Christchurch Astro Tours's blog

We have had a small run of good nights recently, which means I'm wandering about in the daylight hours looking like the walking dead. However, it's all in a good cause, as I'm starting to get a bit more practiced with long-exposure, wide-sky photography. I have to say that it is still a bit odd to see five major targets captured in a single image, even if the overall image covers the border region of three constellations: Sagittarius, Ophiuchus, and Scorpius. 

This is the first image I produced after taking 14 months “off” for pandemic lockdowns, two major injuries, the demands of earning a living, and a keen desire to see if sleep was as highly rated as people seem to think (nope). I chose NGC 3293 – The Gem Cluster – as my get-back-to-it target because it is relatively easy for data acquisition and I needed to brush up those skills. As it turned out, the seeing was less than perfect that night so data acquisition and post-processing were a bit more challenging than usual. Ah, well.

Having just acquired a piece of gear for wide-field photos (which is a tried-and-true way of getting any astrophotographer off their butt and outside), the New Equipment Curse (NEC) promptly kicked in with vigour and the sky stayed cloudy for several nights. It finally cleared enough for me to run out to my backyard and catch some photons – with a very rough polar alignment driven more by excitement than skill, I’m afraid. This image is centred on NGC 3372, the Eta Carina Nebula, and spans approximately 48 degrees by 20 degrees.

Ah, yes, another one of those ‘named’ nebulae. Although a singular honour, I do wonder, occasionally, if the person has ever looked into the eyepiece and thought “Really? I look like that?” IC2599 is also known as the Gabriela Mistral Nebula, in honour of one of Chile’s most famous poets and Nobel Prize recipients. It’s good to see some southern hemisphere folks getting some celestial recognition. The nebula is in the Carina constellation, approximately 7500 ly from us and spans about 40 ly across.

When one has been struggling with cursed objects (DSOs that, despite repeated best efforts, never seem to yield decent data), I have found that it is a good idea to go back to something reasonably basic but still interesting. Messier 17 is just such an object: big, bright, easily identified, and colourful. M 17 goes by several names. The one I grew up with was the Swan Nebula, but it is also known as the Omega Nebula, the Checkmark Nebula, and the Horseshoe Nebula. Most of these names are based on the lighter central region that is seen through most telescopes.

This is a wide field image of the Large Magellanic Cloud. NGC 2070 (The Tarantula Nebula) is clearly visible at centre right, an N11 (The Bean Nebula) is in the lower left corner. In fact, the LMC is chocka with what astronomers refer to as DSOs, or deep space objects. Almost any condensed knot of light has a designation in one or more astronomical catalogues. The central bar of the dwarf galaxy is clearly visible in this image.

The "Cat's Paw" Nebula can be found in Scorpius. NGC 6334 is relatively nearby, astronomically speaking - about 5.5 kly away from us - and, at 50 ly across, it is intrinsically large. Visually, it is covers a section of the sky that is approximately 40' x 23', which is slightly larger than the full moon.

This is not the prettiest of astronomical objects, but I like it for the sheer amount of action that it implies - interstellar dust and hydrogen gas are blowing every which way, and star formation is occurring at quite a clip due to an ancient supernova having taken place nearby. IC 4603 - the central nebulosity in this image - can be found near Antares, but just inside the borders of the constellation Ophiuchus. The dust is illuminated by the light of SAO 184376, a bright (Mag.

I published a wide-field photo of Messier 20 (about 4.1 kly, in Sagittarius) back in June, which prompted me to go after a proper 'head and shoulders' shot - with a twist, as this time I combined luminance and narrowband light. "Narrowband" is a term used by astrophotographers to denote the use of one or more filters to gather image data from very narrow slices of the spectrum. In this image, those filters were hydrogen-alpha (looking through it, an intense red), hydrogen-beta (dark blue), and oxygen-III (cyan/green-ish), bolstered by the luminance data.

This is a rather complex pair of objects in the constellation Centaurus. The blue reflection nebula is NGC 5367. While the nebula is quite pretty, the more interesting object, for me and for the professional astronomy community, is the brownish cloud that envelopes and slightly obscures NGC 5367. This is the cometary globule CG12, which extends somewhat further off the left side of this image.