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ASTRONOMICAL ADVENTURES

Eclipse Tours and More


UPCOMING

2017

OREGON
RIVER
CRUISE

USA Total Solar Eclipse
(2017 Aug. 12)
Details Here!


USA
TOTAL SOLAR
ECLIPSE

USA Total Solar Eclipse
(2017 Aug. 21)
Details Here!


Also See 2017
PREHISTORIC ENGLAND TOUR



PAST TOURS

Indonesia Total Solar Eclipse

Indonesia Solar Eclipse
Makassar Strait
[2016 Mar. 9]


Australia Total Solar Eclipse

Australia Solar Eclipse
Queensland, Kangaroo Isl.
and Adelaide
[2012 November]


Norway Northern Lights Cruise
to Above Arctic Circle
[2010 March 10–21]

China Total Solar Eclipse
2009 China Total
Solar Eclipse

[2009 July]




EXAMPLES
OF OTHER
PAST TOURS

(Links available for some but some links may not work correctly)

Caribbean Cruise Eclipse
[1998 Feb]
African Eclipse Safari
[2001 Jun]
Australia Outback
Solar Eclipse

[2002 Dec]
Transit of Venus
Italy, Athens & Crete

[2004 June]
Hybrid Solar Eclipse
Tahiti Cruise

[2005 April]
Astronomy, Archaeology
& Geology of Arizona

[2005 September]
Egypt Treasures &
Solar Eclipse

[2006 March]
China &
Solar Eclipse

[2009 July/Aug]
EXPOSURE TIMES FOR NO TRAILING

Photographing the eclipsed Sun involves (1) image size, (2) exposure time and
(3) exposure times for no blurring without a clock drive. Here we consider Item #3.


WARNING: Do not observe or photograph the Sun out of eclipse or in partial eclipse without safe solar filters. (No filter needed for totally eclipsed Sun). See Eye Safety

The image size of the Sun when photographed depends on the focal length of your camera (or telescope) focal length. Longer focal lengths produce larger images. See Relative Image Size.

However, if your camera/telescope does not have a clock motor drive to follow the Sun across the sky (an effect of Earth's rotation), images may blur if exposures times are too long. Since long focal lengths produce larger images, exposure times must be shorter to avoid image blurring. (Also see Exposure Times).

Approximate Guide for Sharp Images with No Clock Drive

Longest "Practical" Exposure (sec) = 250/Focal Length (mm)

(For less critical work, increase exposure by 4x)

The following table gives examples of approximate longest exposure times for both critical work and for images where some blurring is not objectionable for photography without a clock drive. The last column also give the approximate diameter of the solar disk (in mm) without its corona for the focal lengths listed. (See box below table for formula.)

Guidelines for Longest Exposure Times for No Blurring
Including Diameter of Sun's Disk (Excluding Corona)

Focal Length Exposure Time
(Critical)
Exposure Time
(Not Critical)
Sun's Diameter
(mm)
50 mm 5 sec 20 sec 0.47 mm
100 mm 2.5 sec 10 sec 0.9 mm
150 mm 2 sec 7 sec 1.4 mm
200 mm 3 sec 2 sec 1.9 mm
250 mm 1 sec 4 sec 2.3 mm
300 mm 3/4 sec 3 sec 2.8 mm
500 mm 1/2 sec 2 sec 4.7 mm
1000 mm 1/4 sec 1 sec 9.3 mm
1500 mm 1/6 sec 2/3 sec 14.0 mm
2000 mm 1/8 sec 1/2 sec 18.6 mm
3000 mm 1/10 sec 1/3 sec 27.9 mm

An Approximate Formula to Compute Sun's Image Size

Image Size (mm) = Focal Length (mm) / 107


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