Satellite Observing Discussion

[MeteorWayne]

I bagged a satellite I've been trying to see for years this morning, so thought I'd start a discussion about observing sats.

The first thing anyone interested needs to do is go to: http://heavens-above.com/
Then select your location as accurately as possible, THEN bookmark the page. That way your location will come up each time you select the page.

For most satellites the exact location is not critical, but for the Iridium Flares (very bright flares from satellites that only last 10-15 seconds) a difference of a few km or miles makes a huge difference.

There are other sites on the web, which others can add here, but I've found this the easiest to use.

 

[MeteorWayne]

So why was I so excited this morning? I finally saw the Hubble Space Telescope! For those of you further south, I know that's no big deal, but it's a real challenge from my home in NJ at 41 North latitude. It seldom gets higher than 12 degrees elevation, and it's in a bad direction for me as well, always due south near the treeline and haze. But this morning's pass was the highest I've ever seen listed, 14 degrees, and it passed just below the bright star Formanhaut.
It was actually easy to spot. Aaaaaagh . Another one to check off my life list.

Two other satellites deserving comment.

UARS (Upper Atmospher Researh Satellite) http://en.wikipedia.org/wiki/Upper_Atmo ... _Satellite

This was launched from the shuttle in 1991 (STS-48) with a lifetime of 3 years, but lasted until 2005 before being deactivated. From my observations over the last few days it appears to be tumbling slowly. The other night it was at least 1.5 magnitudes brighter than predicted, and had 2 soft (low rise and fall time) flares lasting a second or two of close to mag 0. This morning, it was dimmer than predicted and disappeared in the twilight. So watch it for surprises.

GRACE 1 and 2

"The GRACE mission was selected as the second mission under the NASA Earth System Science Pathfinder (ESSP) Program in May 1997. Launching in March of 2002, the GRACE mission will accurately map variations in the Earth's gravity field over its 5-year lifetime (Now extended through 2015-MW). The GRACE mission will have two identical spacecrafts flying about 220 kilometers apart in a polar orbit 500 kilometers above the Earth.

GRACE will be able to map the Earth's gravity fields by making accurate measurements of the distance between the two satellites, using GPS and a microwave ranging system. It will provide scientists from all over the world with an efficient and cost-effective way to map the Earth's gravity fields with unprecedented accuracy. The results from this mission will yield crucial information about the distribution and flow of mass within the Earth and it's surroundings."

These fairly bright, relatively low (hence fast) sats are about 30 seconds apart on nearly identical orbits. I loooked for them the morning, but only caught the trailing one (Grace-1) because they were nearly a minute early and about 5 degrees (half a fist width) off in position. This is despite the fact that the epoch of the orbit was less than 24 hours old. It's the price of being low and fast So my advice is to go out a little early, and watch a little late to see these satellites. That's what I'll try the next time.

X-37B:

The orbit used by Heavens-Above is quite old, (June 8), and using that, I have no visible passes until the early morning hours of July 1. If anyone spots it, I'd be interested in hearing about it. In the meantime, I'll see if I can find an updated orbit somewhere else. 40 degree inclination to the orbit, so on a good pass it could be pretty high for the entire US.

Dragon/Falcon 9:

34.5 degree orbit, so the further south you are, the better your chances. I don't have a visible pass for another 5 days, and they will be a challenge in morning twilight.

Enough for now, I have to sleep :geek:

 

[orionrider]

Hubble, whoaww Congratulations!
I often see passing sats, but I'm too ignorant of astronomy and orbital mechanics to find out which one it is

 

[CalliArcale]

Whoa, you saw HST from 41 deg N? Impressive! I've never seen it; I wonder if it would ever be possible from my location? I'm four degrees further north than you, and with it so low from your vantage point, I'm inclined to suspect "no". I've never seen Heavens Above list it as a visible pass.

That's awesome, MW!

 

[MeteorWayne]

Yeah, Heavens-Above probably wouldn't list it, since they only show passes over 10 degrees elevation, and it probably wouldn't get that high for you. You might try picking a location 5 degrees south of you for passes, then getting a really good souther horizon location Of course, this time of year, you have even fewer dark hours than I do

 

[CalliArcale]

Yeah; it's really hard getting the kids to bed when the sun is up so late. Hard to remember to have dinner in time for bed, for that matter, because it really doesn't look like 6PM at 6PM.

I'm fortunate to live on top of one of the two highest points in the Twin Cities. Unfortunately, most of it is either developed or wooded. However, if I went out onto the green strip between the bike path and the highway, I'd have a great view of a strip of the southern horizon. Unfortunately, though the highway lacks street lights, the intersections into neighborhoods each have a light, so there would be light pollution. But someday maybe I'll try. It would be pretty cool.

 

[orionrider]

51° north. Damn!

 

[MeteorWayne]

I just checked my Heavens-Above page for tonight, and there are an incredible 280 satellite passes listed from sunset tonight to sunrise tomorrow morning.

There's a nice "neckbreaker" (near overhead) pass of the ISS tonight ~ 10:45 PM for the eastern US; mag -3.5 for me (almost as bright as Venus). It will pass directly overhead on a path from Louisiana and up the Appalachians to the Maine coast.

http://heavens-above.com/gtrack.asp?dat ... atid=25544

 

[Captain_Salty]

there are an incredible 280 satellite passes listed

would any of those be spy sats? I presume they're just as visible :?

 

[MeteorWayne]

Yes, quite a few.

 

[MeteorWayne]

Wow, a fascinting time of year. Even with a near full moon and hazy skies, there's an easy satellite evry few minutes; you almost can't look up without seeing one.

A few notables:

ISS:
it's fascinating to me to be able to see the ISS on 3 consecutive orbits 90 minutes apart. I keep waving at the crew, but haven't seen them wave back yet. (347 X 359 km orbit)

I've seen a number of bright, low and therefore fast objects. For example Cosmos 2421 currently 292 x 315 km, not long for the orbiting fleet. It produced a bright zero magnitude 5 second flare which leads me to believe that it's interaction with the atmosphere has caused it to start to tumble. (launched 2006, CIS)

Another interesting one was USA 186 which was about a minute late and more NW than the prediction; it's in a 258 (very low) X 1000 km orbit.

 

[orionrider]

it's interaction with the atmosphere

Before the proverbial 'fiery plunge', is there some other sign to indicate that a sat's orbit is grazing the atmosphere; like a plasma contrail or a glow?... :?:

 

[MeteorWayne]

Well, possibly within the last half orbit there might be some kind of visible trail. That's just an educated guess. Interesting question. Have to just keep watching I guess

 

[MeteorWayne]

Just a reminder for the for the folks between about 35 degrees N and S; the Falcon 9/Dragon is scheduled to reenter during the between Sunday and Tuesday. Here's the latest prediction:

http://reentrynews.aero.org/2010026a.html

It's current orbit as of today is 187 X 201 km, as of 7 hours ago, so if there's a sighting available for you, it will be really movin' !!

Check the Heavens-Above site for your location...they have a Falcon 9 specific link on the front page.

 

[MeteorWayne]

As of 2300 UT yesterday, the orbit is down to 138 X 140 km (87 miles) so it won't last the day for sure.

 

[orionrider]

I saw the ISS last night, despite living in the most light polluted area in the world (middle of Belgium) AND the full Moon AND still a lot of daylight at midnight!
Polaris was almost invisible, Venus was a vague dot, but the ISS was very easy to spot :mrgreen:

It was amazing! No flares, but an incredibly strong light (-3.8 but looked like much more), like the landing lights of an airliner on final. And fast, very fast! It was difficult to follow even with the binoculars (old 7x50 Nikon). I didn't see the shape, but it was definitely not a dot either, larger and stronger than Venus; in fact it was too bright to see any details!

Great days to be outside at night (22°C at midnight). Wish I had a reflector, but the seeing here is too bad to invest that kind of money

 

[Captain_Salty]

A while ago I was wondering if anyone had ever taken a picture of the ISS in transit of the sun, as it would be a good challenge. Turned out they had done years ago, this website has some good pics and even a transit calculator.
http://pictures.ed-morana.com/ISSTransits/

 

[MeteorWayne]

X-37B this morning July 6:

I can report a confirmed sighting. 4:08 to 4:13 AM EDT. H-A predicted brightness was +2.3, I observed a peak brightness closer to mag +1.8, right on schedule. This was my first sighting of this craft.

 

[orionrider]

Last weekend I saw the pair ISS + Progress, just a tiny dot about one hand in front of the ISS

I naively tried to picture the ISS, setting my camera to 1600 asa, 315mm f5.6, 1/60
Using a pole to steady the camera and shooting in sequence, I managed to get a few sharp pictures (no trails). I expected to see some kind of cross, but even at 400% on the PC, the image looks like a bright circle truncated on one side. :?

MW, do you use old-fashioned naked eyes, binoculars, or your telescope? With a tripod? How do you follow the sats? And do you see more than a bright dot?
Ah, maybe too much questions... :lol:

 

[MeteorWayne]

I just see dots as I use my eyes mostly, and sometimes binoculars. When I'm meteor observing, it's eyes only since my primary job is to watch my whole field of view for meteors. But if I'm wandering out the front door at home, I usually sling the binos around my neck, not to see shapes, but fainter sats, and other sights of the sky (planets, star clusters, galaxies, etc)

MW

 

[orionrider]

I tried again to picture the ISS yesterday. It was one of the last good passes, so I took the tripod and the camera and went satellite-chasing

I hoped that it would be better than last time with some tweaks on the Nikon, but afterwards I calculated that even at the closest distance, each pixel on my camera would 'see' about 10m :shock:
The 'blob' looks too large for a 100m object, but that can be due to an out-of-focus magnification, maybe combined with the saturation of the sensor or a digital processing effect.

The little dots everywhere are not stars, but digital noise. The faint object on the right is visible on two shots so it is not noise, but I don't know what it is. It didn't move like the ISS.

Nikon D70, 300mm @ f5.6 and 1/125, image enhancement ON, noise reduction ON, 1600 asa, RAW mode in sequence to avoid trigger interference.

The same @ 400%:

I have no idea what I'm looking at. :? In fact, I don't see much ISS in these shots, but then I had fun trying :lol:

 

[MeteorWayne]

Nice try anyway )

I suspect both visible spots (besides the ISS itself) are internal lens reflections.

MW

 

[aphh]

Using binoculars to sweep a random area of the sky for awhile reveals even more satellites that what is listed on heavens-above. Some do stuff like pulsate, which means they tumble. The Goce gravity satellite races through the sky like an arrow faster than anything on very low polar orbit and glitters in golden hues along the way.

I'd be interested to learn whether it would be possible to receive transmission from a satellite using an antenna of some sort. Besides the TV and radio satellites, I mean. I know that the radio amateurs occasionally have contacted the ISS and perhaps Soyuz too.

Here is a link to a small video I took of ISS in March a year ago with Shuttle docked using just camcorder on tripod:
http://www.editointi.net/fourseasonshd/ ... earch=1047

 

[Mee_n_Mac]

I never gave it much thought but I've seen the ISS many times. Sometimes pretty "high" in the sky (over the horizon) and that's in NH (Alton Bay, 43.4690°N, 71.2330°W). Here's a pic (piss poor) I got of it in 2008 (30 sec exposure) ...

http://www.winnipesaukee.com/photopost/ ... 99&way=asc

 

[MeteorWayne]

That doesn;t really look like the ISS, unless there were some clouds. It rarely fades from view in mid pass, generally stays pretty close to the same brightness except for the rare flare off the solar arrays.

MW