We covered some of the warnings and startup issues with Astrophotography in Part 1 of this series. Now, hopefully with you having some Piggy-Back photography shots under your belt you can start taking a look at more serious Astrophotography shots. Now it is time to start thinking about getting some serious equipment. Here is an overview of what you will need:
A strong, motorized, precisely aimed equatorial mount – The mount is your sturdy base and the anchor to astrophotography. Spindly weak legs, no motorization or lack of being able to precisely align the mount make for the ‘why bother’ category. The tripod’s legs should be steel, rather than aluminum or wood. The mount should not be overloaded with the optical tube optical tube and camera mounted on it. The mount should also be motorized unless you plan to take shots of just the Moon. You should also have checked the motors to make certain to track the stars properly.You also must properly polar-align the mount. With standard viewing you can usually get away with a quick-n-dirty polar-alignment, but for photography you will need to precisely align the telescope. This probably means your telescope will need a polar scope built in the mount’s frame.
The mount is in many ways more important than the telescope’s optical tube or even the camera. It determines how long you can remain on the target, how steady the motion of the telescope & camera are, and a host of other issues. In normal photography it often starts with the camera. With Astrophotography it starts with the mount.
For serious, long exposure astrophotography you just cannot avoid either using a commercial DSLR camera or a specialty astrophotography camera designed to fit in telescope’s eyepiece holder. Small pocket digital cameras can be used with certain styles of astrophotography (which we will cover in part 3), but not for the serious, long-exposure shots or or multi-image stacking. Volumes and volumes of material can be written about what camera to choose, but if you already have a DSLR it is best to try things with that first before investing in a specialty astrophotography camera.
Whatever you do, unless you are so retro as to use film you are going to be using some kind of software to edit your images. From a simple Photoshop to advanced ‘stacking software, this is another area where huge amounts of info and debate go into which software is best. But keep in mind that software now plays a much bigger role in astrophography than in the past.
You’ll Probably Need:
A guide scope is a second telescope on top of the main telescope that is used to keep the main telescope on target. The guidescope is pointed at a star, preferably using an eyepiece with a crosshair. This guidescope is aimed at a star and kept on target by adjusting the motor speed during long exposure shots. A guidescope can cost a fair amount, as can the hardware for mounting it on top of your main telescope. But it is crucial in certain astrophography applications.
Filters on you camera or eyepiece can cut down light pollution, or cut out colors that overwhelm the overall image of the stellar objects. Certain filters can create much higher contrast on stellar objects like nebulas and galaxies. They also can cut down on light outside of the visible spectrum that can cause issues with CCD camera chips. They also aid in monochrome* ‘stacking’ of images. Very often astrophotographers may employ filter wheels to take mutilple monochrome shots without having to unthread and replace the filters.
* “Monochrome” in modern lingo usually gives the impression of just ‘black-and-white’ but in cameras and astrophotography it takes its more literal meaning of ‘1 color’. Images are taken in ‘monochrome’ of just blue, just red, or just green and are later ‘stacked’ on computer software.
So now the question is: What kind of astrophotography set-up will you use? We discuss that in part 3 of this series.