That’s actually not that hard. You need a long lens. there are a few websites that tell you when the ISS crosses the sun in your area with exact time of the cr

That’s actually not that hard. You need a long lens. there are a few websites that tell you when the ISS crosses the sun in your area with exact time of the crossing. When the time comes, you set up your camera with a solar filter and do a burst for a few seconds. I have done it a few times and I am always surprised that it works. While taking the pictures you see nothing so you have to totally rely on the exact time. But it always works out. Same for the moon.