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I managed to catch a glimpse of the ISS flying over the UK last thursday at about 8:15 pm, you can get the times that it will fly over your part of the world from sites such as Heavens Above - it is very cool, if you're into that kind of thing, it starts off as a bright light like a star, rising pretty fast, getting brighter and brighter and then fading out as it enters the Earth's shadow. It faded out before setting. If you have a telescope, or even a decent pair of binoculars, you can make out the shape of the station - it's about 400km up. Apparently when it's finished you will be able to make out the shape with the naked eye :)

Ever see an Iridium Flare?

I think other posters have already explained that very well, so I won't repeat that here.

But talking about the satellite and orbits issue, it may be interesting but bear in mind that orbital elements or ephemeredes are only valid for a certain amount of time after they are issued (up to a few weeks); this is due to the effects of things like atmospheric drag, orbital corrections and the alike. This is particularly true for low-orbit satellites like ISS and the Space Shuttle (when in orbit, off course)

Specially interesting, see here a chart of the orbital height of the International Space Station over time. Quite interesting chart.

Heavens Above is a great site if you want to keep up with the ISS and many other satellites orbiting Earth. It explains when and where you can see them in the night sky, and their brightness. It is all based on your location. I have used it to see several satellites, including a very spectacular showing of the ISS last year.

Take a look at this website, it'll tell you the current locations and distances of spacecraft on solar system escape trajectories. (Pioneer 10, Pioneer 11, Voyager 1, Voyager 2)

http://www.heavens-above.com/solar-escape.asp

Pioneer 11 is actually the least distant of all these spacecraft - and is also essentially a manmade rock at this point - its no longer operational.

Voyager 1 owns the record for farthest out, and will for the forseeable future, as it is travelling considerably faster than the others relative to the sun.

Also interesting is that the Voyager twins will be the two farthest spacecraft out once Voyager 2 passes Pioneer 10.

This should be in late November 2021 by my admittedly crude calculations. Take Pioneer 10's 13.986 AU lead, divide it by the 0.727 AU V 2 is gaining per year on P 10, and you get approx. 19.24 years. Add that to todays date and you arrive somewhere in late Nov. 2021 - I'm not going to bother with the exact date.

From the PDF file, here is a link to a webpage showing the graphical locations and current stats on Voyager 1, Voyager 2, Pioneer 10, and Pioneer 11.

The proper distance unit in the solar system is the "astronomical unit". Voyager 1 is currently 85.601 AU from Earth. That makes it, ahem, 85.601 times further than the sun because the distance of the Sun is 1 AU.

Here are the NASA 2-line Keplerian elements for AO-7:

AO-07
1 07530U 74089B 02167.52996888 -.00000029 00000-0 10000-3 0 935
2 07530 101.7955 212.2077 0012102 193.4285 166.6467 12.53558681262239

Also, you may see it's orbit here

And here's an heavens-above link that will plot AMSAT-Oscar-7's orbit for you

For example, I easily got these results for where I often go camping.

pk

For example, I easily got these results for where I often go camping.

pk

Track the current satellite position on this Heavens-Above page. You'll see that the orbit is confined between 28 N and 28 S. Note that heavens-above doesn't compute reentry, but the position should be pretty accurate until the very last moment.

the field of view is broad enough that you can see the context of what you're looking at, to match with star charts. A good pair will set you back between $100-300. For best results, look for "long eye relief" and try to keep the ratio of the aperture to the power below 7 (e.g., 7x50 binocs have a ratio of 50/7, or just over 7). Binocs don't need to be polar-aligned, which is a pain in the a**, except on the new GPS-equipped scopes that are definitely too pricey for beginners. Also, check out Heavens-Above.

The ion drive aboard the DS1 broke several records with its stellar (literally) tortiose-vs-hare performance. Does anyone know if this technology has any potential for being adapted to the ISS? Due to friction with the upper atmosphere, ISS is constantly losing altitude, necessitating frequent boosts using the Shuttle or a Progress vehicle to keep it on station (pardon the weak pun). A constantly-updated graph of its altitude variations is hosted on Heavens-Above.

Anyway, does anyone know if ion engines of the type used on DS1 would be effective in allowing the ISS to maintain altitude, or could they at least reduce its rate of orbital decay enough to justify the power expenditure?

The ion drive aboard the DS1 broke several records with its stellar (literally) tortiose-vs-hare performance. Does anyone know if this technology has any potential for being adapted to the ISS? Due to friction with the upper atmosphere, ISS is constantly losing altitude, necessitating frequent boosts using the Shuttle or a Progress vehicle to keep it on station (pardon the weak pun). A constantly-updated graph of its altitude variations is hosted on Heavens-Above.

Anyway, does anyone know if ion engines of the type used on DS1 would be effective in allowing the ISS to maintain altitude, or could they at least reduce its rate of orbital decay enough to justify the power expenditure?

The most threatening of space junk is that which is not large enough to detect and manuever around, but not small enough to not worry about. This range holds lots of potentially dangerous objects that could puncture the outside of spacecraft. The problem is collecting and removing most of these objects from orbit.

On a side note, now that the ISS is higher, how is it's visibility from earth affected (if any) and will it stay at its new altitude (if so, for how long)?

Just one more note, Heaven's Above is a great resource for tracking satellites and other close to home astronomical events (such as Iridium flares).

The most threatening of space junk is that which is not large enough to detect and manuever around, but not small enough to not worry about. This range holds lots of potentially dangerous objects that could puncture the outside of spacecraft. The problem is collecting and removing most of these objects from orbit.

On a side note, now that the ISS is higher, how is it's visibility from earth affected (if any) and will it stay at its new altitude (if so, for how long)?

Just one more note, Heaven's Above is a great resource for tracking satellites and other close to home astronomical events (such as Iridium flares).

I invite you to check for ISS/shuttle sightings on the nasa website. Also Heavens above might be updated with the shuttle orbital information within the next few hours.

For example, I see there will be a nice pass almost straight above San Francisco, Thr Dec 06, 05:26 PM for ISS, and 11 minutes later (05:37 PM) the shuttle catching up with it! So I suspect similar opportunies for other US cities in the coming days, weather permitting of course.

Don't expect to see more than a moving point of light, but it is still quite cool.

Go to Heavens-Above and enter your location on earth, and it'll provide you with all the info you need to spot the ISS, the Shuttle, and a host of other orbiting objects as they pass over you before sunrise or after sunset. The site has a wealth of other information about satellites and space exploration in general as well, so it is with a very heavy heart that I expose one of my absolute favorite sites to the eminent threat of slashdottery.

You'll want to use XEphem to plan your Leonid observing. It is freely available software for GNU/Linux that produces great printable star charts and much more. If for some reason you can't get XEphem for your OS you might find Heavens Above to be useful.

Heavens-above.com (one of my favorite sites) provides visibility reports from any location on earth for Starshine, the International Space Station, Hubble, Iridium Satellites, planets, comets, asteroids and more, in easy-to-use format. I've found their data to be very accurate, and it really impresses the neighbors when you can point up and say, "Look right there-that's the Space Station."

Look at the pictures for the Starshine satellites -- Disco Balls in Space! With lots of hand polished retro-reflectors on a spinning sphere. The mirrors are to make it a naked-eye object. Sighting info should be available on the heavens-above.com satellite viewing site , which also calculates sighting info for other sky clutter like the space station and the Iridium satellites...

It's heavens-above.com with a dash. I accidentally hit "submit" instead of "preview".

Another great site for those who are interested in this stuff is Ron Dantowitz's Sky Show. Ron has pioneered some inexpensive methods for getting diffraction-limited images and video from mass-market amateur telescopes and video equipment. You, too, can make a recognizeable movie or snapshot of the shuttle and/or ISS as they pass overhead.

Ok.. I just realised I forgot to post the URL *DOH* smacks self.

Heavens-Above.com

This works no matter wheren you are.

I use Heavens-above to get times for sightings in my area.

SuperID
Free Database Hosting

This article in Yahoo on the Countdown slates re-entry between 1:20 AM and 1:30 AM EST, Friday, March 23.

A site with a real future, www.mirrentry.com

Heavens Above, which has charted the orbital decay.

On the Marx-Spinning-In-His-Grave front:

Leading up to the event have been word of passengers paying $5,000-10,000 a seat to fly around the area in hopes of catching a glimpse (of course, they'll have to be on the correct side of the plane.)

Should the core of Mir hit a 40' square target, Taco Bell will give everyone in the USA a free Taco

An alert eBayer, always right on the cutting edge of capitalism has offered up the Crashing MIR Space Station Detecto-Hat Made of the best stainless steel double-handled colander five dollars could buy... (No word yet from Rambus on patent infringement.)

Lastly I hope that the mutant space fungus will be burned up on re-entry. I don't want to wake up drooling beside a pod.

--

This article in Yahoo on the Countdown slates re-entry between 1:20 AM and 1:30 AM EST, Friday, March 23.

A site with a real future, www.mirrentry.com

Heavens Above, which has charted the orbital decay.

On the Marx-Spinning-In-His-Grave front:

Leading up to the event have been word of passengers paying $5,000-10,000 a seat to fly around the area in hopes of catching a glimpse (of course, they'll have to be on the correct side of the plane.)

Should the core of Mir hit a 40' square target, Taco Bell will give everyone in the USA a free Taco

An alert eBayer, always right on the cutting edge of capitalism has offered up the Crashing MIR Space Station Detecto-Hat Made of the best stainless steel double-handled colander five dollars could buy... (No word yet from Rambus on patent infringement.)

Lastly I hope that the mutant space fungus will be burned up on re-entry. I don't want to wake up drooling beside a pod.

--

Visible passes are always in the couple of hours after sunset or before sunrise, when the sky is black but Mir is still in sunlight. Pass predictions are usually spot-on, except when the satellite in question has just changed its orbit. It sounds like Mir's orbit isn't gonna change until they go for the big burn on Thursday. When you spot it, it'll look like a red (how appropriate) star, moving though the sky. It'll cover half the sky or so in just five minutes or so.

Cheers,

Earl

Now, of course, it's not serious yet, but that's what everybody said would happen when they left it unmanned last year.

heavens-above.com has very nice reports on this kind of thing, espically iridium flares and iis sightings. that link is generated by my preferences for east coast data, but that's easy enough to change.
--

Also, check out the Iridium flare section, 'cept you need a 1km accuracy on your location for those.

There is a phenomena known as "Iridium-Flares" by which one can see the very bright sun reflections off of the iridium satellites. Go to Heavens-Above.com for predictions when you can see this from your hometown.

-Jason

And here is an Iridium tracking site: Heavens Above
They also track the ISS, Mir and a few hundred others. All with the intent of telling you when you can see the critters going by overhead.

http://www.heavens-above.com will locate the ISS and other objects for you relative to where you are (within reason) for various dates/times.

If you look up at the right time, you can see Iridium satellites, even during the day, because they have big panels that reflect sunlight like a mirror. You just need to look up at the right time, in the right place.
The Heavens Above web site can tell you where to look.

Check out http://www.heavens-above.com.

If you plug in your latitude and longitude, or choose your location from a menu, the Heavens above calculator will tell you exactly where and when to look. It also tells you where to look to see the Space Shuttle and other cool stuff. One time I saw Mir + Space Shuttle connected together!

This link gives all the ISS visibility info, PLUS information for Mir and dozens of bright naked eye satellites.

No matter where you live on earth, every evening just after twilight you can sit outside with a timetable and an accurate watch calibrated to the timelady's voice, and watch the "artificial moons" go by.

www.heavens-above.com

The best way to catch any detail (in profile, at least) is to watch it pass in front of the moon with binoculars or a scope. Heavens-Above does a good job predicting when it passes overhead, but doesn't mention transits of the moon or sun. Does anyone know of another site that provides this type of info?

Thusly: The ISS is in a 51.6 degree inclined orbit. Signapore is a maximum of 2 degrees latitude off of the equator. You can't miss the ISS from Signapore. As for Australia, Tazmania is about as far south as the Australian region goes on my map, and that's at 42 degrees south latitude. Still within the visible range.

However... due to the rotation of the earth, the ISS' orbit appears to continuously "shift" across the face of the earth. In Signapore's case, the ISS won't be visible there until September 3, after which it will pass overhead every 90 minutes for about two weeks. Tazmania, on the other hand, can see the ISS beginning just before dawn on August 25 and going for at least two weeks, if not longer.

Here's a URL.

Orbit data for the ISS and maps of the station's orbit path can be found at...
http://www.heavens-above. com/orbitdisplay.asp?satid=25544

--
Jonathan Hunt

The Iridium satellites have large reflective dish antennas that, when hit at the right angle by the Sun, produce spectacularly bright flares in the sky. Sometimes the flares are bright enough to be visible by daylight.

To figure out when and where these flares will be visible in your area, visit Heavens Above. There you can plug in your location and receive data which will tell you where to look.

So far I have seen several. The flares are usually short-lived, much like the company that spawned them.

Heavens-Above public agent for German Space Operations Centre

TangoChaz

"It's not enough to be on the right track -- you have to be moving faster than the train." -- Rod Davis, Editor of Seahorse Mag.

It was a beautiful -6 mag flare. Truely cool, thanks slashdot. :)

The Iridium Flash effect occurs when a great idea for a worldwide product flashes onto the scene, allowing people who want to have the best of everything spend more money. In a flash of bright light, the idea burns out leaving behind an armada of outrageously expensive technology orbiting the earth.

Seriously, though, check out Observing Iridium Flashes and Heavens Above (as someone already mentioned).

According to this article in Sailing Source, the last link: tells you where and when to look for IRIDIUM satellite "flashes" as the sun reflects light off the satellites passing overhead. You plug in your lat/long position and it will tell you where and when in the night or predawn sky to look to see an Iridium "flash."

Some people call them flares apparently to differentiate from meteor flashes.

The reason satellites are made of highly reflective materials is so they reflect the sunlight and not gather heat, sort of like a car baking in the hot sun. I imagine there *are* some coating materials which would reduce the glare and imagine that so far, there has been little reason to use them.

But remember that the Iridium "flare" is the reflection from the solar panels, which cannot be covered so easily as with some kind of paint.

... [read page to get context] ...

That's an attractive but malicious thought, Lew! While we can think and talk of that amongst ourselves, I shudder to think of the child wanting to take his telescope into the back yard some night and Mom objects, saying that watching the sky is "evil" because she has no idea of the difference between a meteor flash and an Iridium flare!

Here we have 80+ satellites in orbit that nobody wants, and I still have to access the net at 56k.

The world is full of irony.

By the way, Heavens Above is a great place to look if you want to know when and where iridium flashes will take place. I'm sure those will be missed...

See also:
http://www.heavens-above.com/. They have web-based software for predicting these, and other satellite events. A cool site all around.

...not affiliated etc.

With a GPS receiver, connect to Heavens-AboveGmbH. This is the satellite predictions page changed locations and is operated by the German Space Operations Center. This URL is the current one.

~afniv
"Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"