Messier 78 in Orion

[TrevorW]

Target: M78 in Orion
Camera: QHY 8 OSC CCD
Exposure Capture: Maxim
Scope: GSO CF RC200
EFR: f/8 or could be 9
Mount: EQ6 Pro
Exposure Setting: Prime focus
Exposures: 10 x 6m and 5 x 10 min 1hr 50min between 9:0029/12/2010 and 1:00pm30/12/2010
Seeing: no moon, no wind, average seeing
Guiding: Orion Starshoot Autoguider using PHD with ED80 (had some guiding issues a number of frames had to be dumped)
Focus: Bahitov mask
Stacking: DSS with darks no flats
Processing: PS CS3

Starforming Nebula M78 (NGC 2068), a reflection nebula, with Open Star Cluster, in Orion

Right Ascension 05 : 46.7 (h:m)
Declination +00 : 03 (deg:m)
Distance 1.6 (kly)
Visual Brightness 8.3 (mag)
Apparent Dimension 8x6 (arc min)

Discovered 1780 by Pierre Méchain.

Messier 78 (M78, NGC 2068) is the brightest diffuse reflection nebula in the sky, situated in the rich constellation Orion.

This object was discovered by Pierre Méchain in early 1780. Charles Messier added it to his catalog on December 17, 1780.
M78 belongs to the Orion complex, a large cloud of gas and dust centered on the Orion Nebula M42/M43, and is about 1,600 light years distant. It is the brightest portion of a vast dust cloud which includes NGC 2071 (northeast, lower right in our image), NGC 2067 (close northwest), and very faint NGC 2064 (southwest), all visible in our image. Together with some other nebulae, including NGC 2024 (Orion B) near Zeta Orionis (sometimes called the Flame Nebula), all these nebulae are associated with the molecular cloud LDN 1630 (from Lynds' Catalogue of Dark Nebula), a part of the Orion complex.

As a reflection nebula, M78 is a cloud of interstellar dust which shines in the reflected and scattered light of bright blue (early B-type) stars, among them the brightest, HD 38563A, and second-brightest HDE 38563B, both of about 10th visual apparent magnitude. The nature of M78 as a reflection nebula was discovered by Vesto M. Slipher of Lowell Observatory in 1919 (Slipher 1919), by the investigation of its spectrum: M78 exhibits a continuous spectrum, which resembles that of the bright stars enlightening it. At its distance, M78 measures almost 4 light years in extension.

[Hagar (Doug)]

Looking good Trevor and I love the description.

[Moon (James)]

Nice looking image. I'm having a go at this one myself right now.

EFR: f/8 or could be 9

You can work this out with a plate solve if you like. The image you posted is 45.66 x 30.29 arcminutes.
Using FOV (degrees) = 57.3 * Sensor Size (mm) / focal length (mm)
45.66/60 = 57.3 * (7.8/1000)*3110/fl
so fl= 1826mm (I think )
If the aperture is 200mm then it seems to be an f/9

Of course this would be more accurate on a single uncropped sub.

Strange how QHY and Theo don't publish the sensor x/y size - just the diagonal size.

James

[h0ughy (David)]

doesnt the dust hide the reflections - nice

[TrevorW]

Thanks for the feedback, I didn't really want to overstretch the image as I wasn't that happy with data collected. I had a number of tracking issues and focus may have slipped during the imaging run. Will have to do this one again as is seldom imaged due to it's proximity to M42 and HH and deserves more than my meager attempt

[multiweb (Marc)]

Nice start Trevor. That's one for dark skies. Too faint for the burbs. (outer neb that is)

[strongmanmike (Michael)]

Echoing Fred Hollows in the advert, "an image is an image, no matter whether it is a Gendler masterpiece or a backyard quick grab"

I like your detailed descriptions, we can tend to just image with little thought to the details behind what it is we are actually staring at in the dark

Mike

[TrevorW]

Thanks Marc and Mike

to true Mike the details supply the knowledge we need to truely appreciate what we are imaging IMO

[TrevorW]

Difficult one too get right and as Marc said needs dark skies (and plenty of data) to do well, as per Marcus's excellent M78