus.phast.umass.edu/

2.) I don't think even near-IR is good enough to see through clouds.

3.) The humidity in the Philippines would probably severely hamper IR observations, as water vapor strongly absorbs IR radiation. This is probably the major reason why IR studies are carried out from dry, high-altitude locations.

In short, I'd go for a radio telescope. After all, one of the best radio telescopes in the world is located in tropical Puerto Rico (Arecibo). Just make sure the instrument is in a remote location, far from towns and cities that generate radio interference.

[antoniseb]

I have nothing really new to add here, except to confirm what Erimus has said.
If it is mostly cloudy and humid where you are, radio is the frequncy for you. I'm not sure what your highest mountain peaks are, but there really are no IR telescopes anywhere near sea level because the water vapour in the air absorbs the IR.

I don't think you need cryogenic coolant for near IR, but if you are doing serious IR work you'll probably want to go deeper, and the coolent is necessary.

[alfchemist]

Thanks for the tips, Erimus and anton! guess we have to settle for a radiotelescope. Our highest peak is at 2950m above sea level but this is a conservation area where rare plants and animals thrive. It's also the home of the philippine eagle, the number of which is near extinction. Btw, this place is an extinct volcano. :D

I'm just wondering, if you fire an EM beam powerful enough to go beyond the atmosphere toward a star, certainly, EM radiation from this star would interact with the beam (constructively and/or destructively), would you get a highly defined interaction? The idea is, instead of collecting photons from a source (a star perharps), you try to actively reach out for these photons using a laser perhaps. (assuming the problems of the "star wars" program were already resolved, e.g. atmospheric interference would make some radiation out-of-phase, etc.)

[antoniseb]

Originally posted by alfchemist@Apr 12 2005, 06:55 AM
e.g. atmospheric interference would make some radiation out-of-phase, etc.)
Except for photons from MASERs how would you ever be able to get light to be in-phase or out-of-phase with the random photons from stars? Also, where do you think you'd observe these nodes and anti-nodes? I'm not saying it's a bad idea, but I sure am missing a few very important pieces of this puzzle.