[Newsbot]

Title: Why NASA couldn't just use Hubble telescope to see Pluto
Category: Tech
Posted By: Hyack
Date: 2015-11-16 21:09:20
Canadian

[DrCaleb]

The same reason spy sattelites can't be used to see the Moon.

[BartSimpson]

Hubble is a spy satellite. Don't think it hasn't been turned around from time to time to take a look at the earth. All those refueling missions it's needed over the years speak to the numerous times it's been retasked.

[DrCaleb]

BartSimpson BartSimpson:

Hubble is a spy satellite. Don't think it hasn't been turned around from time to time to take a look at the earth. All those refueling missions it's needed over the years speak to the numerous times it's been retasked.

I keep saying "That's not possible". Optics that have gyros meant to view a galaxy can't be used to view a planet. It gets turned toward the earth for routine calibration, but it sees no better than Mr. Magoo.

http://www.badastronomy.com/mad/2000/hubbleearth.html

[BartSimpson]

DrCaleb DrCaleb:

I keep saying "That's not possible". Optics that have gyros meant to view a galaxy can't be used to view a planet. It gets turned toward the earth for routine calibration, but it sees no better than Mr. Magoo.

http://www.badastronomy.com/mad/2000/hubbleearth.html

The Hubble is an immediate predecessor for the KH-11.

https://en.wikipedia.org/wiki/KH-11_Kennan

None of this is classified. Connect the dots. Hubble has been upgraded over the years on four, possibly five, shuttle missions. In many circles it is estimated that the Hubble was upgraded with KH-11 hardware and software.

The US government spends dick on NASA but has expended upwards of $65 billion on the Hubble (between dedicated shuttle missions and etc.)

Just to look into outer space? When the government can't be bothered to update our manned space program?

Sure.

[Lemmy]

1. The Hubble telescope can't view earth. It's not designed to. It'd be like trying to use your binoculars or your sniper scope to close-up on a girly magazine 2 feet away. Like Doc said, it'd be like Mr. Magoo.

2. There could be spy lenses on the Hubble satellite (separate from the deep-space telescope), but why would they need to put them there when there are hundreds of other satellites up there that could be used as a platform instead? Doesn't make sense. More kooky internet conspiracy nonsense.

[DanSC]

BartSimpson BartSimpson:

Hubble is a spy satellite. Don't think it hasn't been turned around from time to time to take a look at the earth. All those refueling missions it's needed over the years speak to the numerous times it's been retasked.

Hubble's optics don't allow for focusing on objects only a few hundred miles away.

Hubble is based on spy satellites, and some have made the educated guess that Hubble designers chose a 2.4 m mirror over a 3 m mirror because the infrastructure to manufacture 2.4 m mirrors for spy satellites already existed. But there are plenty of dedicated spy satellites without Hubble wasting its time spinning around to view Earth.

[BartSimpson]

The new spy satellites being set for launch in 2018 use the same 2.4m mirror as is used on the Hubble.

But, whatever. Y'all think what you want and I'll think what I want.

[DrCaleb]

BartSimpson BartSimpson:

The new spy satellites being set for launch in 2018 use the same 2.4m mirror as is used on the Hubble.

But, whatever. Y'all think what you want and I'll think what I want.

But the mirrors will undoubtedly have a different curvature, allowing a closer focal length and faster gyros needed to track ground based images! Honestly Bart, we aren't trying to pull the wool over your eyes or anything. If it were possible, we'd be in with both feet. But it's just not possible, and we can't let someone go around with bad information.

[BartSimpson]

They're the same mirrors.

And I think you're getting the problems with Hubble backwards. Its initial problems with seeing into deep space were due to the device being unsuited to THAT purpose.

[Tyler_1]

Once a year some plane flybombs over our house and then some guy always shows up wanting me to buy a picture. Last time they wanted three hundred and something eleventeens for this tiny little picture of our place.
I said I live here, I know what we look like.
I also think Hubble is a cool name.

[Lemmy]

BartSimpson BartSimpson:

The new spy satellites being set for launch in 2018 use the same 2.4m mirror as is used on the Hubble.

But, whatever. Y'all think what you want and I'll think what I want.

BartSimpson BartSimpson:

They're the same mirrors.

And I think you're getting the problems with Hubble backwards. Its initial problems with seeing into deep space were due to the device being unsuited to THAT purpose.

[DrCaleb]

BartSimpson BartSimpson:

They're the same mirrors.

And I think you're getting the problems with Hubble backwards. Its initial problems with seeing into deep space were due to the device being unsuited to THAT purpose.

They are the same radius, but they are ground to different curvatures.

http://www.scopemaking.net/mirror/mirror.htm
http://www.telescopemirrorblanks.com/

That was the initial problem with Hubble, it was ground incorrectly.

http://www.spacetelescope.org/about/his ... n_problem/
http://www.techworld.com.au/article/420 ... _from_it_/

You can see for yourself why Hubble cannot be used for Earth images. Take a pair of binoculars. You can easily see distant objects with them, because that is what they are meant for. But looking at a book in your hand, not possible. Turn the binoculars around, and you can see the book through the big end, but it's really hard to focus and the image is very dim. That's because it's the other end that is designed to gather light.

Plus, the gyros cannot perform beyond their capabilities. It simply can't rotate Hubble fast enough to track an object on Earth.

[Lemmy]

When I was in highschool, my physics class built a telescope (8" reflector). The mirror grinding process was interesting. We'd open a bag of soluble grit and take turns massaging it into the glass. Then it got sent away, measured and returned with a different bag of grit and markings on the glass where to rub it. The whole process took months. So when we're talking Hubble, that's a piece of glass more than 100 times larger than that 8" mirror. Even when it's being shaped mechanically, using a computer, it's not hard to understand how easily a small error can occur, affecting its performance.

[BartSimpson]

DrCaleb DrCaleb:

Plus, the gyros cannot perform beyond their capabilities. It simply can't rotate Hubble fast enough to track an object on Earth.

The whole device doesn't rotate to track anything. You know this so what are you playing at?