M33 (Nov. 16 & 17, 2012)

Link to full resolution image.

M33 is about 2.88 million light years away (give or take a hundred thousand or so).  That's practically in our backyard.  M33 is, with M31, our next-door neighbor in the universe.  M33's nearness is why it appears so large in this scene.  As galaxies go, M33 is not that big, or that bright.  Compare it with M31, which I shot a couple of months ago with the exact same equipment, and you can see how much larger and brighter M31 is by comparison.

Anyway, M33 is beautiful.  I've always wanted this kind of image of it.  I'm sure this won't be the last time I shoot it.  This image has been shrunk to 80% of original size to hide latent noise; this image could use another six hours or so (and from a darker site).

Telescope: SV80ED (and William Optics 0.8x II fr/ff (eff. at f/5.6))
Camera and Exposure: SXVF-H9C (49x480"), Alnitak Flat-man flats
Filter: Hutech IDAS-LPS2
Guiding: Meade DSI Pro and Hutech 50mm
Mount: Takahashi NJP
Software: Nebulosity, Maxim DL, Photoshop CS3
Location: The Woodlands, TX

IC417 (12-1-2010)

IC 417 is a wonderfully complex hydrogen nebula in the constellation Auriga. So many different things to see here!

This image is just 9x8' with the Atik 16 through the Orion 120mm achromat with WO 0.8x II ff/fr (thus at f/4). Processing was done in Nebulosity, Maxim, and PS CS3.

M97 (11-30 and 12-1-2010)

This planetary nebula in Ursa Major is, like all planetary nebulae, an expanding cloud of gas and dust sloughed off a dying star. The star, which you can see in the center of the nebula, is a white dwarf, the super-hot core of what is left of the dying star. The filters used to take this shot cover three wavelengths common to planetary nebulae: Ha, NII, and OIII. In fact, the Ha filter's bandwidth is 12nm wide, and it takes in the NII line. The consequence is that I can't tell whether the red glow in this image comes from hydrogen or nitrogen. The OIII line is far more prominent, however. Ionized oxygen seems to dominate this planetary. M97's distance (and thus its size) are the subject of wildly varying reports, so I have no idea how far away this thing is.

This image is 24x8' with the Astronomik Ha filter and 23x8' with the Astronomik OIII filter. The camera was the Atik 16, and the image was shot through the Orion 120mm achromat with the WO 0.8x II ff/fr, at f/4. Color was done with Cannistra's bi-color technique.

Here is the Ha [+ NII]:
Here is the OIII:

The Squall Line in the Rosette (12-1-2010)

The Rosette Nebula is about 5,000 light years away in the constellation Monoceros. (In wider images, it really does look like a flower. See RoryG's recent image.) A long chain of nebulosity appears in very deep images to connect it to the Cone Nebula complex. (See Wolfgang Promper's image here.) This part of the Rosette Nebula is where clouds of dust and gas in front of all the lit-up ionized hydrogen clouds are silhouetted in the light. The clouds are slowly disintegrating in the ultraviolet radiation from the bright stars in the lower center of the image, the stars of cluster NGC 2244. Yet still tiny pockets of the dark stuff remain randomly ahead of the front, globs dust and gas perhaps shrinking under gravity and resisting the radiation scattering the rest of the matter around them.

This image is 17x8' with the Atik 16 through the Orion 120mm f/5 achromat, the WO 0.8x II ff/fr (so imaging at f/4), and an Astronomik Ha filter.

The Cone Nebula & NGC 2264 (11-30-2010)

This beautiful area of the sky has no bright stars. Without optical aid, it looks empty from the burbs were I live. But with the light pollution extracted, and with a sensitive camera and a large lens to gather and focus the light, great things can be seen.

On the left of this image is the Cone Nebula, a dark cloud that is slowly disintegrating in the radiation generated by the bright stars to the right of it. The cluster of stars, known as NGC 2264, and the cloud of hydrogen gas shown here, can be found about 2,600 light years away. These objects, like the California Nebula, lie in the same arm of the galaxy that we inhabit.

This image is 18x8' with the Atik 16 through the Orion 120mm f/5 achromat and WO 0.8x II ff/fr (so the image was taken at f/4) and an Astronomk 12nm Ha filter.

This image was published in the April 2011 issue of Ciel Extrême, page 15.  Thanks to the editor, Marc Cesarini.  It's a great privilege.

Central California: NGC 1499 (11-30-2010)

This is the central and most interesting (to me) region of NGC 1499, sometimes called the California Nebula. In moderately deep images, the nebula takes on a shape something like that of the state of California. In deeper images, the shape is more like a scimitar (see, e.g., this image from Don Taylor). This much narrower view only shows the Bay Area, the darker cloud in the middle of the image. The bright nebulosity running from upper left to lower center is the coastline. In this relatively deep image, the nebulosity runs into the ocean and out past the edge of the image. The California Nebula is about 1,500 light years away, and is found in the constellation Perseus. It inhabits the same arm of the galaxy that we do.

This image is 13x8' with the Atik 16 through the Orion 120mm f/5 achromat and WO 0.8x II ff/fr and an Astronomik 12nm Ha filter.

NGC 40, the Bow Tie Nebula

A comparatively shallow view of this nebula looks like a bow tie. See?
But the deeper image shows the central star is actually surrounded by a boxy circle of gas (and dust?). The structure of the nebula is also bipolar, with something happening on the north and south. Just what is unclear. A stretch of gas swings out from the north, and from the south a leg is jutting out. Diffuse gas glows all around what appear to be edges of the circle. Compare my view with Don Goldman's here, taken which much larger equipment.

Here's the riddle: Why does this planetary nebula glow so strongly in an image taken with an Ha filter? A planetary is usually formed when a dying star is dying because it has used up the hydrogen reserves necessary to burn like normal a star. It then swells up like a balloon and starts blowing the outermost layers into space. If the hydrogen left is not prominent in these stars, why does this nebula glow so brightly through an Ha filter, which focuses on the spectral line of ionized hydrogen gas?

There are two answers to this question. The first answer to this question is that my Ha filter lets through not just the important wavelength of ionized hydrogen at 656.3 nm. The filter I have lets through a range of wavelengths 13 nm wide. The 13 nm are roughly centered on the H-alpha line, but the range also includes that of ionized nitrogen at 658.4 nm. So actually everything taken through my Ha filter is Ha + NII.

The second answer is that some planetary nebulae actually contain a great deal of hydrogen. One study that split Ha and NII emissions of planetary nebulae in the Magellanic Clouds (two nearby galaxies) shows that some have more Ha and some have more NII. Some images from the study are here. The upshot is that I do not know which NGC 40 shows more of, Ha or NII. Unless and until I get some even narrower narrowband filters (such as advertised here), I will not be able to discover.

Imaging Scope: Orion 80ED & WO 0.8x II (f/6)
Imager: Atik 16
Exposure: 120" x 31
Filter: Astronomik 13nm Ha + NII
Capture Software: Nebulosity 2
Mount: Takahashi EM-10
Guiding Camera: DSI Pro
Guiding Software: PHD
Guiding Scope: No-name 60mm f/5
Date: Night of 9-26-09
Location: The Woodlands, TX
Processed with Nebulosity 2, Photoshop Elements 7 with Carboni Actions.