Jason Nishiyama @evilscientistca@octodon.social
Teacher, astronomer, political scientist and father.
The Apollo astronauts left laser retro-reflectors on the Moon which allowed us to measure the distance to the Moon to an accuracy of a few centimetres.
The Virgo cluster of galaxies is one of countless large grouping of galaxies in the universe. Our own Galaxy is a member of the Virgo cluster. Rothney Astrophysical Observatory Baker-Nunn telescope mosaic.
This is the Hubble extreme deep field. With the exception of (from what I can find) 3 foreground stars, every object you see in this picture is a galaxy. Can you find the foreground stars? Know the trick?
The arcs around the two galaxies in the centre of this Hubble image are caused by the light from galaxies behind the galaxy cluster in the centre being bent by the gravity of the cluster. This is gravitational lensing.
M17- the Omega or Swan Nebula is a star formation region about 5000ly from us. It glows red because the young stars excite the gas of the nebula.
The ecliptic is the Sun's apparent path through the sky. The Sun's motion along the ecliptic is actually due to the Earth's orbit around the Sun. The 23° angle the ecliptic makes with the celestial equator is due to the Earth's axial tilt.
Open clusters of stars, such as M11 (The Wild Duck Cluster) are amazing labs for stellar evolution. Since the stars in the cluster were formed at roughly the same time one can work out how mass and stellar lifetime relate to one another. More massive stars live shorter lives.
M42- The Great Nebula in Orion, is a massive star formation region. It's also relatively close being in the 1400-1500 ly range of distance.
Planetary nebulae are generally round/elliptical or bipolar-butterfly shaped.
We don't know exactly what the collimation mechanism is for the bipolar PNe. (Left my image of M97, right Hubble image of M2-9)
Stars between about 1 times the mass of the Sun and 6-8 times the mass of the Sun end their days as a white dwarf after becoming a planetary nebula. Some planetary nebulae shown: Owl Nebula, Ring Nebula, and Dumbbell Nebula.
Stars with a mass greater than 8 times that of the Sun die spectacularly. Once the matter in their cores is fused in to iron, fusion shuts down and the star then explodes in a supernova explosion.
The Crab Nebula, shown, is the remnant of a supernova recorded in 1054 by Chinese astronomers.
Want to work out the magnification of a telescope? Well you need to know what eyepiece it is using as changing the eyepiece changes the magnification. Mag=focal length of telescope / focal length of eyepiece. So a 10mm eyepiece on a 1500mm f/l telescope is 150x.
Spectra can be either bright line or dark line. The lines are caused by different elements in the object. Bright lines are from hot or excited gases. Dark from cool gasses in front of a hot object. The lines are in the same position in both for the same elements.
Change your wavelength, change your view. A map of the sky at 800MHz (~37cm wavelength). This is mostly continuum radiation. Done with the 2m dish that we re-mounted today.
2m dish at the observatory finally re-mounted.
The red dot marks the Apollo 11 landing site, the first place humanity has set foot on another world.
Galaxies tend to be found in clusters. This one is Abell 2666. The second images show the 11 galaxies visible.
The planet Uranus was originally called Georgium Sidus (George's Star) by its discoverer William Herschel. This didn't go well outside of Britain so it was named after the Greek deity of the sky. English speaking astronomers have had to deal with the giggling ever since.
M57 - the Ring Nebula - is a planetary nebula in the constellation Lyra. A dying star that has ejected its outer layers, kinematic studies of M57 suggest that it is actually barrel shaped and that we are looking down one end.
Henrietta Swan Leavitt discovered the Cepheid variable period-luminosity relationship. This relationship links the absolute brightness of a Cepheid type variable star to its pulsation period. This gave us an important standard candle to measure distances across space.
