Why doesn't the James Webb Space Telescope have any cameras onboard?

[Admin]

Engineers must make do with traditional telemetry because of a lot of practical problems.

Why doesn't the James Webb Space Telescope have any cameras onboard? : Read more

 

[Gary Brown]

Engineers must make do with traditional telemetry because of a lot of practical problems.

Why doesn't the James Webb Space Telescope have any cameras onboard? : Read more

Great, informative article, as ever. Question - is there any other earth / orbit based telescope that could capture a "natural" image of the Webb, or is it simply too small and dim?

Gary B.

 

[Helio]

Great, informative article, as ever. Question - is there any other earth / orbit based telescope that could capture a "natural" image of the Webb, or is it simply too small and dim?

Gary B.

That would be cool!

Wiki has some info on this.

Gaia is currently at L2, but I don't know if it is capable of imaging the JWST, but perhaps.

There is another scope there but it is only an x-ray scope, I think.

Other missions are scheduled there in the future including Euclid, so if Gaia can't or won't, then there may be more chances in the future.

 

[billslugg]

JWST is in shadow from the Sun, Earth and Moon, is illuminated only by starlight. It is now cooled down to several hundred degrees below zero thus can only be seen in the infrared by something colder than it. I believe Gaia only works in the visible spectrum.

 

[Helio]

JWST is in shadow from the Sun, Earth and Moon, is illuminated only by starlight.

The umbral shadow is only about half the distance, I think.

 

[billslugg]

Right, viewed from this distance the Earth is smaller than the Sun, can't cover it completely. The telescope is in the shadow of its sunshield.

 

[Gary Brown]

So, I was initially wondering if the sunward side of the shield is what could - possibly..... - be picked up by another scope. The business side of the Webb is of course intentionally as locally light-free as possible, and thus all-but-invisible.

 

[Wolfshadw]

Not sure we have anything in orbit that can see something so (relatively) close. Maybe a good home telescope might be able to pick it up.

-Wolf sends

 

[billslugg]

There is a website of the "virtual telescope" that is showing pictures of the sunshield. It is a tiny white dot in a sea of stars.James Webb Space Telescope: a new image - 06 Jan. 2022 - The Virtual Telescope Project 2.0

 

[Gary Brown]

There is a website of the "virtual telescope" that is showing pictures of the sunshield. It is a tiny white dot in a sea of stars.James Webb Space Telescope: a new image - 06 Jan. 2022 - The Virtual Telescope Project 2.0

Great catch!

 

[COLGeek]

See here folks:

https://www.space.com/virtual-telescope-project-james-webb-space-telescope-webcast

 

[Helio]

If my math is correct, the apparent magnitude for the JWST will be a max. of about 14.2 at L2.

This assumes the shields are reflecting the light back towards Earth and with an albedo of 0.92 (SWAG).