May 15, 2022

a cautionary autobiography
May 15, 2022
Last year I got a reasonably sharp photo of a full moon with a Nikon D7200 using the $500 Nikkor 18-300mm zoom lens at f/6.3, 1/160 second, ISO 160. This month I pulled out an old Nikon D3100 and a $100 catadioptric 500mm f/8 lens for a bigger challenge: The cheaper lens really falls short in terms of sharpness. Here is the best I could do with each lens (the more recent shot on the right is colored by atmospheric smoke from western wildfires):
But right now there are some interesting astronomical phenomena: Mars is near its closest approach to earth and is visible to the naked eye. Here the moon passes about one degree below the red plant (top left):
I turned the camera on Jupiter, which is presently close to Saturn and very prominent in the night sky. With the same lens, shooting 1/2 second at ISO 800, I get the following photo showing all four Galilean moons:
Last night after sundown I happened to be outside looking up at the waxing gibbous moon when I saw a satellite zipping near it in low earth orbit. And not far behind it another. And another – all spaced roughly 15 seconds (travel time, north to south) apart on the same orbit. They kept coming in what appeared to be an unbroken chain, and I could clearly see six to seven of them at a time. That’s an astonishingly dense satellite network, so it made me wonder if it was part of the astonishingly large LEO satellite network being built by Starlink.
Today I tried to confirm what satellites I could have been seeing, and it looks like there was indeed a Starlink train passing overhead at that time. The reason they were so close together is that Starlink satellites are launched 60 at a time in “trains” that gradually spread to the network’s operational altitude and separation. I must have spotted this one near the beginning of its transit of my location.
So that was very exciting, but I didn’t have equipment adequate to record it. Instead, here is a photo of a full moon I captured with a Nikon 7200 DX and 300mm lens last November: