Why are Starlink "Racetrack" Flares [Mostly] Reported from Planes?


Senior Member
If your graph was accurate, the flare ought to be reddish, from the sunlight passing through a lot of atmosphere.

Does the angle at the center of the Earth correspond to the actual positions of observer and identified satellites?

What are you basing your 90⁰ sighting angle on? (perfect observer line vs. radius)

I think it is possible that the normal vector of whatever surface is reflecting the sun on the satellite may not be aligned with the center of the Earth, i.e. it might be tilted slightly north or south. Can we determine this from the data?
We've seen from the videos of the pilots that the flares scintillate as we expect.

Mick West

Staff member
If your graph was accurate, the flare ought to be reddish, from the sunlight passing through a lot of atmosphere.
I think if it it was reddish, then the sunlight would be being attenuated to the degree that it would not be visible to the naked eye. Consider that you can see the shape of the sun at sunset, which normally takes a very powerful ND filter. Starlinks in direct white sunlight are would probably not be visible with such a filter.

Red flares would happen though, just super dim. Possibly visible in NV.


Senior Member.
Yes it does, however this is a 2d model that is taken from a slice of a 3d Globe. The actual angle is a function of both the lat and long of the observer and directly below (nadir) of the satellite. Haven't quite worked out the formula for that yet.
The haversine formula determines the great-circle distance between two points on a sphere given their longitudes and latitudes.

assuming you have lat/long for the satellite


Senior Member.
Staff member
assuming you have lat/long for the satellite
Yes you can use the haversine furniture in specific scenarios when you have the lat long of the observer and the satellite. One you've calculatied the straight line surface distance you can compare this to the earth's circumference, which will produce a fraction. Taking this fraction of 360° then gives you the angle between the two radii from the centre of the earth.

In my post above I was referring more to modelling it in 3d (although admittedly I did state 'formula').

Easy Muffin

Senior Member
I haven't got night vision equipment but If the weather's playing along I might pack my camera, head out and try to get them in a long exposure. I guess it would be interesting to see at what elevation they flare out.
So I had the evening to myself and decided to give it a try. I visually spotted three flares at the predicted time and spot near the star Altair. If you knew what to look for you couldn't miss them but they weren't bright enough to draw your attention if you happened to simply look in that direction. The exeption was at peak intensity, which lasted for about five seconds, at which point they brightened to about the magnitude of Altair. They seemed brightest around 5° and flared out around 7°. Individually they reminded me of a low-intensity Iridium flare but the repeating nature of two or more of these was quite extraordinary. I knew exactly what was going to happen and it still weirded me out a little bit. I can certainly see how this might fool people into thinking it's something else.

Unfortunately I didn't manage to take a picture of these as I was still busy setting up my camera. At the time I think I was busy taking the dark frame image of all things to reduce image noise in post so I didn't even have the lens cap off yet...
Anyway this I think is the best I got. Doesn't look like much yet in this version, Altair is the bright streak just right of centre.


But you can see some upwards streaks in this edited larger crop.


They're very faint and I didn't see them with the naked eye but they match Starlink passes at that time.

ISO 800
109 seconds exposure time


Active Member

Why are Starlink "Racetrack" Flares [Mostly] Reported from Planes?​

But this thread is more about why the pilots are seeing and reporting them. i.e., why are they particularly visible from planes.
maybe Im stupid, but isnt that kinda obvious? the why, I mean. lots of light pollution on the ground, people not looking all the time up, especially at night in cities (staring at very bright smartphonescreens instead)...pilots at night looking out the window most of the time, very dim cockpit illumination, hence better nightsight of the pilots, almost no light pollution outside (especially over oceans), flying above most clouds, flying high up, less atmospheric disturbance...



Senior Member.
Staff member
maybe Im stupid, but isnt that kinda obvious? the why, I mean. lots of light
Yes all the factors you state are true, but the not quite so obvious factor is the orientation of the Starlink chassis that, in ideal conditions, will actually reflect the sun's light past any observer on the ground. The brightest part of the flare will only be seen by those at altitude, with only the edges of the reflection being seen from the ground.


The flares are now being seen and reported from the ground, I've seen them for the last 3 nights in a row. please see the other thread....



Senior Member.
Staff member
Yesterday I was contacted via DM by a pilot on PPrune.org (the Professional Pilots Rumour Network) who had read my comments on the thread "Light show between 40 and 30 West" . He was flying over the Bay of Biscay at 0400Z on the morning of 14 Feb 23 and saw the Starlink flares phenomenon. He took some photos and they show that they were visible towards the NE close to the horizon.

I had hypothesised that the region that the phenomenon would be visible would move south as the seasons progressed into spring. I could see the flares from my location in the UK around Christmas time, but in January the sun was getting to -40 degrees later in the day and moving closer to North. This meant that there wouldn't be enough Satellites in the right position to generate flares for me so I could no longer see them. I thought that you'd need to be further south to see them. This sighting from the Bay of Biscay seems to confirm that idea.

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Senior Member.
Staff member

'We're not crazy': Listen to a flight report unusual lights near Yellowknife in January:​

Air traffic controllers and an approaching flight couldn't identify "two white lights … moving in a circular pattern" that were reported over Yellowknife late at night on Jan. 29.

"Good evening, just wondering, do you got two planes that are just to the east of your field doing circuits or manoeuvres?" a crew member aboard a Canadian North flight from Fort McMurray, Alta., to Yellowknife, N.W.T., asked as it approached the city in northern Canada around 11:15 p.m. local time.

"Negative, I have no reported traffic in the area," an air traffic controller in Yellowknife replied. "Do you have a visual on something?"

"Yeah, we're looking at two lights dancing around here, to the east of your field," the crew of the twin turboprop Canadian North aircraft said. "They're above us, about, I don't know what. We're not seeing them on TCAS (traffic collision avoidance system). But we can see the lights moving around."

I don't have anything on the radar either. Let me talk to centre," the tower responded, likely referring to a flight information centre or flight control centre.

A moment later, the air traffic controller was back on the radio.

"Hey, centre doesn’t have anything about any movement in the area, so I'm really wondering what you're seeing there," they said.

"Yeah, so are we," the flight answered.

"All right, I'm trying to look," air traffic control said, likely peering out of a tower window. "I don't see them from the ground here. Well, I'll keep an eye out. I'll talk with centre again."

"Yeah, no worries," the crew replied. "They're not a risk to us."

Based in the Ottawa suburb Kanata, Canadian North services multiple destinations across northern Canada. As the flight got closer to Yellowknife, the Canadian North crew described seeing the lights "moving around in a circular pattern" well above them, approximately 20 kilometres northwest of the airport.

"We'll talk on the ground," the air traffic controller said. "I'll file a CIRVIS report – this is when we have some sightings that we cannot explain."

Civilian air traffic control in Canada is operated by the private company Nav Canada. According to Nav Canada aviation guidelines, CIRVIS reports – short for "Communication Instructions for Reporting Vital Intelligence Sightings" – should be made "immediately upon a vital intelligence sighting of any airborne and ground objects or activities that appear to be hostile, suspicious, unidentified or engaged in possible illegal smuggling activity." Nav Canada even puts "unidentified flying objects" at the front of a list of "vital intelligence sighting" examples, which also include "submarines, or surface warships identified as being non-Canadian or non-American."

The air traffic controller comes back on the radio again to ask what colour the lights are.

"White," is the reply.

"Roger, thanks."

There's then a pause before the crew member comes back on the radio to say, "We're not crazy."

"No, we believe you."

Source: https://youtu.be/Q6JgyhoCyi8

Filed UFO Report....



So... are these Starlink flares...? Lets look at the evidence.

Location of the Plane:


61.97374° N -114.27012° W

Location and position of the sun at 29 Jan 2023 23.15 Local:

(We know that Starlink flares only occur when the sun is around 40 degrees below the horizon)



Sun angle below horizon -42° (this is as we'd expect for Starlink flares, as mentioned in other threads)
Direction of sun 327° = NNW

Checking for the position of Starlink satellites in the sky at 29 Jan 2023 2315 Local (UTC-7)


So, this shows that there were Starlink satellites visible from the aircraft's location at the time of the sighting, and that they meet the conditions for Starlink flares that we have seen in other cases.

This case is interesting because I initially dismissed it due to the location being too far north, but upon proper investigation and checking the data it shows that it was a canditate for Starlink flares.

[edit: changed IntheSky.org snip to local time rather than UTC]
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Easy Muffin

Senior Member
This case is interesting because I initially dismissed it due to the location being too far north, but upon proper investigation and checking the data it shows that it was a canditate for Starlink flares.
Too far north for the majority of SL sats in the lower inclination orbits but in the right spot for the 97.6° high inclination groups, which pass near 83° N when they reach the northernmost point of their orbits.



Senior Member.
Staff member
And there's more...



Source: https://youtu.be/yuwQMa0xL28

location and time fits for the sun position:


Canadian CADORS Report


These are the three aircraft mentioned in the report, all heading northeast , which is directly towards the sun azimuth over the horizon.


Snip of the aircraft data including the track heading.

Snip from https://in-the-sky.org/satmap_planetarium.php for the location, date and time of the sighting shows that the usual concentration of Starlink satellites.
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New Member
Another video posted by pilot Gary Michael from LA to Boston on the 27th of Feb. Mentions observing a number of lights on the horizon for 15 minutes, other pilots reporting the same. Video of the lights is at 1:12 mark. Sun was well below 40 degrees in the predawn hours on approach to Boston. Not sure which direction he was filming when he filmed the lights.
Edit: Actually, I think the stars to the left of the lights are Deneb, Sadr and Aljanah, and the pilot said he was flying over southern Illinois.

Source: https://www.tiktok.com/@garybpilot/video/7205817721546755374?_t=8aK5ZqPmIw7&_r=1
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Senior Member.
Staff member
This is from 10 March 2023 - I have asked for date and location.

Source: https://twitter.com/JeremyKeen13/status/1634547858392186881?s=20

Source: https://www.youtube.com/watch?v=65qTWLSF5qs&feature=youtu.be&ab_channel=WilkesAviation

Wilkes Aviation LLC appears to be based out of Watertown South Dakota.

The are three stars visible above the 'strange lights', these appear to be from the constellation Cygnus, which (if we assume the video was taken over CONUS) currently rises in the early hours of the morning towards the Northeast. This is again consistent with the conditions under which Starlink Flares occur.

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Senior Member.
Staff member
From the Original poster on Twitter...

Details: Flying Eastbound toward Montreal, 150 miles out, 02:00 local time.
“They will change directions, go up, down, left right, sometimes close together, sometime farther apart, disappear from view and then return a minute later. Round bright white flashes closer to our altitude, and a lot closer range, also in the area but those are random” -Pilot

I've taken Kingston ON as the rough position of the aircraft (roughly 150miles west of Montreal). I'm a bit dubious about the statement of "02:00 local time" as this is often the pilots phone time at the departure airport, which we don't know yet, although we can assume was west of Montreal/Quebec. I'm also suspicious of times that are "o'clock" as they are often just a rough estimate. I have asked the OP to request the exact video time from the pilot. However, checking at 3am Canadian EST shows that there were Starlink satellites emerging from the earth's shadow just under Cygnus. And the Sun position checks out too.


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