03/21/2023 – Ephemeris Extra – Spring has sprung without me

Being in the hospital and now in inpatient rehab one loses a sense of time. So the vernal equinox snuck by me unnoticed. My view of the outside world is another part of the hospital, a part of the HVAC system, and a piece of sky.

Yesterday, the Sun passed over the Earth’s equator, heading northward. The Sun is gradually setting at the South Pole and rising at the North Pole. Folks like me who live in the Northern Hemisphere are experiencing longer daylight than those south of the equator, who are beginning autumn. The daylight hours will increase daily until June 21st, the summer solstice. In the Interlochen/Traverse City area, that will be 15 hours and 34 minutes.

The cause of the Earth’s seasons is not our varying distance from the Sun in our eliptical orbit of the Sun of 93 million plus or minus a million and a half miles.By the way, the Earth is currently moving away from the Sun. It will be farthest from the Sun around July 4th or 5th.

Our perception of the advance of spring, besides the gradully warming temperatures and increasing daylight hours, will be the height of the Sun’s path in the sky, and the position of the Sun’s rise and set points on the horizon. All these annual changes are angles having to do with one’s latitude (an angle), Earth’s position in orbit (an angle), and the tilt of the Earth’s axis to it’s orbit (more angles).

Bob

03/19/2023 – Ephemeris Extra – Zodiacal light

This is the time of year when the faint glow can be seen in the west at the end of asttronomical twilight in the evening. It’s called zodiacal light. It is difficult to spot the first time. The final twilight glow tends to be horizontal, along the horizon, while źodiacal light has a thin pyramidal shape tilted to the left along the constellations of the zodiac. Right now, Venus appears in the heart of the glow.

Some of my older blog posts also cover zodiacal light with images of it I’ve taken, so search for zodiacal light in the spot provided.

On a personal note: I’m expected to be discharged from rehab by month’s end. I’m hoping that a couple of weeks after that, I can get back to a regular schedule. Here’s hoping.

Bob

03/17/2023 – Ephemeris Extra – I’m now in Rehab

I’m hoping to be home by the end of the month. My daughter wants me to take some additional time before plunging back in. I don’t actually disagree with her.

A local event I’d like to preview is the Grand Traverse Astronomical Society’s part in International Astronomy Day, Saturday, April 29th. This annual event will be held at the Sleeping Bear Dunes National Lakeshore. I’ve been out of the loop on this, but the GTAS may be offering solar and night viewing. The sun has been unexpectedly active this year, and it is our star. Stay tuned.

Bob