What on (or off) Earth is this

[smartcooky]

I'm doing a little sky photography, educating my nephew about star trails and the night sky. So, I'm doing a few 30 second test exposures, and my nephew says "what's that". I look up and see a bright, slow moving light, about (I would guess) at least a few times brighter than Venus at its brightest, say mag -6.

I'm thinking satellite, except I have never seen one so bright. I'm also thinking, "I hope I caught that on the camera" as it was not pointing exactly in that direction,  but the lens angle was wide enough that I did get it, and here it is..the streak in the bottom left corner. It may have been even brighter as I was late seeing it.



Does anyone know what this could have been?

[gwiz]

Perhaps an Iridium flare.  These are low-orbit satellites with planar reflective antennae that produce these effects when the sunlight catches them at the right angle.  Since the satellites are attitude controlled, these flares can be predicted, so if you google around I'm sure you can find a site that will tell you for sure if that was what you photographed.

[Chew]

Go here http://www.heavens-above.com and click on "Change your observing location" then click on Iridium Flares.

[Zakalwe]

It looks like an Iridium flare to me. The tend to brighten and tail off, whereas a meteor brightens and then dies off much more quickly.

Once you start taking images of the night sky you'll be amazed at the amount of stuff floating around in Earth orbit.

[Luke Pemberton]

Interesting picture showing why Iridium flares are produced.

[smartcooky]

Interesting picture showing why Iridium flares are produced.

Well, my effort certainly does look like the Iridium flare in the photo.

I have Googled around looking for orbits. Even found an ISS Predictor App which I have downloaded for my Android phone. It predicts Iridium Flares.

Haven't yet found a site that will look backwards for and event at a given location, only forwards as in predictions.


ETA:
Found one. I didn't realise that the heavens above site posted earlier worked backwards

http://www.heavens-above.com/flaredetails.aspx?fid=8&lat=-41.2908&lng=173.2629&loc=Toi+Toi%2c+Nelson%2c+New+Zealand&alt=79&tz=NZST

ETA2: Confirmed!



 

[Zakalwe]

Have a look at this video posted on Vimeo:

Its a 2 hour timelapse of Mars...you'll probably need to view it fullscreen and in HD. All those things whizzing through the field of view are geosynchronous satellites. Because Mars was nearing opposition at the time of the recording, the satellites are catching the Sun. There must be about 30+ in that video. It just goes to show how much stuff is up there.

[smartcooky]

Have a look at this video posted on Vimeo:

Its a 2 hour timelapse of Mars...you'll probably need to view it fullscreen and in HD. All those things whizzing through the field of view are geosynchronous satellites. Because Mars was nearing opposition at the time of the recording, the satellites are catching the Sun. There must be about 30+ in that video. It just goes to show how much stuff is up there.

There certainly is a lot of stuff up there.

Interestingly, a 0:13s and again at about 0:18s, there appear to be closely grouped  "clusters" of things going through the field. Space Junk?

[ka9q]

Yes, I concur that it's almost certainly an Iridium flare.

Do note when doing predictions that the ground tracks are actually quite narrow; an offset of a couple of km can reduce the maximum brightness considerably. So be sure to give an accurate location, and consider a short drive to where a good one will be visible.

[ka9q]

Interestingly, a 0:13s and again at about 0:18s, there appear to be closely grouped  "clusters" of things going through the field. Space Junk?

More likely a set of active satellites sharing the same orbital longitude slot.

If they were "junk" they would have drifted out of geostationary orbit, like the many objects you see above and below the main track -- some moving at very noticeable angles. Staying motionless over the equator requires active stationkeeping, and when that fuel runs out perturbations of the moon and sun, and to a lesser extent the lumpiness of the earth, take over. The main effect is on inclination; when a satellite stops doing north-south stationkeeping it no longer perfectly orbits the equator at 0 degrees. The inclination angle slowly oscillates around zero with a magnitude of something like 5-10 degrees (that's from memory). A satellite in an inclined orbit traces out a figure-8 on the earth looking something like an anallema on a globe.

Smaller amounts of fuel are required for east-west stationkeeping; without it satellites tend to fall into a couple of "valleys" at specific locations above the equator.

The fact that Inmarsat 3F1 over the Indian Ocean has an inclination of 1.7 degrees enabled Inmarsat to resolve the ambiguity as to whether Malaysian Airlines 370 flew north or south.

[smartcooky]

Yes, I concur that it's almost certainly an Iridium flare.

Do note when doing predictions that the ground tracks are actually quite narrow; an offset of a couple of km can reduce the maximum brightness considerably. So be sure to give an accurate location, and consider a short drive to where a good one will be visible.

Yes, I've noticed that.

I said earlier that I have downloaded an app for my smartphone, inaptly (no pun intended) called  "ISS Detector". It shows predictions up to 10 days in advance for passes of the ISS and for Iridium Flares. The app gets its location information from the GPS in the phone.

For the Iridium satellites, the predicted magnitude varies markedly between my home and my place of work (about 8 km apart.)

One I am looking at right now is Iridium 53 on Saturday 12 April NZST

Nelson (home)....... -4.5 mag, elevation 49° flaring at 18:38:08
Richmond (work).... -7.8 mag, elevation 49° flaring at 18:38:06

Two seconds earlier at work, and 3.3 magnitudes brighter!!!

[Chew]

You know when you click on a flare and scroll down to the bottom of the page it shows you a Google map of the ground track of the flare center? That was my idea! I submitted that suggestion to the webmaster a few years ago. I don't know if he followed my suggestion or independently thought of it himself but I take full credit for it.

[smartcooky]

You know when you click on a flare and scroll down to the bottom of the page it shows you a Google map of the ground track of the flare center? That was my idea! I submitted that suggestion to the webmaster a few years ago. I don't know if he followed my suggestion or independently thought of it himself but I take full credit for it.

My one is a little different from that.

You tap on a Flare and it brings up a "Radar" tab that shows the compass heading of the flare and a "spirit level" on the side to show the elevation.

If you tap the "Details" tab, you get all the information about the pass
Start time
End time
Start elevation
End Elevation
Start directions
End directions
Magnitude
Below that is a Google geophysical map of the satellite location in real time, and below that is current position...
Latitude
Longitude
Height

If you tap the map, it goes full screen and you can zoom in and out

At the bottom of the full screen is a "map" icon that toggles the map from "geophysical" to "political", There is also a padlock icon that locks and unlocks the map; lock keeps the satellite centred in the screen and scrolls the map.   

[ka9q]

Gee, you guys are almost making it too easy to see these things... :-)

There are "old school" amateur astronomers who dislike modern computer-controlled telescopes, too.

[Andromeda]

ETA2: Confirmed!



 

Is it weird how much I love this?  Something about matching up events like this with a photo just pleases me so much.