Notes:

• 'Stacking' can be thought of as laying many exposures of a single object on top of each other and compressing them down into one image by taking the average value (brightness and colour) of each pixel. While individual exposures are noisy and contain little detail of faint deep sky objects, a stacked image can reveal an astounding level of colour and structure. This is because during the averaging process, noise is cancelled out since it is essentially random across exposures, while details persist since they are common in every exposure, even if very faint. I use the free software Deep Sky Stacker (DSS) to do this.


• 'Editing' one of these images does not involve adding or removing elements - instead it refers to improving the visibility, colour, contrast, etc. of existing details. For example, for an image of a nebula, making the background darker, the faint nebulosity brighter, and improving saturation.


• Lights are exposures of the object itself; darks are exposures taken with the same settings but with the lens covered, used to reduce image noise; flats are taken with the lens covered with a uniformly lit field to capture and correct for the vignetting caused by the optical train; biases are taken with the shortest possible exposure to capture and correct for 'hot pixels' and pattern (not-so-random) noise.


• The base NexStar 6SE mount is an altitude-azimuth mount, which has mediocre tracking and suffers from field rotation. Thus images captured using the CEM25P, an equatorial mount, benefit from longer exposures and are generally better (this is how I convince myself it was worth the upgrade).


• You can click the image below to cycle through: a single exposure; a stacked image; and a final edited image.

This is a compilation of most of the astrophotography I've done over the years. You can click on each image to open a high-resolution version.