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Dalriada n:
Kingdom of the Scots,
home of the residents

Orion nebula from Stuart’s bedroom window

Back to the Orion Nebula (aka M42) again. It’s 1340 light years away and last time we took the big Newtonian telescope all the way to Whitelees Windfarm (9 statute miles away) to see it. This time I used the new Maksutov telescope, and I didn’t leave the house.

The Mak has a longer focal length than the Newtonian, so it magnifies more, but it’s aperture is only 150mm, compared with 200mm, so it’s not much of a ‘light bucket’ and for astrophotography we need longer exposures. Nevertheless when the sky cleared a bit at 05:00 I had a go by walking all the way to Stuart’s bedroom (3 metres). With no sight of the pole star I had to align the mount by dead reckoning and I had to put up with Glasgow’s light pollution. But I was fairly satisfied, and quite surprised, by the result – with a 30s exposure at ISO 3200, and a 150mm x 1800mm Maksutov-Cassegrain telescope:


Not dissimilar to the one Stuart and I took with the SkyWatcher Explorer 200P from Whitelees Wind farm last December – but we achieved that with a 5s exposure at ISO 400, and a 200mm x 1000mm Newtonian telescope:
In Stuart’s bedroom it was very easy to use my laptop to control the camera and it even ran a program called Bahtinov Grabber to help minimise the diffraction spike offset for accurate focussing. The wee images below show the Mak with its various ‘alternative’ front-ends for astrophotography – the Bahtinov mask for focussing; lens-cap on for ‘dark frames’ to help reduce long exposure noise (hot spots) at high ISOs by subtracting ‘dark frames’ from the ‘light frames’ ; t-shirt on for ‘flat frames’ to help reduce the effects of dust or smudges on the camera sensor, and vignetting.