cool shot
in [Digital Cameras]
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From: M-M on 25 May 2010 00:29 In article <4bfa1d04$0$1629$742ec2ed(a)news.sonic.net>, rfischer(a)sonic.net (Ray Fischer) wrote: > M-M <nospam.m-m(a)ny.more> wrote: > > "Jeff R." <contact(a)this.ng> wrote: > > >> > It is an easy shot with the right equipment since you know exactly when > >> > the event will happen and your camera is electronically tracking the sun. > >> > >> > >> Uh huh. > >> Especially when the transit takes about... oh, I'd guess... half a second? > > > >More like 7.5 seconds. And you just put your camera on continuous as > >soon as the transit begins. > > > >An orbit of the shuttle takes 90 minutes. 360 degrees in 90 minutes. The > >sun is 1/2 degree in diameter. That means 1/2 degree in 7.5 seconds. > > That happens to be wrong because you're observing the shuttle not from > the center of the Earth, but from a point that is about 7,600 miles > closer to the shuttle. > > 18,000mph and 0.5 degrees seen from a distance of 300 miles. Let's see > if I still remember trig. > > sin 0.5 degrees (the width of the sun) is 0.00873, times the distance > to the shuttle (300 miles) is 2.7 miles, longer at higher latitudes. > Let's say four miles. > > The shuttle, travelling at 18,000mph will traverse that 4 miles in, > well, not a very large amount of time. Roughly 3/4 second. > > Doable, but hard. I thought 7.5 seconds seemed a bit long. The article does confirm your calculations. But if you know in advance the exact moment of transit (which the photographer did), a lot of the difficulty is removed. He still had to be at the right place at the right time with the right equipment so I give him a lot of credit. -- m-m http://www.mhmyers.com
From: Val Hallah on 26 May 2010 10:14 On May 21, 9:01 pm, "Ivan I" <i...(a)uptheresomewhere.maybe> wrote: > "Val Hallah" <michaelnewp...(a)yahoo.com> wrote in message > > news:5d52ce50-5e07-416f-8b26-e8f24fc0286e(a)j27g2000vbp.googlegroups.com... > > >http://www.dailymail.co.uk/sciencetech/article-1279952/Nasa-shuttle-A... > > Awesome. Just out of interest, why do the ISS and STS appear to be moving > in the wrong direction? > > Some nice recent pics here too, from Cassini:http://www.boston.com/bigpicture/2010/05/checking_in_on_saturn.html http://www.dailymail.co.uk/news/worldnews/article-1281516/Ring-sky-Storm-clouds-form-dramatic-circle-sunset-Hungary.html
From: Ray Fischer on 29 May 2010 01:47 M-M <nospam.m-m(a)ny.more> wrote: > rfischer(a)sonic.net (Ray Fischer) wrote: >> M-M <nospam.m-m(a)ny.more> wrote: >> > "Jeff R." <contact(a)this.ng> wrote: >> >> >> > It is an easy shot with the right equipment since you know exactly when >> >> > the event will happen and your camera is electronically tracking the sun. >> >> >> >> >> >> Uh huh. >> >> Especially when the transit takes about... oh, I'd guess... half a second? >> > >> >More like 7.5 seconds. And you just put your camera on continuous as >> >soon as the transit begins. >> > >> >An orbit of the shuttle takes 90 minutes. 360 degrees in 90 minutes. The >> >sun is 1/2 degree in diameter. That means 1/2 degree in 7.5 seconds. >> >> That happens to be wrong because you're observing the shuttle not from >> the center of the Earth, but from a point that is about 7,600 miles >> closer to the shuttle. >> >> 18,000mph and 0.5 degrees seen from a distance of 300 miles. Let's see >> if I still remember trig. >> >> sin 0.5 degrees (the width of the sun) is 0.00873, times the distance >> to the shuttle (300 miles) is 2.7 miles, longer at higher latitudes. >> Let's say four miles. >> >> The shuttle, travelling at 18,000mph will traverse that 4 miles in, >> well, not a very large amount of time. Roughly 3/4 second. >> >> Doable, but hard. > >I thought 7.5 seconds seemed a bit long. The article does confirm your >calculations. Really?!? >But if you know in advance the exact moment of transit (which the >photographer did), a lot of the difficulty is removed. Sure, it can be done (obviously). Probably best to have the scope track the sun and then have a computer trigger the camera at the right moment. >He still had to be at the right place at the right time with the right >equipment so I give him a lot of credit. Hell yes. -- Ray Fischer rfischer(a)sonic.net
From: Val Hallah on 29 May 2010 02:25 On May 26, 4:14 pm, Val Hallah <michaelnewp...(a)yahoo.com> wrote: > On May 21, 9:01 pm, "Ivan I" <i...(a)uptheresomewhere.maybe> wrote: > > > "Val Hallah" <michaelnewp...(a)yahoo.com> wrote in message > > >news:5d52ce50-5e07-416f-8b26-e8f24fc0286e(a)j27g2000vbp.googlegroups.com.... > > > >http://www.dailymail.co.uk/sciencetech/article-1279952/Nasa-shuttle-A.... > > > Awesome. Just out of interest, why do the ISS and STS appear to be moving > > in the wrong direction? > > > Some nice recent pics here too, from Cassini:http://www.boston.com/bigpicture/2010/05/checking_in_on_saturn.html > > http://www.dailymail.co.uk/news/worldnews/article-1281516/Ring-sky-St... http://www.telegraph.co.uk/earth/earthnews/3352517/Heron-catches-rabbit-Dramatic-photos.html
From: Will T on 29 May 2010 04:00
On Fri, 28 May 2010 23:25:11 -0700 (PDT), Val Hallah <michaelnewport(a)yahoo.com> wrote: >On May 26, 4:14�pm, Val Hallah <michaelnewp...(a)yahoo.com> wrote: >> On May 21, 9:01�pm, "Ivan I" <i...(a)uptheresomewhere.maybe> wrote: >> >> > "Val Hallah" <michaelnewp...(a)yahoo.com> wrote in message >> >> >news:5d52ce50-5e07-416f-8b26-e8f24fc0286e(a)j27g2000vbp.googlegroups.com... >> >> > >http://www.dailymail.co.uk/sciencetech/article-1279952/Nasa-shuttle-A... >> >> > Awesome. �Just out of interest, why do the ISS and STS appear to be moving >> > in the wrong direction? >> >> > Some nice recent pics here too, from Cassini:http://www.boston.com/bigpicture/2010/05/checking_in_on_saturn.html >> >> http://www.dailymail.co.uk/news/worldnews/article-1281516/Ring-sky-St... > >http://www.telegraph.co.uk/earth/earthnews/3352517/Heron-catches-rabbit-Dramatic-photos.html I prefer the sequence I got of a Great Blue Heron catching and eating a 3ft. water-moccasin (a deadly snake for those not in N. America). What surprised me a little is that I had just been ambling around in the tall shore-grasses right where the heron caught it. |