Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

# It's the same Moon...

## Recommended Posts

Fascinating thread. SGC is full of many hidden gems of threads. My dads brother moved to Australia when he was 16, he’s now 66.  He’s been over a few times (funerals!) but I hope to bring my family over to spend some time there. I think I will find the night sky very disorientating.

##### Share on other sites
On 30/05/2018 at 19:58, Captain Magenta said:

Anyway, to bring it back to topic, 80-90 degrees seems to be the rotation between Cairns and Kidderminster, as LukeSkywatcher indicated?

If Kidderminster is 52N and Cairns is 16S, then the angle subtended by them relative to the centre of the Earth is 68 degrees.  I would therefore expect the Moon to appear tilted by 68 degrees when the views from one location are compared to the other.

Taking Mare Nectaris as a reference point in the images from the first post, in the first image I would say it is about 2 o'clock from the centre of the Moon, and in the second it is about half past 11.  As each hour represents 30 degrees that would suggest a figure of around 75 degrees.  I'm sure with something like Photoshop you could lay one on top of the other and do it more accurately.

James

##### Share on other sites
On 01/06/2018 at 00:05, JamesF said:

If Kidderminster is 52N and Cairns is 16S, then the angle subtended by them relative to the centre of the Earth is 68 degrees.  I would therefore expect the Moon to appear tilted by 68 degrees when the views from one location are compared to the other....

Unfortunately it's more complicated than that. What you say is true only if Cairns and Kidderminster are at the same longitude, and the target is directly across the horizon from each place (or if the earth is flat and you're standing on the edge  ). If they were at exactly opposite longitudes, your subtended angle would be 144 or 216 degrees ie 52+(180-16) . The actual apparent angle is a fairly involved function of lat, lon, RAs &Decs, and time.

Edited by Captain Magenta

## Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

×   Pasted as rich text.   Paste as plain text instead

Only 75 emoji are allowed.

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×