Exploring M51: The Whirlpool Galaxy

Image Details:

The image was taken with a One Shot Colour Camera – PlayerOne Uranus-C attached to a Askar 151PHQ at F7. The scope was mounted on a Losmandy G11and guided with a ASI174 and a William Optics 50mm Uniguider. Stellarmate X was used to control the system and Pixinsight was used to process the image. Total imaging time was 60 minutes using 3 minute subs

Galaxy M51: The Whirlpool Galaxy

• Common Name: Whirlpool Galaxy
• Catalog Designations: Messier 51 (M51), NGC 5194 (main galaxy), NGC 5195 (companion)
• Type: Spiral galaxy (with pronounced spiral arms due to interaction with its companion)
• Constellation: Canes Venatici (the Hunting Dogs)
• Apparent Magnitude: ~8.4 (visible with binoculars under good conditions)
• Angular Size: ~11 x 7 arc-minutes
• Distance from Earth: Estimates vary from about 23 to 37 million light-years; most recent sources typically cite 23–27 million light-years.
• Diameter: ~80,000–87,000 light-years
• Discovery: Discovered by Charles Messier in 1773
• Notable Features:
• One of the most famous spiral galaxies due to its clear structure and interaction with companion NGC 5195.
• The first galaxy where spiral structure was observed (by Lord Rosse in 1845).
• Has had three supernovae observed since 1994.

How to Locate M51 in the Sky

Finding M51 Using the Big Dipper (Ursa Major):

1. Locate the Big Dipper:

• The Big Dipper is a prominent asterism in the northern sky, part of the Ursa Major constellation.

1. Identify Alkaid:

• Alkaid is the star at the end of the Big Dipper’s handle.

1. Shift Southwest:

• From Alkaid, move approximately 3.5 degrees to the southwest. This will bring you close to M51.

1. Look for Canes Venatici:

• M51 is located in the faint constellation Canes Venatici, but using the Big Dipper as a guide is much easier.

1. Observing Tips:

• Binoculars: M51 appears as a faint gray patch of light.
• Small Telescope: Both the core of M51 and its companion NGC 5195 are visible.
• Larger Telescope: Reveals more detail in the spiral arms and halo.

Star Maps and Coordinates

• Right Ascension (RA): 13h 30m
• Declination (Dec): +47° 11′
• Best Viewing Season: Spring in the northern hemisphere.
• Star Map Example:
• Use a spring star chart for the northern hemisphere.
• Find Ursa Major (Big Dipper), then trace from Alkaid (end of the handle) southwest toward Canes Venatici.
• M51 will be just south of a line connecting Alkaid and Cor Caroli, the brightest star in Canes Venatici.

Visual Summary Table

Additional Notes

• Companion Galaxy: M51 is interacting with NGC 5195, which is clearly visible in images and through telescopes.
• Observation: M51 is best observed from dark-sky locations, especially in the spring months.