Park School Astronomy Club

http://www.fullmoon.info/en/blog/fullmoon-blue-moon.html

Angular Measurement Consider the following convention which has been with us since the rise of Babylonian mathematics: There are 360 degrees per circle. Each degree can be further divided into 60 minutes (60'), each called an arcminute. Each arcminute can be divided into 60 seconds (60"), each called an arcsecond. Therefore, there are 3600 arcseconds in one degree . Some rough approximations: A fist extended at arm's length subtends an angle of approx. 10º. A thumb extended at arm's length subtends an angle of approx. 2º. The Moon (and Sun) subtend an angle of approx. 0.5º. Human eye resolution (the ability to distinguish between 2 adjacent objects) is limited to about 1 arcminute – roughly the diameter of a dime at 60-m.  Actually, given the size of our retina, we're limited to a resolution of roughly 3' So, to achieve better resolution, we need more aperture (ie., telescopes). The Earth's atmosphere limits detail resolution to obje

https://in-the-sky.org/solarsystem.php http://www.theplanetstoday.com/ https://www.fourmilab.ch/solar/ http://www.fourmilab.ch/earthview/vplanet.html https://www.fourmilab.ch/cgi-bin/Solar/action?sys=-Si