Inspiration4 Crew Dragon over the old Leiden Observatory

click to enlarge

 

The image above, which I shot yesterday evening (16 September 2021) around 19:24 UT, shows the SpaceX Crew Dragon Inspiration 4 with astronauts Hayley Arceneaux, Christopher Sembroski, Sian Proctor and Jared Isaacman onboard, over one of the domes of the old Leiden Observatory. This observatory is located in the center of Leiden, the Netherlands, close to my home.

The photograph is a stack of 37 1-second images taken between 19:24:05 and 19:25:19 UT with a Canon EOS 80D and EF 2.5/50 mm lens (at 800 ISO). The dome is the dome of the 50-cm Zundermann telescope. The brightest "star" is Jupiter, and the second trail near the bottom of the image next to the dome is an aircraft.

Inspiration 4 is the first Crew Dragon mission that was not commissioned by NASA and does not go to the International Space Station. Instead it will orbit for 3 days at an altitude of 570 x 580 km. The orbital plane is inclined by 51.6 degrees and does match the ISS orbital plane, although not the ISS orbital altitude. It was chosen so that the launch could use existing emergency and abort facilities on the launch track. 

Inspiration4 (2021-084A) was launched from pad 39A at Cape Canaveral on 16 September 2021 at 00:02:56 UT. The launch coincided, with a difference of only a few minutes, with a pass of the ISS:

 

While I was photographing the pass (which was a low elevation pass in late twilight at 25 degrees maximum elevation) from a spot at the Witte Singel opposite the observatory, my video setup was running on an automated schedule from my loft window and captured the spacecraft as well (WATEC 902H2 Supreme camera with 1.4/35 mm lens at 25 fps):

The front group of Starlink V1.0 - L26

On May 15, yet another batch of SpaceX Starlink satellites was launched, and they are currently making evening and early night passes over Europe. Since launch, the resulting 'train' of satellites from the launch has split into two distinct groups passing a few minutes after each other.

The video above is from yesterday night (19 May 2021 ~23:17 UT) and shows the leading group, which is still quite tight. The trailing group (also captured but not shown in this video clip) is more dispersed. The video was shot with my DSLR: Canon EOS 80D + Samyang 1.4/85 mm lens.

A night earlier, I captured both the leading and trailing group with the WATEC 902H2 Supreme + FD 1.8/50 mm lens (see video below). They were naked eye during that pass.

Apparent failed deorbit of the Starlink-18 Falcon 9 upper stage [UPDATED]

On 4 March 2021, after several delays, SpaceX launched the 18th Starlink batch (Starlink-18 or V1.0-17). While the launch and deployment profile appears to have been similar to other recent Starlink launches, it appears that something went wrong with the Falcon 9 upper stage near the end of its mission.

On March 8th, Polish observer Adam Hurcewicz reported a bright, fast object in the orbital plane of this launch, passing a few minutes before the main Starlink "train". It was seen on subsequent nights and by other observers as well: the video above is from the early morning of March 9. At it's brightest, this fast moving object reportedly reaches mag -3. It does not appear to match a known object from earlier launches. It also didn't match supplementary TLE's for the Starlink-18 payloads from Celestrak (which are based on State Vectors from SpaceX). The Polish observers therefore speculated it was the Falcon 9 upper stage from the launch. 

But that would be against expectations. The Falcon 9 upper stage normally does not stay in orbit: it is de-orbitted soon after payload release, usually about 1.5 revolutions (about 2.5 hours) after launch. So if this object is the Falcon 9 upper stage, this suggests  something went wrong and it failed to deorbit.

The speculation that this object is the Falcon 9 Upper Stage can now be bolstered by additional information. The first orbital element sets for this Starlink launch have appeared on the CSpOC portal  Space-Track late yesterday (11 March), with catalogue numbers ranging from 47722 to 47786. And they show an extra object!

With Starlink launches, 64 objects are usually catalogued: 60 payloads and four 'Falcon 9 debris' pieces. The latter 'debris' pieces are the payload stack retaining rods: four metal rods which keep the satellite stack together on top of the upper stage. They are jettisoned upon payload release.

An elset for the Falcon 9 upper stage is usually not released by CSpOC: as it normally stays on-orbit for barely more than 1 revolution, it is not catalogued.

But this time, not 64 but 65 objects have been catalogued. The extra 65th object must be the Falcon 9 upper stage, and it indicates it stayed on orbit for more than a few revolutions. Which lines up with the observations by the Polish (and later also other) observers.

Although the 65 objects, at the moment of writing, do not have been individually ID-ed by CSpOC yet (all have the temporary designation "TBA - TO BE ASSIGNED"), the 60 payloads, four retaining rods and the upper stage as such can be clearly identified among them. The objects separate in 3 groups in terms of orbital altitude. The 60 payloads all have (for orbits with epoch 12 March) a perigee above 280 km. The four retaining rods have clearly lower orbits: their perigee is near 243-246 km and apogee near 268-278 km.

The 65th object, which by inference must be the Falcon 9 upper stage, is in a still lower orbit . It has the smallest semi-major axis of all of them with perigee near 237 km and apogee near 270 km. The orbit for this object, catalogue nr 47782 (2021-071BN) also closely matches the observations by the Polish observers.

So why is the Falcon 9 upper stage still on-orbit? It suggests of course that the deorbit went not as planned, i.e. it failed for some reason (e.g. the rocket engine refusing to restart).

That the Falcon 9 upper stage should have deorbitted on March 4, after 1.5 revolutions, is clear from the Navigational Warnings that were issued in connection to this launch. Navigational Warning HYDROPAC 695/21 delineates the usual elongated deorbit zone in the Indian Ocean familiar from earlier Starlink launches:

 

021948Z MAR 21
HYDROPAC 695/21(GEN).
SOUTHERN INDIAN OCEAN.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS
   041024Z TO 041326Z MAR,
   ALTERNATE 051004Z TO 051306Z MAR
   IN AREA BOUND BY
   29-43S 060-07E, 24-55S 064-27E,
   38-45S 084-30E, 45-12S 099-45E,
   49-46S 119-13E, 50-42S 138-19E,
   48-50S 156-44E, 51-46S 158-08E,
   54-42S 148-32E, 56-20S 131-03E,
   55-52S 107-50E, 49-11S 085-05E,
   34-32S 064-13E.
2. CANCEL HYDROPAC 685/21.
3. CANCEL THIS MSG 051406Z MAR 21.

I have plotted the zones from the Area Warnings connected to the launch in this map, along with the groundtrack for the first 1.5 orbital revolutions. The large elongated red zone in the southern Indian Ocean is the planned deorbit area from Navigational Warning HYDROPAC 695/21:

click map to enlarge

The position of the reentry hazard zone indicates a reentry was planned around 10:55 UT (March 4), 1.5 revolutions (2h 30m) after launch, following a deorbit burn some 30 minutes earlier.

But the deorbit evidently did not happen as it should have: the upper stage is still orbiting as we speak, a week after launch. The issued Navigational Warning for the deorbit hazard zone strongly suggests this is not intentional.

So how long will the upper stage stay in orbit? The current orbit is low (237 x 271 km), and the object is large (16 x 3.66 meter, with a mass of 4.5 tons) so eventually the rocket stage will have an uncontrolled reentry, somewhere between latitudes 53 deg N and 53 deg S. 

A first assessment using both SatEvo and a GMAT simulation suggests that the reentry will probably happen in the last few days of March or the first few days of April.

UPDATE 14 March 2021:
CSpOC has now added identifications to the objects, and indeed object 47782 is now listed as "Falcon 9 RB"

Imaging a pass of the Crew Dragon Demo-2, and a close fly-by of the Crew Dragon by USA 245! [UPDATED]

click photograph to enlarge

Yesterday May 30 at 19:22 UT finally saw the launch of the SpaceX Crew Dragon Demo-2 with astronauts Hurley and Behnken on board, returning a human spaceflight capability to the USA after nine years of having to hitch rides on a Russian Soyuz.

When the Crew Dragon first passed over the Netherlands some 23 minutes after launch (see map with the launch trajectory in  a previous post), the sun was still just above the horizon for my Leiden location. I nevertheless tried with binoculars, using the moon as a guide, but saw nothing.

But two hours after launch on the second revolution, near 21:18 UT, we did have a visible pass, albeit in late twilight and very low above the horizon: at a maximum elevation of only 9 degrees over the horizon and a range of almost 1200 km!

To observe this pass I went by bicycle to Cronesteyn Polder at the edge of Leiden, where I have an uninterupted view to the horizon, and set up my photo camera. First, at 23:14 local time (21:14 UT), I saw the ISS pass with the naked eye low on the southwest horizon. I then took to binoculars and waited for the Crew Dragon, which should pass somewhat lower in the sky some 4 minutes after the ISS.

I picked the Crew Dragon up in my 10 x 50 binoculars starting around 21:17:30 UT, while it was passing through Crater and Corvus. I watched it untill it entered Earth shadow at about 21:19:00 UT. It was not particularly bright, due to the low elevation and still bright sky background. By comparison to stars in Corvus I estimate it to have been magnitude +3 to +3.5, too faint at this elevation and with this sky brightness to be seen naked eye. It was at a range of almost 1200 km at that time, over Northern Spain!

Click photograph to enlarge

The image above shows the Crew Dragon during this pass. It is a stack of 45 exposures of 0.5 seconds each, with a Canon EOS 80D and SamYang 1.4/85 mm lens at F2.0, 500 ISO, 21:17:40 - 21:18:09 UT (May 30). Stars in the image belong to the constellations Crater and Corvus. The small breaks in the trail are the brief moments between the successive photographs that make up the stack.

The image below is another stack, this time of 52 photographs with the same camera setup, made between 21:18:25 - 21:18:59 UT. You see the Crew Dragon disappear in Earth shadow at the left end of the image. The image is slightly wobbly - my tripod was on a soft grassy surface. I like this image best though:

Click photograph to enlarge

It was pretty cool seeing the Crew Dragon, while knowing it was carrying two astronauts!

But it becomes even more interesting: in two images around 21:18:19 UT, I have another brighter satellite moving under a slant upwards in the opposite direction. You can see it in the upper right corner of this image (several lay observers saw this brighter satellite too and mistook it for the Crew Dragon):

Click photograph to enlarge

This object is the classified US KH-11 spy satellite USA 245 (2013-043A).

And as it turns out, it was really close to the Crew Dragon, and my image truely captures, within a few seconds, the actual moment of closest approach! This was serendipity, as I had not planned this and the presence of USA 245 took me by surprise.

Nominally, the minimum distance between USA 245 and the Crew Dragon during this fly-by was only 125 km with closest approach happening at 21:18:17 UT. USA 245 was flying this distance 'above' the Crew Dragon. Both objects were over northern Spain around the time of the flyby, with the point of closest approach over 43.40 N, 2.50 W, on the Basque coast.

There is some uncertainty in the actual fly-by distance (see below), but not much.

This is the output from a COLA analysis for this fly-by:

DATE      UT          SSC   NAME    TARGET      KM  
5/30/2020 21:18:16.99 39232 USA 245 CREW DRAGON 125.3

My analysis is based on CSpOC elset epoch 20151.85044152 for the Crew Dragon, and amateur elset 20146.86101776 for USA 245. There is some leeway in the exact time and distance of the flyby, for two reasons:

1)  from my observations, the Crew Dragon was some 3 seconds late on the used elset;

2)  the USA 245 elset epoch, based on amateur observations that include my own, was 5 days old. However, the sky position of USA 245 in the image is very close to the ephemeris, so the 5-day-old orbit nevertheless seems a good fit to reality.

Taking these points into account, I estimate that the uncertainty in the minimum distance between both objects is no more than 30 km, and only a few seconds in time.

In the map below, I have plotted the trajectories of both objects (I have accounted for the fact that the Crew Dragon was ~3 seconds behind on the elset in this map). USA 245 was moving nortwest-wards, the Crew Dragon southeast-wards.

Note that the USA 245 trajectory was situated some 125 km above that of the Crew Dragon. So to be clear, there was no danger of a collision. This is a safe distance.

click map to enlarge

 This is an animation of the close fly-by:




In fact, it could very well be that this close flyby was intentional, and that USA 245 was actually imaging the Crew Dragon at that moment.

USA 245 is a KH-11 electro-optical reconnaissance satellite: a satellite that resembles the Hubble Space Telescope and makes high resolution images of the earth surface (similar to this infamous one) with resolutions of 10 cm or better.

There have long been rumors, reported by amongst others NBC News, that KH-11 satellites were used to inspect the outside of Space Shuttles post-launch (e.g. that of the inaugural STS-1 flight) for tile damage. We also suspect that KH-11 satellites inspect X-37B's after launch, based on the odd jumps in launch times of the latter (see this analysis by Bob Christy).

So there is a real possibility that this close flyby of the Crew Dragon by USA 245 was intentional, and used to image the spacecraft to see if it was not damaged and everything deployed as it should.

UPDATE 1 June 2020 13:50 UT:

I am retracting the notion of intentionality of this encounter. Both Michael Thompson and I have done an extended analysis of potential KH-11 encounters with the Crew Dragon, where we looked at potential encounters had the Crew Dragon launched on the original launch date of 27 May.

There appear to have been no particularly close encounters would the Crew Dragon have launched on May 27, which calls into question the intentionality of the encounter on May 30.

That said: it is still possible that imaging of the Crew Dragon took place, as of course this would have been a perfect opportunity. I guess we'll never know. Unless, as someone put it to me in private, tongue in cheeck: "if they put it in a briefing, maybe Trump will tweet about it!". 

The analysis also found a second close encounter for May 30, with the KH-11 satellite USA 224 (2011-002A), on 30 May 20:07:50 UT, some 45 minutes (half a revolution) after launch, with a nominal miss distance of 105 km. This however was a pass where the Crew Dragon was in Earth shadow, so not illuminated (which does not preclude infra-red imaging however). COLA output for this encounter:

DATE      UT          SSC   NAME    TARGET      KM 
5/30/2020 20:07:50.30 37348 USA 224 Crew Dragon 105.4

New attempt to launch the Crew Dragon on May 30: trajectory

screenshot from the May 27 live webcast

In an earlier post I discussed the SpaceX Crew Dragon Demo-2 launch. Originally slated for 27 May, it was postponed (with the astronauts already seated on board) because of bad weather: Tropical Storm Bertha more north on the US coast was the main culprit.

The new launch attempt will be on May 30 at about 19:22:45 UT (the subminute time comes from Spaceflight Now, not from an official SpaceX or NASA source, so is apocryphal). If that launch is scrapped to, the third backup date is May 31 near 18:59 UT.

As things currently (29 May 21:00 UT) stand, weather prospects are not that good for both these dates either, with currently a 50% chance of a weather violation on the 30th and 40% on the 31st: so perhaps we will see a scrub again.

Click map to enlarge

But in case the launch does happen on 30 May, the map above is the trajectory the Crew Dragon will fly on its first revolution (times on the map are in UT).

Some 23 minutes after launch, the Crew Dragon will pass over Europe, along this trajectory (times are inUT: add one hour to get BST and 2 hours to get CEST):

Click map to enlarge

Note the location of the day/night terminator...only eastern and southeastern Europe has sufficiently dark skies at that moment.

The launch time has shifted considerably forward compared to the May 27 original launch date, by about 1h 10m. As a result, the pass is no longer favourable for NW Europa, as the pass will be before sunset for the UK, and around sunset for coastal Europe.

Only longitudes east of say longitude 13 deg E will have a sufficiently dark sky to see it on the first revolution, so eastern and southeast Europe will have a prime seat this time.

Coastal western Europe and the UK might have, depending on your locality, a theoretical chance to see the second pass 1.5 hours later, near 21:18 UT. For most localities, that will however be a very low elevation pass though, often at a maximum elevation of les sthan 10 degrees.

At the end of this blogpost, I will provide some sky charts for several European localities for both those localities with a chance to see something of the first pass, and those who might theoretically catch the second pass.

The reason that the launch time is 1h 10m earlier on May 30 than on May 27, is that the launch time is instantanious as it is determined by the moment that the orbital plane of the ISS passes over the launch site. This time shifts back by 23m 22s each day, as is clear from this tabel in which I calculated orbital plane crossings over LC-39A (and is visualized in the illustrations below it):

ISS plane crossing over LC-39A:
-------------------------------
Date           UT   
27 May         20:36:52
28 May         20:13:30
29 May         19:50:09
30 May         19:26:47
31 May         19:03:26
-------------------------------

You can also see in the table that the actual launch time is a few minutes before the plane crossing. This has two main reasons.

One is that what is actually of relevance is the position of the orbital plane once the rocket reaches orbital height (a few minutes after launch).

The other is that the Crew Dragon initially is inserted into a ~200 km altitude orbit, which is only half the orbital altitude of the ISS. As a result, the Precession rate of the RAAN is faster than that of the ISS: so launch has to be somewhat earlier or otherwise, over the 19 hour flight, its RAAN would overshoot rather than match that of the ISS upon arrrival at the orbital altitude of the ISS.

The reason May 28 and May 29 were not chosen as backup dates, is because of a second consideration: the ISS has to be within a certain distance window to the launch site in order for the two (Crew Dragon and ISS) to meet up after 19 hours of flight. As it happens, and I am not sure that is deliberate or just a happy coincidence, this also means that on the chosen dates, docking will happen on the night-time side of the Earth (with launch on May 28 or 29 it would have happened on the daytime-side).

Below are a number of sky maps for localities that have a dark enough sky (generally: sun no less than 5 degrees below the horizon) to see the first pass, some 25 minutes (for eastern Europe) after launch near 21:46 CEST. Note that there is a time uncertainty of about 1 minute or so.

TLE's are provided below the maps.

NOTE: if you are not near one of these localities, then Heavens-Above provides you with predictions for your custom location. Please note however that Heavens-Above predictions for the second revolution (the 23:19 CEST pass over Europe) seem to be based on the TLE for the first revolution, resulting in a time difference of about 1 minute with my predictions below.(but also realise there is an uncertainty of 1-2 minutes in the estuimated orbit anyway).

Maps for locations in NW Europe might theoretically be able to see the Crew Dragon on its second revolution, near 23:18 CEST (22:18 BST), some 2 hours after launch. But in most cases this will be very low above the horizon. Please note that the time uncertainty is 1-2 minutes at least!

Here is an estimated TLE for the first revolution:

CREW DRAGON                                      initial orbit
1 70000U 20999A   20151.80474535 -.00003603  11390-4  00000+0 0    04
2 70000  51.6423 075.0039 0122953  45.6251 315.4951 15.99554646    01


And here is an estimated TLE for the second revolution:

CREW DRAGON                                      second revolution
1 70001U 20999A   20151.93029831 -.18507952  12289+0 -23808-1 0    05
2 70001  51.6233 074.5097 0096856  46.3995 314.2887 15.95177824    03

The trajectory of the upcoming Crew Dragon Demo-2 launch, returning the US to crewed spaceflight

Photo: SpaceX

UPDATE: the Crew Dragon launch has been postponed to NET 30 May, 19:22 UT

Below is the original text and maps, which are however no longer valid!
New maps in a new, separate post.

If everything goes well, SpaceX and NASA will launch the Crew Dragon Demo-2 flight with astronauts Bob Behnken and Doug Hurley to the International Space Station on 27 May 2020. The launch is slated for 20:33:33 UT (note: some sources now say 20:33:31 UT), from LC-39A.

This is a historic flight, because after a 9-year hiatus it will return NASA to a crewed flight capacity. It is the first crewed flight launching from US soil on a US rocket since the Space Shuttle program ended in 2011. Over the past 9 years, US astronauts had to hitch a ride on Russian Soyuz spacecraft in order to get to space.

The Crew Dragon Demo-2 will fly this approximate flight trajectory, bringing it over Europe some 23 minutes after launch:

click map to enlarge

click map to enlarge

The times in the map above are in UT (GMT): for CEST add +2 hours; for BST add +1 hour. I created the maps using the (uncrewed) Crew Dragon Demo-1 test flight from March 2019 as a proxy.

Based on that same Crew Dragon Demo-1 flight, I estimate these orbital elements for the first orbit:


CREW DRAGON DEMO-2   
1 70000U 20999A   20148.85443285 -.00003603  11390-4  00000+0 0    03
2 70000  51.6423 089.9835 0122953  45.6251 315.4951 15.99554646    09 

estimated initial orbit for launch at 27 May 2020, 20:33:33 UT


You can use this so called TLE (for an explanation of these numeric lines click here) to make pass predictions and maps of the trajectory in your local sky for your own location, using prediction software like HeavenSat.

Be aware that it is approximate: so allow for a possible error of 1-2 minutes in the time it will pass in your sky, and a small cross-track error (I expect this latter to be less than 1 degree, i.e. less than two moon diameters).

Weather willing,  the Crew Dragon containing the astronauts and the Falcon 9 upper stage will be visible from much of Europe some 23 minutes after launch.

Northwest Europe has it pass in twilight, but Dragon's tend to be bright, so twilight should be no problem and the Dragon and Falcon 9 should be easily visible by the naked eye, except perhaps from the British Isles where it is still quite light.

I do advise using binoculars once you have located the spacecraft, as the Crew Dragon and the Falcon 9 upper stage will be close together, and with binoculars you will see them separately (you can see some photographs of a pass of a just launched Cargo-Dragon and its Falcon 9 upper stage from March this year in an earlier post here).

If you are lucky, you might even catch some small corrective thruster firings as small "puffs", like in this movie which I shot of a pass of the Dragon CRS-20 in March this year (look for the "puff" going upwards around 05:13:00 UT in the video):




(the two slowly varying objects astride the Dragon and Falcon 9 stage in the video above are the two ejected solar panel covers. The Crew Dragon does not have these, as far as I know).

The Falcon 9 upper stage will be deorbitted some 55 minutes after launch, over the southern Indian Ocean west of Australia.

photo: SpaceX

Below are my predicted sky tracks for a number of places in West and Central Europe, valid for launch on 27 May at 20:33:33 UT .

Times listed in the plots below are in local time (generally CEST, except for London which is BST). Please be aware that there is an uncertainty of about 1 to 2 minutes in the actual pass time!!! The track placement in the sky should generally be correct though. Bottom of the plots is either South or North, depending on the location (see the annotations on the plots).


Note added 25 May: the Heavens-Above webservice now provides you with custom predictions for the Crew Dragon for your observing site.

Amsterdam

Berlin

Brussels

London

Paris

Prague

Vienna

Hamburg

Lyon

Marseille

Munich

Reims

Strassbourg

Starlink Galore! [UPDATED]

click to enlarge

Last week was dominated by impressive - if worrying - displays of SpaceX Starlink satellites. Over several nights, objects from the 18 March 2020 launch (Starlink 5) made impressive passes in the sky. And on April 22, there was a new launch, Starlink 6, that could be well observed in the evening of the 22nd and 23rd, causing an impressive satellite 'train' on April 23.

In this blogpost I provide photographs, video, and descriptions.

The new launch on April 22 (Starlink 6)

On 22 April 2020 at 19:30 UT, SpaceX launched the 7th Starlink batch of 60 satellites, Starlink 6, from SLC 39A on Cape Canaveral. Some 23 minutes later, the newly launched objects made a pass over the Netherlands, in a blue twilight sky, and were well visible.

Just some seven minutes prior to this pass, and 15 minutes after launch, the payloads had been deployed from the Falcon 9 Upper Stage while the latter was over the Northern Atlantic.

With the naked eye, the Falcon 9, the just released satellites and the associated debris objects all looked like one bright object (mag 0 to -1) crossing the sky. In binoculars, they could be separated into multiple objects.

The photograph below is a stack of 12 photographs, 2.5 seconds exposed each with a Canon EOS 80D and EF 2.0/35 mm lens at F2.2, 400 ISO, showing it pass over my house in Leiden.

click to enlarge

In 10 x 50 binoculars, the view was spectacular. It consisted of a bright object (the Falcon 9 upper stage), slightly separated from another, elongated bright object (the clump of released satellites), and four fainter flashing objects surrounding them in a paralellogram shape. These were the four tumbling retaining rods that had held the satellite stack together before deployment.

Some of this is visible in this video I shot with the WATEC 902H and FD 1.8/50 mm lens. Falcon 9 and payloads still appear merged as one object here, but the retention rods are visible as separate objects:




The provisional orbit that I had calculated prior to the launch turned out to be quite good: the objects were only 28 seconds early on predictions and less than 0.5 degrees off-track at culmination.

The next night, April 23, saw a twilight pass of the satellites again, that by now had developed into a clear 'train' of objects. They were not as bright as in May 2019 with Starlink 0.1, but in 10 x 50 binoculars the moving string of 60 lights, some 10-15 degrees long, was impressive. While low in the west, in Orion, they briefly became bright and clearly visible to the naked eye for a few seconds, then they grew fainter and I turned to my binoculars to observe them.

My WATEC 902H video camera, this time equipped with a Canon EF 2.0/35 mm lens, captured the train passing in Hydra. The video gives a good impression of the view as it was visible in binoculars:




The next day, April 24, I also filmed the 'train'. This was a low pass (21 degrees maximum elevation) in twilight, at rooftop level, shot from the loft window of my home. Video withe the WATEC 902H and a 1.8/50 mm lens:

Starlink 5 passes, April 19-21

Earlier that week, we were treated on some spectacular, if eerie and worrying, displays of Starlink satellites from the previous launch, the Starlink 5 launch on 18 March.

(worrying, because of the implied impact on the night sky)

A month after launch, the objects from this launch are dispersing as they one-by-one are lifted to a higher orbit, but mid-April there was still a recognizable main group that took about 20 minutes to pass. When passing south of the zenith they are bright (but faint when passing north of the zenith, due to satellite orientation and sun-satellite-observer angles), on the first few passes even very bright (up to magnitude +0.5 for almost a full pass).

At any given moment during the pass of this group, there were 5-8 bright satellites moving in the sky at the same time, following each other in file, typically some 20 degrees apart. It was a very eerie sight reminiscent of a Science Fiction Movie: almost like the Mothership had unloaded the invasion fleet into earth orbit! The long duration, 20 minutes that satelite after satellite after satellite appeared in file, made it very impressive.

Here is a single photographic image from 19 April, showing 4 Starlink satellites traversing the sky (the fainter one that is somewhat off-set is already rasing its orbit). It is a 5 second exposure with an EF 2.0/35 mm lens on a Canon EOS 80D:

click image to enlarge

Below is a stack of 202 images from 21 April, showing 39 Starlink satellites that appeared over a 20-minute period. Note how the trails become fainter when located more north (image is looking west, so north is at the righthand side of the image). Also note the two flaring satellites:

click image to enlarge

Here are single images showing the two flaring satellites, Starlink- 1274 and Starlink-1309, flaring close to Pollux:

click image to enlarge

click image to enlarge

I used the 202 photographs, shot over a 19-minute period,  to create this time-lapse movie showing the steady stream of satellites:




This is another time-lapse video, from images from the deep-twilight pass of the previous night, 20 April:



Below are three more stacks of photographic images from April 19 and April 20 (the gaps in the trails are the brief moments between two consecutive photographs, hence the dashed appearance of the trails):

click image to enlarge

click image to enlarge

click image to enlarge