Spitzer: Questions and answers about shooting the stars
After getting a number of emails, local photographer shares some equipment advice and other pointers
The images in my Wednesday photo essay, “Color in the Night Sky,” require a few pieces of specialized equipment to capture. In addition there is a steep learning curve to become proficient with the hardware, software, and the subjects you will photograph. As with any hobby or sport, you can start with the basics and work your way up.
Long exposures are required to gather enough light to see the nebula color and detail of targets in the night sky. Many of my exposures are anywhere from three to five minutes. In addition to long exposures, one technique requires multiple exposures.
A device called an intervalometer allows you to capture 30-50 images that are then combined (stacked) for the final image. The problem is that the stars are moving across the night sky and exposures of that length produce star tracks which means the nebula would be a blur.
The most important hardware on an astrophotography rig is a star tracker. This is the hardware that is sitting on the tripod and supports the telescope. The job of this device is to follow the stars across the sky during those long exposures. Due to the spin of the Earth, the stars in the Northern Hemisphere appear to rotate around the North Star, Polaris. This star is used to “polar align” the axis of the star tracker so that it moves to counteract the movement of the stars and keep them in the exact same place in the image.
The telescope is a 73mm, f/5.9, Apochromatic (APO) Refractor. APO lenses are designed to bring three wavelengths of light (red, green, and blue) into focus in the same plane. A standard telephoto lens does not focus those colors as well as an APO lens, but many standard telephoto lenses can produce good results.
The camera is a standard 35mm DSLR camera body. There are special bodies available that record different wavelengths of light. The camera is attached to the scope with a T-Ring adapter and field flattener.
A good computer and processing software are also required. Some software can be obtained free of charge on the app stores on the Internet.
Just like any hobby, there are all kinds of gizmos to make it easier and more fun. A myriad of adapters, connectors, filters, smartphone utilities, and tools are also part of the mix. A search of the internet will provide you with all kinds of options to help out.
This hardware is not cheap. There is a lot of used equipment available at the many camera and astronomy stores. It is not necessary, or advisable to buy it all at once. As with any hobby, start with the basics and work your way up.
We have a huge advantage based on where we live. Our area has fairly low light pollution and a lot of nights with clear, calm skies. Better images can be obtained during the new moon. Shooting at night and in the cold adds further complications.
Astrophotography can be a unique and fun challenge and it is not necessary to travel to the ends of the Earth to get great images. We see the same stars and nebula in our skies as the folks anywhere else in the Northern Hemisphere. Most of us can do a lot of astrophotography from our decks and driveways which makes it a lot easier. You do not need to leave home to be entertained and challenged.
If you want to get involved in a different kind of photography, give astrophotography a shot! (Pun intended!)
Rick Spitzer is an acclaimed wildlife photographer who lives in Wildridge.