Astronomy Group

[Astrochef]

Astronomers say, "comets are like cats, they do what they want"
Comet Neowise back in the summer of 2020 surprised a lot of people and became visible to the naked eye. I enjoyed a couple weeks observing it with binoculars, telescopes and naked eye. I took several photos of it with my cell phone. I'll try to upload an image from a local soccer field with pretty severe light pollution.

First try adding a pic here so fingers crossed

[Astrochef]

OK, looks like I figured it out. I consider myself mildly "tech-tarded" so yay me. Here's hoping for clear skies on April 8th and maybe I'll have some good solar eclipse pics to post.

Cheers all,
Ty

[GordMay]

Astronomical Equinox: First day of Spring/Fall

Today [Tuesday, March 19, 2024], at 11:06 P.M. EDT, is the first day of spring [Astronomical Vernal Equinox], in the Northern Hemisphere, and the the first day of Fall [Autumnal Equinox], in the Southern Hemisphere.

Because the Sun crosses the celestial* equator, on the March equinox, the Northern Hemisphere and Southern Hemisphere receive roughly* equal amounts of sunlight; neither hemisphere is tilted more toward [or away from] the Sun, than the other.

* It’s called the “celestial” equator because it’s an imaginary line in the sky above the Earth’s equator.

* In practice, they are not exactly equal. There’s actually more day, than night, on the day of an equinox. Earth’s atmosphere bends (refracts) sunlight upward, and, the Sun isn’t a single point of light, but a large disk. Together, these factors add more daylight to the equinox. The real date of sunlight equality is three or four days ahead of the equinox.

Equinoxes* are the only two times, yearly, that the Sun rises due east, and sets due west, for all of us on Earth. On other days, the Sun rises either north or south of “due east”, and sets north or south of “due west.”

While the Sun passes overhead, the tilt of the Earth is zero, relative to the Sun, which means that the Earth’s axis neither points toward, nor away from, the Sun. However, that the Earth never orbits upright, but is always tilted on its axis, by about 23.5 degrees.

The equinoctial Sun always misses your zenith [straight-up overhead point] by the same number of degrees, as your latitude.

* The word equinox comes from the Latin words for “equal night”: aequus [equal], and nox [night].

Meteorologically speaking, the official first day of spring is March 1 (and the last is May 31). Weather scientists divide the year into quarters to make it easier to compare seasonal and monthly statistics from one year to the next. The meteorological seasons are based on annual temperature cycles rather than on the position of Earth in relation to the Sun, and they more closely follow the Gregorian calendar. Using the dates of the astronomical equinoxes and solstices for the seasons would present a statistical problem, as these dates can vary slightly each year.

[GordMay]

The 8 April total solar eclipse (visible in parts of Canada, the United States, and Mexico) will be more than just a visual phenomenon.
The NASA-funded “Eclipse Soundscapes Project” [1] is collecting multi-sensory observations, and recorded sound data, from community scientists, on the day.
Another effort, “GLOBE Eclipse” [2], asks volunteers to document air temperature, and clouds, during the event.

[1] “Eclipse Soundscapes Project” ➥ https://eclipsesoundscapes.org/

[2] “GLOBE Eclipse” ➥ https://observer.globe.gov/do-globe-observer/eclipse

[GordMay]

Originally Posted by slowlysailing

Speaking of light years, any other star gazers ever considered that the light they are seeing from these distant objects has been traveling for years-sometimes millions of years? For example, M31 (the Andromeda galaxy) is 1.5 (?) million LY from us, so when you see it (quite clearly with just binocs on a good night), you are seeing it as it appeared millions of years ago!!!
AND ....space is so darn empty, mostly, that M31 is the closest galaxy to our own, with over a million LY of mostly nothing in between...

Indeed.


Alpha Centauri is a star system with components 4.2 to 4.4 light-years from Earth and comprises three stars. It is the closest star system to the solar system, and one of its stars, Proxima Centauri, is the nearest star to our planet, other than the sun.
Proxima Centauri, the closest star to our own, is still 40,208,000,000,000 km away. [Or about 268,770 AU.]

When we talk about the distances to the stars, we no longer use the AU, or Astronomical Unit; commonly, the light year is used [equivalent to 63,000 AU].
A light year is the distance light travels in one year - it is equal to 9.461 x 1012 km.
Alpha Centauri A & B are roughly 4.35 light years away from us. Proxima Centauri is slightly closer at 4.25 light years.

The Moon is about 1.25 Light Seconds away from the earth, or in terms of light years 3.96 × 10 − 8 Light Years.
The sun is 8.3 light-minutes away, or 149,668,992 km [93,000,000 miles].

[GordMay]

Climate Change Bringing One Shorter Day, As 'Negative Leap Second' Coming
Scientists say the pace, of the Earth’s rotation, is increasing [± 6 millionths of a second per year] so much, that a “leap second” REMOVAL will be needed, by the end of the decade.

Leap seconds have occurred before, when an extra tick was put on world clocks.
But, this time, a second will need to be removed.

According to Nature*, leap seconds have been added 27 times since 1972, or about one every two years. They came with only six months’ notice, each time. A resolution, adopted by the General Conference on Weights and Measures, says something must be done, about a negative leap second, by 2035. That conference will hold its next meeting in 2026.

“A global timekeeping problem postponed by global warming” ~ by Duncan Carr Agnew
➥ https://www.nature.com/articles/s41586-024-07170-0

“ABSTRACT:
The historical association of time with the rotation of Earth has meant that Coordinated Universal Time (UTC) closely follows this rotation1. Because the rotation rate is not constant, UTC contains discontinuities (leap seconds), which complicates its use in computer networks2. Since 1972, all UTC discontinuities have required that a leap second be added3. Here we show that increased melting of ice in Greenland and Antarctica, measured by satellite gravity4,5, has decreased the angular velocity of Earth more rapidly than before. Removing this effect from the observed angular velocity shows that since 1972, the angular velocity of the liquid core of Earth has been decreasing at a constant rate that has steadily increased the angular velocity of the rest of the Earth. Extrapolating the trends for the core and other relevant phenomena to predict future Earth orientation shows that UTC as now defined will require a negative discontinuity by 2029. This will pose an unprecedented problem for computer network timing and may require changes in UTC to be made earlier than is planned. If polar ice melting had not recently accelerated, this problem would occur 3 years earlier: global warming is already affecting global timekeeping...”

* “Melting ice solves leap-second problem — for now”
➥ https://www.nature.com/articles/d41586-024-00850-x

[GordMay]

A ‘once in a lifetime’ comet, “12P/Pons-Brooks”, that astronomers have dubbed the "Mother of Dragons", is now visible, after dusk, in the Northern Hemisphere.
This comet completes a single orbit around the sun, once every 71 years. The last time it passed by Earth was in 1954, according to a statement, from the European Space Agency.
ESA ➥ https://www.esa.int/Space_Safety/Pla..._the_night_sky

[CaptTom]

Originally Posted by GordMay

A ‘once in a lifetime’ comet, “12P/Pons-Brooks”, that astronomers have dubbed the "Mother of Dragons", is now visible, after dusk, in the Northern Hemisphere...

What the headline giveth, the last paragraph taketh away:

If you are lucky, it may be possible to observe it with binoculars, or even the naked eye, but you will have a better chance with even a small telescope, as its brightness is unpredictable.

(1) I'm not lucky, (2) I have a hard time finding a faint dot in the night sky with binoculars, never mind holding them steady enough to see that dot in any detail, and (3) I don't own a telescope.

Let me know when there's going to be one of those big, bright comets like in the old paintings. I wish the media would stop teasing us with these telescopic images which are nothing like what we'd actually be able to see.

[GordMay]

RAIN DAY for Today's Solar Eclipse:
The next total solar eclipse, in North America, will arrive on March 30, 2033; but, only in Alaska.
For those living farther south, we'll have to wait, until August 23, 2044, when the moon's shadow will sweep across Western Canada, Montana, and North & South Dakota.
There will be eight total solar eclipses, visible from North America, in the 21st century, with one occurring about every 12 years, on average.
Be safe!

[SeanPatrick]

It was a perfect, clear day for the eclipse here in Virginia. I took one of my sextants to work (an Astra IIIb, the same type as my avatar) and all of my coworkers and even a passerby had a great time looking at the partial eclipse through the 7x scope.

[CaptTom]

Perfect day here, too. Best I could do was a pinhole projector, but it worked great. We were actually surprised it didn't get a bit darker than it did at 95%.

I decided not to travel to where it would be total, because (1) traffic, (2) I'm busy, and (3) it would probably be cloudy wherever I chose to go.

Anyone travel and get cloud cover at their destination?

My daughter had thin clouds, which turned out perfect for getting some good photos with an ordinary cell phone.

[Astrochef]

My daughter and I drove to Ohio to get in the path. We Had some thin clouds so not a great view of the corona, but still spectacular. I brought my telescope and binoculars with homemade solar filters. At totality I was able to take off the filter and actually capture some nice solar activity shooting out from behind the moon. Was using about 36x magnification with my cell phone attached to the eyepiece.

Once I get some of the lead up pics resized for posting I'll add them. We had a couple decent sunspots as well.

Thanks for looking,
Ty

[Astrochef]

The last second before I figured I had better get the filter back on I almost caught the "diamond ring" effect.

[Astrochef]

Hmm, didn't load??

[GordMay]

News Chanel accidentally shows man's testicles, during solar eclipse coverage

Mexican TV viewers were left shielding their eyes, during coverage of Monday’s solar eclipse, and not for the reasons you might expect.

RCG Media’s ‘24/7’ news programme was covering the celestial event, when it broadcast clips submitted by fans.
Unfortunately, the footage clearly hadn’t been rigorously checked, and the show’s three hosts fell victim to a mortifying prank.

During the segment, the male anchor was listing the cities, from where the eclipse could be witnessed, when images of the jaw-dropping spectacle gave way to a video of a man blocking out the sun with his … testicles.

➥ https://twitter.com/CollinRugg/statu...ipse-testicles