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Gary

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Everything posted by Gary

  1. 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. It is another of those popular objects for astrophotographers, and for good reasons; it's big, bright, and has an interesting shape. In a wider view of the object, there is no mistaking why it was given its name. With this image, however, I chose a much closer framing of the object to sho
  2. Gary

    IC 4603

    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. 7.6), pre-main sequence, B-type star, which gives us that distinctive blue of a reflection nebula. Photo stuff:
  3. 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. Besides making for some very striking p
  4. Gary

    NGC 5367 and CG12

    This is a rather complex pair of objects in the constellation Centaurus. The blue reflection nebula is NGC 5367, which is mainly notable for being illuminated by the binary star h4636. 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. Cometary globules get their name from their appearance, which vaguely resembles a rather poorly formed comet. Most of these types o
  5. Gary

    IC 4605

    A welcome run of clear nights recently allowed me to lose yet more sleep and get some imaging done. This is the result of one of those runs. IC 4605 is a beautiful reflection nebula that is lit up by the bright (magnitude 4.8) blue, main sequence star, 22 Scorpii, which lies about 413 light years away from us. Although the star is visible from a reasonably dark sky site, long exposures with a camera are needed before the tenuous dust clouds that envelope it can be seen. This nebula is part of the much larger and very colourful Rho Ophiuchi Nebula complex. I have an image of that somewhere tha
  6. As I was making my way through my past images, I came across one from 2017 that - rather oddly - I had not yet fully processed. This is a wide field photo of the Trifid Nebula (Messier 20). It is a perennial favourite of astrophotographers, and a relatively easy target for beginners to learn data gathering and post-processing. M20 is a stellar nursery located about five degrees west from Lambda Sagittarii and two degrees northwest of Messier 8 (Lagoon Nebula). It has the unusual characteristic of having several distinct components: reflection (blue), emission (pink), and dark (the 'lanes') n
  7. This one was unplanned. The sky cleared, I stepped out into the backyard, and there was Jupiter about 3 degrees from a just-past-full moon. I grabbed a few shots and created this composite. The composite was necessary to show all the objects, of course, because exposing for the moon completely dims Jupiter and loses its Galilean moons, while exposing for Jupiter makes the moon look like the lens is staring at the sun. In the end, I processed three separate frames (Moon, Jupiter, and the Galilean moons) as they appeared through the viewfinder. Date: May 21, 2019 (about 01:00) R.A. (appr
  8. Gary

    NGC 2736

    This is another of those "challenging" objects I unwisely decide to tackle occasionally. This one is worth it, though, I think. Herschel's Ray, also known as the Pencil Nebula, is a beautiful swipe of blue and pink shock waves in the constellation Vela. At 3/4 of a light year in size, it is a reasonably sized object in its own right. However, it is just a tiny portion of the truly gigantic Vela Supernova. That "remnant" is what was left after a very large star cataclysmically exploded as a Type II supernova about 11,000 years ago. The force of this destruction, in turn, created a swath of deli
  9. I know, I know - not the prettiest name for a such an interesting galaxy, but I didn't come up with it. NGC 2442 is an example of a peculiar, barred spiral galaxy. In this case, its peculiarity is most likely due to gravitational tides when it interacted with another galaxy at some point in its history; possibly the smaller one (PGC 21456) visible to its right. Besides leaving it with an odd shape, the interaction would have started a burst of star formation evident in its arms. The Meathook, which is approximately 56 Mly away, can be found in the constellation Volans. Although not the brighte
  10. A while back, I had picked up a "new" (to me) Tamron 24 mm lens. I decided to do some wide-field, night-sky photography to try it out and, eventually, came up with this image. The Moa (in NZ) or the Emu (in Australia), seen in profile, is a series of visually connected dark regions in this portion of the Milky Way. Look for the two bright stars in the middle of the image. These mark the neck and shoulder. Just above and to the right is the head and beak, which, to astronomers, goes by the unlovely name of Caldwell 99 ("The Coal Sack Nebula"). Just above that is the Southern Cross. Moving down
  11. NGC 346, which resides in the Small Magellanic Cloud (SMC), is an open star cluster with surrounding nebulosity. At magnitude 10.3 and having a smallish size (~14 x 11 arcseconds), it is relatively easy to spot with a small telescope. This photograph was taken through H-alpha, H-beta, and OIII narrowband filters, which reveal the different densities of ionised hydrogen and oxygen gases in NGC 346 and the surrounding N66 gaseous region. My guess is that the apparent structural elements of the nebula in this image are likely the result of high-velocity stellar winds causing interstellar gas to p
  12. Gary

    Quarter Moon

    Among astrophotographers, I suspect that our moon is a seen as a bit too common to spend much time on. After all, we can observe it with the naked eye - why waste precious minutes on it when we can be chasing down some truly weird objects out there in the universe? And yet, I find that I come back to it quite often, either for a photograph or, more often, just to consider it's many features through a decent telescope or set of binoculars. There is still something beguiling about getting up close and personal with all those craters. There are quite a few interesting features visible in th
  13. This one is well-named. The Little Gem Nebula subtends a tiny visual angle; just 22 by 15 arcseconds. For those visitors unfamiliar with astronomical measurements, look at the back of your hand while it is at arm's length covering part of the sky. Point your little finger upward. It's width is about one degree. Take that width and divide it by 3600. That is one arcsecond - as I said, tiny. It's no wonder we need good telescopes and clear, still skies to view some of these objects. The Gem Nebula is a planetary nebula (PN) that sits about 6.4 kly away in Sagittarius. Like all PNs, it is t
  14. These are a collection of gas nebulae in the Small Magellanic Cloud. Chadwick and Cooper, in their excellent book "Imaging the Southern Sky", have named the collection The Magnificent Seven (tilt your head to the right to see why). The photograph is an example of narrow-band imaging. The term narrow-band refers to the fact that the filters used during the data collection process allow light only from very specific regions of the visual spectrum in which electrons are jumping between energy levels. In this case, the image is a composite of the light from hydrogen (H-alpha @ 656.28 nm, reddish;
  15. This wee object is a bit of a challenge to capture & process, but worth the effort. Planetary nebulae typically subtend a very small visual angle; this one is no exception at approximately 30 x 24 arcseconds. The Saturn Nebula sports some very clear ansae (the two bright knots in the 'rings') and a very pretty blue-green halo that suggests ionised oxygen. Aller's (1961) spectrograph seems to confirm this (Kaler, 1997). It is no great surprise, given the quality of optics at that time, that Lorde Rosse (~1848) thought that it might be a planet similar to Saturn, and thus gave it its current
  16. Gary

    IC 4685

    This image covers a massive star formation region approximately 4 kly away, and contains several nebulae. The largest is the emission nebula IC 4685, in the central portion of this photograph. The dark, dust lane of Barnard 303 snakes across it and points to the bright, white star (V3903 Sgr; an Orion-type variable) in the middle right. The blue reflection nebula on the lower right is NGC 6559. In the lower left corner is fainter IC 1275. It is possible that the emission nebulae are part of a river of hydrogen connecting to M8, the Lagoon Nebula, which is a nearby neighbour. Date: 11 July
  17. 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. It is thought that some of the LMC's spiral arms were ripped off in tidal interactions with the Small Magellanic Cloud and our own, much larger, Milky Way galaxy, whic
  18. Gary

    IC 1274

    There is rather a lot going on in this image. IC 1274 is the circular structure in the top, middle-right section of this photo. It is an HII region, sitting on the near edge of a seriously large molecular cloud known as Lynds 227. A dark nebula (Barnard 91) defines the top edge of the nebula. The bright star in the center of IC 1274 is a young, energetic B0 V star (HD 166033); current thinking is that this is the star that has blown this massive bubble (Dahm et al., 2011). The nebula, itself, contain many stars in the B0-B5 range, which suggests that this is a population of new stars. The ent
  19. Gary

    The South Pillars

    The Carina Nebula, where the South Pillars region exists, has an incredible array of fascinating objects and processes. In this image, for instance, we see pillars - also known colloquially as "elephant trunks" - of dust in which stars are being born. The best example in this photo is in the lower left quadrant. Recent research (McLeod et al., 2016) has suggested that such pillars are likely to disappear once the star comes into being due to a process known as photoevaporation, in which the powerful stellar wind from the new star literally blows away its cocoon. Date: 20 March 2018 Cons
  20. Gary

    Fornax Cluster

    These four are a suite of galaxies that are part of the Fornax cluster. Clockwise from top left: NGC 1375 (34 Mly), 1380 (86 Mly), 1373 (61 Mly), & 1374 (59 Mly). There are plenty of other galaxies visible in the background. Look for the elongated smudges of light. Date: 10 October 2016 Constellation: Fornax RA: 03h 35' 57" Dec: -35° 05′ 04.1″ Photo stuff: 32 subs@300s ea.; ISO 800; Canon 60Da on Meade RCX400 16" f/8; .70 focal reducer
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