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    Re: Daylight Venus sight prediction
    From: Modris Fersters
    Date: 2023 May 18, 12:13 -0700

    Hello, Paul!

    I am glad that you managed to find Venus. Today I took Venus daylight sights too. I tried both:

    1) to measure the distance between the Sun and Venus;

    2) to measure the altitude of Venus.

    The first task was very easy. Some days ago I looked in Stellarium that the distance between Venus and Sun is about 45 degrees. I preset sextant to that angle, put shades on horizon mirror and looked at Sun. Slowly rotating sextant along telescope axis I found Venus very easily. Then I adjust micrometer.

    On Second task I was experementing with optimal method to find Venus in horizon mirror. The best method for me was following: I preset sextant to actual distance angle. Then put shades on index mirror. With sextant oriented vertically I looked in the direction of the Sun, but telescope oriented about 45 degrees (this is the angle of Venus/Sun distance) downward from the Sun untill I found the reflection of the Sun in telescope field of view. It is easy. If, for example, the altitude of the Sun is about 45 degrees, I should direct telecope horizontaly. If altitude of the Sun is about 30 degrees, I should direct telescope about 15 degrees below horizon to get Sun image in the telescope.  

    Then I rotated sextant and at the same time moved it upward, keeping the Sun in the field of view until I found Venus. Then I rotated sextant along telescope axis until the instrument was vertically oriented. Then I removed index shades and, looking at Venus, moved index arm to 0 degrees. At that moment I could see two images of Venus. Next step was bringing Venus down to the horizon to measure the altitude.

    I will add that I could not sea Venus without telescope (7X magnification).

    You wrote that you took the sights near sunset. I was able to take these sights close to the noon. But your choice near sunset is better.

    I will calculate the actual distance between Sun and Venus with your Lunar4.4. to test my sextant. 

    Thank you for sharing your experience!

    Modris Fersters

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