Astronomy and meeting nice random people in Sydney, Australia

While visiting in-laws in Sydney, Australia, I woke up very early on December 25, 2018, and took a walk to try to look at stars that are only visible in the Southern hemisphere.  I ended up meeting some very nice people in a park from Venezuela and Chile!  It was magical to be out in the city at such an odd hour and have the feeling of discovery by looking both around and up.
Here's the path I took:  https://www.strava.com/activities/2033727075.  On my way to Green Park (didn't know it was called that at the time, I passed a closed restaurant where the employees where having an impromptu dance party that appeared very carefree and fun (S. Thada Thai Cuisine).  I didn't plan it out in advance - I just headed uphill and periodically checked my map.

I had some of the best viewing from Surrey Lane, Darlinghurst - it is a small street with minimal light pollution.  There was cat chasing something when I showed up that watched me for awhile.  I also had some success viewing from Green Park, which is Darlinghurst Rd, Burton St. and Victoria St (other side is St. Vincent's hospital, a clear landmark).

Green park is also / more importantly where I got to meet some wonderful people from Venezuela and Chile who welcomed me into their group.  They sounded like they were having a friendly discussion in the park and it reminded me of what my friends and I had done in high school.  I was actually pretty terrified / uncomfortable approaching a random group, but I figured that was a good way to grow and they were really nice.  One woman who I spoke to the most was from Venezuela, she told me everyone else was from Chile.  She was there for school to learn english, and was gracious enough to speak english with me.  They had been having a Christmas Eve party, and we talked about how it seemed that Sydney was less festive than where we were from.  They took the party outside when it got late and were enjoying the park when I got to meet them.

Stars / constellations I saw

For the groups of stars below, I didn't realize these were the constellations until after the fact, I just wrote them down in my notes together because they were visually near each other.  I list them below in the order I saw them.  I also saw Sirius but I don't call it out specifically b/c it is visible from the northern hemisphere as well.

Edit: Following up, I took some pictures with a digital SLR camera and captured some of the stars / constellations / asterisms and annotated them - in this google slide deck.

part of Lupus and Centaurus

Both are only visible from the southern hemisphere FTW!  Lupus was previously part of Centaurus.

name / link	notes / excerpts
Beta Lupi	"has an apparent visual magnitude of 2.7,[2] making it readily visible to the naked eye. Based upon parallax measurements, this star is located at a distance of about 383 light-years (117 parsecs) from Earth.[2]"
Alpha Lupi	"its apparent visual magnitude of 2.3[2] makes it readily visible to the naked eye even from highly light-polluted locales." Yes, yes it does.  Also from the above it appears to be a candidate to be a supernova, and is relatively close to us (460 light years), so that should be interesting (from "OBSERVATION OF 23 SUPERNOVAE THAT EXPLODED <300 pc FROM EARTH DURING THE PAST 300 kyr", table 4)
Eta Centauri	"It has an apparent visual magnitude of +2.35[2] and is located at a distance of around 306 light-years (94 parsecs).[1]"
Zeta Centauri	a binary star, "has the proper name Alnair, from the scientific-Arabic[11] Nayyir Badan Qanṭūris (نير بطن قنطورس), meaning "The Bright (Star) of the Body of the Centaur".[12] With a combined apparent visual magnitude of +2.55,[2] it is one of the brighter members of the constellation. This system is close enough to the Earth that its distance can be measured directly using the parallax technique. This yields a value of roughly 382 light-years (117 parsecs), with a 1.6% margin of error.[1]"
Alpha Centauri	"the closest star system to the Solar System at 4.37 light-years (1.34 pc) from the Sun. It is a triple star system, consisting of three stars: Alpha Centauri A (officially Rigil Kentaurus[15]), Alpha Centauri B (officially Toliman[15]), and Alpha Centauri C (officially Proxima Centauri[15]). Alpha Centauri A and B are Sun-like stars (Class G and K), and together they form the binary star Alpha Centauri AB. To the naked eye, the two main components appear to be a single star with an apparent magnitude of −0.27, forming the brightest point of light in the southern constellation of Centaurus and the third-brightest in the night sky, outshone only by Sirius and Canopus."
Hadar / Beta Centauri	"a triple star system in the southern constellation of Centaurus. The system's combined apparent visual magnitude of 0.61 makes it the second-brightest point of light in Centaurus and one of the brightest in the night sky. According to parallax measurements from the astrometric Hipparcos satellite,[12][13] the distance to this system is about 390 ± 20 light-years (120 ± 6 parsecs).[1]"

Southern Cross

This was a "constellation" I was very much on the lookout for, but FYI it is not officially a constellation - it is instead an "asterism" so it did not show up in the app.

name / link	notes / excerpts
Alpha Crucis	acrux in the app. "a multiple star system 321 light-years from the Sun[1][12] in the constellation of Cruxand part of the asterism known as the Southern Cross. With a combined visual magnitude of 0.76, it is the brightest star in Crux and the 13th brightest star in the night sky. It is the southernmost first-magnitude star, 2.3 degrees more southerly than Alpha Centauri.[13]"
Gacrux (Gamma Crucis)	"the nearest class M giant star to the Sun.[7] The distance to Gacrux has been determined using parallax measurements made during the Hipparcos mission, which yielded a value of 88.6 light-years (27.2 parsecs) away from the Sun.[1] With an apparent visual magnitude of +1.63,[11]"
Mimosa (Beta Crucis)	"a binary star system; the second-brightest star in the constellation of Crux (after Alpha Crucis or Acrux) and the 19th-brightest star in the night sky... located at a distance of 280 ly (86 pc) from the Earth... The pair orbit each other every 5 years with an estimated separation that varies from 5.4 to 12.0 Astronomical Units.[5] The system is only 8 to 11 million years old.[4] The primary, Beta Crucis A, is a massive star with about 16 times the Sun's mass." Also from wikipedia:  Beta Crucis B has 10x Sun's mass.  Also may be a third star in the system - a "low mass, pre-main sequence star."

Various

More luck seeing these southern gems, many only visible from the souther sky!

name / link	constellation / asterism	notes / excerpts
Achernar	Eridanus	"binary system[7] designated Alpha Eridani (α Eridani, abbreviated Alpha Eri, α Eri), ... tenth-brightest in the night sky. The two components are designated Alpha Eridani A (the primary) and B (the secondary, also known informally as Achernar B). As determined by the Hipparcos astrometry satellite,[13][14] it is approximately 139 light-years (43 pc) from the Sun.[1] Of the ten apparent brightest stars in the night-time sky,[nb 1] Alpha Eridani is the hottest and bluest in color, due to Achernar being of spectral type B. Achernar has an unusually rapid rotational velocity, causing it to become oblate in shape. The secondary is smaller, of spectral type A, and orbits Achernar at a distance of roughly 12 astronomical units (AU)."
Canopus	Carina	"the second-brightest star in the night sky, after Sirius. Canopus's visual magnitude is −0.74, and it has an absolute magnitude of −5.71. Canopus is a bright giant of spectral type A9, so it is essentially white when seen with the naked eye. It is located in the far southern sky, at a year 2000 declination of −52° 42′ and a right ascension of 06h 24.0m. Its name is generally considered to originate from the mythological Canopus, who was a navigator for Menelaus, king of Sparta (see below)"
Epsilon Cannis Majoris	Canis Major	adhara in the app - almost certainly visible from the northern hemisphere. "binary star and, despite being designated 'epsilon', the second-brightest star in the constellation of Canis Major and one of the brightest stars in the night sky with an apparent magnitude of 1.50. About 4.7 million years ago, it was the brightest star in the sky, with an apparent magnitude of −3.99.[9] Based upon parallax measurements obtained during the Hipparcos mission, it is about 430 light-years distant from the Sun.[4] The two components are themselves designated Epsilon Canis Majoris A (also named Adhara[10]) and B"

Spring Triangle / part of Leo

name / link	notes / excerpts
Spica	"brightest star in the constellation of Virgo and one of the 20 brightest stars in the night sky. Analysis of its parallax shows that it is located 250 ± 10 light years from the Sun.[3] It is a spectroscopic binary and rotating ellipsoidal variable; a system whose two main stars are so close together they are egg-shaped rather than spherical, and can only be separated by their spectra. The primary is a blue giant and a variable star of the Beta Cephei type." "Beta Cephei variables, also known as Beta Canis Majoris stars, are variable stars that exhibit small rapid variations in their brightness due to pulsations of the stars' surfaces, thought due to the unusual properties of iron at temperatures of 200,000 K in their interiors. These stars are usually hot blue-white stars of spectral class B"
Denebola	"the second-brightest star in the zodiac constellation of Leo, although the two components of the γ Leonis double star, which are unresolved to the naked eye, have a combined magnitude brighter than it. Denebola is an A-type main sequence star with 75% more mass than the Sun and 15 times the Sun's luminosity. Based on parallax measurements from the Hipparcos astrometry satellite, the star is at a distance of about 36 light-years (11 parsecs) from the Sun. Its apparent visual magnitude is 2.14, making it readily visible to the naked eye. Denebola is a suspected Delta Scuti type variable star, meaning its luminosity varies very slightly over a period of a few hours."
Regulus	"brightest star in the constellation of Leo and one of the brightest stars in the night sky, lying approximately 79 light years from the Sun.[1] Regulus is a multiple star system composed of four stars that are organized into two pairs. The spectroscopic binary Regulus A consists of a blue-white main-sequence star and its companion, which has not yet been directly observed, but is probably a white dwarf.[7] Located farther away are Regulus B, C, and D, which are dim main-sequence stars."

Phone app was key - Stellarium

I want to thank the makers of Stellarium Mobile (Noctua Software), "a fully-featured planetarium for your phone".  It has worked really well for me - it was very easy to align the phone screen with the section of the sky and match the stars I could see with what was shown on the phone.  And now I can confirm it works in both the Northern and Southern hemispheres. I've always liked looking at the stars - occasionally, and especially on a clear night - but now being able to easily identify what I'm looking at and/or search for something I'm interested in has me really excited to go out at night.  Some minor caveats/quibbles though:

• the constellations feature does not show obvious ones like the Big Dipper or the Southern Cross, because these are technically asterisms
• Given that these are actually easily recognized and useful (the southern cross points south - you can use it to navigate!  The Big Dipper points to the North Star!) it's odd to me that it isn't an official constellation.  It seems that the definition of constellation should be "very hard to see and not of any practical use"
• It identifies star systems by the largest member of the system (e.g. largest one in a binary system) instead of the name of the system.  For example, the app reported I was looking at Rigel Kent which I had no idea about / never heard of, but then later when I looked it up I learned I was looking at Alpha Centauri which I had heard of.  Given I was zoomed out pretty far on the app b/c I was looking with the naked eye, there was no way I was observing Rigel Kent separately from the other members of the system, so this labeling is confusing / misleading

Epilogue

If you reached the epilogue, thank you for reading and for a special reward/gift email me at github dot 20 dot dllahr at xoxy dot net.

If you'd like to learn more consult your local library!