2021-05-26 - Downey, CA - Unknown

Saw an unknown object through telescope pass in front of the Moon during Lunar Eclispe

Date: 26 May 2021 Location: Downey, CA. Lat. 33.928N Long. 118.0134W Elev. 37m Time: Approximately 02:52 PDT Temp. 62°F, RH 93% Mostly Cloudy Wind Calm I've been an amateur astronomer for 18 years and it was also a hobby of mine for a few years growing up. This is the second telescope I've owned and have had it since January 2003. I've viewed 6 planets with it, Orion Nebula, star clusters, and at least a dozen total lunar eclipses. I've seen the ISS and the Space Shuttle Orbiters docked and undocked through binoculars and with the naked eye. I've watched the Geminid Meteors a half a dozen times and have viewed several comets. I'm familiar with most of the Northern Hemisphere constellations and the stars in them visible to me. I'd like to think I know what I'm looking at in the night sky.

I was viewing the beginning of the umbral phase of the total lunar eclipse through my 6" Dobsonian, focal ratio f/8. It has a resolution of 0.77 arcseconds. I was using a 25mm Plossl eyepiece which yields AFOV = 1.2° (Actual Field of View) at 48x magnification.

The umbral phase of the total eclipse began at 02:44 PDT (local time). I expected overcast skies so I didn't bother to even check conditions until 02:40 PDT. Even though the sky was mostly cloudy the Full Moon was visible through some light haze. I quickly set up on my front yard but then had to move to the driveway. By this time the Moon had already began to move into Earth's shadow (umbra) at about the 8 o'clock position on the Moon's face. I quickly brought the Moon into view through the telescope. The Moon covers about 0.5° in the sky and fills about half of my field of view with the aforementioned setup. I took a few picture with a digital camera just by holding it up to the eyepiece of the telescope. By now it was about 02:52 PDT. I took another look to see if I had to adjust the telescope to keep the entire Moon in view. This must be done every 1-2 minutes to keep it centered. As I looked with the entire Moon still within the field of view I saw a very small black o! bject travel across my field of view in a straight line from right to left very near where the equator would be. This took about 3-4 seconds. There were no lights on the object and it was only visible when passing in front of the moon. A characteristic of a reflecting telescopes is that they invert the object being viewed 180°. So top is bottom and left is right etc. So in reality it was traveling left to right or east to west. It was in focus and was too small to accurately determine any shape. I continued to view the eclipse, adjust the telescope as needed, and take a few more pictures. Then about 10 minutes later I saw the same thing again. By about 3:15 PDT the sky was completely overcast and the Moon was no longer visible.

I did some calculations using the distance the Moon was from the Earth at that time 357,422km and the resolution of my telescope 0.77 arcseconds. The smallest object I can see at that distance would be at least 1,330 meters which is 0.82 miles. I have heard other reports where people said what they saw was larger than this. The largest object in orbit is the ISS which is 109 meters and orbits at about 400km from Earth. I thought it could possibly be small satellite thousands of miles high but they all orbit in the opposite direction than this did.