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M33 – Triangulum Galaxy

The Triangulum Galaxy is a spectacular sight when photographed through a telescope.  It’s large, colorful, and has a distant spiral formation.  This galaxy is a mere 3 million light-years from Earth in the constellation Triangulum.

The photo below showcases the M33 Galaxy captured using an Explore Scientific ED80 telescope, with a modified DSLR camera. The Triangulum galaxy is a challenging target from the backyard, but with plenty of integrated exposure time, the true beauty of M33 can shine through.

Triangulum Galaxy


Find the Triangulum Galaxy

Although M33 shows up quite clearly in photographs, it is actually quite dim visually.  Unlike the Andromeda Galaxy, the Triangulum Galaxy requires dark skies and a telescope with enough aperture to view it.  If you are lucky enough to observe in really dark skies, the Triangulum Galaxy can be spotted with the naked eye in the constellation Triangulum.

This face-on galaxy is often referred to as the “Pinwheel Galaxy”, but I prefer to reserve that title for M101. No matter what you call it, Messier 33 is one of the most magnificent galaxies seen in our night sky.

The final image above went through several stages of image processing.  Have a look at the original image below.  The reason the sky is an ugly yellow-red color is because I shoot through heavy light pollution in the center of my city.


Processing the Triangulum Galaxy in Photoshop

Look at all the light pollution! M33 is in there somewhere…

I’ll discuss the details of processing the image further down the page.  First, let’s locate the Triangulum galaxy in the night sky:

Where is M33 located?

To help find the galaxy, look left of Andromeda and Pisces, above Aries.  If you can find M31, you are almost there.  Use the star map from Sky and Telescope below to help you.

Find the Triangulum Galaxy

Through long exposure photography, we can see that this galaxy is full of hydrogen gas.  These are the pink areas seen throughout the spiral arms in the galaxy.  M33 is a member of the local group of galaxies that also contains our home galaxy, The Milky Way, and Andromeda.  These giant H-II regions are some of the largest known “stellar nurseries” where new stars a being born.

A camera modified for astrophotography makes a big difference when capturing hydrogen regions.  These reds and pinks will show up much brighter in a camera with the IR cut filter removed.  Capturing narrowband data in the H-Alpha wavelength will brighten these areas even more.

Read: How a DSLR Ha filter can improve your astrophotos

The right telescope for the job

I used my primary imaging telescope at the time (Explore Scientific ED80) to photograph this galaxy.  This telescope was well suited for the Triangulum Galaxy because it is quite large.   I often recommend this specific telescope to beginners because of my positive experience with it.  This instrument produced consistent results on a nightly basis from an astrophotography perspective.

Astrophotography Telescope

Photographing M33 from the backyard

Back in September of 2015, I spent a number of clear nights focused on this galaxy.   From the Northern hemisphere, the Triangulum Galaxy rises high into the sky.  This is a prime location for imaging, as it is as far away from ground-based atmospheric disturbances as possible.  It is also free from obstructions like the roof of my house, and tall trees!

As with most astrophotography targets, the real challenge is in the image processing!  Processing images of galaxies is quite different than most nebulae.  The isolation of the galaxy amongst a black sea of space helps it really stand out when imaged.  The tough part about processing M33 is the overall low surface brightness of the galaxy.  It is much dimmer than Andromeda.


Triangulum Galaxy - Astrophotography

Processing M33 in Adobe Photoshop

My original stacked image had a horrible gradient due to the poor sky conditions I shot in.  This was easily removed in Adobe Photoshop using methods I learned from Jerry Lodriguss.  Expect an astrophotography tutorial on removing gradients in Photoshop on my YouTube Channel soon.

Astrophotography Tutorials – Deep Sky Processing

Astrophotography telescope

The capturing process went smoothly.  I used BackyardEOS to control my modified Canon 450D.  Autoguiding was used via the Orion Mini 50mm and Meade DSI Pro II combination riding on my Sky-Watcher HEQ5.   For complete details of my astrophotography equipment, please visit that section of the website.

My Complete Astrophotography Equipment Setup


M33 – The Triangulum Galaxy

Read the full blog post about photography this galaxy

M33: Triangulum Galaxy – Photo Details

Total Exposure: 7 Hours 4 Minutes (90 frames)
Processing Software: Deep Sky Stacker, Photoshop CC
Support Files: 20 darks, 20 flats, 20 bias

Telescope: Explore Scientific ED80 with WO Flat III 0.8x FR/FF
Mount: Skywatcher HEQ5 Pro Synscan
Guiding: Meade DSI Pro II and PHD Guiding
Guide Scope: Orion Mini 50mm
Camera: Canon EOS 450D (Modified)
ISO: 800

Read more about the Triangulum Galaxy