Peering at Galaxy NGC2403 tonight. It has no informal name, though I'm going to call it Hydrogen Helix.

As we look beyond the last stars of our own galaxy, HH comes into view looking like an egg over-easy. The nucleus is not particularly bright; perhaps it holds a smaller black hole than found in other galaxies. What's striking about Helix is the sheer size of the red nebulae distributed about its spiral arms. The biggest are interstellar hydrogen clouds, spawning new stars like crazy.

"Interstellar hydrogen clouds" are what galaxies are made of. When the clouds are not reacting with something, they can be nearly invisible or even a sort of brown color, depending on what they are mixed with. Heavy concentrations will collapse on themselves with such force that new stars are ignited. When nearby hyrogen electrons are knocked silly by the radiation, the ionized cloud begins to glow red.

There are too many spiral arms (should only be two). Some look like fragments rather than radiating out from the nucleus in a continuous form. This probably means Hydrogen Helix has gobbled up other galaxies.

NGC2403 is 8 million light years away in the constellation Camelopardalis. It's 50,000 light years across, which is about half the size of our own Milky Way galaxy.

The galaxy was first noted by William Herschel in 1788, though he wouldn't have know what it was. Edwin Hubble (yup, that Hubble) knew it was a galaxy and studied it with the Hale telescope 150 years later.

Scientists have noted two supernovas on HH in recent years. When a large star grows old and explodes, it also creates a nebula, but one smaller than the giant displays most visible here. Of the billions of stars in a galaxy, only a few age out and explode every 20 Earth years, which is amazingly rare. Those supernova make up a lot of the tinier specks of orange in the image.

Hydrogen Helix is fairly small in our sky and actually pretty dim. The telescope followed it for 5 hours to pick up enough light to show detail and color.

It's nasty cold out tonight. It reminds me of just how empty and cold space above can be, even though 5°F here is nothing like the -450°F out there.

I suddenly feel the need for hot chocolate!

Tonight's entry was accompanied by 𝘛𝘶𝘳𝘯 𝘖𝘶𝘵 𝘛𝘩𝘦 𝘚𝘵𝘢𝘳𝘴, by jazz pianist Bill Evans.