Winter is usually a great time for astronomy with longer nights and the sun setting at a reasonable hour. The forecast for last Friday was clear until 12am, enough time for a few hours of imaging. I hadn’t realised it was a waxing gibbous moon until after lugging all the gear outside and setting up.

A nearly full moon, combined with a slightly hazy sky limited the choice of objects severely. The moon was out of the question, as I’ve yet to buy a moon filter, even on the lowest exposure setting of 0.001 seconds the ccd chip was becoming too saturated. So I turned instead to the Orion Nebula, M42.

At magnitude 4.0 the nebula is visible as a fuzzy gray blob to the naked eye, just below the belt of Orion. I took a total of 90 exposures (81 usable) at 15 seconds each in an attempt to not burn out the central core.

Setting Value
Exposure Time 15x81s Avg
Date 2007-11-23 23:47:55 UTC
CCD Starlight XPress MX716
Scope LX90 8”
Dark Frames 15x15s Median
Apparent Dimension 85x60 arc min
Visual Brightness 4.0 mag

Since it looked neat, I’ve uploaded a pseudo colour version, this isn’t in anyway the true colour of the Orion Nebula, I don’t own any colour filters yet.

I believe this is my best image to date. Although it’s still not quite in focus and the exposure was perhaps too long resulting in a burnt out core. Not to mention the moon/haze made post processing a nightmare with a bright central light gradient to remove.

Collimation of the scope is still slightly out. I spent an hour before taking this image to improve it a little, but it’s going to take stabler skies before I can collimate at a reasonable magnification. I think the sky stability and lack of good collimation is partly to blame for the difficulty in achieving a good focus.

I’m looking forward to re-imaging this object on a moonless night to see how big an improvement I can achieve.