# Thread: Angle of view as it relates to the solar eclipse

1. ## Angle of view as it relates to the solar eclipse

I plan to photograph the solar eclipse (weather-permitting) with both my 4x5 (210mm lens) and 8x10 (12" lens). From my viewing spot in Nebraska, the sun's azimuth will change nearly 80 degrees from start to finish. Does anyone know how to convert that to angle of view when the elevation is 60 degrees above the horizon? (It's not a simple calculation, since the vertical lines converge.) Thanks.

2. ## Re: Angle of view as it relates to the solar eclipse

First, I would put the 12" lens on the 4x5. Even then you image is going to be quite small. The Sun and Moon each intercept an angle of only about 0.5 degrees.

3. ## Re: Angle of view as it relates to the solar eclipse

No, the 12" goes on the 8x10. Yes, the sun's disc is roughly 0.5 degrees.

Originally Posted by Jim Noel
First, I would put the 12" lens on the 4x5. Even then you image is going to be quite small. The Sun and Moon each intercept an angle of only about 0.5 degrees.

4. ## Re: Angle of view as it relates to the solar eclipse

I'm thinking about observing and photographing the eclipse from San Francisco with a 10" Meade SCT at prime focus (2500mm equivalent) equipped with a solar filter. The Meade has dual axis electronic drive (tracks in both declination and right ascension) which eliminates problems due to the earth's rotation making a several second exposure doable.

Thomas

5. ## Re: Angle of view as it relates to the solar eclipse

Originally Posted by couldabin
I plan to photograph the solar eclipse (weather-permitting) with both my 4x5 (210mm lens) and 8x10 (12" lens). From my viewing spot in Nebraska, the sun's azimuth will change nearly 80 degrees from start to finish.
Are you mad? In Nebraska the sun's azimuth changes in several minutes nearly 80°?

6. ## Re: Angle of view as it relates to the solar eclipse

No, I'm not mad. I live 2 hours from the center of totality, so I thought that might be a convenient viewing spot.

7. ## Angle of view as it relates to the solar eclipse

The total event time (moon just touching the sun to moon just leaving) in Nebraska will be ~3 hours, with the sun traversing (3*360/24) 45 degrees of sky during that time frame. (15 degrees per hour). Totality time will be about 1 min, 30 s

An extended fist (back of the hand towards you) covers approximately 10 degrees.

This should give you an idea of the amount of sky the sun will traverse.

To satisfactorily fill the frame of a 35mm camera with an image of the eclipsed sun (or of the moon if doing astrophotography), you need a focal length of about 1250mm. To capture the entire corona during full eclipse would call for about 200-300mm.

You should be able to scale to required 4x5 focal length from there.

8. ## Re: Angle of view as it relates to the solar eclipse

Originally Posted by Nodda Duma
Totality time will be about 1 min, 30 s
According to this source https://www.space.com/33797-total-so...017-guide.html the totality time will last about 2min 40s.

9. ## Angle of view as it relates to the solar eclipse

Originally Posted by Pfsor
According to this source https://www.space.com/33797-total-so...017-guide.html the totality time will last about 2min 40s.
"At most". That, is, at the center of the eclipse path.

You need to look up the information for your specific location.

http://www.eclipse2017.org/2017/comm...ncoln_1125.htm

10. ## Re: Angle of view as it relates to the solar eclipse

Originally Posted by Nodda Duma
"At most". That, is, at the center of the eclipse path.

You need to look up the information for your specific location.

For Lincoln, Nebraska, the totality will last 2 min. According to this source - https://www.space.com/33797-total-so...017-guide.html