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03/13/2020 – Ephemeris – Looking for Cancer the crab

March 13, 2020 Comments off

Ephemeris for Friday, March 13th. Today the Sun will be up for 11 hours and 49 minutes, setting at 7:47, and it will rise tomorrow at 7:56. The Moon, 3 days before last quarter, will rise at 1:01 tomorrow morning.

Between the stars Castor and Pollux in Gemini high in the southeast and the star Regulus in Leo the Lion in the east-southeast lies the dimmest constellation of the zodiac, Cancer the crab. To me its 5 brightest stars make an upside down Y. There’s the stars in the center of the constellation Asellus Borealis and Asellus Australis, the north and south donkeys. There’s a fuzzy spot between and just west of them called Praesepe, the manger from which they are supposedly eating. In binoculars it resolves into a cluster of stars called the Beehive cluster. We amateur astronomers also know it as M44, the 44th object on 18th century comet hunter Charles Messier’s list of fuzzy objects that might be mistaken for comets.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Cancer the Crab

Cancer the crab finder chart. Note the beehive cluster, also known to amateur astronomers as M44, along with other catalog names. Prior to the invention of the telescope this cluster was known as Praesepe which means “Manger”. Click on the image to enlarge. Created using Stellarium and GIMP.

The constellation Cancer with star names and Praesepe. Asellus Borealis, the Northern Donkey; and Asellus Australis, the Southern Donkey are next to Praesepe the manger. Created using Stellarium.

We only hear about a manger at Christmas time.  It is simply a trough that horses, donkeys, and cattle eat from.

03/10/2020 – Ephemeris – A Closeup look at Gemini’s namesake stars

March 10, 2020 Comments off

Ephemeris for Tuesday, March 10th. Today the Sun will be up for 11 hours and 39 minutes, setting at 7:43, and it will rise tomorrow at 8:01. The Moon, 1 day past full, will rise at 9:07 this evening.

At 9 p.m. the constellation of Gemini the twins will be seen high in the south-southeast. The namesake stars of the two lads are the two bright stars at the upper left of the constellation. Pollux the pugilist, or boxer, is the lower of the two, while Castor, the horseman, is the other star, or rather a six star system. In telescopes two close stars may be seen each is a spectroscopic binary, meaning the two stars can be detected by the rainbow colors of light from the star. A faint nearby spectroscopic binary also belongs. Pollux, though a single star, does have at least one planet, over twice the mass of Jupiter orbiting it at a distance somewhat greater than Mars is from the Sun. Pollux is 34 light years away while Castor is 50 light years away.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Gemini finder

Gemini finder looking south-southeast at 9 p.m. March 10th, 2020. Created using Stellarium.

Castor and Pollux namesakes of Gemini

Castor and Pollux namesakes of the twins of Gemini in its position at 9 p.m. EDT March 10th. Created using Stellarium.

Castor star system

The Castor star system exploded in this JPL/NASA infographic.

 

Categories: Ephemeris Program, stars Tags: , ,

03/05/2020 – Ephemeris – Apparently Betelgeuse, though dimming wasn’t cooling as expected

March 5, 2020 Comments off

Ephemeris for Thursday, March 5th. Today the Sun will be up for 11 hours and 24 minutes, setting at 6:36, and it will rise tomorrow at 7:10. The Moon, 3 days past first quarter, will set at 5:31 tomorrow morning.

Betelgeuse, the red star in the constellation Orion’s shoulder has apparently stopped dimming and has begun to brighten. The guesses as to the cause of the dimming are many. One suggested by a photograph taken of the star in December shows the southern half dimmed like it was covered by something. Betelgeuse out gasses lots of material, some of which condenses into dust. Could some of this dust mask the star and make it dimmer? I suspect that we’ll find out before too long. Many astronomers are wishing Betelgeuse would explode in a core collapse or type 2 supernova. At its approximate 700 light year distance we’d be safe, though a bazillion neutrinos would pass harmlessly through each one of us just before the light would get here.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Betelgeuse's dust plume

An image of the star Betelgeuse taken in infrared shows it’s surrounded by a vast cloud of dust that erupted from the surface (the bright star itself is masked out, though an image of it has been superposed there for scale — it’s about the size of the orbit of Jupiter, over a billion km wide). Credit: ESO/P. Kervella/M. Montargès et al., Acknowledgement: Eric Pantin via Phil Plait’s Bad Astronomy blog on syfy.com.

Betelgeuse before and after dimming

This comparison image shows the star Betelgeuse before and after its unprecedented dimming. The observations, taken with the SPHERE instrument on ESO’s Very Large Telescope in January and December 2019, show how much the star has faded and how its apparent shape has changed. Credit: ESO/M. Montargès et al.

More on this from Dr. Phil Plait’s Bad Astronomy blog on syfy.com: https://www.syfy.com/syfywire/mea-culpa-betelgeuse-and-its-dusty-convective-pulsations

Categories: Ephemeris Program, stars Tags: ,

03/03/2020 – Ephemeris – Betelgeuse, apparently, has stopped dimming and may be brightening

March 3, 2020 Comments off

Ephemeris for Tuesday, March 3rd. Today the Sun will be up for 11 hours and 18 minutes, setting at 6:33, and it will rise tomorrow at 7:14. The Moon, 1 day past first quarter, will set at 3:41 tomorrow morning.

Betelgeuse the red giant star in the constellation Orion’s shoulder has apparently stopped dimming and may be brightening again. The process of recovery is slow. It may recover its former brightness. We’ll know this later in summer when Betelgeuse and the rest of Orion moves from behind the Sun and enters the morning sky. Betelgeuse is known to be irregular in brightness, but has never been recorded as being this dim, dropping it from being a first magnitude star. Betelgeuse is no longer dimming. There is lots of speculation as to why it’s now brightening. One is the thought that there are several periodic cycles that govern Betelgeuse’s variability. That the troughs of these cycles happen to coincide is one explanation.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Orion at 7:07 p.m. January 6, 2020

Betelgeuse in Orion (the bright star on the left) at 7:07 p.m. January 6, 2020. Taken with my Samsung Galaxy S10+ in the moonlight. Compare the brightness of Betelgeuse with Rigel, Bellatrix and the belt stars.

The brightness of Betelgeuse from late November 2019 to 23 Feb. 2020 shows it dimming dramatically (the y-axis is in magnitudes, where a bigger number is fainter). A close-up on just the past 20 days (right) shows it starting to rise again around 18 Feb. Blue dots are estimates by eye, black using digital cameras, and the red line is a smooth fit to the data. Credit: Betelbot on Twitter, run by Michael Hipke via Dr. Phil Plait’s Bad Astronomy post https://www.syfy.com/syfywire/no-supernova-for-you-betelgeuse-is-brightening-again-right-on-schedule

 

 

01/02/2020 – Ephemeris – Orion’s great red star Betelgeuse is dimming

January 2, 2020 Comments off

Ephemeris for Thursday, January 2nd. The Sun will rise at 8:20. It’ll be up for 8 hours and 53 minutes, setting at 5:13. The Moon, at first quarter today, will set at 12:48 tomorrow morning.

The bright red giant star in the constellation Orion’s shoulder is in the news. It is dimming, and it is dimmer now than it has been for a very long time. A chart by the American Association of Variable Star Observers shows that this is the dimmest it’s been going back to 1970 and maybe a long time before that. Betelgeuse was first noticed to vary in brightness in 1838. It is the left star at the top of Orion’s upright rectangle of stars. Bellatrix is the right corner star. Betelgeuse is now only a little brighter than it, and much dimmer than Rigel the lower right corner star. A couple of years ago it was brighter than it had been since 1970. Astronomers are watching and waiting. They expect Betelgeuse to explode as a supernova sometime in the next million years.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Orion's brightest stars

Orion’s brightest stars with their names for 9 p.m. January 7. Click on the image to make Orion a giant hunter. Created using Stellarium, which shows Betelgeuse at its average magnitude of 0.45.

Orion and Betelgeuse

Orion and Betelgeuse on Christmas night 2019 by David Dickinson. Photo from a smart phone from Virginia Beach. Note that Betelgeuse is not much brighter than Bellatrix and much dimmer than Rigel.

Magnitude estimates of Betelgeuse

Magnitude estimates of Betelgeuse since 1970. Credit AAVSO.

Note on the magnitude scale:  The lower the magnitude the brighter the star.  Stars with magnitudes less than 1.5 are first magnitude stars.  Second magnitude stars are between 1.5 and 2.5, and so on.

For more information check out Universe Today: https://www.universetoday.com/144465/waiting-for-betelgeuse-whats-up-with-the-tempestuous-star/

And Dr. Phil Plait’s Bad Astronomy: https://www.syfy.com/syfywire/dont-panic-betelgeuse-is-almost-certainly-not-about-to-explode

Categories: Ephemeris Program, stars Tags:

11/19/2019 – Ephemeris – Spying Capella low in the northeast

November 19, 2019 Comments off

Ephemeris for Tuesday, November 19th. Today the Sun will be up for 9 hours and 26 minutes, setting at 5:11, and it will rise tomorrow at 7:46. The Moon, at last quarter today, will rise at 12:09 tomorrow morning.

As I was driving northward in the country at 6:15 Saturday night under partly cloudy skies I spied a bright star low in the north-northeast. It was Capella, the northernmost of the 21 first magnitude stars, and the 4th brightest star visible from our earthly location near 45 degrees north latitude. It’s in the pentagon shaped constellation of Auriga the Charioteer, which I couldn’t make out due to the clouds and the fact I was driving. Capella has the same color as the Sun, but there the similarity ends. Capella is made up of two massive stars that are so close that they appear as one. Capella is 43 light years away. At that distance a star the brightness of the Sun would barely be visible to the naked eye.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Low northern stars about an hour after sunset

Low northern stars about an hour after sunset on November 19, 2019. Click on the image to enlarge. Created using Stellarium.

10/31/2019 – Ephemeris – The perfect Halloween star

October 31, 2019 Comments off

Ephemeris for Halloween, Thursday, October 31st. Today the Sun will be up for 10 hours and 14 minutes, setting at 6:33, and it will rise tomorrow at 8:20. The Moon, half way from new to first quarter, will set at 9:22 this evening.

Not all the ghosts and goblins out tonight will be children. One is out every night, because it’s a star. Its name is Algol, from the Arabic for Ghoul Star or Demon Star. It’s the second brightest star in the constellation Perseus the hero, rising in the northeast this evening. The star is located where artists have drawn the severed head of Medusa, whom he had slain. Medusa was so ugly that she turned all who gazed upon her to stone. Algol is her still glittering eye. Astronomers finally found out what was wrong with Algol. It does a slow 6 hour wink every 2 days 21 hours because it is two very close stars that eclipse each other in that period. It’s next nighttime minimum will be 1:46 a.m. on November 12th.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Algol Finder

Perseus, Cassiopeia, Andromeda with Algol finder animation for Autumn evenings. Created using Stellarium and GIMP.

Eclipsing Binary Star

Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky

Here is a web sit where you can calculate the minima of Algol and other eclipsing stars:  http://www.astropical.space/algol.php