Thursday, 29 January 2009

The "69" nebulae...

Click on image to enlarge

Object: IC 410 and IC 405 (The "Flaming Star" Nebula, Caldwell 31)
Type: Emission Nebulae
Distance: 1,600 light years
Constellation: Auriga
Date: 23 January 2009
Equipment: SXV-H9, Zeiss 135mm telephoto lens @ f3.5 (40 mm aperture), ATIK filter wheel with Ha, G&B filters
Subframes: 40 x 200s 2x2 binned subframes in H alpha, 12 x 200s 2x2 binned in G, 5 in B, 16 darks, 16 flats/flat darks in Ha, calibrated and stacked in AIP4Win. Final processing in AstroArt, Paint Shop Pro7 and NeatImage.

Despite an ever-increasing haze that cut short my imaging session for this one (hence only 5 blue subs in the end), I was reasonably pleased with the end result. I had planned to take loads more subs if the sky held but given recent history, I was glad I had decided to take a few subs through each filter in turn rather than long sessions through each one.

The channels were stacked in AIP4Win and assigned and aligned in PSP7. The final image was a touch noisy because of the small number of subs, but a quick pass with the freebie version of NeatImage did quite a reasonable job in cleaning it up.

As for the name I gave it, I was just surprised at how sharp the "small 6" of IC410 and "big 9" of IC 405 stood out on the H-alpha frame. The effect isn't quite so striking on the final colour version.

Maybe the final result maybe isn't as good as this one from Greg Parker's New Forest Observatory, but given my somewhat "lower budget" set-up (below), I think I've got value for money on this occasion - especially given the weather...

The shot above (click on the image for a clearer view) shows my current system for wide-field imaging. The equipment is all mounted on a Vixen plate, with the SXV-H9 clamped in a simple bracket made out of a bit of copper tube that I flattened down and drilled. This allows me to rotate the camera for image framing. The filter wheel and lens (with mandatory dew heater) sit on the camera: I've found the filter wheel leaks a bit of light so that's what the silver foil is for. An old Celestron 7 x30 finder is used for rough alignment, with the Vixen guidescope and reticule eyepiece that's above it being used for precise alignments.

It's a simple and robust set-up that stands up quite well to being bounced around on my gadget box when I roll it out of the garage.



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