# 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

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

4. ## 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°?

5. ## 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.

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

Originally Posted by couldabin
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.
You don't need any calculation at all. Make yourself a viewing frame for whatever film format and FL you want to use, and see the sun through it at whatever time lapse you want to use. Up to you how to keep the frame and you eye in the position for the time needed.

7. ## 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.

8. ## 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

9. ## 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

10. ## 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. 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.
I don't have an answer to your request for a calculation, however if I understand correctly you intend to capture the complete eclipse period from first contact to last. Since you have already determined your lens focal lengths, and this determines the angle of view, the primary task that remains is the aiming of the camera to set the point of totality in the center of the frame. To do this the azimuth of totality at your location is needed. Here is a website that may help https://www.timeanddate.com there is a comprehensive database that allows the location to be entered and precise values obtained. Good Luck.