🌌 Astronomy Evening at Valley View Hot Springs

Tour of the Universe with the 20" PlaneWave Telescope

Framing options:

We often dream of travelling the world and seeing its many wonders, but few people have the time or money to see much of it. Even though the distances are much greater, astronomy is more accessible than geography: half the universe is visible on any clear evening, and you can look at most of it in one night.

The universe is easy to observe, dynamic, deeply related to our existance (the hopfully-familiar story of the big bang and creation and supernovae creating the elements that our bodies are made of.)

See the Moon, constellations, stars, planets, Earth satellites, and more via the naked eye, binoculars and a small telescope. For your mind’s eye we’ll point out newly-discovered solar systems, black holes, X-ray sources, the Hubble Deep Field and bask (as always :-) in the presence of the 2.73 degree K cosmic microwave background radiation from the Big Bang.

Cosmic Distance Ladder (Orders of Magnitude)

8 factors of 1000 in distance → 24 orders of magnitude!
48 orders of magnitude in brightness!!

1. Setting the Scene: Valley View’s Dark Sky

• Dark site: Bortle 2 skies.
  • Compare to nearby Great Sand Dunes NP.
  • Naked-eye phenomena possible here:
    • Zodiacal light (cone after dusk/dawn)
    • Gegenschein (opposite the Sun at midnight)
    • Zodiacal band stretching across ecliptic
    • Airglow (green/red natural skyglow from upper atmosphere)
    • Clouds look black not lit from below
    • Dark nebulae in the Milky Way
    • Milky Way shadows on the ground

2. Our Telescope: Beyond Magic

• 20" PlaneWave telescope + L-500 mount + CCD imaging + computer.
• Why remarkable:
  • Would have sped up worldwide science immeasurably even 50 years ago.
  • Beyond magic 100 years ago.
• Detector progress:
  • Photographic plates: QE ~1%-3%
  • CCDs: QE ~10% (1980s)
  • Modern CMOS/CCD: QE ~90%
  • → ~100× more efficient in half a century.
• What this system can do:
  • Detect exoplanet transits.
  • Invaluable for variable star tracking.
  • Reveal faint galaxies, nebulae, and streams.
• Historical aside: Laurent Cassegrain’s reflecting telescope design was ridiculed by Newton and Huygens, suppressing it for centuries. His full identity was forgotten until rediscovered in 2000. Tonight’s telescope vindicates him.

3. How the Naked Eye Misleads Us

1. Our cosmos is filled with galaxies.
   • Yet only Andromeda (M31, ~2.5 Mly) is obvious to the eye.
2. Light pollution is erasing stars.
   • Star visibility drops ~9–10% globally each year.
3. Stars move.
   • Barnard’s Star and 61 Cygni show rapid proper motion, but imperceptible to the human eye in one lifetime.
4. Bright stars are unusual.
   • Most stars (~75–80%) are faint red dwarfs.
   • None visible to naked eye.
   • Our Sun is brighter than 95% of stars, but dwarfed by O-type-stars millions of times more luminous.
5. Stars are often in systems.
   • ~50% in doubles or multiples.
   • Castor in Gemini = 6 stars.
   • TIC 168789840 = 6 eclipsing stars, all interacting.

4. Dynamic, 3D Sky

• Summer Triangle:
  • Altair: 17 ly
  • Vega: 25 ly
  • Deneb: 1,500–2,600 ly (uncertain; Gaia saturates on such bright stars)
  • → same sky triangle, immense depth difference.
• Sagittarius stream:
  • Stars from the Sagittarius Dwarf Galaxy, which is being torn apart by the milky way.
• Rubin Observatory (LSST):
  • Will catalog more galaxies than stars - tens of billions.
  • Will produce a movie of the sky from Chile - the whole southern sky every 3 days. Will alert us to about 10 million changes in the sky every night, all public.

5. Galaxies per Field of View

• 20" eyepiece (~0.4 sq deg TFOV) [verify this]:
  • Visual, random field: ~1–5 galaxies.
  • Rich regions (e.g. Virgo): ~10–30 galaxies.
• Imaging with cooled CCD/CMOS:
  • Thousands of galaxies.
• Best space-based surveys (HST XDF, JWST UNCOVER):
  • Over a million galaxies per 0.4 sq deg field.

6. Cosmic Highlights

• M31 Andromeda Galaxy:
  • Distance: ~2.5 Mly.
  • Angular size: 8 full Moons across (~3°).
• 3C273 (brightest quasar): near Eta Virgo
  • Distance: ~2.4 Gly (z=0.158).
  • Varies between mag 12.5–13.5. both daily and yearly.
• Einstein rings:
  • Galaxy acting like a funhouse mirror, bending light from something billions of light-years farther away.
  • We see multiple copies of the same object, or a perfect ring if the aligment is perfect.
  • Einstein Cross (Q2237+0305) in Pegasus.
• Cygnus X-1:
  • Distance: 7,260 ly.
  • Black hole mass: ~21 M☉, near-maximal spin.
  • First confirmed stellar-mass black hole.
• Betelgeuse:
  • Will explode as supernova (sometime in next ~100k yrs).
  • Current variability: 0.0–1.3 mag over ~423 days.
• Nearby supernova candidate: IK Pegasi, ~150 ly. Type Ia progenitor.

7. Largest Structures

• Hercules–Corona Borealis Great Wall:
  • ~10 billion light-years across.
  • Detected via clustering of GRBs.
  • Highly controversial; may contradict cosmological principle (homogeneity at >300 Mpc).
• Other debated “walls” and “rings” (e.g. Sloan Great Wall).
• Likely selection effects—worth presenting as tentative, under debate.

8. Scale of the Universe

• Betelgeuse: would extend beyond Jupiter if at Sun’s place.
• M87 black hole: angular size ~42 micro-arcseconds = a penny on the Moon.
• Andromeda: nearest large galaxy, visible naked-eye.
• Cosmic microwave background: 13.7 Gly light-travel time.
• Quasar 3C273: photons left before the first land plants evolved.

Cosmic Distance Ladder (Orders of Magnitude)

8 factors of 1000 in distance → 24 orders of magnitude!
48 orders of magnitude in brightness!!

9. Closing Themes

• Dynamic sky: stars move, vary, explode.
• Half of Earth’s internal heat flow comes from radioactive decay; the rest is “primordial heat” left over from planet formation. So when you soak, you are literally bathing in the warmth of Earth’s nuclear heart.
• We are stardust: every atom of our bodies forged in ancient stars.
• So while you soak here in the warm springs, remember — the hydrogen in the water of your cells was born in the Big Bang, the calcium in your bones was forged in dying stars. The gold in a ring and the uranium keeping the earth hot both needed cataclysms far beyond Earth: supernova explosions, and collisions of neutron stars. You’re surrounded by atoms forged in the most violent places in the cosmos. Valley View isn’t just connected to the Earth — it’s connected to the whole universe.
• The heat beneath your feet: Half of Earth’s warmth comes from slow radioactive decay of uranium, thorium, and potassium, the rest from the planet’s fiery birth. The springs here are literally powered by Earth’s nuclear furnace.
• The atoms within you: Your body is made of stardust — oxygen and carbon from stars, calcium and iron from dying suns, trace metals from the most violent explosions in the universe.
• The story that connects it all: The gold in a wedding band, the uranium that keeps the crust hot, even the water in your cells — all came from cataclysms beyond Earth: supernovae and neutron-star collisions. Tonight at Valley View, you’re soaking not only in warm mineral water, but in the story of the universe itself.