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Photography Question 
Rose 
 

How to shoot the night stars


How do I take pictures of stsr? How long should the shutter speed be to get the circular smeared look?


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7/10/2004 4:47:26 PM

 
Damian P. Gadal
BetterPhoto Member Since: 4/22/2002
  Check out Art's Gallery http://www.artsdigitalphoto.com/-/artsdigitalphoto/


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7/10/2004 6:36:43 PM

 
Rebecka Franklin   Hi! I thought that was a great question my self, so I did an internet search real fast and this is what I found. http://www.space.com/spacewatch/astrophotography_101_030627.html
I am going to keep looking for more tips.


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7/12/2004 10:06:03 AM

 
Rebecka Franklin   Here is another

http://www.fotoinfo.com/info/techniques/astroexposure.html


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7/12/2004 10:31:41 AM

 
John A. Lind
BetterPhoto Member Since: 9/27/2001
  Rebecka,

The "circular look" you asked about are called "star trails."

If you aim at the North Star (in nothern hemisphere; South Star in southern hemisphere), it will remain "stationary" and the other stars around it will make a complete circle in approximately 24 hours. That's about 15 degrees of arc per hour (360 / 24 = 15).

How long an exposure must be to show star trails depends on focal length of lens as longer focal lengths magnify the view and therefore magnify the motion of the stars in the sky. It also varies by area of area of the sky you are photographing (how close it is to the pole star) and a little by your geographic latitude. For 35mm - 50mm focal lengths showing large expanse of sky, exposures must exceed about 30-45 seconds to show star trails. YMMV depending on focal length and area of sky you're aiming at.

If you want long star trails, plan on exposures measuring in hours! This requires dark sky; too much light pollution with too long an exposure will fog the sky and wash out the trails.

One of the best and most comprehensive books on the subject of astrophotography:
_Astrophotography_for_the_Amateur_ by Michael A. Covington.
http://www.covingtoninnovations.com/astro/

Most public libraries should have one.

-- John Lind


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7/12/2004 10:39:54 AM

 
Rebecka Franklin   Ok I feel silly. I should have checked the past discussions right here at BP first! I used the search on this site and found some great tips and sites. This has been the best site that I have seen yet! http://www.danheller.com/star-trails.html


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7/12/2004 10:42:05 AM

 
Rebecka Franklin   Hi John! Thanks for the info. Most of these sites suggest using film of an ISO of 400 or faster, and wide open fstop. What do you suggest? I live 4 miles away from the middle of nowhere! Street lights are not problem here! In fact two nights ago I sat out on my deck looking at the milky way and wondering how I would photograph it! I want to do both star trails and were the stars do not move(or I guess I should say were the earth does not move;) As far as my location goes, I am about 60 miles directly south of Yellowstone National Park. I know a lot is just experimenting to find the right exposure, but a starting point would be very helpful!
Sorry Rose that I hijacked your question! I hope this is all helpful to you too!


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7/12/2004 11:27:09 AM

 
John A. Lind
BetterPhoto Member Since: 9/27/2001
 
 
  Wasatch Nightwatch II
Wasatch Nightwatch II
Film: Plus-X Pan
Exposure: likely f/4, 2-3 minutes
Mt. Olympus
Salt Lake City, UT

Climbed on top of my sister's house in the middle of the night to make this one. Late Fall, the mountain had some snow on its peak. Took several as the cloud cover was moving and continuously changing. I liked this one best with the clouds streaked from the long exposure. The white pinpoints in the clouds are not noise or artifacts. They're stars that peeked through breaks in the clouds for a number of seconds during the exposure; long enough for the film to record them, but not long enough to star-trail (from Earth rotation).

© John A. Lind
Olympus OM-4 35mm ...
 
 
Well . . . oops . . . I had intended to put "Rose" in the reply but it is applicable to both of you.

Most sources recommend starting with ISO 400, but this stuff is done using everything from ISO 25 to ISO 1600 films. There are many factors involved such as darkness of sky, how long an exposure you intend to make, focal length of lens, magnitude of stars you want in the photo, etc.

I suggest shooting some 100, 200 and 400 with a variety of focal lengths, lengths of exposures, etc., for each one to get a feel for these relationships and what works best for you.

BTW, my style of night shooting is not so much star trails as it is doing some constellations, smaller star clusters, and letting moon illuminate landscape. The one I've uploaded is the Wasatch Mountains from the roof of my sister's house on the outskirts of Salt Lake City. They're illuminated by the moonlight filtering through the cloud cover and the city lights. Used Plus-X Pan (ISO 125) with aperture likely f/4 and exposures on the order of 2-3 minutes. The pinpoints are too small to have survived the scanning; there are some stars peeking through the cloud cover and exposure was long enough for them to have trailed slightly.

Soooo . . . if it's not a dark sky night, you can do very long exposure landscapes too! (When you end up with lemons, make lemonade.)

-- John Lind


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7/12/2004 7:15:38 PM

 
Rebecka Franklin   Holy Crap! What a Small World! If I am not mistaken that is Mount Olympus and the brightest light in the photo is of the shopping complex Olyimpus Hills. I USE TO WORK THERE!!! I have spent a good share of my life in Salt Lake. Thanks for that picture John! I love B&W. And thanks for the advice! MMMMMMM...Lemonade


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7/13/2004 9:16:20 AM

 
John A. Lind
BetterPhoto Member Since: 9/27/2001
  Rebecka,
You have good eyes and a sharp memory!

It is Mount Olympus . . . all 9,000-plus feet of it. The lights are not Olympus Hills Shopping Center though (home of Einstein Bros. Bagel; great coffee and bagels) . . . I was just south of it. Not certain what the lights are . . . possibly street lights or another parking lot's lights . . . cannot remember if there's another shopping center a little farther south of Olympus Hills but north of the mountain or not. It was made in November a couple years ago. I remember freezing my hind end in a moderate breeze shooting it at about 2 AM to reduce risk of commercial aircraft flying through the view. Air traffic volume shrinks considerably after midnight. It's not difficult to capture plane nav lights near a large city. I've done it before and sometimes you don't see it until the film is back!

My sister thought I was nuts being up on her roof in the middle of the night to do the photograph. She is a SLC "transplant" . . . was a soloist with Ballet West and retired from it a little over 15 years ago. Much like pro sports, you can't continue too many years past 30 unless you're someone like Rudolph Nureyev.

Thanks!
-- John Lind


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7/13/2004 5:33:11 PM

 
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