The Triangulum Galaxy and The Soul Nebula
A week or two ago, Society member Keith Elliot took us through a selection of his recent astrophotos. He has now processed two more images, so here they are along with the details behind them (again, you can click on each image for a larger version):
M33 (NGC 598) – Triangulum Galaxy (sometimes nicknamed “The Pinwheel”)
This picture is a composite of twelve 15 minute exposures taken at the Kelling Heath Autumn Equinox Star Camp this year.
M33 is a large (64 x 35 arc minutes) face-on spiral galaxy in the constellation of Triangulum and is part of the Local Group of more than thirty gravitationally bound galaxies of which we are a member. It is the third largest of the group, after Andromeda and our own Milky Way, and is about 2.8 million light years distant and 52,000 light years across.
The small pink star-like object at the edge of the left spiral, about halfway up the image, is the massive stellar nursery NGC 604. At 1300 light years across, it is 100 times larger than our own Orion Nebula. This object has been beautifully photographed by the Hubble Space Telescope:
Sh-2 199 – The Soul Nebula
This is a composite image of eleven 15 minute exposures taken from Chelmsford on the 21st and 22nd of this month.
It is an emission nebula, located in our galaxy, surrounding the cluster IC 1848 and is about 60 arc minutes across and 7,500 light years distant.
The subframes were taken through a Lumicon DS filter, which is perfect for this type of image. It blocks light in the mid part of our visible range, populated by most light pollution sources, but passes the blue/green and red at each end of this spectrum. So colour images in light polluted back gardens become possible.
Hardware and Software
- Modified Canon 350 DSLR. The internal infrared filter has been replaced with a sharper cut-off filter to extend the red end of its spectral response, particularly to give improved sensitivity to the hydrogen alpha line.
- Starlight express SXV guide camera in a separate, piggy backed, guiding telescope (70mm f/10).
- Televue x0.8 focal reducer/field flattener to give a plate scale of 2.2 arc seconds per pixel (1.8 without the reducer).
- William Optics ZS 105, f/7 apochromatic refractor.
Posted on 27 October, 2008, in astrophotography, Popular Science, Society News and tagged galaxy, nebula, soul, triangulum. Bookmark the permalink. Comments Off on The Triangulum Galaxy and The Soul Nebula.