[Chaos-l] Nice Animated GIF Of Comet Lulin

Thu Feb 26 12:10:31 EST 2009

Thx Christopher, that makes sense now, especially 
the 'scope tracking motion (I should have tho't of that being needed).
What was the interval between frames & how long 
was each frame exposure? Just curious...nicely done in any case!

At 09:37 PM 2/25/2009, Breivogel, Christopher wrote:

>I think those streaks that kept appearing were 
>satellites rather than meteors.  I did "mispeak" 
>about the stars "slewing" past, though.  Let me clarify my hypothesis...
>
>Meteors probably would have been to brief to 
>appear at in the time-lapse movie and even if 
>they did show up, they would have passed through 
>the field way too fast to be appear like for so 
>long in that movie.  Each image of the "movie" 
>showed a steak about an "inch" long in the 
>frame.  Orbiting satellites would also have 
>moved too quickly to appear as short streaks in 
>each exposure.  If they were geosynchronous 
>satellites, the apparent motion (which showed up 
>a the short streak in each image) would be due 
>not to the relative motion of the satellites, 
>but to the slewing of the telescope to counter 
>the rotation of the Earth (and make the stars 
>appear stationary).  It seems to me that the 
>telescope slewing speed would be the only motion 
>slow enough to keep those lights in the frame 
>for so long (since even a split second in that 
>film would have to represent a minute or more in 
>real time).  Furthermore, the position of the 
>meteor at that time had to be near the ecliptic 
>(since it was near Saturn) which is where you 
>would expect to see geosynchronous satellites.
>
>I had some similar pair of apparitions appear in 
>some webcam images I made a few years back, and 
>this was the explanation given to me by someone 
>on a listserve.   I was hoping they were 
>invading alien ships, but I must admit that the 
>satellite explanation seems more likely.  The 
>guy even looked up some satellites and told me 
>which ones they probably were.  Now that might 
>be interesting to figure out--which satellites 
>they could have been if that's indeed what they were....
>
>Chris Breivogel
>CHAOS member wanna-be
>
>
>-----Original Message-----
>From: chaos-l-bounces at rtpnet.org on behalf of Terry Crook
>Sent: Wed 2/25/2009 8:17 PM
>To: robertnielsen at nc.rr.com; chaos-l at rtpnet.org
>Subject: Re: [Chaos-l] Nice Animated GIF Of Comet Lulin
>
>I now know what the 'fuzzy' is!
>  From the Sky & Telescope site,
>http://www.skyandtelescope.com/observing/objects/comets/35992534.html:
>
><In telescopes and low-light images, it has been
>showing both a dim gas tail and a dust-spike
>antitail pointing in nearly the opposite
>direction. Its current brightness is about magnitude 5.2.  >
>
>There's lots more photos & text, including much
>on anti tails & the comet's peculiar motion/orientation.
>
>On 2/24, 8:42, I wrote:
>Yes, I'm familiar with the ion tail vs the more visible dust tail.
>However, this fuzzy area is preceding the comet
>coma, not trailing away (from the Sun) as is normal.
>Possibly some gas eruptions from the head of the
>coma, illuminated and/or excited by solar radiation?
>It seems in synch with the comet's motion, at
>least for now/during this photo series.
>
>Someone tho't the streaks were earth satellites
>but I'd bet on meteor trails. The former would
>leave a longer trail than the meteors, it seems
>to me. Surely we may be able to identify the
>meteor shower?  His reference to camera slew is
>weird, as none of the star trails have moved
>during the ~2-minute duration/exposure.
>
>There was one isolated bright spot very briefly,
>just ahead & above of the comet; possibly electronic noise?
>
>OTOH, I can't make out NGC 4073 but then you know
>much better than I what to look for & have better eyesight!
>
>   At 04:24 PM 2/24/2009, you wrote:
> >Terry,
> >
> >An explanation of why we see two tails (one a
> >dust tail and one an ion tail) is visually given
> >at: 
> <http://www.sidleach.com/comet_c2007_n3_lulin_antitail.htm>http://www.sidleach.com/comet_c2007_n3_lulin_antitail.htm.
> >
> >I'm not entirely sure ... but looking at the
> >rough general area of the sky where Comet Lulin
> >was last Saturday, and matching up some of the
> >stars, I would say the bright star is beta
> >Virginis, or Zavijava.  And I think the faint
> >galaxy above the comet when it starts is NGC
> >4073 ... although there are a lot of galaxies in that area.
> >
> >Robert
> >
> >Terry Crook wrote:
> >>Remarkable pix, thanks! I would have gone out
> >>to look for it locally (with binocs) but have
> >>been fighting a nasty sinus infection lately!
> >>Two questions (for anyone):
> >>         What is the star in the upper right center?
> >>         If the Sun is to the right (w/ tail
> >> extending behind comet), what is the 
> variable cloud ahead at about 1'oclock?
> >>
> >>At 12:02 PM 2/24/2009, Robert Nielsen wrote:
> >>>Everyone,
> >>>
> >>>This has been making the rounds on some
> >>>astronomy forums: 
> <http://www.ccdargo.com/lulin.gif>http://www.ccdargo.com/lulin.gif
> >>>
> >>>It's a really nice animated GIF of Comet
> >>>Lulin, taken last Saturday night where 61
> >>>images cover about 2 hours of the comet's 
> movement against the star background.
> >>>
> >>>Credit: Tom Carrico
> >>>
> >>>Robert
> >>>
> >>>_______________________________________________
> >>>Chaos-l mailing list
> >>>Chaos-l at rtpnet.org
> >>><http://rtpnet.org/mailman/listinfo/chaos-l>h 
> ttp://rtpnet.org/mailman/listinfo/chaos-l
> >>
> >>Taurus Terry in Chapel Hill
> >>35ï¿½ 55' 47"N, 79ï¿½ 01' 00"W
>
>Taurus Terry in Chapel Hill
>35ï¿½ 55' 47"N, 79ï¿½ 01' 00"W

Taurus Terry in Chapel Hill
35° 55' 47"N, 79° 01' 00"W  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://rtpnet.org/pipermail/chaos-l/attachments/20090226/d32b811b/attachment.htm>