Astrophotography is not a straight forward process – it requires technical skill, very precise equipment and clear crisp skies.
In order to take the photos, several factors have to be taken into account. Firstly, the different galaxies and nebuale are very far away, thus the light from these is exstremly faint. This in turn requires very long exposures on the cameras part, in order to get any worthy data.
It’s not unusual that a nebula needs more than 10 hours + of exposure. Because of this, you run into several problems. There are only so many hours a night where it is dark enough to take the exposures, and the perfect sky conditions rarely hold up for more than a few hours at a time – on the lucky occasions, some winter nights can yeild up to 8 hours of perfect crisp night sky.
Since the different nebulae and galaxies require so much exposure, the process has to be broken down in steps; taking several medium long exposures and then combining them in a final image. This is called stacking, combining e.g. 150 seperate exposures into a single image where the faintest of details can be digitally enhanced.
Firstly getting the camera to take these exposures requires a powerfull telescope and a sturdy mount as even the slightest vibration will ruin the image. For long 5 or 10 minute exposures, a small guiding telescope is needed to counterbalance any drift, vibrations or small wind gusts, so that the main telescope effectively “locks” the sky for the camera.
Because of these requirements, some images can take many weeks, even months to complete – add into the mix that the equipment regularly needs adjustment, and you’ve got one very complicated setup.