discovery chasing ISS - sighting question

[boki_san]

i've been waiting for the chance to see them flying together.

assuming no clouds 12 hours from now, i will watch the ISS flyover.
aside from just checking what the following graphic from nasa looks like 11 hours from now,
is there a more precise way of knowing how far behind the ISS, the shuttle will be?

they are scheduled to dock about 13 hours after the flyover in the morning.

assuming no clouds,
i should probably be able to watch them both, even if they are many minutes apart.

the question is, if they'll both be close together enough to get them both in a single photograph,
and if i'm skilled enough to get a photograph of them both, without cheating.

i took this photograph of the ISS a couple weeks ago, with my now sold digital camera.
i'll have two film cameras out tomorrow morning, ... we'll see what i can get.

 

[3488]

Welcome to SDC boki_san.

Try the link below. Put in your location, either from the long list of cities & towns, or if you know it your Latitude & Longitude. Despite the name, it is a proper scientific site.
Heavens Above.

Or please let me know if I can help.

Like your ISS trail.

Andrew Brown.

 

[boki_san]

hey now andrew, thanx.

that website looks very promising, ... a lot to explore there

i've been monitoring the orbital tracking, and i'm estimating she's near 30 minutes behind the ISS about now.

my tripods are set up & covered for the current rain, @ 39.0344N, 105.3446W, atop some huge bedrock boulders next to my home.
my cameras are packed.
i hope the clouds give me open sky low in the north, tomorrow morning

 

[boki_san]

damn the clouds, and the turning earth

was able to see & photograph a partial trace of the ISS,
but with increasing clouds & lightening sky, no sign of discovery,
which i reckoned was between 10 and 20 minutes behind

 

[MeteorWayne]

I should point out that the predictions for the shuttle on Heavens-Above (as well as the NASA site itself) are only valid until an orbital maneuver has occurred, which happens a few times during the catch up phase of the mission. So it's best to consider them a guideline, rather than hard predictions. Of course the ISS orbit doesn't change, so that info is accurate, but after the shuttle fires it's engines the orbit changes, and until the orbital parameters are updated, the predictions for the shuttle will no longer be accurate. For example the current shuttle ornit is based on an orbit calculated at Epoch (UTC): 08:37:16, Sunday, August 30, 2009, so will no longer be accurate if any engine firngs hace occurred since then.

If you click on the "orbit" link on the shuttle prediction page, you can see the last time the orbit has been updated. When I can, I try and catch when maneuvers are made...if I hear of any I'll post them here; then you will know for sure the predictions will need to change.

The same happens after undocking.

Wayne

 

[boki_san]

hey now meteoricW,

yeah, i wasn't basing anything off the 'heavens above' website.

i don't trust their name,
and i don't trust their data, yet.

for instance, tomorrow morning they show the shuttle lagging the iss by more than fifteen minutes.
a neat trick, to pull that off when you're docked :roll:

but it looks like a very useful site, for the most part.

i made my estimate from nasa tv info, combined with nasa.gov.
at one point last night, announcer said the shuttle was roughly 5800 miles behind,
and was gaining approximately 500 miles per orbit.
at that time there were five orbits left until sighting,
so taking 3300 miles and dividing by 17,300mph, i got about 12 minutes

looking at nasa's orital tracking graphic, i broadened my guess, and watched intently from immediately after the iss flew over,
until about 25 minutes later, no sign of the shuttle.

the clouds were increasing, and they were becoming illuminated a bit as the eastern sky brightened.
all the stars that were there when the iss came over, were no longer discernible.

hoping for clear skies on un-docking day

 

[MeteorWayne]

The Heavens-Above site is quite good, as is it's data.

The reason for the discrepency for the shuttle is as I stated above. They use the latest released orbital elements; until new elements are issued (following an orbital burn) it's based on the old orbit. The shuttle is the only satellite where that is the case.

For all other satellites the orbital elements only change very very very slowly so the predictions are valid (to within a few seconds) for weeks at a time.

Wayne

 

[MeteorWayne]

OK, looks like the H-A predictions for the shuttle should be valid for about the next hour when rendevous operations begin.
After that, it will be getting closer to the ISS and will be docked by 9:04 EDT, 0104 Aug 31 UTC/GMT

 

[MeteorWayne]

Just a little tidbit, after the most recent Epoch (~ 0400-0800 UTC/GMT this morning) the ISS orbit was 91.5 minutes (342x354 km), the STS-128 orbit orbit 89.5 minutes (227x272 km) , so it was catching up 2 minutes per orbit or about 32 minutes per day. All that becomes moot after a 40 minutes from now from now when the first rendevous burn takes place.

 

[gmcollin]

Try http://www.n2yo.com then click the 5 day forcast (right side) and click one of the times displayed. It will draw a line showing the direction of flight. Good for checking other 'stuff' up there as well...

 

[3488]

Try http://www.n2yo.com then click the 5 day forcast (right side) and click one of the times displayed. It will draw a line showing the direction of flight. Good for checking other 'stuff' up there as well...

Welcome to SDC gmcolin.

I have been using that whilst updating the STS 128 Discovery thread. It shows you the exact lat, lon, orbital altitude & speed. Also there is a 'footprint' option that shows the area visible from the craft in question & the location on the ground where said craft is visible.

Also you can choose what to track, Hubble Space Telescope & much more. I like the map showing the international boundaries too.

Heavens Above is great for your or other location to observe bright satelittes, astronomical bodies, stages of twilight, etc. So really both can be used together.

Andrew Brown.

 

[toph]

I got a pretty good pic of a similar chase flyby a couple of years ago:

That bright "star" they are headed towards is Jupiter. The full size picture and a couple of others are available here:

http://itoph.no-ip.com/pictures/2007/ST ... age_3.html

Chris

 

[MeteorWayne]

Very nice Chris! Welcome to Space.com.

 

[3488]

Very nice Chris! Welcome to Space.com.

Fantastic shot, absolutely love it, brilliant. Love the slide show too.

There should be opportunities for more before the Shuttle is retired.

Welcome to SDC Chris.

BTW, where are you? I see Illinois, near Chicago?????????

Andrew Brown.

 

[toph]

I've actually had an account here since almost the beginning (created it on 8/22/2000) - but I obviously have not been actively posting.

Yes, I'm in Downers Grove, a western suburb of Chicago. Difficult lighting conditions for just about any astronomical observations. In the pic with Jupiter it might have worked to my advantage - the glowing clouds might have made the picture look better.

 

[andrew_t1000]

That is an excellent photo Chris!
Great job!
I didn't get a pic, but a couple of weeks ago I saw the ISS.
Even without binoculars I could see a bit of detail!
The 2 solar arrays joined by a thin bright line!

 

[boki_san]

I got a pretty good pic of a similar chase flyby a couple of years ago:

Chris

brilliant photograph, chris!

... Even without binoculars I could see a bit of detail!
The 2 solar arrays joined by a thin bright line!

wow! you have an imagination with amazing resolving power

 

[halman]

A couple of years back, I just happened to see the ISS and the shuttle traveling across the sky a short distance apart. What a thrill! I have tried to catch that duet again, but no luck. To see TWO bright points of light moving through the sky a short distance apart is truly one of the hallmarks of our advancing technology.

 

[MeteorWayne]

Over all the years I've only managed to see them a degree apart once, on a cruise in Norfolk VA. I didn't even know the shuttle had undocked until I saw it. Only a friend who worked in California (who now lives back in the UK) and I were outside on the toip deck to see it.

Maybe I'll get lucky this time...we have a series of evening passes coming up over the next week or so.

 

[MeteorWayne]

Discovery Leaving ISS - sighting question

Undocking is minutes away, and the shuttle will be hanging aorund for a bit less that two hours before the final separation burn. Once that data is ingested (Say after 2200 UT Sept 9 for the epoch) the Heavens-Above prediction should be valid for this evening's passes.

Wayne

 

[boki_san]

did you see um, wayne? did you see um?!!! ISS following the

did you see um, wayne? did you see um?!!! ISS following the shuttle by ~12° !!!!

i finally got to see and photograph two spacecraft,
with two separate groups of humans,
flying through the sky in formation.
i can die , now.

the shuttle was between 10° and 15° ahead of the international space station,
as i measured with my two foot long carpenter's angle finder device.

i was following tracking data all afternoon,
since the undocking, and it looked like they were going to be quite distant from each other.
and my sky was heavy overcast all day, with a forecast of 75% cloud cover for flyover time.
... somehow the two craft got back into psuedo conjunction,
and the northern sky was clear as a bell

i was able to fire four photographs, ... two each, at two different exposures.
i hope they are exposed correctly.
now, i'll have to drive down to town tomorrow and get them to the lab.

that was thrilling.
you kids maybe don't get how big a deal it is.
i remember being up past my bedtime, on my ninth birthday,
watching our pre-solid state black & white tv
as armstrong was setting the first human footprint on the moon.

to see two sets of folks, cruising through space,
to see them from the earth, with my naked eyes,
just blows my cooks

now, ...
... i'll just throw on some king crimson or eno,

and eat some thai volcano noodles

 

[john181818]

There was a great sighting tonight of STS 128 and the ISS from the Phoenix area, where weather in the NW was perfect, at about 7:48 MST. I had not realized that the shuttle had separated earlier and was surprised to see two tracks, probably 100-200 miles apart.

Good stuff!

 

[MeteorWayne]

Re: did you see um, wayne? did you see um?!!! ISS following the

did you see um, wayne? did you see um?!!! ISS following the shuttle by ~12° !!!!

No , the weather screwed me again; complete overcast

As I've said, if you have an opportunity to see these two craft close in the sky, don't miss it. Because the timing and the weather may never give you another chance. I was only lucky once.

Congrats to those who had a little luck on their side!!

Wayne