Friday, November 23, 2018

The Wizard Nebula in SHO (The Hubble Palette)

Thanksgiving night was a good clear evening, and I wanted to get some Sii subs to add to the Wizard Nebula that I imaged earlier this month. Since NB imaging can be done even in moonlit skies, and with no more clear nights in the near future, I decided to go ahead and capture about 100 minutes of Sii light even though there was a near full moon out.

The result was not too bad. Here is the redo of the Wizard Nebula in SHO, known as the Hubble Palette, since the Hubble telescope frequently images in this way:  Sii ->Red, Ha ->Green and Oiii ->Blue.

The resultant image shows that I really need to add much more data to get a cleaner, less noisy image; probably another 2 hours of each filter.

NGC 7380 - The Wizard Nebula
November 10,11 and 22, 2018
GT102 (f/5.6) with ASI1600mm Pro Camera
15x60sec RGB; 10x300sec Ha and Oiii; 20x300sec Sii

Sunday, November 18, 2018

The Cocoon Nebula in RGBHa

After capturing the remaining green and blue subs on November 4th, I was able to complete the RGBHa composite of the Cocoon nebula.  I had already shot the 1 hour of Ha and most of the color subs before the clouds moved in on October 19th.

IC 5146 (also known as Caldwell 19, Sh 2-125, and the Cocoon Nebula) is a reflection/emission nebula in the constellation Cygnus. The NGC description refers to IC 5146 as a cluster of 9.5 mag stars involved in a bright and dark nebula. The cluster is also known as Collinder 470. It shines at magnitude +10.0/+9.3/+7.2. It is located near the naked-eye star Pi Cygni, the open cluster NGC 7209 in Lacerta, and the bright open cluster M39. The cluster is about 4,000 ly away, and the central star that lights it formed about 100,000 years ago; the nebula is about 12 arcmins across, which is equivalent to a span of 15 light years. (Wikipedia)

IC 5146 - The Cocoon Nebula in RGBHa
WO GT102 (4", f/5.6)
ASI1600mm 20x60sec ea. RGB; 15x240sec Ha

Saturday, November 17, 2018

Astrophotography Session in Early November

Clear skies are hard to come by these past 2 years, so when they do come along you gotta take advantage of them. Early November was a good time - clear skies, no moon.

First up is the Eastern Veil Nebula, NGC 6992. The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of what is known as the Cygnus Loop, a supernova remnant, many portions of which have acquired their own individual names and catalogue identifiers. The source supernova was a star 20 times more massive than the Sun, which exploded around 8,000 years ago. The remnants have since expanded to cover an area of the sky roughly 3 degrees in diameter (about 6 times the diameter, or 36 times the area, of the full Moon). (Wiki)

The complete nebula is too large to capture in a single image and would require a multiple image mosaic. But that would require a lot of time (and some techniques that I have not mastered yet).  So I've imaged the eastern section by itself. The nebula was captured over two nights, November 3 and 10, 2018, with a total exposure time of 5 hours. Using a monochrome camera with narrowband (NB) filters the resultant bi-color photo was a combination of thirty, five minutes exposures in both the Hydrogen Alpha wavelength, Ha, and the doubly ionized Oxygen wavelength, Oiii. This combination, applying the Ha to the red channel, and the Oiii to the green and blue channels produces what is known as an HOO image.

NGC 6992 - The Eastern Veil Nebula
Nov 3 & 10, 2018 - WO GT102 APO Refractor (4", f/5.6)
ASI1600mm Pro Camera - 30x300sec Ha; 30x300sec Oiii
Next is NGC 7380 (also known as the Wizard Nebula) which is an open cluster discovered by Caroline Herschel in 1787. William Herschel included his sister's discovery in his catalog, and labelled it H VIII.77. It is also known as 142 in the 1959 Sharpless catalog (Sh2-142). This reasonably large nebula is located in Cepheus. It is extremely difficult to observe visually, usually requiring very dark skies and an O-III filter.

Located 7200 light years away, the Wizard nebula, surrounds developing open star cluster NGC 7380. Visually, the interplay of stars, gas, and dust has created a shape that appears to some like a fictional medieval sorcerer. The active star forming region spans about 100 light years, making it appear larger than the angular extent of the Moon. (Wiki)

Similar to the process of imaging the Veil, the Wizard Nebula was captured using the two NB filters, Ha and Oiii, but also merging in the complete RGB for capturing the correct color of the stars. This image is typically named RGBHOO. Captured on Nov 10 and 11, 2018, it is the result of 2.4 hours of exposure (15x60sec in each color, RGB, and 10x300sec in the NB).

NGC 7380 - The Wizard Nebula
Nov 10 & 11, 2018 - WO GT102 (4"; f/5.6)
ASI1600mm camera - 15x60sec each RGB; 10x300 Ha and Oiii

Comet 12P/Pons Brooks

So I finally got around to capturing the periodic comet 12P/Pons Brooks. Since I was not able to capture this comet from my permanent telesc...