Next steps: tracking and stacking
Use a DSLR with a star tracker to follow the motion of your targets, and then stack and process the results
To get the best from a DSLR, a tracking mount is needed. Most of these come equipped with ‘lunar’, ‘solar’ and ‘sidereal’ (star) tracking capabilities, meaning that you can image planets, the Moon, or deep-sky objects and increase your DSLR’s exposure times. It also ensures the object is kept at the same place in your field of view for the entire imaging session.
A portable star-tracker or lightweight equatorial mount is a great first step. Because these mounts can track an object for hours, it means you can also stack multiple images. Stacking allows you to increase the signal to noise ratio, reducing the overall image noise. This means you can process the image data more.
A comparison between a single frame image (below, left) and stacked image (below, right) of the Horsehead Nebula demonstrates the difference that stacking can make. While the left-hand image is a single exposure, the right-hand version consists of multiple frames from the same night and same camera. The images were stacked in DeepSkyStacker (DSS) and processed in Adobe Photoshop.
Stacking images reduces much of the DSLR noise (unwanted artefacts); however, calibration frames are also important. Darks, flats and biases are each a type of calibration frame. Dark and bias frames remove electronic and sensor noise, while flat frames help remove vignetting. Dark frames can be taken before or after your imaging session: simply cover your lens or telescope and take 20–30 frames at the same ISO and exposure as the light files.