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Field of view angle for eclipse
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Aug 16, 2017 11:35:27   #
big-guy Loc: Peterborough Ontario Canada
 
While I am no where near totality I figured I'd try a time-lapse of the eclipse but that brings up 2 problems.
1. If I use a tracker the setup must be in place during the night before which leaves me sitting twiddling my thumbs while guarding the rig for 8+ hours before the event. I suppose I could approximate Polaris and back off the zoom a little and hope for the best but....
2. If I don't use the tracker but utilize a static field of view what focal length (FF) will capture the entire event?

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Aug 16, 2017 12:56:38   #
Leitz Loc: Solms
 
big-guy wrote:
While I am no where near totality I figured I'd try a time-lapse of the eclipse but that brings up 2 problems.
1. If I use a tracker the setup must be in place during the night before which leaves me sitting twiddling my thumbs while guarding the rig for 8+ hours before the event. I suppose I could approximate Polaris and back off the zoom a little and hope for the best but....
2. If I don't use the tracker but utilize a static field of view what focal length (FF) will capture the entire event?
While I am no where near totality I figured I'd tr... (show quote)

What's your sensor size?

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Aug 16, 2017 13:11:57   #
big-guy Loc: Peterborough Ontario Canada
 
As stated in #2 it is FF.

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Aug 16, 2017 13:20:30   #
wmurnahan Loc: Bloomington IN
 
The sun goes thru 15 degrees an hour. To cover 3 hours, which is pretty well from the beginning to end, you need 45 degrees of coverage. Here is a listing of degrees of coverage for each lens size. https://en.wikipedia.org/wiki/Angle_of_view A 50mm covers almost 40 and a 35mm covers 55 degrees. If you can align the track to go diagonally a 50mm would cover the whole thing. A 300 would give you about 20 min so start 10 min before peak and go 10 minutes after or cover 20 min up to since the other side is a mirror.

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Aug 16, 2017 13:31:51   #
big-guy Loc: Peterborough Ontario Canada
 
Thanks for that. I also looked it up and discovered with my Canon APS-C (yes I know I said FF but I can do the math myself) a focal length of 55mm would cover it in a static format. But that leaves the sun so small it's not worth the effort. So it looks like tracking is the way to go. So I guess on Saturday or Sunday (depending on weather) night I will set everything up, align with Polaris, mark the tripod leg positions and get ready for Monday. I don't think the drift will be any appreciable factor. Again, many thanks.

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Aug 16, 2017 14:40:34   #
Leitz Loc: Solms
 
big-guy wrote:
As stated in #2 it is FF.

Life's too short to use abbreviations!!

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Aug 16, 2017 20:15:47   #
wmurnahan Loc: Bloomington IN
 
Here is a shot of the sun with my 55


(Download)

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Aug 17, 2017 06:17:11   #
jerryc41 Loc: Catskill Mts of NY
 
big-guy wrote:
While I am no where near totality I figured I'd try a time-lapse of the eclipse but that brings up 2 problems.
1. If I use a tracker the setup must be in place during the night before which leaves me sitting twiddling my thumbs while guarding the rig for 8+ hours before the event. I suppose I could approximate Polaris and back off the zoom a little and hope for the best but....
2. If I don't use the tracker but utilize a static field of view what focal length (FF) will capture the entire event?
While I am no where near totality I figured I'd tr... (show quote)


Maybe you're being a bit too ambitious. You'll have a short time to do a lot.

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Aug 17, 2017 08:50:04   #
peterg Loc: Santa Rosa, CA
 
big-guy wrote:
2. If I don't use the tracker but utilize a static field of view what focal length (FF) will capture the entire event?

There are at least three iPhone apps that can show you where the sun will be at specific times: TPE, PhotoPills, SunSeeker, etc.
I use PhotoPills (http://itunes.apple.com/us/app/photopills/id596026805?mt=8) because it has an Eclipse Planner that will show you the direction of the sun at any time (thin yellow line to the southeast), beginning & end of the eclipse (top center) , how much of the sun is visible at any time (top left), etc.



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Aug 17, 2017 09:37:15   #
big-guy Loc: Peterborough Ontario Canada
 
Not being in totality gives me the added benefit of nothing to change throughout. The eclipse will last 2 hours and 36 minutes (plus 10 minutes before and after) and 1 shot every 18 seconds will give me a 20 second video @ 30 fps. I did a preliminary polar alignment last night which seemed to work perfectly. No trails on a 5 minute exposure, excluding the trees in foreground. The photo was only a star trail test taken off the deck in town with all the light pollution to see how I did with polar alignment with a 5 minute exposure. I believe I'm pretty close to nailing this as long as Mother Nature cooperates.

jerryc41 wrote:
Maybe you're being a bit too ambitious. You'll have a short time to do a lot.

5 minute exposure, f4, ISO 100 at 105 mm (168 mm APS-C equiv)
5 minute exposure, f4, ISO 100 at 105 mm (168 mm A...
(Download)

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Aug 17, 2017 09:39:29   #
big-guy Loc: Peterborough Ontario Canada
 
Now if I only had an iPhone... I do have the equivalent apps on Android. Thanks.

peterg wrote:
There are at least three iPhone apps that can show you where the sun will be at specific times: TPE, PhotoPills, SunSeeker, etc.
I use PhotoPills (http://itunes.apple.com/us/app/photopills/id596026805?mt=8) because it has an Eclipse Planner that will show you the direction of the sun at any time (thin yellow line to the southeast), beginning & end of the eclipse (top center) , how much of the sun is visible at any time (top left), etc.

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Aug 17, 2017 09:45:35   #
big-guy Loc: Peterborough Ontario Canada
 
A paradox if I ever heard one.

Leitz wrote:
Life's too short to use abbreviations!!

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Aug 17, 2017 09:47:37   #
big-guy Loc: Peterborough Ontario Canada
 
What are you using as a filter? I managed to acquire 2 #12 welding glass sheets 4x5 and seemed to work fine although with a greenish tint, easily correctable.

wmurnahan wrote:
Here is a shot of the sun with my 55

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Aug 17, 2017 09:50:22   #
gvarner Loc: Central Oregon Coast
 
Do a Google search on photography calculators. You plug in the variables and can get field of view.

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Aug 17, 2017 09:54:58   #
peterg Loc: Santa Rosa, CA
 
big-guy wrote:
Now if I only had an iPhone... I do have the equivalent apps on Android. Thanks.
PhotoPills is available for both iPhone & Android. http://www.photopills.com . Lots of features, which can be overwhelming at first. Many video tutorials available.

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