testpictures of zenith

Vulcanoid Imaging Techniques

- Originally, this thread contained a message I posted earlier on march 10th 2006. (Subject: testpictures of zenith)
On april 4th, I accidentily wiped out the original message in this thread.
I hope Mr. Noll can restore this in future. -

regards
Harro Treur

» next forum topic | 1051 reads
Submitted by chongo on Mon, 2006-03-13 16:40.

What ISO was your camera set at?  How long was the exposure?  What is the f/ratio at 200mm?

Did you use a filter? 

chongo (Landon Curt Noll - http://www.isthe.com/astro.html) /\oo/\

register to post comments
Submitted by Harro Treur on Sat, 2006-03-18 09:08.

I did a sequence of zenithpictures March 15th 2006.

Camera used was a canon 300D
F=199mm F/5,6 No redfilter was used
Below are some of the results.
The results are clustered in 4 groups, each for a certain sunlevel.

exp - iso - limit - sun below
time - ... - magn - horizon
2,5 - 400 - 8,1 - 4 47
1,5 - 400 - 8,1 - 4 49 - max exposure at sun minus 4.49 is 2 sec (iso 400)

4 - 400 - 8,6 - 5 20
5 - 400 - 9,0 - 5 22
6 - 400 - 9,1 - 5 24 - optimum exposure was 6 sec
7 - 400 - 9,0 - 5 26 - 7 sec is about overexposure (iso 400)

5 - 100 - 9,0 - 5 45
7 - 100 - 9,3 - 5 47 - expected optimum exposure ca 10 sec
9 - 100 - 9,3 - 5 49 - expected max exposure i estimate at 20 sec (iso 100)

7 - 100 - 9,7 - 6 02
8 - 100 - 9,5 - 6 06
9 - 100 - 9,5 - 6 07
12 - 100 - 9,6 - 6 09
14 - 100 - 9,8 - 6 12 - expected max exposuretime i estimate at 30 sec (iso 100)

Note that I switched from 400 to 100 iso inbetween.
Conclusion is that the position of the sun has a large influence on the results.
As mentioned on this website, the lightconditions during the eclipse will correspond to a sunlevel of about 5.30 degrees.

During the eclipse I plan to use exposure times of 10 seconds and 15 seconds. To reduce noise I prefer the iso100 setting.

Good hunting everyone

Harro Treur
Netherlands

register to post comments
Submitted by chongo on Mon, 2006-03-20 13:45.

Thank you for the detailed update.

See my up to date plan for Landon Noll for details on how our results match.

register to post comments

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.