Spiral Galaxy M33 (NGC 598), type Sc, in Triangulum

RA 01:33.9 DEC +30:39 ; Distance 3.000.000 light years.
Visual Brightness 5.7 (mag); Apparent Dimension 73x45 (arc min)

The Triangulum galaxy M33 is another prominent member of the Local Group of galaxies. This galaxy is small compared to its big apparent neighbor, the Andromeda galaxy M31, and to our Milky Way galaxy, but by this more of average size for spiral galaxies in the universe.

For the observer, this galaxy can be glanced with the naked eye under exceptionally good conditions; for most people, it is the most distant object visible to the naked eye (there are rare reports that some eagle-eyed stargazers managed to see M81 under exceptional conditions, but this is exceptional with all respects). It is outstanding in good binoculars, but as its considerable total brightness is distributed quite evenly over an area of nearly four times that covered by the full Moon, its surface brightness is extremely low.

Source and more: SEDS


M33 - Triangulum Galaxy.
October 19, 2008 20:57 - 22:40 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 17x300s [1x1]; RGB: 5x60s [2x2]; unguided.

December 28, 2007 17:48 - 19:21 UT.
Imaging: William Optics Zenithstar 80 ED II APO with Meade 3.3 Focal Reducer at f/3 [focal length 240 mm], ATK16IC camera, Astronomik LRGB filters.
Exposures: L: 13x300s; RGB: 5x60s; unguided.

October 14, 2007 00:02 - 00:48 UT.
Imaging: William Optics Zenithstar 80 ED II APO, f/6.8 with 0.6 Mogg focal reducer [focal length approx. 245 mm], Astronomik LRGB filters; ATK16IC b/w camera, K3CCDTools. Exposures: Luminosity 11x90s + 4x180s; RGB 5x60s; unguided.

August 26, 2006 00:27 - 00:41 UT.
The heart of M33.
Imaged with LX200 10-inch f/10 telescope with 0.33 Focal Reducer operating at f/4.06 [focal length 1015mm] and Baader Infra Red Blocking Filter.
Camera: Vesta Pro SC3a b/w RAW webcam, 11 autoguided exposures of 60 seconds.
Here is an animation which shows that the core of M33 is not yet very well charted in Megastar, even with the USNOSA 2.0 catalogue attached.

October 10, 2005 22:03 - 22:28 UT.
Imaged with 200mm SLR Photolens and Baader Infra Red blocking filter.

October 6, 2004 21:21 - 21:37 UT.
Imaging and postprocessing as per my DSO imaging tutorial, enhanced with iPrep and NeatImage.

October 28, 2003 20:45 - 21:26 UT .
Imaged with 135mm SLR Photolens and Baader Infra Red blocking filter.
Camera: Vesta Pro SC3a colour; 52 x 45 seconds exposures, unguided.
YRGB post processing.
Note: I combined this colour image with the luminance layer of my image of October 17, 2003.

October 17, 2003 21:44 - 22:07 UT.
Imaged with 135mm SLR Photolens, Baader Infra Red blocking filter and Contrast Booster.
Camera: Vesta Pro SC3a bw; 27 x 40 seconds exposures, unguided.
YRGB post processing.