Astro Anarchy

Thursday, February 17, 2011

New project, Sharpless object 132, Sh2-132

Sh2-132, an emission nebula in Cepheus

Ra 22^h 19^m 20^s Dec +56° 06′ 00"

Bi-color composition from the emission of ionized elements, R=100% Hydrogen, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum.

This is a start of the new project. I will shoot more O-III and a S-II channel later.

Sharpless 132 is a very faint emission nebula, it locates at the border of Cepheus and Lacerta. Distance is about 10.000 light years. This image covers about 210' x 160', that's about 3,5 x 2,7 degrees. Resolution is 3,79 arc seconds/pixel.

With this image, I had my QHY9 and the Tokina AT-X 300mm f2.8 lens perfectly perpendicular to each others. Due that, the image is very sharp, there is no sharpening or star reduction methods used.

At f2.8, everything hast to be perfect, collimation, focus and orthogonality. The critical focus zone is only about 14 microns at this optical speed. If it's missed at all, the sharpness of the image collapse. At perfect focus, light ends up in a pixel, if focus is missed, even lightly, light will fall to all nine pixels, not just one!

The temperature compensating focuser, TCF-s, works as a heart of my DIY lens focusing system. It keeps focus perfect at all night when ambient temp. drops, typically 15 or more degrees up here. (Half a degree drop is enough to destroy the focus.) You can see my focusing device here:

http://astroanarchy.blogspot.com/2008/09/new-equipmets-and-some-development-work.html

A closeup

No sharpening or star reduction methods used

An experimental starless version as an animation

The purpose, of this animated image, is to show the actual nebula complex under the dense star field .

Processing work flow:

Image acquisition, MaxiDL v5.07.

Stacked and calibrated in CCDStack.

Levels, curves and color combine in PS CS3.

Equipments:

Tokina AT-X 300mm f2.8 @ f2.8

Platform and guiding, Meade LX200 GPS 12" @ f5

Camera, QHY9

Guider, Lodestar

Image Scale, 3,79 arc seconds/pixel

Exposures:

Baader H-alpha 7nm 12x1200s, binned 1x1

Baader O-III 8,5nm 36x200s, binned 1x1

Wednesday, February 16, 2011

IC 1848, the "Soul Nebula", finalized

IC 1848, the "Soul Nebula"

Ra 02^h 51^m 36.24^s Dec +60° 26′ 53.9"

Image is in HST-palette, (HST=Hubble Space Telescope)

from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.

Star colors are mixed from the NB channels, Red=H-a, G=O-III and B= 85%O-III + 15%H-a.

This is a final version of IC 1848. I shot more H-alpha, 15 x 20min., since the first set was ruined by the orthogonality problem between the optical path and CCD. Now all stars are pinpoints at a whole field of view.

Soul Nebula, (Sh2-199, LBN 667) is an emission nebula in constellation Cassiopeia. IC 1848 is a cluster inside Soul Nebula. Distance is about 7.500 light years. This complex is a Eastern neighbor of IC 1805, the "Heart Nebula" and they are often mentioned together as Heart and Soul.

Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum.

A closeup