View Full Version here: : comets much?
02-01-2012, 12:19 PM
hey guys i pulled out my new 6inch dob last nite and i noticed as i was looking at Jupiter i saw what i thought was a comet quickly going by past my view, i didnt think much about it but then i was just randomly point my telescope at stars and i saw another go buy.
is it normal to see "comets?" that much ?
02-01-2012, 12:42 PM
Comets are quite slow moving, it would more than likely have been a meteor or a satellite, depending on the speed.
Yes, you do see them quite often, but it is always a bit of a thrill. :)
02-01-2012, 01:31 PM
:thumbsup: yep satallite or metor , As JJJnettie said , they are a thrill and move so fast , past the field of view.
On that note I once had the ISS pass thru my field of my ED80 and luckily I was using my Astrotech/ Gso alt az mount and was able to follow it once I sussed its tradectury , it looked like a big letter 'E' flying on its side , Awsome:D , one I wont forget . The joy of stargazing .
Good luck with your new scope , the perfect begineers scope..
06-01-2012, 12:04 AM
A satellite? Sorry new kid on the block here, but whenever I saw satellites they would move slowly (unless I had mistaken them for (http://www.zanui.com.au/kids/kids-furniture/) comets). My guess is that they are meteors?
06-01-2012, 12:09 AM
Through the eyepiece, a meteor would just zip through the field of view, a satellite would take a few seconds.
06-01-2012, 01:47 AM
Just to be clear, comets even when moving 'fast' relative to Earth observers at typically speeds of a few degrees per day will only show apparent movement across the fields if you observe them for quite a while (say several minutes). Their position relative to adjacent stars will gradually change. For telescopic comets moving slowly relative to Earth observers, you might notice notice slight relative movement over a much longer period. Also, comets generally show as diffuse objects, not the bright star-like points of satellites.
Satellites can move at varying speeds too, from zippers like the ISS to ones that take several seconds to cross the field, to geosynchronous satellites that never leave the untracked field while the stars arc slowly through the field.
Meteors would literally flash across the field, but for any new observers your chances of actually seeing one would be pretty remote I'd imagine. I've been observing frequently for years and never seen one (or recognised one! :P ). I'd imagine that you'd just be left with the impression of a flash across the field, not a moving star-like point, even for the slowest of meteors. I'm sure that a few people here would have seen them though, especially amongst the hard-core of lifetime telescopic observers.
06-01-2012, 02:42 AM
The thing with telescopes is that I've noticed people often spend heaps of time looking at one tiny patch of sky, but not so much at the whole sky! :)
During my recent comet chasing in really dark skies, I just set the camera to shoot away on its own with wide angle lenses and decided not to set up my telescope at all. I just say and watched the sky for hours with dark adapted naked eyes.
After several nights out, I'd say that I spotted over 50 satellites - usually one every few minutes, especially around dusk/dawn. It's amazing they don't collide up there... virtually every long exposure wide angle photo I have has a satellite trail somewhere.
I also spotted about 10-20 meteors per night. I assume they were meteors because of both how fast they travel - equivalent to crossing the whole sky in a second or two - and how bright they are (much brighter than I've ever seen the ISS).
Some meteors I've seen have been spectacular - a huge bright streak over about 150 degrees of the sky in about a second. The brightest one I've ever seen lit up Salt Lake City, Utah as if it were daytime... check out this security camera video of it (http://www.youtube.com/watch?v=Jhf4ezudqQU). I've also seen a couple light up parts of the Brisbane sky as if it were lightning :)
06-01-2012, 10:40 PM
A relative of mine who works with satellite communications tried to explain to me how the satellites work up there. From what I understood, they don't collide because they are all set to different hights.The thing I'm surprised with is how rockets can be launched into space without colliding into one of them!
Sorry Rob, this is a newbie question but what are these "flash impressions" you mentioned? Is this just from magnetic forces?
07-01-2012, 12:07 AM
Bit out of my depth here as I've never seen one through a telescope! No eamsie, I just mean like a bright visual flash across the field (for bright meteors). I've read that the average meteor duration in visual sightings is 0.4 sec. People often estimate longer averages because it is difficult to reconcile such fleeting phenomena against a full second, which is actually quite a long time. Of course meteor speeds vary and with a bright 'slow' fireball travelling a long distance across the sky you might have a second or two (or more) to observe it with the naked eye.
With a 0.4 sec duration meteor scribing say a 10-degree arc through the sky, and viewing a half-degree diameter field through your telescope, the meteor would cross the field in 0.02 sec. That's two one-hundredths of a second! If it was a dim one it mightn't even register to your eye - a very bright one might register more or less as an instantaneous flash. But no meteor (however 'fast' or 'slow') would be the sort of thing you could calmly watch enter one side of your telescopic field, cross the field, and exit the other side.
Maybe someone who's seen one could comment. :shrug:
07-01-2012, 12:12 AM
The thing I'm surprised with is how rockets can be launched into space without colliding into one of them!
Plain and simple space is a bloody big place.
07-01-2012, 12:23 AM
Sorry, I was just being a bit tongue-in-cheek :P The Occam's Razor answer is that they check the orbits of existing satellites before sending a new one up there (not difficult considering how accurately amateurs can track satellite movements). According to our good friend wiki, there have been eight known high-speed satellite collisions:
My personal experience agrees with this. I've never observed a meteor through a telescope (plenty of satellites though!), but they move so fast enough that I can barely follow them with my naked eyes - let alone through a telescope.
I've been very fortunate, most nights I've observed I've had one to two meteors fly thru my eyepiece per session. I always chuckle to myself that's my reward for my night for all the hard work (I don't have an Argo Narvis- It's hard work, lol) They're very fast, about the time it takes (for example I would say) to slowly blink your eye and it's gone (and that's thru a 65deg wide field eyepiece). Oh hail the person that could actually "observe" one.
The joys & rewards of constellation learning is that if you stand outside long enough and look at the whole sky, chances are that you will often see at least one in an hourly session, as I do.
A night I won't forget in a hurry is the recent total lunar eclipse we had- there it was the moon in a glorious orange ball eclipsed, and I caught two Geminid meteors (at different times) travelling next to it. *sigh*
Satellites as said before, travel slower thru the eyepiece and I often track them, they're easy.
That was really something!
While I was there I came across the news footage of it. http://www.youtube.com/watch?v=8gcWeLGNLgA&feature=related
hehe, I've finally got myself one of those space rocks that came in the form of an xmas pressie- one very happy astro chick this xmas I was. :D No, it didn't land in my yard. :rolleyes::screwy: Sheez for all the time I spend out there seeing so many you think one at least would land here.. even got the magnet out one day thru all the slush and goo thru the downpipe to no avail.:mad2: Okay, so I made hubby do it - symantics :rolleyes: Haven't given up yet tho.:P
08-01-2012, 11:43 AM
It frustrates me that media has created this idea that comets just flick by. The reality with most things in space is they dont just shoot by (based on our view of them, thousands of kilometers per hour is still fast). Meteors do, that is possibly what you saw, Satellites take 2-3 seconds to pass across your field of view.
Media frustration also includes end of days style comments etc. I have had so many emails from people I know and work asking me about 2012 ending, planex x blah blah blah. I often give them JJJ's responce.. if it were happening we'd all be out there imaging it and not replying to emails :).
That's my whinge for the morning.
By the way, congrats Str8upnub you saw somthing that is uncommon to see and although it only lasted a fraction of a second, now you know you saw it take a second to look up, maybe it will be visible in the naked eye. if not enjoy the fact that you managed to see a meteor or satellite in only around 1" of sky. Pretty cool huh?
08-01-2012, 12:00 PM
That news story has some great footage of it. The living room of my apartment (at the time) faced the wrong direction to see the meteor itself, but I happened to be staring out the window looking over Salt Lake City at the time... it was an amazing sight.
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