Shadow across Ptolemaeus

[Stu]

Observing the Moon tonight, what drew my attention the most was Ptolemaeus sitting right on the terminator. There was a lovely long shadow, presumably from a mountain peak around the rim, which was very striking. I managed a smartphone shot of it to show what I mean. I had to over expose it a little to catch the shadow. Anyone else catch it?

 

[RobertI]

Very prominent, interesting one to watch next time round, sadly clouded out here. 

[Stu]

Interestingly, it wasn't visible when I took a shot earlier at 17.20, the pic above was at 20.48. Just shows how much the terminator evolves even during one evening.

[John]

Nice observations and pics Stu

I agree that the presentation of features does change as the hours pass. Some features have a really short "window" of clear definition.

 

[Marvin Jenkins]

Sorry to say I was clouded out yesterday but came in an hour ago from a half hour unexpected session. 
Marvellous. Terminator cutting Mare Imbrium clean in half. In fact cutting Lambert right down the middle.

Mons Pico just breathtaking, the shadow was so long. Not able to view long enough but I am sure I have seen the shadow change length in past sessions. Is this possible? Or is it my imagination?

Tried something new tonight and ditched the Nd filters. 25mm ep no filter and I could clearly see ridges in the Mare floor, but a bit too bright. Added an Nd and the ridges were harder to see. Tried a blue filter which was nice and easy on the eye.

I then remembered a comment from a fellow SGL er(sorry I forget who) who said they just use the aperture reducer. I put the tube cap on and removed the small cover and it worked a treat.

Marvin

[Marvin Jenkins]

No filters but not over bright.

[Stu]

27 minutes ago, Marvin Jenkins said:

Sorry to say I was clouded out yesterday but came in an hour ago from a half hour unexpected session. 
Marvellous. Terminator cutting Mare Imbrium clean in half. In fact cutting Lambert right down the middle.

Mons Pico just breathtaking, the shadow was so long. Not able to view long enough but I am sure I have seen the shadow change length in past sessions. Is this possible? Or is it my imagination?

Tried something new tonight and ditched the Nd filters. 25mm ep no filter and I could clearly see ridges in the Mare floor, but a bit too bright. Added an Nd and the ridges were harder to see. Tried a blue filter which was nice and easy on the eye.

I then remembered a comment from a fellow SGL er(sorry I forget who) who said they just use the aperture reducer. I put the tube cap on and removed the small cover and it worked a treat.

Marvin

You certainly can see shadows changing during the course of a session. With something like the Lunar X, you can see it starting to form then become a full X, great to watch.

Reducing the aperture will reduce the resolution of the scope, so is not necessarily the best option if going after very fine detail. A variable polarising filter is a good option so you can tune the brightness to suit (put one part on the diagonal and one part on the eyepiece, then twisting the eyepiece changes the brightness). Many will say, just up the magnification and that will dim the image, which is fine so long as the seeing will support it.

[Marvin Jenkins]

20 minutes ago, Stu said:

You certainly can see shadows changing during the course of a session. With something like the Lunar X, you can see it starting to form then become a full X, great to watch.

Reducing the aperture will reduce the resolution of the scope, so is not necessarily the best option if going after very fine detail. A variable polarising filter is a good option so you can tune the brightness to suit (put one part on the diagonal and one part on the eyepiece, then twisting the eyepiece changes the brightness). Many will say, just up the magnification and that will dim the image, which is fine so long as the seeing will support it.

Just love those moments when you are the ep and and for a couple of seconds total clarity. Didn’t use much mag, just stuck to 17mm ep in my 130 Orion. That A15 landing site looks really interesting. The Apennine Mountains were just incredible.

I will look into polarising filters as I have not entirely reached a happy medium.

Marv 

[Paz]

Snap! I was observing on Saturday and homed in on the same crater and the same shadow! I don't do photography but I take the odd picture of the moon so I can check what I was looking at - here's a pic taken at 20:11.

[Stu]

7 minutes ago, Paz said:

Snap! I was observing on Saturday and homed in on the same crater and the same shadow! I don't do photography but I take the odd picture of the moon so I can check what I was looking at - here's a pic taken at 20:11.

Great shot Paz, glad you saw it too. I must remember this phase to try to catch it better next time around in a bigger scope.