Wednesday, May 3, 2023

M101 - The Pinwheel Galaxy


M101 - The Pinwheel Galaxy - captured on 04/26/2023

What is it?

M101 is a very large, face-on spiral Galaxy also known as The Pinwheel located in the constellation Ursa Major. It is a Grand Design Spiral Galaxy. It's asymmetric shape and very well defined spiral arms are likely the result of gravitational interactions with neighboring galaxies. It also has high levels of star formation, also likely caused by the same gravitational interactions. 

How big is it?

It has an angular size of 24 x 23 arcminutes on the night sky. It's about 170,000 light-years across (almost twice the size of our Milky Way Galaxy). It has about a trillion a contains the mass of about 100 billion solar masses.

How far is it?

M1010 is 7.1 Mega Parsecs (Mpc) or 23 million light-years (Mly) from Earth.

How to find it?

Even though M101 is fairly bright at magnitude 7.9. Unfortunately, due to its large angular size, it has a low surface brightness. Larger aperture and dark skies will help in finding and observing this object. 

Refer to the finder chart below. 

  1. Find the Big Dipper
  2. Find the star at the end of the handle (Alkaid)
  3. Find the second star in the handle of the big dipper, Mizar, where the handle bends. Mizar is not labeled in the finder below. Side Note: See if you can see Mizar's fainter companion, Alcor. Alcor and Mizar are naked eye double star. 
  4. Referring to the finder chart, draw an imaginary isosceles triangle with Alkaid and Mizar as the first two vertices of the triangle. M101 is the third vertex.

Finder chart for M101

Image Details:

Capture Date: 04/26/2023
Location: Eden, NY
Telescope: Explore Scientific ED80 Essential Series Air-Spaced Triplet Refractor
Camera: ZWO ASI2600MC Pro
Mount: Sky-Watcher USA EQ6-R Pro
Exposure: 124 exposures at 120 sec each / Gain 100 / Offset 50 / -10°C  for a total exposure of 4.13 hours
Software: NINA, SharpCap Pro, PHD2, and PixInsight


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