I can't follow exactly what happened from this string of tweets - I'm not really twitter-literate. It seems like there was a predicted conjunction of the ISS with the moon, and an actual video of what could be a satellite crossing in front of the moon.

However, it looks like the trajectory is roughly parallel to the moon's terminator?

Can anyone reconstruct this? We have a timestamp, a distinct crater Theophilus on the terminator, and possible IDs both as a Russian satellite and a Ferrari. Are there "reverse-satellite-lookups?"


Manual Screenshot of the tweet, showing (presumably) a speeding satellite as a little blurred white thing moving roughly parallel to the moon's terminator. The tweeted image says it's a GIF, but it's not!

screen shot of tweet


2 Answers 2


I had difficulty with the site in the other answer, so I tried a newer website.

It turns out the ISS did indeed pass by the moon about a minute later.

Home-made GIF from screenshots:

The Moon is the Purple Dot and CRS-8 is shown together with ISS

TIME in UTC is shown just above the image on the left.

enter image description here

The satellite that transited the moon seen from the Royal Observatory is Reseurs DK-1 a Russian civilian remote-sensing spacecraft (i.e. 0.9m resolution earth-pointing telescope) that looks pretty amazing! .


Here is the screenshot again from the original tweeted GIF which is really a faux-GIF. The short white streak in the lower-left is probably the DK-1 satellite moving fast in LEO. Since this is just after sunset locally, the satellite, at an altitude of 572km here, is probably still in full sunlight and therefore very bright!

screenshot twitter.com/ROGAstronomers/status/720254837095575552

The crater is Theophilus and this image from the linked tweet shows the sun rising on the central peak of the crater, taken with the 28 inch Refractor at the Royal Observatory Grenwich.

from twitter.com/ROGAstronomers/status/720541433837568000

The crater is nearest the Apollo 16 landing site.

Theophilus crater in google.com/moon

The satellite trajectory data was obtained like this. I used user-specified location instead of the London preset, to make sure the time was UTC.

in-the-sky.org setup


I just used the CalSky web tool. When set up for a location and a timeframe, this should be able to predict close ISS passes to the sun or moon.

When I set it up for London, there are no ISS passes that close to the moon for that date.

But trying the Resurs DK-1 satellite shows a good match.

This link should show the pass from london at that time. You can see it shows a pass near the moon along the general direction of the terminator.

  • $\begingroup$ The link doesn't work for me - it resets to current time and my local coordinates. When I change to 12-4-2016 20:15:00 UT, and Grenwich, London, UK (51.48N, 0.0E) I DO see the ISS pass next to the moon and a larger ZOOM shown here, but I don't know how to add the satellites. $\endgroup$
    – uhoh
    Apr 14, 2016 at 22:55
  • $\begingroup$ After you set the location and timezone, Click the "satellites" tab, then underneath, "satellites within interval". On that page, set the time and a short interval. After you hit "go" you should be able to scroll down and see sats visible from during the interval. One is DK-1. On that line, click the "star chart" link. $\endgroup$
    – BowlOfRed
    Apr 14, 2016 at 23:01
  • $\begingroup$ I can't get it to work for some reason. I was able to generate those maps in my first comment showing the ISS passing the moon, which seems to be at about 19:38 BST which is daylight time and would be 20:38 UTC. Apparently the site uses local time and you have to KNOW if it is daylight time or not - times are listed without reference to what time zone is used! However it seems that there WAS a pass of the ISS near the moon. $\endgroup$
    – uhoh
    Apr 15, 2016 at 0:23
  • $\begingroup$ Timezone is set in intro. Step 1 is location, Step 2 is timezone. Once that is set, should be easier to plug in the time and see the sat passes. $\endgroup$
    – BowlOfRed
    Apr 15, 2016 at 7:05

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