Skywatchers' Journal

[Buffy]

#1 since Earth passes through comet tails for many meteor showers, does this mean the comets that left the dust could hit Earth in the future?:eek:

That's the idea. You have two cars on intersecting race tracks. Fortunately for us the tracks are *really* long and there's not a lot of synchronicity in their periodicity.....

#2 why do the dust bits stay in the same place in Earth's orbit year after year? why doesn't the solar wind push the tail material outward?

They might be very light, but they still have a lot of inertia!

 

They do get blown out, but slowly and so the drift in the calendar of the showers is slow too.

 

Referring back to #1 though, this also means that where the trails are now are not necessarily where the comet last traveled, so the shower debris isn't necessarily an indicator of a future possible catastrophic conjunction.

 

that's a wrap. :hyper:

I like turkey wraps myself!

 

Coordinating conjunction,

Buffy

[Turtle]

That's the idea. You have two cars on intersecting race tracks. Fortunately for us the tracks are *really* long and there's not a lot of synchronicity in their periodicity.....

They might be very light, but they still have a lot of inertia!

 

Ok, i understand inertia in principle. in the case of the trail of debris as a track, is the track moving? that is to say do the particles have movement along the course as did the comet, or do they shed & stay put?

 

Referring back to #1 though, this also means that where the trails are now are not necessarily where the comet last traveled, so the shower debris isn't necessarily an indicator of a future possible catastrophic conjunction.

 

Yes, I understand the comet may take different tracks each time around due to perturbations from the Sun's/Jupiter's/other body's gravity. So we may have multiple tracks of debris as well for a single particular comet?

 

I like turkey wraps myself!

 

Coordinating conjunction,

Buffy

 

interrogative participle dangling? :hyper:

[Buffy]

Ok, i understand inertia in principle. in the case of the trail of debris as a track, is the track moving? that is to say do the particles have movement along the course as did the comet, or do they shed & stay put?

There's nothing to slow them down is there? Its not like tossing a plastic bottle out of a speeding car, so they drop off but keep on moving...

Yes, I understand the comet may take different tracks each time around due to perturbations from the Sun's/Jupiter's/other body's gravity. So we may have multiple tracks of debris as well for a single particular comet?

Sure why not? But I would not discount your original concept of the orbits being perturbed by solar wind, however I'd still say that the inertia trumps the wind (or the gravitational effect of other passing bodies), and thus keeps the "track" coherently persistent over long periods of time.

interrogative participle dangling?

Eww! That sounds gross!

 

Split infinitely,

Buffy

[modest]

Sky Watching & Listening

 

When I was a kid, my neighbor had an amateur radio antenna. I remember listening to Jupiter. It sounded like thunder – very scary – very cool

[Turtle]

Well nows! What a difference this digital photography is from the days of film. I used to prefer Kodachrome for color and kept a darkroom for the B&W and a Black Art for sure it was, but no less the digital wizzardry methinks as I stumble round with it like Mickey with a wand. :P:camera::evil:

 

Anyway, I took a still shot 2 nights ago of the waxing crescent Moon as it happened to be in the way of some clouds I was videographing. :eek2: Just got around to looking at it on the computer & it appeared as the attachment below on the left. Spectacularly crappy. Started playing around with the enhancement tools and clicked Equalize and WOAH! Attached image on right is what appeared.

 

That's a lot of hidden information. Keep in mind it was dark out and I was using the Nightshot infrared setting, but it's still a lot of detail. Especially the colors, as with the old infrared system everything went a gray-green color.

 

Here's an informative article on the Equalize function; you're apparent sky-photo trash may be treasure afterall. >> :eek: ;)

 

Image Enhancement

... The third automatic command is the Equalize command. This works like the Auto Contrast command by mapping the darkest and lightest pixel's values to the shadow and highlight endpoints, but then goes a stage further by attempting to equalize the image brightness that is, to distribute the intermediate pixel values evenly throughout the grayscale. In other words the command fine-tunes the redistribution of values to flatten out the RGB histogram's peaks and troughs. Trying this on an underexposed image can be a huge eye-opener revealing detail in shadows that just isn't originally visible, but the damage done to colour balance and accuracy is huge. ...

[max4236]

Pretty neat, all that hidding in the darkness.:lightning

[DougF]

Yes most excellent,

 

Oh so very wise of you,

Oh great Turtle master of the nighttime,

Of the daytime.

Of inter space,

Of outer space,

Of...

Of...

Oh you know how it goes,

thats why your the great one.

 

 

No I mean it, relay good video.

[Turtle]

...Oh great Turtle master of the nighttime,

Of the daytime.

Of inter space,

Of outer space,

Of...

Of...

Oh you know how it goes, ...

 

Yes Sir; and it goes so. :shrug: Another advantage of many of the digital video cameras is the inclusion of an infrared remote control. This allows you to operate many camera functions without any physical contact and so eliminate a major source of blurring due to vibration as in the olden days. Tonight's video takes advantage of just this feature as I take us on a virtual flight to the Moon via zoom. (Camera is on a tripod if that's not obviously implied or otherwise misundertaken. )

 

"Which practice?"

"NO! "Witch" practice!"

:hihi:

YouTube - Moon flight http://www.youtube.com/watch?v=1FNMItXPDSM

[TheBigDog]

:naughty::)

[Turtle]

:):love:

 

That kind of retort will get you the fuller explanation; or, The Making of Moon Flight. :( The following techniques apply to window astrovideography in general. :evil:

 

*Don't shoot through glass; open the window and take out the screen. Position the camera & tripod as close to the opening as possible. Make a cardboard filler with a camera port to keep heat loss to a minimum during Winter.:)

 

*Find the Manual Focus function if you have one and use it to set focus to infinity. Nothing more irritating than a bug flying close in front of the camera and having the focus go whack. :) Having this setting also keeps focus constant during zooms. :naughty:

 

*for Moon and planet shots, find the camera's Manual Exposure function -if it has one- and switch it on, then turn down the exposure until you see details (craters in the case of the Moon) instead of the bright splotch of white the camera thinks is good. :)

 

I think thats all I got. :evil: Say cheeeese!

YouTube - Moon flight http://www.youtube.com/watch?v=1FNMItXPDSM

[Turtle]

Mmmmm...astronomy? meteorology? geology? ornithology?conspiracy? :hyper: :) :hihi:

 

Moonrise Over Mt. Hood Volcano With Pink Contrail Highlights & Birds

[TheBigDog]

Mmmmm...astronomy? meteorology? geology? ornithology?conspiracy? :rolleyes: :phones:

 

Moonrise Over Mt. Hood Volcano With Pink Contrail Highlights & Birds

 

Omniology :eek2:

 

Bill

[Turtle]

More omniology. Looking South over Portland Oregon as the Moon transits the sky & lights up passing contrails. 10/22/07. 4 clips, 44 minutes elapsed time between 10:30PM & Midnight. The second clip is the best, even though we don't see the plane that made the contrail.

 

YouTube - Moon Illumes Contrails http://www.youtube.com/watch?v=jJsE781ArKE

[Turtle]

Happy Cross Quarter Day!! :shrug: Huh? :confused: What does Halloween have to do with Astronomy? :eek2: Well, today is the half-way point between the Fall Equinox and the Winter Solstice; a cross-quarter day. According to today's article at Spaceweather.com, in days of yore, this was the first day of Winter. >> SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids

 

"Long ago, the Celts of the British Isles used cross-quarter days to mark the beginnings of seasons. Winter began with Halloween, or as they called it, Samhain," says John Mosley of the Griffith Observatory. "Halloween marked the transition between summer and winter, light and dark -- and life and death. On that one night, according to folklore, those who had died during the previous year returned for a final visit to their former homes. People set out food and lit fires to aid them on their journey -- but remained on guard for mischief the spirits might do."

 

:evil: :ebomb: :eight: :moon: :bat:

[Jay-qu]

Happy Cross Quarter Day!! :shrug: Huh? :confused: What does Halloween have to do with Astronomy? :eek2: Well, today is the half-way point between the Fall Equinox and the Winter Solstice; a cross-quarter day. According to today's article at Spaceweather.com, in days of yore, this was the first day of Winter. >> SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids

 

 

 

:evil: :ebomb: :eight: :moon: :bat:

Well its not really for a week, but that is the point :hihi:

 

Another cross quarter day is groundhog day.

 

Have any of you northern hemispherians been looking out for comet Holmes? It coma has been mysteriously expanding and now its so big its about the same angular size as jupiter :eek: so go and have a look tonight, you dont even need binoculars, though they will help ;) It is currently in the constellation of Perseus.

[Turtle]

Well its not really for a week, but that is the point :evil:

 

Another cross quarter day is groundhog day.

 

Have any of you northern hemispherians been looking out for comet Holmes? It coma has been mysteriously expanding and now its so big its about the same angular size as jupiter :evil: so go and have a look tonight, you dont even need binoculars, though they will help ;) It is currently in the constellation of Perseus.

 

Keepin' me on the straight & narrow eh? :evil: Good for you. :note:

 

I haven't looked for the comet yet but will now give it a shot tonight :evil:. I have read about it however, and it has had a least 2 sudden expansions that you mention. Also unusual is that the comet has virtually no tail yet!?:note:

 

Pop QUIZ! Put your books under your desks and take out the ol' #2.

 

Q: We have named Halloween and Groundhog's day as cross-quarter days; what are the other 2 holidays that fall on the remaining cross-quarter days? :)

[Jay-qu]

Once I had the approximate dates I couldnt think of any holidays.. so I had to look them up, and I hadnt heard of them but they are there :evil: