A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2021 Oct 20, 17:51 -0700
David C, you wrote,
"The clue is in the heading. It says "Veus in daylight". It does not say "venus when the sun is above the horizon"."
Oh, but I meant what I said, and you will see it smack in the middle of the day! You have more fun coming. Not only did I mean Venus with the Sun above the horizon, but Venus when it is right on the meridian (in your latitude, due north) in the middle of the afternoon with an altitude above 70° at your latitude. Just yesterday I managed to see Venus with a sextant and also with binoculars here on Conanicut Island, near 41.5°N. Its apparent altitude as it transited the meridian was just about 23.0°. I could not see it with unaided "naked eye" vision, and I didn't expect to at that low altitude. Venus crossed the meridian at 2:52pm local mean time which was about 3:38 Eastern time here in the US (one hour for daylight saving and 14 minutes for zone offset since I'm about 3.6° east of the time zone central meridian). For now you may not be able to see Venus in the middle of the day without optical aid, but the timing is the same there as here. Look for it around 2:52pm LMT in the next few days, and look quite high in the sky. With binoculars you should have no trouble finding it. Double-check that your optics are finely focused for distance before you try.
In November and into early December Venus will be significantly brighter. Wait for a nice clear day next month, and you will almost certainly be able to see Venus with your own two eyes and no binoculars, no telescope, no sextant. Of course you'll still need ordinary eyeglasses if you require them for long distance vision, but other than that you'll discover that Venus in the middle of the day during one of these periods is an easy mark. You'll be able to find it day after day and show it off to your friends, too, right in the middle of the afternoon. And early next year when it slides around to the other side of the Sun you'll have a few weeks when you'll be able to see it just as easily in the morning, too. By contrast here in mid-northern latitudes, I don't expect to see Venus in the middle of the day without optical aid. This is a poor Venus season in my latitude -- an excellent Venus season in yours.
Tips and tricks: use building alignments to find good sighting azimuths. Meridian passage is often the best time, but the altitude may be painfully high. At least on meridian passage you can often find a building wall aligned north-south. Sight along it on the shady side, and you'll be able to pick out Venus much more easily. Also try to find a way to aim visually at the right angular altitude in the sky. This is the hardest part. Most observers look too low when told to look at a spot that's 45° or 60° or 75° high. Test it at night with stars of known altitude. Find a spot where you can look exactly in the proper azimuth and altitude at some feature on a building or some clearly identifiable spot in the branches of a tall tree. Mark that spot with a rock on the ground at night as a star passes the right azimuth and altitude. Then stand there again in daylight when Venus is expected at that azimuth and altitude. Use binoculars or a sextant scope first. Then look "naked eye". If you can't see it now, try again in two weeks or four weeks. You will succeed.