The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory • Hacker News Board

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#11

Post by privong » Thu, Jul 03, 2014, 6:09 PM UTC

goodcanadian wrote: post #9

privong wrote: post #6

Earlier quoted context omitted.

At wavelengths which they both observe (~1–28.5 microns; SOFIA goes out to longer wavelengths than JWST), JWST will be far superior in terms of both sensitivity and resolution. For one, the mirror on SOFIA is less than half the diameter of that on JWST ([0],[1], so the resolution is less than half as good and the collecting area is down by more than a factor of four). Even though SOFIA flies above a lot of the infrar…

Indeed, there are a couple of key things to note: 1) JWST has not been launched, yet. 2) SOFIA's wavelength coverage is different that JWST's or anything else that is in the pipeline. So, really, they are complimentary observatories.

> 2) SOFIA's wavelength coverage is different that JWST's or anything else that is in the pipeline.

Depending on what you mean by "pipeline", that isn't quite true. Work is being done on several far-inrared missions, such as SPICA[0]. I'd consider SPICA to be in "in the pipeline" and it will cover much (if not all) of the far-infrared that SOFIA does. So I wouldn't call JWST and SOFIA complementary; rather, SOFIA is a precursor observatory and a potential technology development platform (for things like SPICA; not so much for JWST, since the JWST instruments are already being built).

[0] https://en.wikipedia.org/wiki/SPICA_telescope

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#12

Post by astrobokonon » Thu, Jul 03, 2014, 6:12 PM UTC

nawitus wrote: post #7

How long are the exposures? One would think that due to vibration etc. the exposures need to be extremely short, but long exposures are beneficial in astrophotography. EDIT: Wikipedia answers the vibration issues: http://en.wikipedia.org/wiki/Stratospheric_Observatory_for_I...

Vibration isn't the reason why exposures tend to be short, and at the longer wavelengths SOFIA operates at it's not the dominant source of the image quality. The real reason is that at the infrared wavelengths seen on SOFIA the sky that we're looking through is very bright, and can quickly saturate detectors.

If you're interested in the nitty-gritty (with pictures!) there's a PDF that describes one of the methods: http://www.sofia.usra.edu/Science/instruments/FORCAST_observ...

Edit: More nitty-gritty here: https://www.sofia.usra.edu/Science/ObserversHandbook/FORCAST...

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#13

Post by jessedhillon » Thu, Jul 03, 2014, 6:16 PM UTC

goodcanadian wrote: post #8

netcraft wrote: post #5

I wonder if the plane flies during the day or night? I would assume that for a given mission its one or the other, which makes me also wonder how fast or slow it flies. Even though it is looking in the infrared - wouldn't the daylight still affect it?

We only fly at night. Well, technically speaking, we can observe with the sun up, but the guider cameras are optical which makes it nearly impossible to track any targets when the sky is bright. Moreover, we have to stay well away from the sun as the telescope would focus the sunlight with enough intensity to destroy itself. So, yeah, we only fly at night. Airspeed is roughly mach 0.85.

Is there some way that civilians admirers can ride SOFIA and get to participate in some of those activities set aside for grade schoolers? I would certainly be as excited as any 6th grader to have that chance!

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#14

Post by goodcanadian » Thu, Jul 03, 2014, 6:17 PM UTC

nawitus wrote: post #7

How long are the exposures? One would think that due to vibration etc. the exposures need to be extremely short, but long exposures are beneficial in astrophotography. EDIT: Wikipedia answers the vibration issues: http://en.wikipedia.org/wiki/Stratospheric_Observatory_for_I...

There have been a couple of good answers with regard to exposure time. With regard to vibration, the telescope is floated on an oil bearing and gyro stabilized. It is well isolated from aircraft vibrations.

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#15

Post by goodcanadian » Thu, Jul 03, 2014, 6:23 PM UTC

privong wrote: post #11

goodcanadian wrote: post #9

Earlier quoted context omitted.

Indeed, there are a couple of key things to note: 1) JWST has not been launched, yet. 2) SOFIA's wavelength coverage is different that JWST's or anything else that is in the pipeline. So, really, they are complimentary observatories.

> 2) SOFIA's wavelength coverage is different that JWST's or anything else that is in the pipeline. Depending on what you mean by "pipeline", that isn't quite true. Work is being done on several far-inrared missions, such as SPICA[0]. I'd consider SPICA to be in "in the pipeline" and it will cover much (if not all) of the far-infrared that SOFIA does. So I wouldn't call JWST and SOFIA complementary; rather, SOFIA is…

Funding for SPICA is still far from certain, and if it happens, it will likely be toward the end of the SOFIA mission. I would agree, however, that it is appropriate to call SOFIA a precursor to SPICA.

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#16

Post by goodcanadian » Thu, Jul 03, 2014, 6:28 PM UTC

jessedhillon wrote: post #13

goodcanadian wrote: post #8

Earlier quoted context omitted.

We only fly at night. Well, technically speaking, we can observe with the sun up, but the guider cameras are optical which makes it nearly impossible to track any targets when the sky is bright. Moreover, we have to stay well away from the sun as the telescope would focus the sunlight with enough intensity to destroy itself. So, yeah, we only fly at night. Airspeed is roughly mach 0.85.

Is there some way that civilians admirers can ride SOFIA and get to participate in some of those activities set aside for grade schoolers? I would certainly be as excited as any 6th grader to have that chance!

Grade schoolers don't fly on SOFIA. The Airborne Astronomy Ambassadors program is for grade school teachers and other educators. I can't think of any obvious way for the general public to fly on SOFIA. If you are a professional astronomer, apply for time, and you may be invited to fly. If you are an educator, apply to the Airborne Astronomy Ambassador program.

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#17

Post by batbomb » Thu, Jul 03, 2014, 6:40 PM UTC

goodcanadian wrote: post #8

netcraft wrote: post #5

I wonder if the plane flies during the day or night? I would assume that for a given mission its one or the other, which makes me also wonder how fast or slow it flies. Even though it is looking in the infrared - wouldn't the daylight still affect it?

We only fly at night. Well, technically speaking, we can observe with the sun up, but the guider cameras are optical which makes it nearly impossible to track any targets when the sky is bright. Moreover, we have to stay well away from the sun as the telescope would focus the sunlight with enough intensity to destroy itself. So, yeah, we only fly at night. Airspeed is roughly mach 0.85.

Nice to see another NASA-related astronomer here. I work on Fermi Gamma-Ray space telescope project, although I'm deep into the data processing and data management side of things.

I also have been helping out with a ton of LSST camera related things.

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#18

Post by ddrmaxgt37 » Thu, Jul 03, 2014, 7:55 PM UTC

My favorite 747! It's the 747SP. I love how short and fat it looks.

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#19

Post by dnautics » Thu, Jul 03, 2014, 8:12 PM UTC

dylanrw wrote: post #2

During one of my many Lyft rides I learned the driver was also one of several managers on this project. We had an interesting chat about it, and it left me wishing that the people involved in this sort of work were paid substantially more.

oh interesting. I'm also a lyft driver/scientist. I'm doing a series of in-car interviews of scientists, I'd love to try to talk to him, would you be able to contact me (details in profile)?

Re: The Jet With a 17-Ton Telescope That NASA Uses as a Flying Observatory

#20

Post by rbanffy » Thu, Jul 03, 2014, 8:51 PM UTC

john_b wrote: post #3

dylanrw wrote: post #2

During one of my many Lyft rides I learned the driver was also one of several managers on this project. We had an interesting chat about it, and it left me wishing that the people involved in this sort of work were paid substantially more.

Agreed, unfortunately meaningful projects such as this are not a high priority for the US electorate (and thus the US Congress) [1]. My hope is that growing interest by college students in STEM subjects [2] will ultimately lead to an increased understanding of the importance of these projects in the long term. [1] http://en.wikipedia.org/wiki/Budget_of_NASA [2] https://www.stemconnector.org/sites/default/files/store/…

One could always ask for support saying a given experiment could prove the, say, biblical flood or somethimg equally silly. If someone believes that all animals on Earth descend from the living cargo of a wooden ship, it should be possible to convince them of anything.

Hacking a right-wing nutty congresscritter is an intriguing concept.