Satellite Photo: Is It Plausible?

[DaveC426913]

I'm highly skeptical. This guy claims to have just luckily caught this pic of a satellite through his scope with a handheld digital camera.

Is this plausible at all?

http://img237.imageshack.us/img237/4535/dscn0210mq7.jpg"

 

[Kurdt]

Interesting shot whatever it is.

 

[sdemjanenko]

i don't see anything that looks like solar panels, the ovals are odd. I suppose they would be tilted dishes but... we'll never know. Unless does it have a time associated with it? cause then we could see if there was a satellite in the area.

 

[russ_watters]

It's about the right size. Heckuva lucky shot, but I'd say it is probably legit. If you can find where/when it was taken, I may be able to verify it with StarryNight...

 

[feb2_sg]

Where did you find this? Send me a message.

 

[xAbsoluteZerox]

I did some rough calculations using the following very rough approximations:
Moon ~ 1482 pixels vertical
Object ~ 24 pixels vertical
Moon Diameter ~ 3476km
Average Distance to Moon ~ 385000km
Average Distance to a Orbiting Satellite (This is where it gets tricky, it can range anywhere from about 480km [low-earth orbit] to about 35,760km [geostationary orbit]. For this, let's assume it is in low-earth orbit (best chance of actually seeing the satellite)) ~ 480km

With some quick algebra we find that the actual satellite would appear to be 70m in length...feasable considering these are very rough calculations, and if you can refine them, that could make it more convincing.

Math:
(24px/1482px)*3476km = 56.29km <- Projection of satellite onto surface of moon
(480km)*(56.29km/385000km) = 0.070km = 70m <- Projection of satellite dimensions onto a plane 480km into space

As for the image itself, it seems as if there is a lighter edge around the edges of the 'black blob'. This may be from the moon itself, seeing as how the bright light from the sun would tend to 'invade' the edges of the darker object, a common phenomenon in photography and eyesight in general. Any ideas?

In conclusion, I do believe that this could be a real lucky image of a satellite overhead, however, it seems that it could also be an easily doctored image.

*EIDT* P.S. - I believe this is only my second post on the forum. I hope to post much more in the future.

 

[Vast]

looks like four balloons to me. No way it would be a satellite, would be way too big, and it doesn't appear to be streaking across the image.

 

[Vast]

For comparision.

ISS passing infront of the sun:
http://www.perseus.gr/Images/sat-trans-20050728-vrml.jpg"

which is about the same size as the moon.
And infront of the moon:
http://www.lpod.org/wp-content/uploads/2006/04/sat_trans_20060414.jpg"

 

[Kurdt]

Well from downloading the photo and looking at the summary it was taken on 9/9/06 at 12:56. Now we just need the position.

 

[russ_watters]

I did some rough calculations...

Thanks. I was too lazy for that. But...

Average Distance to a Orbiting Satellite (This is where it gets tricky, it can range anywhere from about 480km [low-earth orbit] to about 35,760km [geostationary orbit]. For this, let's assume it is in low-earth orbit (best chance of actually seeing the satellite)) ~ 480km

LEO is 100-300 miles (160 - 380 km). The ISS flies at 220mi (360 km). The Hubble is at the extreme limit of the Shuttle's range at 353 miles (569 km).

So the altitude could be as little as half to a third what you used and thus the size could be half to a third (20 to 35m) what you calculated. That would be more reasonable, but it is still pretty big to be a satellite.

looks like four balloons to me. No way it would be a satellite, would be way too big, and it doesn't appear to be streaking across the image.

A reasonable possibility, though with the short exposure for a moon pic, I doubt there'd be any motion blur.

 

[Kurdt]

The exposure time was 1/229 seconds according to the data on the image so with a few crude assumptions a satellite could travel approx. 30 meters in that time. if I'm not too shabby with my rough estimates taht would translate to a 1 second of arc movement. This is about 1/1800 the size of the moon so my guess is blurring would not really be discernable.

 

[carlos_dfc]

I saw that pic too Dav, and I am also sceptical...

He says it was done with a 'cheap digi-cam' (his words) held up to the eyepiece of a 8" newt.

First of all - the resolution of that pic is something around 2250 x 1700 (about 4 megapixels) - so - OK - maybe just about borderline 'cheap digicam'
However, the Moon just about fills the frame, and I don't see any vignetting around it - so if it was truly taken through an eyepiece, then I'm guessing it would have had to be cropped, and the original image may have been quite a bit higher resolution.

Another thing is that it is an incredibly good image of the Moon, to have been done by that method. I've tried similar myself, with GOOD digital cameras, and never got anything near as clear and well defined as that shot - only way I've ever had images that good was by using the 'prime focus' method.

Kurdt...
If, as you say, the satellite would travel 30 metres (approx) in that time, then surely there WOULD be motion blurring.
30 metres will be a sizeable percentage, af even the largest satellites, so surely the image would be 'smeared'?

Just one more thing to consider - look around the edges of the Moon - there is a slight blue-ish edge... Chromatic aberration? - From a reflector?
OK - it is only slight, but it IS there - I suppose it could be from the eyepiece - but could it maybe also be consistent with either a good quality achro (or semi-apo) refractor? - or maybe some sort of Cassegrain model, with a focal reducer lens added to lower the magnification?

Overall - inconclusive.
It may be faked, or could be an INCREDIBLY lucky shot - hard to say for sure.
Or maybe it IS genuine, but not his pic?

 

[DaveC426913]

Well from downloading the photo and looking at the summary it was taken on 9/9/06 at 12:56. Now we just need the position.

"The photo was taken at 12:56AM EST, at 40N 73W."

 

[Kurdt]

Yeah I think I bodged that calculation that's why I posted the warning with it. 15 arcseconds is more likely and is very much more visible.

Here is the camera he used

http://www.nikonusa.com/template.php?cat=1&grp=2&productNr=25546

shutter speed was 1/229 seconds and iso was 50.

As people who photograph the moon should know this is a fairly slow exposure I normally photograph at iso 1600 for 1/2000 of a second.

i'm fairly skeptical about this photograph now. could just be a bit of debris that has fallen onto the mirror or eyepiece or camera lens. The shape would also indicate that to me as it does not look too much like a satellite.

 

[Kurdt]

"The photo was taken at 12:56AM EST, at 40N 73W."

Oh cool I'll check starry night.

 

[Kurdt]

Mine doesn't have a full list of satellites unfortunately but I'm sure someone will.

 

[carlos_dfc]

I have SN5 pro - I'll give it a shot - I'll also update sat info before checking...

How far off GMT is EST? - and what date was the pic taken?

edit - I just saw the date - D'oh!

 

[carlos_dfc]

Forget that last question - I just entered New York as location.

Ran it through, and there was nothing (listed in SN-5 pro) within 15 mins either side of 12.56am, that got aywhere near the Moon.

Looking more like either a fake, debris on EP/cam/scope, or something terrestrial, like the aforementioned 'balloons'

I still think the pic is possily TOO good to have been done handheld with that camera though.

 

[tony873004]

I think its balloons. If you consider a balloon to be a foot long, or about 0.3m, then you count pixels of the object and compare it to the Moon's pixel count, The balloons would be about 2.5 km from the observer.

I've been searching the web trying to figure out how high a normal helium-filled party balloon would rise. Most sites say they will pop from the decreased pressure, but I'm not sure. There's pleanty of stories of balloons with attached notes traveling hundreds of miles. If they were going to pop, I imagine they would reach pop altitude way before they had a chance to travel more than just a few miles.

So my guess would be that as the balloon rises, and the air pressure outside the balloon decreases, that the balloon's buoyancey would decrease until the balloon reached a cruising altitude. And I'm guessing cruising altitude would be below pop altitude.

How high that would be depends on a lot of factors, but I imagine it would be in the low thousands of meters, consistent with my estimate of 2500 meters.

The author of that picture claims it took the object about 4 seconds to cross the Moon's disk. This is too slow for orbital velocity of a LEO satellite. If I'm right about it being 2.5km altitude, that would be about 10m/s, about what I'd expect for a moving mass of air at that altitude.

Any thoughts?

 

[russ_watters]

If the time is off by an hour, there are several that pass close, but nothing at all nearby at the indicated time.

One thing about that angular velocity - that's the angular velocity at zenith. It is much slower near the horizon because it isn't moving perpendicular to your sight line.

I think it still could be a satellite, but the time, date, and/or location would have to be off by a little.

 

[russ_watters]

This is one of the more likely candidates: http://www.astronautix.com/craft/tselina2.htm

Cosmos 1833, flew over at 11:49, half a degree away. The configuration roughly matches, but it orbits at more than 500 miles, so unless it is enormous, that's probably not it.

 

[DaveC426913]

This is one of the more likely candidates: http://www.astronautix.com/craft/tselina2.htm

Cosmos 1833, flew over at 11:49, half a degree away. The configuration roughly matches, but it orbits at more than 500 miles, so unless it is enormous, that's probably not it.

Note a couple of things to factor in when looking for candidate satellites.

1] The initial coords the poster gave correspond to a point about 50 miles SE of NY in the middle of the Atlantic.

He's since provided exact coords: 40"54'29N 73"47'48W

2] We don't know what angle the moon was at. If it were near the horizon that would change the "window" of satellite passage.

My calcs for the date and time show the Moon to be at about 50 degrees from the horizon.

 

[xAbsoluteZerox]

Thanks. I was too lazy for that. But... LEO is 100-300 miles (160 - 380 km). The ISS flies at 220mi (360 km). The Hubble is at the extreme limit of the Shuttle's range at 353 miles (569 km).

So the altitude could be as little as half to a third what you used and thus the size could be half to a third (20 to 35m) what you calculated. That would be more reasonable, but it is still pretty big to be a satellite. A reasonable possibility, though with the short exposure for a moon pic, I doubt there'd be any motion blur.

Yeah...I realized that after I posted last night and was too lazy to correct it haha. If we assume an altitude of 200km, then that makes it about 29m wide, which is conceivable.

 

[carlos_dfc]

Well - working from those exact co-ords - using SN-5 pro, with satellite data updated today - Nothing even remotely close, for 25 mins either way of the stated time - nearest thing within an hour each way, was iridium 37, at 12:06, but that was still 3 degrees away.

 

[tony873004]

Using Stellarium, the Moon was 60 degrees above the horizon at the time of the picture, or 30 degrees from the zeinth. That would increase its distance by about 14% (1-sin(60)) from an overhead passage.

Let's not dismiss that this thing looks nothing like a satellite (oval solar panels?) and exactly like a cluster of 4 helium ballons.

If the OP's claim that it took 4 seconds to cross the Moon's disk is accurate, it is moving way too slow to be a satellite. But it's speed is consistent with something traveling in a wind stream 2-4 km in altitude.

The object is way too small to be a satellite, unless it is the ISS, which doesn't even pass over the northern hemisphere on the globe's dark side on the date photographed. But it's the perfect size to be a cluster of helium balloons 3-5 km from the camera (2-4 km altitude).

However, can helium balloons filled at sea level rise that high without popping?

I don't think the picture was doctored. "Hand held" probably meant applying slight pressure against the eyepiece or eyepiece holder, which is much steadier than hand-holding a camera while leaning against nothing, especially if the telescope has a hefty mount.

If the photo was doctored, why would he have chosen to paste a silhoutte of something that looks exactly like balloons instead of the silhoutte of an actual satellite?

 

[DaveC426913]

Let's not dismiss that this thing looks nothing like a satellite (oval solar panels?) and exactly like a cluster of 4 helium ballons.

I have to agree. This is not a fuzzy, indistinct photo. The object is quite clear.

If the photo was doctored, why would he have chosen to paste a silhoutte of something that looks exactly like balloons instead of the silhoutte of an actual satellite?

I don't think 'doctoring' is the issue either. I think if anything were suspect it would be the circumstances of the shoot. eg. that the poster has taken a professionally-shot pic and claimed it as his own. I find it very hard to believe that this shot was a 'fluke' of timing.

 

[Kurdt]

I wonder if there is some sort of mount for a digital camera of that type because as you say its very hard to get an image of that quality through the lens of your telescope while hand holding a camera to it. Yet I have examined the image and all the data that was stored to the image by the camera is genuine. Unless he went to the bother of doctoring that but its highly unlikely.

 

[russ_watters]

It isn't that hard to take it handheld, especially since the exposure is so short - but they do make cheap mounts that clamp onto the eyepiece holder: http://www.telescope.com/shopping/p...e=PRODUCT&iMainCat=6&iSubCat=29&iProductID=65

 

[DaveC426913]

I wonder if there is some sort of mount for a digital camera of that type because as you say its very hard to get an image of that quality through the lens of your telescope while hand holding a camera to it. Yet I have examined the image and all the data that was stored to the image by the camera is genuine. Unless he went to the bother of doctoring that but its highly unlikely.

If I were to doubt any element of the account, it is that he took the picture, and that he took it under the circumstances he describes.

 

[carlos_dfc]

If I were to doubt any element of the account, it is that he took the picture, and that he took it under the circumstances he describes.

Dave - check out the ADP forums - same guy has now put the same pic in another post, claiming it to be a CCD shot

 

[DaveC426913]

I saw that. CCD - that just means digital camera, right? Or am I misunderstanding the term?

 

[carlos_dfc]

A 'proper' CCD is different from a camera - it has no lens, or the usual camera controls, you use the 'prime focus' method - Focus the telescope directly onto the sensor (basically using the scope as a large telephoto lens) - it connects to a computer, and exposure, etc are controlled through the software
Entry-level models include the Celestron Neximage, or Meade DSI.

I understood that this was the sort of thing the OP used for his Moon pic (it does look very similar to the results I got using a webcam at prime focus (CMOS sensor) with the lens removed

It may just be that he misunderstood the difference though...
Some digital cams use a CMOS sensor, some (usually the better ones, like DSLRs) use a CCD
As a general rule of thumb, a camera that is capable of longer exposures (half a second, and longer) will have a CCD, as CCDs can handle longer exposures than a CMOS

 

[DaveC426913]

Would this then mean he is either mistaken in his terms or falsifying one of his stories?

cuz I'd like to ask him.

[EDIT] Already did.

 

[russ_watters]

Probably not falsifying the story, but ususally if it is a DSLR they say "DSLR" and not "CCD". Some atrocams actually use the same CCDs as higher end DSLR cameras and a DSLR without a lens produces excellent prime focus photos. You wouldn't hold the camera with your hand, though - it would have a T mount for that.

 

[DaveC426913]

Probably not falsifying the story, but ususally if it is a DSLR they say "DSLR" and not "CCD". Some atrocams actually use the same CCDs as higher end DSLR cameras and a DSLR without a lens produces excellent prime focus photos. You wouldn't hold the camera with your hand, though - it would have a T mount for that.

But a CCD in astronomy is an actual accessory device on a telescope, which would definitely make it a different ball of worms from "holding up a camera to the lens".