You want to get started in astrophotography - what telescope should you get? The answer is simple. Don't get a telescope!
For astrophotography the best beginner telescope is a camera lens. Almost any DSLR or mirrorless interchangeable lens camera can take great astrophotographs of many kinds of targets. With the light weight of a camera, stable tripods and mounts are more portable and less expensive.
Here's an example of an image made with a camera, tracking mount, tripod, and telephoto lens that cost less than $700 (2nd hand).
You need to learn skills and techniques that you don't need for regular photography. These same skills are needed with a telescope. They are easier to learn with a simpler, lighter, and less expensive camera based setup. Mistakes in equipment choice are easy to make when you are getting started. These mistakes are more expensive with a telescope based setup.
Some of skills that you will need to learn include:
Good single image astrophotography "snapshots" are rare. Combining multiple images and post processing tools are very important for astrophotographers. Most astro-photos that you see have had significant processing done after the image was taken. This isn't taking shortcuts, but necessary to overcome camera limitations. Some tasks require specialized image processing software tools and the skills to use them well. It is not unusual to spend hours gathering data for an image and then hours processing the image.
These examples demonstrate the importance of the tripod, mount, and processing. They were taken with an RX100 point and shoot camera using only its built-in telephoto lens. The first is single image astrophoto of Orion with just a bit of exposure adjustment:
Adding a star tracking motorized mount and stacking multiple images, produced the image below.
There are much better cameras for astrophotography, but you can start simply with almost any camera you own and take on new challenges one at a time. A camera, a steady tripod, and understanding the "rule of 500" to set your exposure time are all that you need to get started.
For images from a fixed tripod the Rule of 500 gives an approximate maximum exposure time before star trails are visible in your image.
Max-exposure-time = 500 / (lens-focal-length * crop-factor)
Divide 500 by the full frame equivalent focal length of your camera lens to get your maximum exposure time in seconds. For a crop sensor APS camera you must multiply the lens focal length by about 1.5 to get the full frame equivalent focal length. For a micro 4/3 sensor use 2 X, for a 1" sensor 2.7 X.
Wind and vibrations can easily spoil long exposure or long focal length images. Use the tap test to figure out if your tripod and mount are steady enough for astrophotography with your camera and lens.
You will usually want to shoot with your aperture set wide open to shorten exposure time, although reducing it a stop or two may increase sharpness.
Typical ISO speed settings will range from 400 to 1600. Higher settings are useful for focusing and framing. Setting ISO too high will reduce the dynamic range of your image and may cause bright stars to loose their colors. ISO is just a gain setting and doesn't change the sensitivity of your camera sensor. You can often get better results by exposure stretching in post processing, than by increasing ISO.
Careful attention to focusing is important. Manual focusing with electronic aids like magnified image focus peaking is easier and more accurate than using an optical SLR focuser. Focus scales on lenses may not be accurate, so check your focus. Lenses with completely manual focusing are easiest to use for astrophotography.
Starting with equipment that you already have, quickly teaches you its limitations and clarifies the value of additional features. I've found the features and equipment below to be valuable. Listed in rough order of importance:
Many astrophotographers find that they never need a telescope for imaging. You will want a telescope to image certain types of targets: close up images of the planets or small far away galaxies. The kind of telescope will depend on what you want to image. Starting with a camera first, you will learn the skills needed for the next step and have a better idea of the telescope you need. Be prepared to spend an order of magnitude more in complexity and expense for astrophotography with a telescope.
An excellent resource with lots of tutorials for beginning astrophotographers is Lonely Speck. I've put together a couple of walk-throughs of equipment and techniques that I use for astrophotography without a telescope:
Content created: 2016-05-18 and last modified: 2019-04-29
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