APOD: The Largest Satellites of Earth (2023 Jun 12)

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APOD Robot
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APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by APOD Robot » Mon Jun 12, 2023 4:06 am

Image The Largest Satellites of Earth

Explanation: What’s that near the Moon? It’s the International Space Station (ISS). Although the ISS may appear to be physically near the Moon, it is not — it is physically near the Earth. In low Earth orbit and circulating around our big blue marble about every 90 minutes, the ISS was captured photographically as it crossed nearly in front of the Moon. The Moon, itself in a month-long orbit around the Earth, shows a crescent phase as only a curving sliver of its Sun-illuminated half is visible from the Earth. The featured image was taken in late March from Shanghai, China and shows not only details of Earth's largest human-made satellite, but details of the cratered and barren surface of Earth's largest natural satellite. Over the next few years, humanity is planning to send more people and machines to the Moon than ever before.

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RocketRon

Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by RocketRon » Mon Jun 12, 2023 5:10 am

Marvelous photo !

Both of them would have been travelling at a fair rate of knots - in different directions ? - so capturing them in the
one image in focus must have taken some doing/precision . (As a sequence of images ? )

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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by Knight of Clear Skies » Mon Jun 12, 2023 8:13 am

RocketRon wrote: Mon Jun 12, 2023 5:10 am Marvelous photo !

Both of them would have been travelling at a fair rate of knots - in different directions ? - so capturing them in the
one image in focus must have taken some doing/precision . (As a sequence of images ? )
The technique is to track the Moon (any motorized telescope mount will do this) and wait for the ISS to pass. There are websites that can tell you when and where transits will occur. Astronomers use a technique called lucky imaging to take sharp images of the Moon, Sun and planets.

[youtube]https://youtube.com/shorts/uI-v1vtw9Pc[/youtube]

A video is taken, using software to combine the sharpest frames. If the timing is correct the ISS will shoot across the Moon or Sun rapidly, but it will show up in a few frames.

Focus isn't an issue as both the ISS and Moon are at 'infinity' focus.

Hope that helps.
Caradon Observatory, Cornwall, UK.

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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by Rauf » Mon Jun 12, 2023 10:21 am

Is it possible to capture two unrelated satellites in one frame? Like having ISS and HST in one picture together?

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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by De58te » Mon Jun 12, 2023 11:18 am

Pictured are the two 'largest' satellites orbiting Earth. Out of curiosity, what is the third largest satellite around the planet Earth? The James Webb telescope? Is there any satellite bigger than the JWT?

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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by orin stepanek » Mon Jun 12, 2023 12:28 pm

IssMoon_Yang_960.jpg
I think China's Space Station would be noted before the JWST! :mrgreen:
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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by Sa Ji Tario » Mon Jun 12, 2023 1:09 pm

De58te wrote: Mon Jun 12, 2023 11:18 am Pictured are the two 'largest' satellites orbiting Earth. Out of curiosity, what is the third largest satellite around the planet Earth? The James Webb telescope? Is there any satellite bigger than the JWT?

Sa Ji Tario

Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by Sa Ji Tario » Mon Jun 12, 2023 1:13 pm

Yes, 2010 TK7 is the first discovered Trojan asteroid that accompanies the Earth's orbit around the Sun at the L4 Lagrange point of the Sun-Earth system.2 It was discovered in October 2010 by the WISE (Wide-Field Infrared Survey Explorer) space telescope. ).

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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by johnnydeep » Mon Jun 12, 2023 7:54 pm

De58te wrote: Mon Jun 12, 2023 11:18 am Pictured are the two 'largest' satellites orbiting Earth. Out of curiosity, what is the third largest satellite around the planet Earth? The James Webb telescope? Is there any satellite bigger than the JWT?
I don't know which satellite might be bigger than the JWST, but the JWST actually orbits the Sun (and the L2 Lagrange point), not the Earth! See https://jwst.nasa.gov/content/about/orbit.html for a good animation and text.
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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by Chris Peterson » Mon Jun 12, 2023 8:01 pm

johnnydeep wrote: Mon Jun 12, 2023 7:54 pm
De58te wrote: Mon Jun 12, 2023 11:18 am Pictured are the two 'largest' satellites orbiting Earth. Out of curiosity, what is the third largest satellite around the planet Earth? The James Webb telescope? Is there any satellite bigger than the JWT?
I don't know which satellite might be bigger than the JWST, but the JWST actually orbits the Sun (and the L2 Lagrange point), not the Earth!
From an orbital dynamics viewpoint, the same can be said for the Moon. It orbits the Sun with a tiny wiggle introduced by the Earth. If the Earth simply vanished, the Moon would sail right along in its current solar orbit with almost no change at all.
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Re: APOD: The Largest Satellites of Earth (2023 Jun 12)

Post by johnnydeep » Mon Jun 12, 2023 8:25 pm

Chris Peterson wrote: Mon Jun 12, 2023 8:01 pm
johnnydeep wrote: Mon Jun 12, 2023 7:54 pm
De58te wrote: Mon Jun 12, 2023 11:18 am Pictured are the two 'largest' satellites orbiting Earth. Out of curiosity, what is the third largest satellite around the planet Earth? The James Webb telescope? Is there any satellite bigger than the JWT?
I don't know which satellite might be bigger than the JWST, but the JWST actually orbits the Sun (and the L2 Lagrange point), not the Earth!
From an orbital dynamics viewpoint, the same can be said for the Moon. It orbits the Sun with a tiny wiggle introduced by the Earth. If the Earth simply vanished, the Moon would sail right along in its current solar orbit with almost no change at all.
Hmm. From that pov then, EVERYTHING orbits the Sun! But some things are also in orbits around other things, and some things aren't, right? I was just trying to say that the JWST does not orbit the Earth in any sense of the term, but something else.
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