Sunday, 24 September 2017

Early Autumn Skies

In Early Autumn, you can catch a nice glimpse of the Milky Way in dark skies, rising from the SSW, where we look into the centre of the galaxy. Unfortunately it is very low down so we look through a lot of interfering atmosphere and consequently light pollution (produced by either ignorant, paranoid, or uncaring folk that install inappropriate outdoor lights). Despite this impedance, the power of long exposures, stacking and a lens that runs at f/2 (stopped to f/2.2 in an attempt to cut down abberrations) can be used to produce a good image. Cloud, twilight and mist were threatening to spoil my attempt but the moon was out of the way at last! There is so little time for astronomers to get good viewing conditions we have to seize opportunities like this. I have stacked 7 x 1 minute images taken at ISO 800 tracked with an RA motor, with my modified Canon 1000D, with a 100mm prime f/2 lens from a quiet, dark site south of Norwich. The region is North Sagittarius/Scutum and it contains M24 - the sagittarius star cloud, M17 the swan nebula, M16 the eagle nebula, and numerous other nebulae and clusters.

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