What does resolve as a disc mean

[Tink_Archived]

Pretty much as the title says really

Seen this phrase a few times on here so far ...

ie: I can see Uranus as a blue/green dot but cannot resolve it as a disc

[oldfruit]

It means when you can see a plante as a disc and not looking like a star.

[steppenwolf]

The Moon, Sun and planets will all resolve as 'discs' in a suitable telescope because they are relatively close objects but a star will always just remain a dot no matter how much magnification you use because it is so very far away.

[robbieince]

Well when you focus on a star you get a point of light. With a planet, you get a disk that is clearly extended beyond a point of light. If the planet is small it can be hard to tell the difference. Hence resolve(tell the difference) as a disk rather than a point.

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[Matthew.Blake]

It just means when you have it properly focussed you should see a disc. It might be a very small disk but importantly it is not a point source as stars appear to be.

[Tink_Archived]

Thank you

[brantuk]

Errr - the moon sometimes resolves as a crescent lol

[John]

Errr - the moon sometimes resolves as a crescent lol

As do Venus and Mercury. Mars has gibbous phases as well

[dph1nm]

... and stars are not point-like either due to seeing!

NigelM

[robbieince]

Lol

Well crescents etc are only the sunlit parts of disks so it's still valid......

Raspberry!!!!!!!!!

[Matthew.Blake]

... and stars are not point-like either due to seeing!

NigelM

I've fitted my 200p with adaptive optics....

[NickH]

The Moon, Sun and planets will all resolve as 'discs' in a suitable telescope because they are relatively close objects but a star will always just remain a dot no matter how much magnification you use because it is so very far away.

http://www.obspm.fr/actual/nouvelle/jan10/betel-f1.jpg

tum tee tum tee tum

I'll get me coat :-) lol

[steppenwolf]

Blimey Nick, you must be bored!

[NickH]

lol...

about to operate a £5,000,000 scope in Hawaii... to image a comet...not likely

[barkis]

Errr - the moon sometimes resolves as a crescent lol

:D. But True.

[sbooder]

Talking of resolving to a disk, I have never got Venus to a disk, it is OK when it is a crescent, but when fullish, it is just a fiery ball.

Is there a good filter for Venus that will bring it right down in brightness or glare please?

Edit:

I had better clarify, that I want a filter for viewing and not imaging.

[yesyes]

http://www.obspm.fr/actual/nouvelle/jan10/betel-f1.jpg

tum tee tum tee tum

I'll get me coat :-) lol

I was wondering when someone was going to mention Betelgeuse. probably the only star that can be resolved as a disc from here.... With the proper equipment....