Register | Login
Attackpoint - performance and training tools for orienteering athletes

Discussion: Starlink L23 group pass Wed night

in: biggins; biggins > 2021-04-04

Apr 7, 2021 6:57 AM # 
eddie:
Assuming an on-time launch at 9:34 AM PDT today (Wed, Apr 7), the Starlink group L23 bunch will make a nice visible pass over Truckee on its 8th orbit tonight at 8:30 PM PDT. Here's the sky chart for Truckee Will pass through Orion just below and along the belt (very close to the Great Nebula in the sword), then on past the bright blue star Sirius. Mars is a nondescript orange dot above Aldebaran right now.

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 10-15s 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. I should be able to provide a brightness report after the east coast pass 3 hrs earlier.

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.
Advertisement  
Apr 7, 2021 4:16 PM # 
eddie:
Countdown still proceeding normally. Livestream starting in a few mins:

https://www.spacex.com/launches/
Apr 7, 2021 5:48 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 (27 mins into the video). Neat to see the ocean swells and the shadow of the vehicle on the surface of the water.
Apr 8, 2021 1:50 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 at f/4.5 105 gain 800 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. Be sure to watch the beginning of the pass closely as it will probably be brightest there. You might be able to see more of the pass under your dark skies, but in any case maybe pick a spot along the pass and let the shutter rip. I'd probably go with even shorter exps to get less trailing to see the individual sats. Maybe 1/10s. Video would work if you have enough aperture. Use big glass and a wide stop.
Apr 8, 2021 2:17 AM # 
eddie:
Greg, I just sent you a .kml file for tonight's Truckee pass (to gmail). You can use it in google earth to simulate ground views. The one I made for Baltimore seemed accurate, at least for the part of the pass I could see :)
Apr 8, 2021 8:50 AM # 
biggins:
That onboard camera view during the landing is pretty cool. A lot better than the ones on the ship that always cut out just at the exciting part.
Apr 8, 2021 1:39 PM # 
eddie:
Yeah, I wonder why they haven't tried to fix that. Seems like buffering the vid and sending it on a 30s delay would do the trick. Viewers wouldn't know the difference and at least we'd get to see it. Its a bit like Charlie Brown and the football. "This time I know he's gonna kick it for sure!" Aww, rats. 79 landings and still no field goals.
Apr 8, 2021 7:47 PM # 
eddie:
One more pass for this group tonight. Same timing and direction, just lower in the sky. That might actually be better for the lighting. Here's the sky chart for Truckee (times are PDT):

https://www.heavens-above.com/passdetails.aspx?lat...

Timing will be about the same for the rest of SoCal, with the pass a little higher. 16s spread on the sats tonight. It was 2s last night.
Apr 9, 2021 2:33 AM # 
eddie:
No luck for me tonight. Didn't see or photograph anything. There was a thick cloud low on the W horizon, but the expected path just above it seemed clear.
Apr 9, 2021 3:44 AM # 
biggins:
Nothing here. It's crystal clear but we couldn't see anything. They must have turned their lights off.

Please login to add a message.