I didn't care for the use of specific camera models and lenses (it's
never up to date) but did find something I'd never thought of before.
When using a short focus lens the area of the sky that's covered is
quite large. Since exposure time is based on declination the top and
bottom of the frame of a wide angle view see a much different view and
the maximum time varies considerably between top and bottom of the frame.
Chuck Norcutt
On 7/29/2014 6:03 PM, Mike Gordon via olympus wrote:
I have no idea how to find it now but I used to have a reference
table (from the web somewhere) where you could determine the maximum
exposure >>time for a motion free image given focal length and
magnification.
I vaguely recall the "600" rule where 600mm lens can be used at about 1
sec--somewhat depends on angle of declination too. max time=600/fl
Oh, I see this calculator--better yet.
http://www.sceneplanner.com/tool3.php
Yea, there is also a phone app of course.
I am still still not sure how to use DSS w/o much repositioning. Better
watch a tutorial.
Mike
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