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ARCHIVE 2015INTRODUCTIONImaging from the worst place on Earth? Possibly! Welcome to my image blog from Lancashire, UK. Living in Lancashire does make imaging a challenge. Our incessant damp cloudy weather is legendary and coupled with light pollution probably as bright as can be found anywhere (I am 15 miles NW of the centre of Manchester) makes for testing times! Add to that flight path one with constant aeroplanes, which is why it has been suggested as possibly the worst place on Earth for imaging. Now the good news. With modern light pollution filters we can still produce excellent results - at least when the clouds clear - but of course we cannot match dark sites - I avoid looking at images from such sites as they are very depressing and un-representative of what the rest of us have to suffer! So if you too live in cloudy suburbia then I hope the following images offer some encouragement. I often shoot the luminance and the colour simultaneously - there are not enough clear spells to alow the luxury of shooting separately. Having two telescopes and two cameras is obviously essential for this - as is having a dome slot wide enough for both to have a clear line of sight. The luminance is usually taken with the RCOS + Apogee Alta and the colour Takahashi + Canon 40D. Despite their disparate focal lengths this works reasonably well as the Canon has 5 micron pixels (plate scale 2 arcsecs/pixel) and the Apogee 18 micron ones when binned 2x2 (plate scale 1.3 arcsecs/pixel). I find binning essential to maximise signal and improve the signal-to-noise ratio. The images are all taken from my back garden and appear in order of me processing them - we have plenty of cloudy nights for that. I use a combination of IRIS and Maxim for processing with final tweaks in Photoshop CS2. To get rid of the light pollution takes much trial and error. IRIS scores here with several options but processing often comprises many nights work - certainly always longer than the actual taking. The exception are images taken with an h-alpha filter which is a superb light pollution filter. It also permits imaging with strong Moonlight present - isn't it funny how it always seems to be clear at full Moon! |
20th DECEMBER 2015Compact Galaxy Group, Hickson 99 |
Not one of the most spectacular of the Hickson groups with its brightest galaxy down at magnitude 14. It comprises 4 spirals and 1 elliptical. According to Hickson, they are a genuine "accordant" group ie their redshift tally (around z=0.029). He reckoned b and c were interacting but c (the barred spiral) looks beautifully symmetrical. Galaxy a is clearly a spiral but the bright star in front of it spoils the view. There are several galaxies around the group so it could be the case of a compact group at the centre of a loose cluster. Most don't have recorded reshifts but the elliptical at the bottom right of the full image does and it matches that of the group. Image Details
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Hickson 99
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6th DECEMBER 2015Globular Cluster, Pal 13 |
Located just below the Square of Pegasus and near to NGC7479, Pal 13 one of the smallest and faintest globular clusters known. It was discovered by A.G. Wilson in 1953. Its distance is 85,000 light years and its brightest stars mag 17. Palomar 13 was the only known globular cluster with possible evidence for dark matter, based on a Keck/HIRES 21 star velocity dispersion. However, research by Bradfod et al. (2011) found its dynamics could be explained on the basis of its stellar mass alone and the presence of dark matter was not required. Trouille et al. (2003) found its age to be around 10.5 billion years - a bit younger than most other Milky Way globulars. Image Details
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Pal 13
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22nd NOVEMBER 2015Compact Galaxy Group, Hickson 94 (Arp 170) |
Located within the Square of Pegasus, this Hickson group of 7 galaxies is not all that it seems. Arp also included this, or at least the central 3, as no. 170 in his Atlas of Peculiar Galaxies. The extended envelope around (a), (b) & (c) is very odd and very asymmetric. I was not very convinced that this is really a "Compact Group" - there are several galaxies around the Hickson 7 and when I checked their redshift many had the same redshift as the central 3. So in all probability they are all located nearby. In addition, (d) and (f) have larger redshifts. The redshifts of (a), (b) & (c) indicate a distance of around 550 million years whereas that of (d) and (f) indicate a distance of 590 mly. Quite a disparity for a true group. I trawled the research papers to try and resolve what was the real situation. It turns out, Ebeling et al. (1995) had already come to the same conclusion. Hickson 94 is not a galaxy group but a the core of a loose cluster of galaxies. They termed it the most extreme misclassification in the Hickson catalogue.
Notes: Image Details
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Hickson 94
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8th NOVEMBER 2015Compact Galaxy Group, Hickson 93 (Arp 99) |
Located within the Square of Pegasus, this compact group of 5 galaxies is centred on the distorted elliptical galaxy NGC 7550. Paul Hickson described this group as an accordant quartet (a, b, c & e) with (d) the odd one out and not part of the group. In reality (e) is the background galaxy with a much higher redshift. Perhaps when he compiled his catalogue there was redshift error? Interestingly the anonymous galaxy (see right) has the same redshift as (e) so these 2 probably form a background pair in their own right.
Notes: Image Details
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Key to group members |
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Hickson 93
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25th OCTOBER 2015Planetary Nebula, Abell 72 |
Located in Delphinus, this rather poorly known planetary nebula is catalogued as magnitude 13.8 and with a size of 2.2 arcminutes on its long axis. The central star is magnitude 16.1 visual but much brighter in the ultra-violet. I could find very little information for this nebula and the only research paper mentioning it I could find is "Spectroscopy of six highly evolved Abell planetary nebulae" - J. P. Phillips et al., 2005. Even so there wasn't a lot of startling revelations - just "the structure of this shell appears complex, and reveals evidence for at least four primary emission peaks". Oh well, that's the price for imaging obscure objects. Just below (south) of the nebula is the background galaxy PGC 65491, which appears to be a somewhat distorted spiral. Image Details
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Abell 72
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7th OCTOBER 2015Emission Nebula, Sharpless Sh2-90 |
Located in Vulpecula, this is not one of the most spectacular Sharplees objects. Sh2-90 has a diameter of around 10 light years and is at a distance of 10,000 light years. According to "Galaxy Map", Sh 2-90 is a blister on a 60 thousand solar mass molecular cloud and appears to be affected by gas streaming from the Vul OB1 association. It contains a cometary elephant trunk structure on its eastern edge which appears to have originated from a past disturbance from the southwest. Lafon et al. (1883) thorougly investigated this nebula and the following is based on their conclusions. The exciting star they thought must be too well hidden to detect discounting other previous suggestions. However, they thought this star had formed at the near edge of the molecular cloud. The HII region was composed of a cavity, dug into the molecular cloud, and of an extended region lying outside the molecular cloud. The densest regions cover the cavity, thus producing a shell structure of low excitation with the south diffuse extension formed by the ionized gas, streaming away supersonically from the open cavity, more or less in the direction of the observer. A pretty complex object! Image Details
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Sh2-90
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23rd SEPTEMBER 2015Milky Way over Kelling Heath |
This year's star party at Kelling Heath was a great success with several clear nights. There were though clouds passing over rather too frequently to make all-sky imaging easy. The light pollution has got worse over the year's but it is not a show stopper. Tried a Samyang 8mm Fish Eye lens this year on my Canon. This lens has a strange optical design and cannot be used with clip-in filters. The back focus distance of this lens doesn't change with focusing so cannot reach focus with the filter in place. I would have used a CLS light pollution filter if I could to stop that glow from Holt (bottom right). Still the quality of the lens was impressive with very little fall off in sharpness in the corners. Image Details
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Milky Way, Kelling Heath
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1st SEPTEMBER 2015Planetary Nebula Abell 56 |
First image of this autumn's session. Listed as magnitude 14.1 but effectively it is much fainter than that! The large number of stars makes it difficult to drag it up out of the background. I couldn't find any information on this planetary - no research papers seem to have covered it. The following is from Reiner Vogel's catalogue of Abell Planetary Nebulae: Names: Abell 56, PK 37-3.2 Image Details
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Abell 56
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20th JULY 2015NGC 5005, (Caldwell 29) |
A spiral galaxy with a small bar and classed as a LINER, somewhat similar to Seyfert galaxies (Viegas-Aldrovandi & Gruenwald, 1990). LINER stands for Low-Ionisation Nuclear Emission-line Region and was devised by Hechman (1980) to describe a new class of emitting region in the nuclei of galaxies. The existence of a LINER in the galactic nucleus is related to the presence of a compact nuclear radio source. The source of the emission of LINERS could be from the ionising radiation caused by massive stars (called “warmers”) or from the accretion disc around a black hole. The latter seems to be more in favour. Paul Eskridge et al. (2002) described this galaxy in detail "Appearance—SBa: System is fairly inclined. Bright, elliptical bulge with a flattened nuclear source. Bulge is threaded by a bar with a P.A. skewed 30 from that of the bulge. The outer bulge isophotes are boxy, and the bar crosses the diagonal of the bulge. There are two ansae near the ends of the bar. Two very narrow spiral arms. The inner arms have some evidence for star-forming knots and are quite open. However, the outer arms tighten and appear to wrap several times around the system. The outer disk shows an occasional knot, but there is no coherent star-forming pattern associated with the outer arms". Kazushi Sakamoto et al. (2000) studied the gas dynamics of NGC 5005 in detail - see their figure 8 to the right. Another Caldwell object for which I needed a better image but nights were getting too light so only a short exposure. The faint dwarf galaxy towards the top edge (north) is PGC166157. This was my last image before the summer shut down. Image Details
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 Diagram copyright Sakamoto et al., 2000. Note UHR = ultra-harmonic resonance. |
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NGC 5005
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8th JULY 2015Saturn - altitude 18 degrees |
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A much more severe test of whether the ADC I had built last winter would work. Well it certainly has cancelled out the atmopheric dispersion - no adjustment of the colour planes was needed for this image. However, it cannot (unfortunately) cancel out the mushy Lancashire atmosphere! Still it's an image at an altitude where really nothing much can be expected. Roll on Mars at 15 degrees altitude next year. Image Details
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| Saturn 2015
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5th JULY 2015The Draco Trio, NGC 5981, 5982 & 5985 |
Appearances can be deceptive - probably not a true trio at all. The redshifts for these 3 galaxies pose questions as to their proximity to each other:- NGC 5981: redshift velocity = 1894 km/sec Probably NGC 5982 and NGC 5985 form a wide non-interacting physical pair but NGC 5981 is more likely not associated and nearer to us. NGC 5982 & 5985 are probably around 115 million lightyears with NGC 5981 probably well under the hundred mark. Edge-on spiral NGC 5981 is slightly disturbed and asymmetric. The inner disc is tilted against the outer disc and the bulge component is furthermore slightly tilted against the inner disc. NGC5982 is an elliptical shell galaxy with regular major axis shells (Sikkema et al. 2007). This galaxy harbours a Kinematically Decoupled Core (KDC: Wagner et al. 1988), and probably a rotating central disk (Emsellem et al. 2004). Outside the core, the galaxy is slowly rotating (Emsellem et al. 2004). Face-on spiral NGC 5985 has thin and well defined arms and perhaps a short bar. I had taken a luminace image 6 years ago but had no colour information. As I was returning (at last) for colour I took the opportunity to take more luminance as well. Image Details
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Draco Trio
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21st JUNE 2015Caldwell 36 and X7 (Galaxy NGC 4559) |
Galaxy Caldwell 36 or NGC 4559 is classed SAB(rs)cd. It is inclined at 67°to our line of sight and is around 30 million light years away. When I wrote "Observing the Caldwell Objects" in 1999, I reported that several x-ray sources had been observed in NGC 4559 by Vogler et al., 1997. Aside from the (expected) one at its centre the next brightest, denoted X7, was located in an odd position, way out near the western edge of the galaxy. Since then the story has moved on with further observations by Soria et al., 2005 of the ultra-luminous x-ray (ULX) sources in NGC4559. Using Hubble images they were able to search the error box where X7 was located - the dotted box in the top inset in the image below. Vogler et al. had thought it must be from a 100 year old supernova, but Soria found that a black hole of around 50 solar masses accreting material from a 20 solar mass companion fitted the data better. The trigger for the formation of this huge black hole and companion they believed was an interaction with a dwarf galaxy (g in the inset). Soria et al. stated they would do further observations to check if the galaxy g was associated with Ngc 4559. So far I can find no published confirmation and, rather worryingly, this galaxy does look very small and therefore remote! In 2012, the story got a bit more complicated. A possible supernova was discovered just south-east of X7. It turned out to be a Luminous Blue Variable (LBV) and it flared again in 2014. It seems to have been relatively quiet when I imaged it and also when Hubble imaged it. Perhaps it will flare again in 2016? Image Details
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NGC 4559
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14th JUNE 2015Venus - shot using ADC |
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With the observatory shut for the summer, It was time to try out the ADC I had built last winter. Venus was a tempting target and its white colour would be a good test to see if atmospheric dispersion could be cancelled out - any false colour should be immediately apparent. It was at around 21 degrees elevation so the prisms were set to a spacing of 30mm. The image below has had no re-alignment of the colour planes and is a stack of 4000 images - no selection of best frames took place. So first signs are encouraging. Image Details
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| Venus 2015
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7th JUNE 2015Galaxy NGC 4449, Caldwell 21 |
At last a galaxy perhaps worthy of its inclusion in the Caldwell Catalogue! NGC 4449 is located 12.5 million light-years from Earth and is a member of a relatively nearby group of galaxies in the constellation Canes Venatici. It is classed as a dwarf galaxy and is very similar in size and morphology to one of the Milky Way's satellite galaxies, the Large Magellanic Cloud. It is famous for its starburst activity and it seems that gravitational interaction with a merging galaxy has probably disturbed the gas in the main galaxy and caused the burst in star formation. Evidence for this interaction is the tidal or stellar stream (at about 7:00 o' clock in the images) that was first detected as a mysterious faint smudge in digitized photographic plates from the Digitized Sky Survey project. It is also visible in images from the Sloan Digital Sky Survey. Authors of a recent study led by David Martínez-Delgado of the Max Planck Institute for Astronomy in Heidelberg, called it a stealth merger, where an infalling satellite galaxy is nearly undetectable by conventional means, yet has a substantial influence on its host galaxy. I was surprised that just 7 x 20 minute exposures were enough to record the tidal stream despite being labelled as "nearly undetectable by conventional means". The Subaru image actually resolves both into their individual stars. Image Details
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NGC 4449
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31st MAY 2015Galaxy NGC 3626, Caldwell 40 |
Again not a very spectacular object to warrant inclusion in the Caldwell Catalogue but it is a typical lenticular galaxy. Its fame (and its inclusion no doubt) is due to the fact that its gas orbits in one direction whilst its stars go in the opposite direction. It is around 65 million light years away and is on the outskirts of the Leo II Group of galaxies. NGC 3626 is a large galaxy which has a huge amount of extended Hi gas which counterrotates to the stars. This is thought to as a result of a recent merger and this was recently confirmed by O. K. Sil’chenko et al., 2010. According to Friedli & Benz (1993) who studied this scenario, the initially counterrotating gas begins to inflow because of a bar and forms a stable highly inclined ring near the center due to resonance effects. Though classified as SO/SA (non-barred), NGC 3626's large-scale structure reveals multi-tiered stellar disks and an inner oval disk. Therefore, O. K. Sil’chenko et al. suggest that the bar was present some time ago, but has now dissolved, or almost dissolved. The current star-forming ring in NGC 3626 may then be related to the resonance of this dissolving bar. O. K. Sil’chenko et al. explained this "The whole scenario of the galaxy transformations from spirals into lenticulars may include the following sequence of related events: first, a minor merger occurs, then the acquired gas and stars inflow to the center, the large-scale stellar disks develop bars and are heated, and the gas is compressed near the center and exhausted by the intense induced star formation. After a few billion years, we have typical lenticular galaxies, except for their unrelaxed gas behavior. Within such a scenario, the main mechanism of the lenticular galaxy formation is gravitational and not at all related to the intragroup hot medium impact". In the case of NGC 3626, they suggest its transformation from spiral to lenticular took place about 1 to 2 billion years ago. Image Details
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NGC 3626
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24th MAY 2015NGC 4725 & LoTr5, Widefield |
An amazing combination which shows clearly the huge apparent size of the planetary nebula, Lotr5. NGC 4725 is probably the biggest and best galaxy omitted from both the Messier and Caldwell catalogues. The distorted galaxy above the yellow/red bright star is NGC 4747. I had taken the widefield shot last year and although Lotr5 was there, it was far too faint to have done it justice. So with this year's deep image of the planetary nebula I was able to put the two together and finish the job. Image Details
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NGC 4725 & LoTr5
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17th MAY 2015LoTr5, Planetary Nebula |
A British discovery! Examining plates taken with the 1.2 metre UK Schmidt Telescope in 1980, Longmore and Tritton identified 11 new planetary nebula candidates of which this was number 5 - hence its catchy name of LoTr5. Longmore & Tritton's description: "This is a very large very faint non-uniform disc, slightly brighter towards the centre. Two members of a distant group or cluster of galaxies can be seen through the nebula. It has been confirmed as a planetary nebula from a spectrum taken by David Allen using the IPCS on the AAT. The lines of [O m] II 4959, 5007 were seen, very weak after an 800-s exposure. It is the highest galactic latitude planetary known. The star SAO 82570 = HD 112313 = BD + 2602405, at a (1950) 12h 53m 07s.76, d (1950) 260 09' 44".3 is positioned at the centre of the nebula within reasonable measurement error. Its spectral type (from the SAO Catalogue) is G5, mpg = 9.5, mv = 8.7. Thus if the nebula is associated with the G5 star the latter probably has a hot dwarf companion". They were right - the bright G star is much too cool to illuminate the nebula and does indeed have a very hot dwarf binary companion responsible for the PN. This companion star is one of the hottest known in the range 120,000 to 185,000 degrees. The cool G star is rapidly rotating and close to break-up. It is also barium rich making a very odd combination. Ref: Thevenin & Jasniewicx, 1997. Set as a challenge by Owen Brazell, this planetary is large but faint and required 11 hours worth of exposures to record it. However, that OIII signal may make it visible to the big Dob boys. It is located close to NGC 4725. Image Details
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The discovery image taken with the UK 1.2 metre Schmidt and spotted by Longmore & Tritton (1980). The small blob at 11:00 o'clock is a background galaxy.
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LoTr5
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7th MAY 2015Palomar 4, Globular Cluster |
One of the Milky Way's most remote globular clusters - further away than our satellite galaxies the Magellanic Clouds. Until very recently is was the second most remote known. However, a very distant object at 145 kpc, PSOJ174.0675-10.8774, or Crater, was recently discovered simultaneously in two independent surveys (Laevens et al. 2014; Belokurov et al. 2014). As yet it has not been confirmed as a globular cluster so Pal4 is the second most remote at least for a bit longer. The most recent research paper on Palomar 4 is by Akram Hasani Zonoozi, Hosein Haghi, Andreas H.W. Kuepper, Holger Baumgardt, Matthias J. Frank, Pavel Kroupa in 2014. A. Kuepper summarised their results: "By looking at the distribution of masses of stars within the cluster and their distance from the center of the cluster, we see that Palomar 4 must have been born as a very extended ball of stars and – and that’s the surprising discovery – with a very odd configuration for the masses of the stars. Massive stars must have been much more abundant in Palomar 4 than in young star clusters we observe today. And these massive stars must have preferentially been closer to the cluster center. It is not obvious why a globular cluster like Palomar 4 should have been born with an overabundance of high-mass stars, with a segregation of massive stars towards the cluster center, and with a very large extent. Models of star formation and cluster formation will have to explain this result". Image Details
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Properties (Frank et al., 2012) Age: 11±1 billion years Distance: 102± 2.4 kpc 333,000 light years (note this is lower than previous estimates of around 356,000 lys) Half-light radius = 18.4 ± 2.0 pc 60 light years Total mass = 29800 ± 800 solar masses Brightest Star: 18th magnitude
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Pal 4
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28th APRIL 2015Holmberg 124 (Galaxy Group NGC 2805) |
Holmberg 124 is a group of four interacting galaxies: NGC 2805, NGC 2814, NGC 2820 and Markarian 108 at a distance of 90 million light years. The most recent research paper for this group is by Mishra et al. 2013. They analised Hi 21cm data from the Giant Metrewave Radio Telescope (GMRT). They detected spectral line emission from all the four galaxies and noted several signatures of tidal interactions among the member galaxies. The results for the northern triplet (namely NGC 2820, NGC 2814 and Mrk 108) confirm the earlier results of Kantharia et al. (2005) - see diagram right. They also reported possible detection of small discrete clouds between NGC 2820 and NGC 2805 which might be stripped Hi in the intragroup medium (IGrM). The Hi distribution of NGC 2805 is asymmetric with peak Hi column densities seen along the southern spiral arm and along a northern arc. Vigorous star formation has been observed along the southern spiral arm of NGC 2805. They also supported the scenario given by Kantharia et al. (2005) that both tidal interactions and ram pressure are currently playing a role in the evolution of the triplet galaxies. From the observed northern Hi arc and extensive star formation in the southern spiral arm of NGC 2805 and additionally the systemic velocities of the four galaxies, they suggest ram pressure effects are also playing a role in the evolution of NGC 2805. They believe interaction with the IGrM would have triggered star formation in the southern spiral arm. This model for NGC 2805 succeeds in explaining the compressed Hi in the north, widespread star formation and the diffuse Hi detected in the south/south-west of the optical galaxy. Image Details
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Holmberg 124
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19th APRIL 2015Galaxy NGC 2775, Caldwell 48 |
Not one of the best Caldwell Objects - it's hard to understand why this very ordinary galaxy was chosen. There was a supernova discovered in it in 1993 just about when the Caldwell Catalogue must have been compiled so I guess that's the likely reason. Although classified as a spiral galaxy (Sa) and viewed almost face-on, it has no prominent spiral arms or dark lanes. This is the reason for it being visually rather featureless. What appears to have happened is that this spiral galaxy turned its star making inter-stellar material into stars very early in its life. Proof of this can be found in its spectrum, which is characterised by the presence of absorption lines rather than by emission features more typical of spirals with prominent arms and star forming regions. This is particularly noticeable in the Calcium H and K lines. NGC 2775’s spectrum is therefore dominated by the light from old cool stars, which themselves are characterised by absorption, not emission lines. This is more common in elliptical or SO type galaxies. It therefore has a smoothish appearance with faint spiral arms and little star formation now taking place. Just above (north of) NGC 2775 there is a tiny background group of 4 or 5 galaxies. Image Details
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NGC 2775 Catalogue position for epoch J2000.0 Constellation: Cancer Object information:
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NGC 2775
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7th APRIL 2015Born Again Planetary Nebula, Abell 30 |
Very easy to locate, just south-east of the Beehive Cluster in Cancer but boy is it faint. The detail is in the OIII band but my camer's senstivity is very poor here. I could have done with running longer but after 5 nights I decided enough was enough. Headlined by Nasa as the "Born Again Planetary Nebula" in the press release accompanying their iamge (right) in 2012. In reality most planetary nebulae go through several ejection phases so why, when this one was discovered to have had 2 discrete events it was such a big deal - who knows? The Born Again name actually seems to originate with Wesson et al in 2003 and Nasa just latched on to it. In the Nasa/ESA image (right) they have reversed the colours. Hydrogen is blue and Oxygen is red. Until I found this out I couldn't come to terms with what my image was showing!!!! Image Details
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Abell 30
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15th MARCH 2015Planetary Nebula Abell 13 |
Appropriately numbered no. 13 - this object took 3 nights and 4 different filters to record it! According to Frew et al. (2012) "A catalogue of integrated H fluxes for 1,258 Galactic planetary nebulae" this PN is strongest in NII rather than in H-alpha. An ultra-narrowband H-alpha filter is not therefore ideal but one that includes NII as well will do best. The central star is catalogued as magnitude 18.8. However, it appears to be predominantly violet in colour as it did not record either with the OIII or H-alpha filters - I had to shoot an extra sequence of luminance images with a filter (IDAS-P2) passing violet in order to record it. I guess this will be a difficult object visually as there was litte OIII and H-beta will probably be weak. Type of object: Planetary nebula PK 204-8.1 Image Details
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Abell 13
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22nd FEBRUARY 2015Planetary Nebula HaWe 2 (Sh2-200) |
This object was catalogued by Sharpless as SH2-200 probably on the basis of the fainter outer (red) halo but it is in all probability a planetary nebula. This was first recognised by Hartl & Weinberger in 1987 in their paper "Planetary Nebula of low surface brightness: Gleanings from the POSS". It was no2 in their list so its name is generally abbreviated to HaWe 2. Their description is as follows: No. 2 (138 + 04°1) : This object, listed as Sharpless 200, appears as a relatively large, slightly deformed ring in E (Blue), fainter and more disk-like in 0 (Red). Most remarkably, there appears to be an extended halo around the PN with a diameter six times as large as the central nebula ; note that the halo's size would then amount to 0.4, that is 4 pc at a distance of 580 pc ! The brightest part in the south- east of the halo has a red surface brightness of only ---- 24715. Although there is no visible blue central star, we suggest that this is a PN due to its enormous brightness in OIII according to the Emission Line Survey of Parker et at (1979) ; the halo, however, is not detectable there. A detailed study of nebula and halo is needed. This object is faint and despite taking four years to get luminance and colour I still don't really have enough signal to do it justice. Image Details
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HaWe2
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8th FEBRUARY 2015Planetary Nebula Kahoutek K2-1 (PK 173-5.1) |
Another object brought to my attention by the big Dob boys - this time by Owen Brazell. He had seen this nebula several years ago and thought it would make a good a target. It was categorised as "status not clear" by Zijlstra et al. (1990A&AS...82..273Z). However, It has a strong OIII signal so is, in all probability, a planetary nebula. It does though have a very untypical appearance. If I was prone to naming objects then perhaps the Fleur de Lys Nebula would be apt. It is located in Auriga and its magnitude is given as 12 - it is surprisingly bright. The magnitude of its central star is given as 18.2 or 18.8 depending on which catalogue you consult. This object deserves to be better known but for some reason some catalogues record its position incorrectly. Both Skymap and The_Sky6 plot this object in the wrong position so if you load a DSS image to check it out then nothing is visible. I guess many must have been put off looking for it by this error. Kahoutek is, of course, best remembered for his (in)famous comet for which spectacular things were predicted. The reality was somewhat disappointing and a very insignificant comet was actually observed. In later years Kohoutek worked in observatories in Spain and Chile specialising in planetary nebulae. Image Details
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K2-1
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1st FEBRUARY 2015M38 and Abell 9 |
Brought to my attention by Andrew Robertson, who was struggling to see this faint planetary nebula with his big Dobsonians. This image was subsequently posted on the Deep Sky Forum by Owen Brazell to see if anyone had succeeded visually and if so, with what aperture. It is pretty faint and the OIII is weak so visually it will be a very tough target. Little published information for this planetary nebula (PK 172+ 0.1) and about all I could find is Magnitude Nebula: 18.9 It was also flagged up as a "possible" planetary nebula as if there was some doubt. However, in my image at least, it looks like a planetary nebula so Abell was right to include it. It is amazing he spotted something so small and faint. Image Details
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M38 and Abell9
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22nd JANUARY 2015Comet Lovejoy (C/2014 Q2) Switched to a much wider field of view and broader light pollution filter. The clouds cleared quite late so shot when past the meridian and low so quite a bit of light pollution to remove. Image details: |
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Comet Lovejoy |
20th JANUARY 2015Comet Lovejoy (C/2014 Q2) With just a short period forecast between clouds I didn't have much time to prepare for this image. I underestimated the tail length and used the wrong filter. The Tak was already loaded with a UHC clip filter for my next target and is not ideal - hopeless really - for comets. I should have switched to the 200mm lens and a broadband LPR filter. In the end I got just under an hour before the clouds returned. Image details: |
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Comet Lovejoy |
11th JANUARY 2015Sharpless Sh2-187 |
This young star formation/ HII region is most likely ionised by a B0 class star (star 4 - see right) and is surrounded by a 4600 solar mass molecular cloud. It is partially obscured by the Lynds dark nebula LDN 1317 and contains the infrared star cluster BDS2003. (Ref: Galaxy Map). It has its own "trapezium" - stars 4, 5, 6 & 7 (see right). The definitive research into this object was carried out by Joncas, Durand and Roger (1992) and they concluded: 1. Star 4 was probably the ionising star. 2. Sh187 is 100,000 to 200,000 years old. 3. We are actually only observing visually about 3% of the HII present. 4. There is an HI disassociation area around the HII region. 5. Sh187 resides in relatively "quiet" area of the local arm with no supernova remnants or OB associations. 6. It could eventually produce massive stars. Located in Cassiopeia but not the brightest of Sharpless objects so I pressed on imaging for 5 hours. Only 152 Sharpless Objects still to do! Image Details
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Figure 1: Joncas, Durand & Roger, 1992 - Central region with star 4 believed to be the ionising star of the nebula. |
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4th JANUARY 2015Dwarf Galaxy, IC 1613 |
IC 1613 (Caldwell 51) is an irregular dwarf galaxy in the constellation Cetus just below the star 26 Ceti. It was discovered in 1906 by Max Wolf IC 1613 belongs to the Local Group and is approximately 2.3 million light years distant. This is slightly nearer than M31 and is possibly a satellite of it. In 1928 Water Baade recognized this galaxy as a member of the Local Group because it could be resolved into individual stars using the Mount Wilson 100" reflecting telescope. He also could find no bright globular clusters and this is still true today. Its importance lies in the calibration of the Cepheid variable period luminosity relationship for estimating distances as it has many of these variables. If you suffer from light pollution, then this is one of most difficult of galaxies to image - its very low surface brightness and low altitude mean it is never going to be spectacular for us. However, there is a slight suggestion of a bar running 2:00 o'clock to 8:00 o'clock. In the top right hand corner of my image is a short trail of the asteroid Sara (533) at magnitude 14.8. Image Details
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