Capturing Andromeda

Submitted by Keith Bridgman

Kentucky is a difficult location in which to photograph the night sky...especially in winter. During the winter season there seems to be a perpetual covering of overcast obscuring the sky, a great deal of moisture, and not much else. Even during the warmer season, the skies in Kentucky are at best marginal with a great deal of light pollution and more cloud cover than one might expect. However, on those occasions when the clouds move away and the sky clears, if you can find yourself away from the inner city on a moonless night, the night sky can be filled with the brilliant sparkles of countless stars.

The winter season of 2018 and 2019 has been an exceptionally difficult year for seeing the night sky. Not sure how many clear dark evenings we've had in the past 90 days or so, but I'd bet you could count them on a single hand. Even so, on those few eventfully clear evenings, as cold as they were, we saw some of the clearest night skies we could have ever hoped for. We also were privileged to witness a spectacular lunar eclipse where the moon turned blood red as it floated high overhead spaced between a momentary lapse in cloud cover.

On another of those clear evenings, I setup a primitive DIY barn door star tracker and attached my camera along with a medium focal length lens and pointed it toward that partition of the sky where the galaxy Andromeda resides. Andromeda is the sister Galaxy to the Milky Way and is the most distant object you can see unaided using just your eyes. It is roughly twice the size of the Milky Way and is on a collision course with us. One day, Andromeda and the Milky Way with collide, or rather merge into a new blended galaxy, but that is quite some time off into the future. On a clear and dark evening it appears as an indistinct faintly dim smudge of light. But add in the light gathering ability of a digital camera and its amazing formation is relatively easy to captured.

Using the W shaped Cassiopeia Constellation as a reference pointer I made a couple of quick wide area images to zero in on Andromeda, then zoomed in closer using ever more tightly articulated actions until Andromeda hovered in the upper right quadrant of the image composition. It is actually a quite large object about the same relative size in width as the full moon, it's just a lot further away and a great deal less bright.

Using the star tracker to compensate for the earths rotation and the apparent motion of the stars across the field of view, I was able to track the galaxy with enough precision to capture some of the outer cosmic dust bands that arch around the outer edge of the Andromeda spiral, a spiral glow that consists of billions of stars. You do need to look closely at an enlarged image, but the dust rings are clearly there. It is not one of those Hubble Space Telescope quality images, nor does it qualify as one of those crystal clear images that many astro-photographers capture using more sophisticated equipment. It is however, so far the best image I've ever captured of this amazing and alluring deep sky object.

As we approach the end of winter and with spring looming a few weeks away, the Night Photography Mini Group will be planning to offer opportunities to capture the night sky. It is much easier to do than what most people realize. Even so, I hope to improve on this technique and capture ever more clear and exciting images of this wonderful night sky object...that is if the clouds ever clear off.