Apparent diameter of objects

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Topic author
Beddu
Posts: 1
Joined: 21.07.2018
With us: 30 days 13 hours

Apparent diameter of objects

Post #1by Beddu » 21.07.2018, 10:02

Hi everybody,
I'm new to Celestia and astronomy itself.
I have a quite basic question, to make it simple I will make a practical example:

I land on earth with CTRL+G, orbit sync, select Moon and center it in my view by pressing C.
On the top left corner of the screen I have the Moon's data, including apparent diameter (angular diameter) from my point of view, I activate the equatorial coordinate grid by pressing ";" and after a quick comoaration of the moon mesh with the grid, I feel that the diameter of the moon mesh from my point of view does not match the one written on the top left corner of the screen.

Can you help me to understand why? Thank you in advance.

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selden
Posts: 10229
Joined: 04.09.2002
With us: 15 years 11 months
Location: NY, USA

Post #2by selden » 25.07.2018, 13:54

It looks fine to me.

Please provide a Cel:// url so others can see what you do. (Under Windows, type a Ctrl-C while running Celestia and then a Ctrl-V to paste it into your message.)

Below is a framegrab what I see when I use Celestia v1.6 to look at today's Moon from the point on the surface of the Earth which is right below the Moon. Here's the URL of this viewpoint:

cel://Follow/Sol:Earth/2018-07-25T13:44:38.69976?x=GAF2clDdBQ&y=HLOZ2fTsAQ&z=grM7mfwxLA&ow=0.0663576&ox=0.00176653&oy=0.997556&oz=-0.0218115&track=Sol:Earth:Moon&select=Sol:Earth:Moon&fov=1.50046&ts=1&ltd=0&p=0&rf=35331319&lm=0&tsrc=0&ver=3
Attachments
moon_diameter.jpg
Moon from Earth
Selden


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