Finding the Southern Fish

Wednesday, November 9, 2016

I have saved this the fifth and final constellation of the southern ocean because it is my favorite. Not because there is anything great to be found there or it is spectacular to behold. I a.m. someone who tends to favor the underdog and if there is an underdog in the sky, this one is it.

We are looking this week at a constellation called Piscis Austrinis, otherwise known as "The Southern Fish." To see it you will need a very dark-sky location far away from any artificial light. In fact, the only way you will be able to see it is by locating it's brightest star.

Piscis Austrinis consists of 10 or so fourth or fifth magnitude stars in a rough rectangle about 15 degrees long with the brightest star on the left end of it. This star is called Fomalhaut (pronounced form-a-LOW), "The Mouth of the Southern Fish."

It has also been called the loneliest star in the sky (see underdog above) because of its location in the far south. It is also been called the "Star of Autumn" because of its annular appearance at that time of year.

In fact it is the only star you will see if you look that direction because of its first magnitude brightness, about the same as Vega, Fomalhaut is also about the same distance as Vega--25 light-years.

Fomalhaut wasn't always lonely, it was once rated as one of the Four Royal Stars of the Persians. The other three were Aldebaran, Regulus, and Antares.

To find this lonely critter look almost due south at about 6 p.m. (that is about an hour and a half after local sunset, thank you Daylight Savings Time) Fomalhaut will be hanging just above the horizon with the body of the fish extending to the right--if you can see the stars.

Binoculars will help in locating them.

Speaking of Daylight Savings Time, all of us astronomers are glad it is over because we have earlier darkness for observing. For example, in southwest Nebraska sunset today is 4:35 p.m. making astronomical twilight (the time the sky will be dark enough for good viewing) 6:08 p.m. as opposed to 7:08 p.m. before DST ended.

Now true, astronomical twilight comes earlier in the morning, but I a.m. not a morning astronomer (unless there is something really good and worth looking at).

SKY WATCH: Full moon, Monday, Nov. 14, which will pretty much wipe out any viewing of the Leonid meteor shower peaking on Nov. 17. There is some preposterous blather about a so called "Super Moon" during this full moon. My considered astronomical opinion is "nonsense." True the moon will be at perigee (the closest point in its orbit for the month), however, that will not make it any appreciably larger to the human eye.

I a.m. not being harsh, I just don't want you being disappointed if you are expecting something really large. Now, having said that, let me say that the full moon rising over the horizon will look large from something we call the "Moon Illusion."

The moon will only look like it is large. Want to test it? Dig in your pocket, pull out a dime and hold it up next to the rising moon, they will both be about the same size. Come back out a few hours later, when the moon is overhead and put the same dime up next to it. They will still be the same size.

Haven't got a dime? Then simply turn around and look at the moon between your legs, see, it is not big at all.

NEXT WEEK: More astronomical blathering.

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