Question 1

What is astrophotography?

Accepted Answer

Astrophotography is a specialized style of photography that involves capturing images of objects in the night sky, from the Milky Way to distant galaxies, comets, planets, and more, often using specialized cameras, telescope lenses, and mounts.

Question 2

If astronomy is science-based, how can astrophotography be art?

Accepted Answer

It is a common source of debate how much creative license and processing a photographer should put into their work. Some processing is necessary. Nebulae can be incredibly faint and require far more exposure than ordinary targets. In fact, some nebulae require 10 - 20 hours minimum total exposure time!

Many nebulae emit radiation at specific frequencies that can be captured with special filters. The famous Hubble space telescope photographs use a false color scheme to provide the beautiful images that could not be seen with the unaided eye (it's called the "Hubble palette.")

For these reasons, I believe an astrograph can become a work of art because it is transformed by a sum of decisions around contrast, color, and other concerns that lead to a unique piece.

There is a very active and thriving market for fine art based on astronomical observations and for a good reason: the universe is a beautiful canvas that was painted by a Master Artist.

Question 3

What are the steps involved in taking an astrograph?

Accepted Answer

The process varies depending on the type of target, but every project undergoes the same four phases:

Planning - Jeremy follows weather forecasts to plan for clear nights. Some targets require a "dark site" away from light pollution, which involves a portable setup. He also needs to know where the target will be in the sky, and for faint targets, how long. Some images are the result of multiple nights, sometimes spread over multiple years! Different targets also require different setups. Planets benefit from specialized "large" sensors and extremely long focal lengths (~6,000mm). The Andromeda Galaxy, on the other hand, is large and requires a smaller focal distance (~300mm) to be able to fit in the frame.
Acquisition - capturing the target can be extremely time consuming. Jeremy may bring a portable equipment set up to a dark site and attach the components to a battery. For accurate tracking, he typically has to perform what's called "polar alignment" to ensure his telescope is oriented in a way that makes it easier to track long exposures. Focusing on faint targets can also be challenging. While imaging in the summer is comfortable, it can increase air turbulence and make imaging more challenging. The winter has more overcast days and uncomfortably cold nights but provides many more hours of time to shoot a target. 
Processing - for some targets, Jeremy may capture hundreds of 5-minute exposures using a variety of filters (red, green, and blue light, hydrogen alpha, oxygen, etc.). These images must be carefully and precisely aligned, then "stacked" for each filter. Stacking allows multiple exposures to be combined and helps reduce unwanted noise in the image. The stacked filters must then be mapped into color channels to produce the final image. Some images required days of compute time to process the stacking and then hours of Jeremy's time pulling everything together.
Presentation - the final step is determining how to present the image. Nebulae and galaxies look great on metal but Milky Way prints often appear more clear on photographic or canvas mediums. Jeremy takes into account the composition, type of target, resolution, clarity, and color to determine the right way to present it. In some cases, he may produce a video or simply share a web-based version of the image.

These are the reasons why more people are not doing astrophotography!

Frequently asked questions

What is astrophotography?

If astronomy is science-based, how can astrophotography be art?

What are the steps involved in taking an astrograph?