New Forest Observatory ®

I said I wouldn’t divulge the secret if the result was good. As the result wasn’t particularly good, I’ll tell you how it was done. The ultra-fast Hyperstar 4 at f#2 will blow the core of M42 (the Trapezium region) with anything over 1-second exposures. I suppose you could use even shorter exposures, but then you would be adding more camera noise to the image as well as having the poor SNR of a short exposure. So my idea was to take longer exposures, to get away from the camera noise, by reducing the luminosity of the core region. But how can you do that? I was given the idea over 17 years ago when I was visually observing the core region with the C11 at its native f#10. I couldn’t see the Trapezium stars of course, as the region was just too bright – but then a cloud drifted across M42, and just for a moment I saw the Trapezium stars, very clearly. So there was the clue. To mimic the cloud I bought a Neutral Density Filter (10 stops) and it certainly did a great job in cutting down the luminosity, but the resulting image at f#2 is a bit disappointing as the region takes up too little space in the whole field of view. So although the idea works, in principle, it’s not the best way to image this one.

Clear Moonless sub-zero night last night so I was expecting some great results from the Hyperstar 4.

Managed to get 25 x 5-minute subs with good collimation, and the above image is the result. It’s terrible. Virtually no dust which came out well using the Sky90 array.

Must admit, the sky did look rather light, and I guess it was full of ice crystals. First time I’ve had that as an issue.

This is the result of 60 x 30-second subs on the Hyperstar 4 with the C11 and a secret ingredient optical device. Still plenty of noise even with 60 subs, so it looks like I’ll be needing nearer 200 subs to get the noise down. However as these 60 subs took up 3Gb, and then de-Bayering and processing added another 9Gb, it looks like this data will be needing its own hard drive just for this one image!