The Triangulum Galaxy

This is M33, a neighbouring spiral galaxy which is the third largest in our Local Group and only slightly further than the Andromeda Galaxy M31.

M33 is estimated to contain up to about forty billion stars.

Object Details:

Messier 33, NGC 598, UGC 1117, PGC 5818, MCG 5-4-69, CGCG 502-110.
Constellation: Triangulum.
Visual magnitude: +5.8
Apparent diameter: 62 x 36 arc-min. (about 2 Lunar Diameter).
Actual diameter: 50,000 light years (about half our Milky Way diameter).
Distance: 2,800,000 light years.
Altitude: 24° above Northern Horizon.


Exposure: 16 x 4 min, ISO 1600 (+ 6 dark, 20 bias).
Date: 2017-12-10.
Location: Field night at The Oaks, NSW, with Macarthur Astronomical Society
Sky: semi-dark rural with metropolitan sky-glow between East and North.
Cloud: mostly clear, some minor high cloud interference.
Moon: No.
Processing: Canon DPP > Deep Sky Stacker > GIMP.
Cropping: no.

Imaging telescope: Skywatcher Esprit 120ED Super APO triplet refractor.
Focal length: 840 mm, focal ratio: f/7.
Imaging camera: Canon EOS 60D.
Guiding camera: Orion StarShoot.
Guiding control software: PHD2.
Guiding accuracy: 1″ rms approx.
Telescope mount: SkyWatcher EQ6-R.
Polar aligning: QHYCCD PoleMaster.
Field flattener: yes; filter: no.


My Galaxy Portfolio

Image © R.Powell



  1. What an admirable object to capture!
    It is said that It is one of the most distant permanent objects that can be viewed with the naked eye. How amazing that we can see across such vast distances of space.
    We are living for a short while on our loving, beautiful home – the Earth, enjoying the beauty and the mystery of space, hopefully without contaminating or destroying it!
    Wonderful work, Roger.


  2. M33 was a difficult find in my early astronomy hobby days, eluding all attempts to “log on.” M31, nearby was easy, bright, but despite it’s glaring presence in our star charts, M33 was not visible – until we left the New York City suburbs (in New Jersey) and headed to “The Jersey Shore” where dark skies (back in the early 1960’s) was …awesome. And …there it was. My friend and I would essentially jump with a hi five, finally, …there it was… M :-
    Thanks for the reminder, and beautiful capture.


    1. Thanks for that.

      Actually this image of M33 was somewhat fortuitous. Here in Southern latitudes that region of the sky is only available during a short window of opportunity each November.

      I was on a field trip with my Society and all set to image M31. Then I realised that everyone else around me was doing just that, so preferring to be different, I opted for nearby M33 instead. This was the result.

      M31 can wait…


Leave a comment or ask a question . . . .

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s