Call this the exciting finale to my latest article trilogy. In my first two posts, I explained how I photographed the Sun and Moon on back-to-back days with essentially the same equipment, but also demonstrated the key differences. Here, I take a look at both posted images side-by-side.
Because I used the same telescope, eyepiece, and camera setup, we can gauge the apparent sizes of the Sun and Moon to each other as seen from my vantage on Earth. Four years ago, I did a very similar comparison of Venus, Jupiter, and Saturn as shown through my Dobsonian telescope. Both of these Sun and Moon images were take with NightCap on my iPhone, so the proportions and field of view are exactly the same.
I drew two red horizontal lines to highlight how the Sun’s image is wider in total diameter at this point in time, February 2022. So right now, the Moon appears “smaller” than the Sun, and I will take the reasonable guess, without looking it up, that this is due to the position of the Earth’s orbit being at or near its closest approach to the Sun this time of year (i.e. near its perigee).
One does not need to be an astrophysicist to conclude that given this relative size difference, it is not possible to have a total solar eclipse in this present orbital configuration. The Moon is seen right now as smaller than the Sun, and though it could cover all but a portion of the Sun’s circumference, it would be impossible to completely block all of the Sun’s light. I am sure it is possible at apogee, when the Earth is farthest from the Sun, hence the Sun will appear smaller. I should try this exercise again in six months.
Another factor is that the Moon’s relative size from Earth is always changing as well.
(If my understanding of a total solar eclipse is wrong, please let me know in the comments section!)