#messier31

The Andromeda Galaxy has a similar size and structure as our own galaxy. Its proximity, 2.5 million light-years, makes it easier to investigate than others more distant. The similarity helps us understand the colourful regions of gas and dust that we see up-close and nearby in our own galaxy.

We keep returning to photograph this target because it is beautiful, intriguing and certainly iconic. My goal this year is to combine new images with those previous to reveal the structure and locations of star-forming regions (H II regions) in the Andromeda Galaxy. Many of my photos are of star-forming regions nearby in our own galaxy. They fill my images with a brilliant pink tapestry. Seeing these regions from a distance helps us understand their overall structure. We find the telltale pink regions on the spines of the spiral arms.

This is an ensemble of 310 photos where each was a 3 minutes exposure (15 hours of astrophotography over 3 years). I combined 80 recent images with 160 images from autumn 2024, both sets using the Optolong L-Pro filter to create an interim image that captures the fine details. I then photographically merged this detailed image with a different image from 2022 that used the Optolong L-Enhance filter to reveal the locations of pink-coloured star-forming regions on the spines of the spiral arms (70 images combined in autumn 2022).

I photographed the Andromeda Galaxy from my garden in Strasbourg France on five nights over three years, 2025, 2024, 2022.

Equipment used to capture images:

Telescope: Redcat51

Computer: ASIAIR

Mount: AM5

Filter: Optolong L-Pro, Optolong L-Enhance

Camera: ASI183MC-PRO

Processing Software:

Pixinsight

Blur Exterminator

Noise Exterminator

Star Exterminator

The Great Andromeda Galaxy

In late summer and early autumn, the Andromeda Galaxy is high in the eastern sky after sunset in the northern hemisphere. This is the best time to capture a photo of the Andromeda Galaxy, the most iconic of astrophotography images.

Catalogued as Messier-31 or M31, it is the nearest galaxy at 2.5 million light years. It appears to have a similar size and structure to our galaxy, but there are significant differences. With this proximity, it appears too large in most backyard telescopes.

It is quite bright at the centre, and easily visible with binoculars. The challenge for astrophotographers is to render the faint edges without over-saturating the intense core. However, I keep the core lightly saturated to remind us that the Andromeda Galaxy has a super-massive black hole at the centre.

There is a tenuous halo of stars with darker dust around the galaxy, and the outer edges seem disrupted. Current thinking is that one or both of the smaller satellite galaxies in the photo (M32 and M110) passed through the Andromeda Galaxy long ago.

This is an ensemble of 180 photos where each was a 3 minute exposure (9 hours of astrophotography). I photographed M31 from my garden in Strasbourg France on 2 nights in September 2024.

More information about the Andromeda Galaxy:

The Andromeda Galaxy will collide with the Milky Way about 4.5 billion years

A false-color image of the mid-infrared emission from the Great Galaxy in Andromeda, as seen by Nasa's WISE space telescope.