M65 – A Spiral Galaxy in LRGB technique

The spiral galaxy M65 is a beautiful object located in the zodiacal constellation Leo. Together with the galaxies M66 and NGC3628 (the latter also known as The Hamburger Galaxy), it forms the famous Leo triplet. These galaxies are well-known because they are relatively close to Earth and can be easily observed with small telescopes or even binoculars. They have also distinctive shapes and interesting gravitational interactions with each other. Out of these interactions, M65 has changed the least in its shape.

A supernova explosion occurred in M65 ten years ago, which was the first time scientists saw a supernova in this galaxy. Typically, two to three supernova explosions occur in a century in galaxies of similar size. The study of supernovae is important as it helps us understand the life cycle of stars and their impact on galaxies. For example, the shock wave produced by the supernova explosion can trigger the formation of new stars by compressing gas and dust in the surrounding region.

The galaxy M65 contains approximately 200 billion stars. Although new stars are continually forming in the galaxy (especially in the blue regions), the proportion of older stars is also significant. The galaxy is located at a distance of 35 million light-years and has an apparent size of just 0.14° x 0.04° (for comparison: the apparent size of the full Moon is about 0.5° x 0.5°). Its diameter measures 95,000 light-years.

The redshift value of the M65 galaxy is 0.0025, indicating that it is receding at a speed of 750 km/s (466 mi/s). The redshift value indicates how much the light from M65 has shifted towards the red end of the spectrum due to the expansion of the Universe. Redshift is similar to the Doppler effect in sound in that it involves a shift in wavelength. However, redshift is a distinct physical phenomenon caused by the expansion of the Universe.

Imaged in LRGB technique with the SW Esprit 120ED refractor (diameter 120 mm/4.7") and a monochrome camera. The total exposure time was 6 hours and 18 minutes.

Equipment and acquisition details:

Galaxy M65 • Telescope Sky Watcher Esprit 120ED APO @ f/7 • Monochrome camera QHY268M cooled at -15 °C, mode 1, gain 56, offset 20 • Mount Sky Watcher AZ-EQ6 PRO • Total exposure time 6 h 18 min (L 64 x 140 s, R 32 x 140 s, G 32 x 140 s, B 34 x 140 s) • Processed in PixInsight • March 2023, Vurmat / Radlje ob Dravi / Slovenia