Terrain at the lunar limb ?

[John]

I'm not sure if this is a daft question or not but here goes...

I've been looking at the lunar limb a bit lately at various magnifications - mostly to see if my new apo refractor is showing any colour if I'm honest. At magnifcations over 100x if I examine the linb carefully it looks slightly uneven against the blackness of space - at one or two points there seem to be distinct "wrinkles" and I wondering if these could be the outline of the lunar terrain along the limb.

Is this possible or am I fooling myself ?.

I know that it is possible detect the uneven landscape during a total eclipse - it's what causes the "baillys beads"effect I think - ie: the sun peeking through valleys at the limb. I just don't know whether this uneven terrain can be detected at other times.

John

[GazOC]

John,

I'm not sure if I understand you right, but I can def. see the wrinkles and undulations of the Moons landscape against the dark sky. I'm pretty sure its not an optical illusion.

Gaz

[Chubster]

Do you mean like this ?

[FLO]

I used to use a 10" Dob' which routinely showed landscape along the limb.

[John]

John,

I'm not sure if I understand you right, but I can def. see the wrinkles and undulations of the Moons landscape against the dark sky. I'm pretty sure its not an optical illusion.

Gaz

Yes thats what I mean Gaz - along the limb and against the dark sky. I suppose you could say it's the lunar horizon.

This picture shows what I mean (although I think it was taken from a spacecraft).

John

[John]

Do you mean like this ?

Yes thats it - I've just posted a similar pic to illustrate it myself.

Thanks,

John

[mightymonoped]

You can see it at the terminator too. An apo should be good for this as you won't have the 'purple haze' and contrast is exceptionally good.

Here an example of a wrinkle or two on the 'false' horizon of the terminator last night..

Tony

[John]

You can see it at the terminator too. An apo should be good for this as you won't have the 'purple haze' and contrast is exceptionally good.

Here an example of a wrinkle or two on the 'false' horizon of the terminator last night..

Tony

Thanks Tony,

I have seen these sort of details around the termintor side of the moon but I was not expecting the uneveness around the sunlit limb. You are right - both the terminator and the sunlit limb appear sharp and colour-free against the black sky with the apo - I'm rather hooked on that sort of image quality now - despite the fact that the apo apetures that I can afford are modest - 90mm at the moment. I've not tried a mak yet though which are also supposed to deliver fine, aopo-like images.

John

[Kain]

If your talking about the non terminator side of the lit moon, then yes, you can see its not a perfect snooker ball shape.

Through my dob, theres all sorts of bumps and lumps at higher powers. These are crater walls, mountainous areas stuff like that.

HTH

Kain

[The Warthog]

Sometimes the moon occults a star along the limb, and it appears to flash on and off as it peeks through between mountains. This is called a 'grazing occultation.' I have yet to see one.

[SteelRat]

Sounds cool 8)

[daz]

I'm really looking forward to some lunar watching with my new newt!