The chocolate box of Orion contains a selection of objects from visible to photographic beauties. The area around Alnitak (ζ Orionis) is particularly striking with a good telephoto lens. This particular lens has produced a couple of new nebulae via internal starlight reflections. The spike at top left is Alnilam trying to peek into the edge of the shot. I piggybacked my modified 1000D camera on the club's 9 1/4" scope on a CG5 mount and without guiding, got some 2 minute exposures through an old f/6.3 400mm lens. The RA drive had a wobble with a 10 minute period, causing most of the pics to be slightly trailed, but I managed to stack 12 of them with a combining method that minimised trails. So, here I present 24 minutes of exposure centred on the dark cloud called the Horsehead nebula B33, which protrudes against the hydrogen-red background of IC 434. The blue reflection nebulae NGC 2023 and IC435 can be seen below the horse, shining from within the sooty cloud. The more yellow or pinkish Flame nebula, NGC 2024, appears attached to the other side of Alnitak, and this can be seen, albeit dimly, in telescopes much more easily than IC 434. The grapefruit like colour tells us that it is not exclusively shining in hydrogen red light and there must be some cosmic dust scattering component to its colour, rendering it visible to human night vision.
Showing posts with label Horsehead nebula. Show all posts
Showing posts with label Horsehead nebula. Show all posts
Monday, 26 December 2011
More delights of Orion
The chocolate box of Orion contains a selection of objects from visible to photographic beauties. The area around Alnitak (ζ Orionis) is particularly striking with a good telephoto lens. This particular lens has produced a couple of new nebulae via internal starlight reflections. The spike at top left is Alnilam trying to peek into the edge of the shot. I piggybacked my modified 1000D camera on the club's 9 1/4" scope on a CG5 mount and without guiding, got some 2 minute exposures through an old f/6.3 400mm lens. The RA drive had a wobble with a 10 minute period, causing most of the pics to be slightly trailed, but I managed to stack 12 of them with a combining method that minimised trails. So, here I present 24 minutes of exposure centred on the dark cloud called the Horsehead nebula B33, which protrudes against the hydrogen-red background of IC 434. The blue reflection nebulae NGC 2023 and IC435 can be seen below the horse, shining from within the sooty cloud. The more yellow or pinkish Flame nebula, NGC 2024, appears attached to the other side of Alnitak, and this can be seen, albeit dimly, in telescopes much more easily than IC 434. The grapefruit like colour tells us that it is not exclusively shining in hydrogen red light and there must be some cosmic dust scattering component to its colour, rendering it visible to human night vision.
Monday, 23 November 2009
Messin' with filters
Lumicon’s 1 ¼" UHC filter is a superb addition to my visual astronomy toolkit. I’ve seen the stringy, fluorescent shockwaves of the supernova remnant in Cygnus, the North America nebula, and now I have faintly seen the glow behind the horse head nebula. But for photography it is a bit disappointing. The light is mostly rejected - it seems to be too narrowband for good imaging and the light really should be collimated first for it to block the correct wavelengths. I can’t quite work out why the photographic result should be so different to the visual experience at the eyepiece. Any comments welcome. I did 5 exposures that tested the tracking of the 20” scope (60-90 seconds each). Detrailing, stacking and processing resulted in this faint but fairly decent picture of the Horse head nebula's Hydrogen Beta (H-β, λ = 486.1342 nm) emission.
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