Six satellite-like light observation?

[polardan]

At 2157AEDST tonight my wife and I were at the nick cave concert at the Myer music bowl in Melbourne.

I noticed in the light polluted mostly dark sky, due north what I asssumed was a satellite at an altitude of approximately 40 degrees and be visible for about 30 seconds moving directly downwards then fade away at about 30 degrees altitude. It was about the same magnitude as Betelgeuse, which was visible above, and brighter than elnath to its left. Castor and Pollux were obscured by the dome.

I thought little of it until 30 seconds or later another one came visible in the same place, travelled over the same arc then disappeared in the same place.

And then another did the same.

And then another appeared and I was watching it my wife said "is that a satellite?" and it disappeared in the same place.

Two more then appeared and disappeared which my wife also saw, confirming that I was not being affected by the interesting "cigarette" odours coming from somebody upwind of us.

All in all six points of light appearing in roughly the same patch of sky, similar brightness and disappearing in the same place over then course of about 4-5 minutes.

Im certain they are not aircraft, no flashing strobes and I am quite familiar with the airways around Melbourne as they were using rwy 16 for arrivals which is not due north of the cbd.

No more were visible after that.

Any thoughts? It's got me stumped.

[deanm]

SpaceX launched 10 replacement Iridium satellites on Jan 14.
They may take a while before assuming their operational orbits, so it's conceivable that this is what you saw.
Some years ago, I saw 2 satellites very close to each other: one was a dead Iridium and the other its replacement being maneuvered into the same orbital spot. Quite a sight.
Dean

[polardan]

Thanks Dean. I was aware of the takeoff and the mission but didn't make the possible connection.

I've checked heavens-above.com but i can't see where to view historical observations. Does anyone have any pointers where to get historical satellite predictions please?

Cheers

Dan

[deanm]

I checked HA, but the recently-launched satellites aren't listed yet because they're not in their operational orbits.
Dean

[beren]

whitecloud /NOSS US navy satellites ?

[speach]

could it have been planes coming into Tulla?

[polardan]

Almost certainly not. They were using RWY 16 at the time and there is no STAR that points the aircraft due south for the landing lights to be visible. The track from what used to be Bolinda is off to the NW. This was almost due north.

I've checked my approach charts (I fly for a living) and nothing correlates.

Additionally flight aware was not showing any aircraft doing anything odd at that time.

Dean's suggestion might be on the money. On another forum I've messaged a guy who seems to know about the SpaceX and Iridium launch and had posted they are parked in a test orbit with 100 second spacing before being fired up to their final orbits... this seems to correlate.

[deanm]

Horse's mouth:
"The first ten Iridium NEXT satellites were delivered to a 625 kilometer (km) temporary parking orbit where they will be tested and exercised by Iridium over the coming weeks. Upon meeting testing and validation requirements, the satellites will then be moved into their 780km operational orbit and begin providing service to Iridium's customers. One-by-one, the new satellites will be positioned near a current generation satellite, each moving at approximately 17,000 miles per hour as testing begins. Iridium's unique inter-satellite communication links from nearby satellites will be repositioned to point to the new Iridium NEXT satellite as it prepares to take over service. Existing satellites will eventually be de-boosted and de-orbited."
http://investor.iridium.com/releasedetail.cfm?ReleaseID=1007978

[polardan]

I had the following reply, after I'd posted more accurate data in another forum after using SkySafari to recreate the field of view. The SkySafari plot showed that they appeared at about 35° altitude and tracked directly down to about 18° altitude. Azimuth about 010°



I'd say that's fairly conclusive that it's what we saw.

And Dean, from your link, that they are half as high again as the ISS would explain their relatively slow movement (compared to the ISS).

Thanks