A Naked Eye Geo Sat?

Hi all

I need some help with the identification of an object observed on Dec 6th between 17.00 and 17.30 local time.

Conor and myself were under the evening twilight sky imaging the Moon and Venus. I glanced to the zenith to do a quick check of the sky when i got a shock. Above me there was a bright 2nd mag 'new star' located in the sky sector between Vulpecula and Cygnus at a very rough position of RA 20h 24m Dec + 26* 30'. I dismised it as a slow moving sat and joked to Conor that it looked like a bright Nova but then it became apparent that the object was completely stationary in the sky. It was visible for several mins in the same spot then began to fade scintillating rapidly as it did so even though others stars nearby remained steady. It dropped below 6th mag and was lost from sight.

Of course it was not a Nova as it faded so quickly however the only other explnanation i can think of is that it was a bright geo stationary Sat although normally they are very faint so this one must have been a rare event. Can anyone please confirm if this as a geo? as i have never seen one before and hence would like confirmation. It was very exciting for those first 2 mins!

Heres a poor image showing the star as it was fading. To the unaided eye it was a stunning sight!



Thanks

Martin,

Geosats are placed in an orbit around 38000 km away from the surface of earth and generally have a magnitude of 11 to 12. There are two points during the year, around the equinoxes, when these magnitudes rise to 5th magnitude or so due to favourable position relative to the sun for an earth-based observer.

Furthermore, geosats are very small. To this end, I would be very surprised if it was a geosat since the season and your magnitude estimate are not what one would expect.

There is a well-know FLASHING geosat (Superbird A) but this is the only exception that I can think of but it flashes and does not behave in the way you describe below.

The only possible explanation I can give if it was a satellite is that perhaps you saw a relatively dim Iridium flare do its thing. These flares can get as high as -8.6 magnitude but there are many examples where the flaring is much less and can easily fall into a +2 magnitude as per your description.

I would love to hear of others' opinions.

Anthony.

Thanks for that Anthony.

I wonder what it was, i feel certain it most be some kind of satellite but asi said it was completely stationary with no movement at all so if its not a geo could be military?

I dont know of may other options

Martin i caught it at a bright period. I am not using my user so when i get on i will have a look through my set of images from that night.

Cheers Conor. If you get a chance throw it up to see if you have got it too Your image should have alot more detail. Cheers

I had seen an identical event back in the early 1990s. I was on top of a mountain in the south west of Ireland with another astronomer (professional).
We both saw a star that shouldn't have been there of about 3rd magnitude. After about 15 seconds it faded away beyond naked eye reach.

We thought that it might be a satellite, but also we thought it may have been a gamma ray burster (GRB). A gamma ray burster (GRB) at this magnitude would have been extremely rare but had the characteristics for a GRB. It was unfortunte that we didn't have recording equipment at the time. We did mention it to other astronomers, and they tended to agree that it might be an GRB.

Eamonn A