This infographic is from Gowrishankar Lakshminarayanan of New York. He’s comparing the size of the sun’s disk when Earth is at aphelion (farthest point from the sun, every July) and perihelion (closest point to the sun, every January). He wrote:
As you know, Earth was at perihelion on January 3, 2019. I was lucky to do solar imaging over the weekend on January 6 and compare it with solar images I had captured in July 2017, the day before aphelion.
Also, from Fred Espenak’s website, I gathered the ephemeris data to find the months where Earth is at approximately one A.U. – one average Earth-sun distance – and it turns out it’s in the initial weeks of April and September. That average distance should yield the average size of the sun in our sky. I created another comparison chart for the aphelion, perihelion and average-distance sun. I had taken a shot of the solar disk in September 2017 (when the sun was quite active, with many sunspots).
All shot @ 800mm with Thousand Oaks Optical Filter using my Canon 5D Mark III, Canon EF 100-400mm F4.5-F5.6 L Lens with 2x Extender.
If I keep the aphelion sun as reference, the sun at perihelion is approximately 3.4 percent bigger. Hard to notice but perhaps still significant in the astronomy world.
Thank you, Gowri!
Bottom line: Composite image showing comparing the size of the sun as seen in Earth’s sky at at aphelion (farthest point from the sun, every July), average distance, and perihelion (closest point to the sun, every January).
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.