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Discussion: Starlink L23 group pass Wed night

in: ken; ken > 2021-04-06

Apr 7, 2021 5:59 AM # 
eddie:
Assuming an on-time launch at 12:34 PM EDT today (Wed, Apr 7), the Starlink L23 group will make a nice visible pass over D.C. and the mid-Atlantic on its 6th orbit tonight at 8:30 PM EDT. Here's the sky chart for D.C. Will pass very close to the Pleiades, Aldebaran, Beetlejuice, above Orion's belt and the bright star Sirius. Mars is a nondescript orange dot above Aldebaran right now.

Max elevation 44 deg for D.C., higher for points south and lower toward the north but still quite good up to Philly. The group of sats should still be very compact at this point, and at only 260 km alt. I haven't seen a group this soon after launch so not sure how bright it will be, but this is the best time to look. Should appear as a short string of pearls with all 60 sats maybe 10s apart. Should have individual orbits by sunset for a better estimate of the spread. Sky will be nice and dark by 8:30, with no moon. Worth a look even if partly cloudy.
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Apr 7, 2021 6:08 AM # 
eddie:
Also I missed this in the news, but a falcon 9 second stage from an earlier Starlink launch accidentally re-entered over Seattle a couple of weeks ago. Normally they are dumped into the Pacific, but there was a problem with the de-orbit burn - low fuel or something. Some neat doorbell cam movies over the Sound at space.com. A Helium tank survived and landed on a farm in central Washington. I presume the tank (COPV) that reached the ground is a re-design of the same type that caused the pad explosion and loss of the AMOS 6 sat back in 2016.
Apr 7, 2021 4:15 PM # 
eddie:
Countdown still proceeding normally. Livestream starting in a few mins:

https://www.spacex.com/launches/
Apr 7, 2021 5:47 PM # 
eddie:
On-time launch, good orbit, good deploy. I'll post this evening if they revise the orbits.

They showed an unusual view of the landing on the livestream today, from the 1st stage onboard camera all the way through landing leg deploy to touchdown on the barge. You can watch it in the replay at the link above from T+8:00 to T+8:38 mins. Neat to see the ocean swells and the shadow of the vehicle on the surface of the water.
Apr 7, 2021 11:10 PM # 
eddie:
No updates on the orbit, so just have to rely on the preliminary timing. Give it a few mins on either side of 8:30 to be sure.
Apr 8, 2021 1:41 AM # 
eddie:
I saw it. It was bright enough to see naked-eye when the pass first started, low in the NW. I got four 1/4s exposures before it went into the clouds. When it came out it flashed once and then I couldn't see it. Pointed the camera again, at Orion, but didn't expose because I couldn't see anything. That was a mistake - camera is more sensitive than the eye. Should have just fired blind. Didn't get anything after that. You can see the individual sats in the pic. It was a very short string - maybe 1s from end to end. They're still very close together after 6 orbits.

I think the sun was glinting off the flat surfaces while it was lower on the horizon, then no glint up high.

Were you able to get out for a look?
Apr 8, 2021 7:42 PM # 
eddie:
One more pass tonight (Thurs). Same timing and direction, but lower elevation. That might actually be better in terms of sun glint. Start watching at the very start of the pass, due west. Orbits for all the sats have been posted. The spread should be about 16s tonight. It was 2s last night. Here's the sky chart for D.C.:

https://www.heavens-above.com/passdetails.aspx?lat...
Apr 9, 2021 2:22 PM # 
ken:
Was out running during the first one, forgot to look up.

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