The Eta Carinae Nebula (NGC 3372) in Carina - Mark III
Full view, please.Save your retinas: click here for a version on a black background, therefore preserving shadow detail.
Here it is, proper first light for the SBIG STL-11000M and the Takahashi FSQ-106N. My very first ever hydrogen alpha + LRGB image. This is the first time I've ever combined monochrome images to form a composite. Wow, what a rush it was to finally see colour on screen.
It's only taken me, what, nearly a year to take my first proper image since purchasing this immaculate gear? I think the wait was worth it.
This image was captured over six nights, totalling 10.5 hours of data. That's right, I don't do anything half-arsed.
To say that I'm pleased would be an understatement.
I ditched IRIS and switched to MaxIm DL 5 to calibrate, register, align and stretch. I really miss IRIS' stellar registration routine, as it's second to none, but, IRIS is really designed more for DSLR work.
Hα+LRGB; 160 187.5 93.75 93.75 93.75
Hα and L bin 1x1, RGB bin 2x2
Hα was blended as a luminosity layer at an opacity of 64% to help suppress the overwhelming star field and to provide further contrast/definition in the nebula. Slightly cropped to remove registration artifacts between frames and to maintain a 3:2 aspect ratio.
The Eta Carinae Nebula is the largest and most beautiful diffuse nebula in the sky, surpassing even The Great Orion Nebula (M42) in size and grandeur. Only its position far south of the celestial equator (and, hence, its invisibility in much of the northern hemisphere) prevents this nebula from being a household name.
The nebula is a massive star-forming region of hot gas, heated by ultraviolet rays from the hot young stars. It covers a full two degrees of sky (four times the width of the full moon). Eta Carinae is obvious to the naked eye as a bright, elongated glow, but that only hints at its telescopic splendour. In binoculars it is a large and bright nebulosity split in half by a V-shaped dark lane, which is called the Keyhole Nebula. The field of view in binoculars is just stunning with Eta Carinae embedded in a star-studded region of the Milky Way. A telescope will reveal wisps of nebulosity, dark lanes, and subtle detail that will keep most observers busy for years.
The two open clusters that flank the Eta Carinae Nebula are NGC 3532 and NGC 3114. The star at the centre of the nebula is a unique story in its own right. Eta Carinae is one of the biggest stars, 100 times the mass of our own sun. It emits 4 million times as much light as our sun. Eta Carinae is a highly unstable star which fluctuates greatly in brightness. It will most likely explode as a supernova, perhaps in our lifetime.
Nowadays, the star is at the edge of naked eye visibility, but an outburst in the mid-18th century temporarily made Eta Carinae the second brightest star in the night sky, following only Sirius. This outburst ejected gas which now surrounds the central star and is known as the Homunculus Nebula.
The bubble-shaped nebula to the top left of NGC 3372 itself, is NGC 3324, also known as the Gabriela Mistral Nebula.
The beautiful open cluster of stars to the top left of frame is NGC 3293, also referred to as the Gem Cluster.
NGC 3293 is a 4.7th magnitude open cluster. This small clump of stars numbering roughly 50 constituents is easily seen in binoculars. The brightest star in the group is a 6.5th magnitude red giant which is surrounded by a bunch of hot blue stars. You can see a thin veil of nebulosity surrounding the stars in this image.
NGC 3293 is considered a young cluster, about 20 million years old. This cluster is about 1.5 degrees away from the star Eta Carina.
Target: The Eta Carinae Nebula (NGC 3372) in Carina
Date(s): 8th, 9th, 16th, 29th, 30th and 31st January, 2011
Location: Manar, NSW, Australia
Detector: SBIG STL-11000M at -20 degrees Celsius
Telescope: Takahashi FSQ-106N
Focal length: 530mm
Mount: Losmandy G-11 (Gemini)
Guiding: Self guiding through SBIG STL-11000M
Exposure: Hα+LRGB (160 187.5 93.75 93.75 93.75); total: 10.5 hours
Exposure: Hα and L bin 1x1, RGB bin 2x2
Software: MaxIm DL 5: Image capture, and autoguiding, calibration, registration, stacking, stretching; PinPoint LE: Plate solving; Adobe Photoshop CS4: post-processing and framing