Double flyover ISS and Discovery tonight

[Trudy]

Starting at 7:23 pm here in the mid-Hudson Valley. Rising in the WNW with an altitude of 33 degrees, will traverse to the S.

This is rare, so hopefully conditions will be good.

There will also be two flyovers tomorrow evening, the first at 6:14 pm.

 

[Quietman]

Thanks Trudy!! I hadn't checked recently.

Check for flyover times for your location HERE

Darn, I missed my chance last night!

 

[Chip]

cool, we're heading outside now !

 

[Chip]

Well, we just got in from the back yard and saw them both ! Thanks ! I assume the lower/brighter/bigger looking one was the shuttle.

 

[Tom Rankin]

Just saw them! The Space Shuttle is leading the ISS by quite a bit now!

 

[BIGEarl]

If you're interested in this sort of thing, you can check in on a wide range of space-related things here including the ISS, other satellite flight information, and lots of "space junk" that is visible.

Heavens-Above

Sorry, the location is set to my back yard. Feel free to change it to your back yard.

 

[Chip]

It'd be nice to know their altitudes last night. I'm assuming the ISS was higher/dimmer and the Shuttle lower/brighter.

 

[erugs]

The moon was pretty...

 

[DougPaul]

It'd be nice to know their altitudes last night. I'm assuming the ISS was higher/dimmer and the Shuttle lower/brighter.

The ISS is a lot bigger and, I believe, is usually brighter.

Obviously, the orbits had to coincide for some period for them to dock. The apparent positions from the ground would diverge very rapidly if they were at different altitudes, so they were probably still at similar altitudes.

Doug

 

[Tom Rankin]

The ISS is a lot bigger and, I believe, is usually brighter.

Obviously, the orbits had to coincide for some period for them to dock. The apparent positions from the ground would diverge very rapidly if they were at different altitudes, so they were probably still at similar altitudes.

Doug

The shuttle was definitely in the lead. I checked http://heavens-above.com

It was hard for me to discern which was brighter, as I was viewing thru thin clouds, and they both fluctuated in brightness, but like you said, typically the ISS is brighter, as it is much larger.

There are some fairly small satellites called Iridium, that can appear extremely bright for a few seconds. They have a smooth flat surface, and if it is pointed right at you, it can be 20x brighter than Venus! I once 'saw' one even though it was completely cloudy! This article says they can even be seen in broad daylight!

 

[Chip]

Interesting. I guess logic would dictate the ISS is brighter due to size. This site indicates the shuttle is generally brighter because of its white surface.

Typically, the station will appear dim and then as it rises in elevation it will get brighter and brighter. During optimal times when it is crossing high overhead - it will shine brighter than any star in the sky. Interestingly, although the shuttle is smaller than the station - it is brighter in the sky because of its white surface colour.

For me the dimmer object appeared first and was nearly out of sight by the time the brighter object appeared. Both remained pretty evenly dimmer or brighter. I didn't get the impression they were traveling at a similar speed or altitude, but again, that was just my impression.

Anyway, I'm happy we saw them and that I also caught the shuttle landing before lunch.

Edit:

This NASA Science site indicates the same.

Which ship is which? The brighter light is the shuttle. Although Discovery is smaller than the ISS, its super-white top reflects more sunlight. Both ships should be easy to see in the deep-blue dawn sky.

Edit:

And this site indicates the ISS is brighter, so I don't know.

 

[DougPaul]

There are some fairly small satellites called Iridium, that can appear extremely bright for a few seconds. They have a smooth flat surface, and if it is pointed right at you, it can be 20x brighter than Venus! I once 'saw' one even though it was completely cloudy! This article says they can even be seen in broad daylight!

I saw one in 1999--it looked like someone was turning a search light (aimed at me) on for ~20sec. (They occur fairly frequently--I simply haven't looked since.)

The reflective surface is an antenna.

There used to be a website that took one's location and provided
a table of future flares, but it doesn't seem to answer now. A quick
search located no replacement.

Doug

 

[erugs]

Some will recall this thread a few years ago: http://www.vftt.org/forums/showthread.php?t=18385&highlight=wonderland+trail+blink

The comments about what I saw were wide-ranging. I still think it was a LGM (Little Green Man) sent to look after me as I hiked solo those few days.

 

[DougPaul]

Interesting. I guess logic would dictate the ISS is brighter due to size. This site indicates the shuttle is generally brighter because of its white surface.

OK.
Brightness = area * reflectivity * illumination
Orientation could also be a factor.

The reflectivity of any spacecraft is designed in--it is a critical factor in temperature control. Except for some energy included at launch (ie charged batteries, maneuvering fuel), the satellite is heated by energy received from the sun and cooled by energy radiated back out to space. Highly reflective (eg white) surfaces both absorb and radiate poorly, highly absorbing surfaces (eg black) both absorb and radiate well. A satellite can cool off by presenting a reflective surface toward the sun and a dark surface toward space and warm up by presenting a dark surface toward the sun and a reflective surface toward space.

Doug

 

[Nessmuk]

I saw one in 1999--it looked like someone was turning a search light (aimed at me) on for ~20sec. (They occur fairly frequently--I simply haven't looked since.)

The reflective surface is an antenna.

There used to be a website that took one's location and provided
a table of future flares, but it doesn't seem to answer now. A quick
search located no replacement.

Doug

On average you can see an "Iridium flare" every day or two, at either evening or morning dusk. They are quite spectacular... especially if you can arrange to be giving a talk at the appropriate time while not appearing to be glancing at your watch, raise your arm to say.... "and over here we have"...
You get some amazed jaw-dropping reactions from the group. I've done that while guiding in the backcountry a number of times. Catch one at magnitude -8 and it is blinding.

The heavens-above website is still the place to go for predictions.

I saw the STS/ISS pair last night too. I figured the much dimmer lead ship was the Shuttle. I don't know what the orientation of the shuttle was at the time, but if it was bottom toward us, that could account for the relative low luminosity when compared to the much brighter ISS. Even though the shuttle was "half a sky" ahead, both took the exact same path and disappeared into shadow at the exact same point, which indicted they were still in very similar orbits at the same altitude. The ISS was also distinctly yellower in color.

 

[Chip]

Even though the shuttle was "half a sky" ahead, both took the exact same path and disappeared into shadow at the exact same point, which indicted they were still in very similar orbits at the same altitude.

Just adding this for content, or context, at this point, not to try to argue:

Here, at about 7:25 it was clear sky with the crescent moon above the horizon. The first object was the dimmer one which flew just "below" the moon. We watched that ascend on its northwest to southeast path. The second brighter object appeared a while after the first and followed the same direction, but not the same path, maybe just "above" the moon. FWIW. Our various perceptions of orbit paths and altitudes are different. Paths is one thing. Perception of altitudes probably has more to do with the brightness of the objects, which would vary.

 

[DougPaul]

The heavens-above website is still the place to go for predictions.

I saw that one, but after a very quick look it didn't seem to have any way of entering your location.

After a second try and 10 minutes wasted, I finally found out how to enter my location and it now works.

The original website was simpler and quicker--just enter your location and get the table of future visibility...

Doug

 

[Nessmuk]

Just adding this for content, or context, at this point, not to try to argue:

Here, at about 7:25 it was clear sky with the crescent moon above the horizon. The first object was the dimmer one which flew just "below" the moon. We watched that ascend on its northwest to southeast path. The second brighter object appeared a while after the first and followed the same direction, but not the same path, maybe just "above" the moon. FWIW. Our various perceptions of orbit paths and altitudes are different. Paths is one thing. Perception of altitudes probably has more to do with the brightness of the objects, which would vary.

No argument.
I interrupted our Search and Rescue monthly meeting to take the team outside for the event. We are not far from Utica NY, so if you are considerably to the east, our perceptions could well be different. I definitely remember commenting that both objects passed just "below" the moon from our POV as I put my thumb over the moon to block its glare, and both objects disappeared as predicted into earth shadow at virtually the same point somewhat to the lower left (southeast) of Orion. The fact that the Shuttle was ahead of the ISS does indicate that it was likely in a very slightly lower orbit after it separated after undocking (lower orbit = faster), but I doubt very much lower. STS fired its de-orbit burn at about 11:30 this morning.

Here are the heavens-above print outs for each that I took to the meeting, showing the STS about 30 seconds ahead of ISS, and distance to each orbit virtually the same at equivalent points of orbit.

 

[TomD]

I saw the shuttle and then fairly far behind it what may have been the ISS. The sky in SoCal is fairly polluted with light but I was at the beach so it wasn't too bad. Just seeing the shuttle was enough for me. It was pretty bright, but the ISS was much dimmer.

I found several sites with info on spotting satellites. Also two a couple of apps for your phone if you have an Android or IPhone.

 

[Nessmuk]

I saw that one, but after a very quick look it didn't seem to have any way of entering your location.

After a second try and 10 minutes wasted, I finally found out how to enter my location and it now works.

The original website was simpler and quicker--just enter your location and get the table of future visibility...

Doug

If you save your location as a registered user on heavens-above.com, it takes exactly two clicks and about a half second to get a table for either 24 hours, or 7 days.