January 18, 2016

"Big Headless Running Giant" Nebula (Jan. 2016)

Larger resolution image here.

This is the name for the nebula given by my 7-year-old son.  Of course, the blue signifies reflection of starlight and the red emission of light by ionized hydrogen.  These are natural colors.

This is first light for an Orion 203mm f/4.9 Newtonian I just bought.  It's not an expensive scope, and it obviously has some diffraction problems.  I trace most of the problems to the mirror clips and the bevel around the mirror, which needs to be blackened or covered.  A mirror retaining ring would do the trick nicely.  I did attach a FT focuser, electronically controlled.  But the scope held collimation and imaged around the sky for five hours with up to 7-minute exposure without a hitch.  Seems to be enough to work with here.

This image is 39x180" with the SXVF-H9C.  I used the Baader MPCC flattener, which magnifies 1.15x, so this focal length is effectively 1150mm.  The image was shrunk to 67% to hide some noise and the funny star shapes caused by the diffraction and perhaps by a mirror that had not settled into the temperature early in the imaging run.

January 13, 2016

Sole Nebula (Collinder 34 and IC 1848) (Fall 2015)

 Higher resolution image here.

This large patch of emission nebulae is the effect of two bright star clusters, from left to right comprising Collinder 34 and IC 1848.

Collinder 34 is on the left.  The nebula around it is lit up in large part by the cluster's type-O star HD 18326.  Source.  The source notes that Collinder 34 and 32 are parts of Collinder 33three clusters appearing around and on top of each other, so if the cluster is hard to pick out, no surprise.  On the left, trace the direction of the source of radiation back to the type-O star.  However, there are several O- and B-type stars throughout this area, and they all surely contribute to the glow.

IC 1848 appears to be the name for both the cluster on the right as well as the whole nebular complex.  The cluster on the right contains the two type-O stars HD 17520 and HD 17505, which play a leading role.

This image is an HaRGB, combining 18x1800" of Ha with 16:16:16 x 900" RGB through Deep Sky West's FSQ.

I frankly am baffled why this complex is sometimes called the "soul nebula," though I have some ideas.  Nearby is IC 1805, which is shaped like a heart.  "Heart and soul" seem to go together better than "heart and sole."  But no nebula looks like a soul.  This complex does look like a sole, however; doesn't it remind you vaguely of a footprint?  The complex is sometimes called the fetus nebula because of its shape.  A fetus is a soul, but so is a full-grown human being, so that cannot be it.  I conclude that wishful emotionalism and poor spelling created the misnomer.

Here is a close-up of the most intricate part of the nebula, at full resolution for the FSQ setup.

And here is a large-size Ha frame.