The Andromeda Galaxy, or M31, is the nearest large neighbor of our Milky Way, though it sits some 2.5 million light-years away. That makes it the most distant object regularly visible with the naked eye.
By some estimates, the Andromeda Galaxy contains roughly one trillion stars. And it stretches more than 200,000 light-years in diameter. That’s significantly bigger than the Milky Way, which more recent estimates suggest is 150,000 light-years across (though the exact boundary of where either of these galaxies “end” is a bit nebulous).
Astronomers are still struggling to get an accurate count, but our galaxy also appears to have roughly a quarter to a half as many stars as Andromeda.
Takahashi apochromatic FSQ 85 telescope with 0.73x QE taka reducer AZEQ6 mount Inova guide camera mounted on a Kepler 60/240 guide telescope (F / d = 4.0) Monochrome Atik One 9 CCD camera, sensor temperature at -10 ° c Guidance software: phd guiding + phd max Processing software: Pixinsight1.8 Ha, Cls & RVB filter from Astronomik L: 80x300s of 2018 + 158x300s of 2020/2021 in bin1 Ha: 20x180s of 2018 + 23x180s of 2020 in bin2 R: 19x180s of 2018 + 21x120s of 2020 in bin2 V: 19x180s of 2018 + 24x120s of 2020 in bin2 B: 10x180s of 2018 + 30x120s of 2020 in bin2 Total: ~ 27 hours