On what day does Mercury reach its greatest elevation (in degrees from the horizon) at sunset a given location?
The obvious answer is the day of Mercury's greatest elongation from the Sun, but, since the ecliptic is slanted with respect to the horizon, I'm not convinced this is correct.
In other words, on the day after greatest elongation, Mercury's total angular distance from the Sun will be smaller, but it's vertical distance in elevation (for a given location) at sunset might be higher.
Same question for Venus, and for when the sun is 6 degrees below the horizon (ie, civil twilight), and for sunrise/dawn.
I'm guessing the date might vary based on position (mostly latitude) since the ecliptic's slant varies at different locations.
I googled and found nothing. My (preliminary and possibly wrong) expierments with stellarium show that Mercury's elevation at sunset IS higher 1-3 days after its greatest elongation, but by less than 1/2 degree.
So, it's possible that the date of greatest elongation is a close enough approximation.