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The Trifid nebula, aka M20 or NGC 6514, a popular and bright nebula about 4300 light years away in the constellation Sagittarius.
This image was taken through my Celestron 8" SCT on the CGEM at f6.3 using a cooled and astro-modded DSLR.
RGB subs: 6x60s, 5x120s, 5x180s, 5x240s, 4x300s
HII subs: 10x600s
OIII subs: 9x600s
Total Time: 04hr 21min.
Most of this image is natural color because I only used 10% of the HII and OIII stack to emphesize the detail in the red and blue hues.
I was bitten by the Messier bug back in the beginning of 2013. By the start of that summer I had seen over 70 Messiers with the help of my Helios NatureSport 10x50 binoculars, Sky-Watcher Explorer 130P and my two favourite dark sky sites: a “local” one in the north of the Cheshire plain and a location further afield in North Wales.
The objects that had eluded me were mainly the fainter galaxies in Ursa Major and Virgo and the southerly Messiers, i.e. those lying below -30 degrees in declination: M55, M54, M70 and M69 in Sagittarius and M6, M7 and M62 in Scorpius.
My 2013 summer holiday to Switzerland coincided with a new moon and some marvellously clear skies. To my great surprise and satisfaction I was able to bag all the southerly Messiers. The open star clusters M6 and M7 twinkled almost as bright as city lights in the 10x50 bins. Globular cluster M55 was large and diffuse and M54 was also a straightforward sighting in the bins. For the small and faint globular clusters of M69 and M70 I had to resort to my newly acquired SkyMaster 10x70 bins, and even then it was a struggle to see them. The 10x50 bins, however, were sufficient to pick out globular cluster M62 further west in Scorpius. The fact that these objects were 8 degrees higher in the sky than when seen from home was a key factor in my success.
Subsequent summer holidays in Portugal and Spain benefitted from being another 5 degrees further south, so once again with clear dark skies, the most southerly Messiers were easily seen. In fact, conditions were sufficiently favourable at our holiday home 80 miles south west of Barcelona, that M7 was a naked eye object. That sky was a wonder to behold!
As a side note, when locating M6 and M7 on these holidays I followed the instructions of my Messier guidebook which recommended navigating from the tail of Scorpius. More recently, after studying my star atlas, it was clear that navigating from the spout of the teapot asterism in Sagittarius was a better bet, especially from more northerly latitudes where only the top half of Scorpius is visible.
About a year ago I started to wonder if it might be possible to see M6 from my North Wales site, latitude of 53 degrees, as the sky there stays remarkably dark right down to the horizon. At that latitude M6 should lie almost 5 degrees above a low horizon. Alas, such things are a rarity in North Wales!
After several failed attempts last year and this, I celebrated success a couple of months back on 17th June. M6 was clearly visible as a faint fuzz in my 10x50 bins. By now I had graduated from the 130P to a Sky-Watcher Skyliner 250PX Dob. Looking through the Dob with a 17.3mm eyepiece, the cluster occupied a significant part of the 1 degree FOV. There was a suggestion of a "V" shape at its centre and a bright orange star (BM) glowed in the upper right of the eyepiece. I estimated M6 to be about 2 degrees above the hilly horizon so I knew straight away that M7 wouldn't be visible, as it lies 2.5 degrees further south than M6. Not yet beaten, I turned the Dob a few degrees west into Scorpius and with a "seat of the pants" navigation (due to a lack of any prominent star patterns) just managed to locate a faint M62 in Scorpius.
A reconnaissance of the local area uncovered another suitable viewing spot a couple of miles away where I estimated the horizon was 2 degrees lower which, in theory, gave the opportunity to see M7.
My first visit to this new site on 17th July was a disappointment as a band of thin, low lying cloud mostly obscured the area of interest.
My next visit on 24th July was a different story. I arrived at 11:15 when M6 and M7 should have been at their highest, and set up poste-haste. The sky wasn't fully dark yet and the only star in the teapot asterism of Sagittarius I could see with the naked eye was Nunki, the top of the handle. Thanks to my success in June, I was able to navigate quickly using my 10x50 bins to M6, which again showed as a definite fuzz. I then swept around the teapot looking keenly for Kaus Australis, the base of the spout which was roughly the same declination as M7. To my surprise and excitement I found it, so I knew M7 was at least above the horizon. I then navigated from the top of the spout, still using my 10x50 bins, to where I reckoned I would find M7 and sure enough, a very faint fuzz appeared. I then dashed over to my Dob using the same eyepiece as previously, navigated through the finderscope, and there in the eyepiece was M7, occupying most of the FOV! I could discern a definite "V" shape with 4 stars in each arm on a west-east axis. Looking through the binoculars, I estimated M7 to be about 1.5 degrees above the horizon, which fitted with my previous calculations.
I then mounted my Canon 500D on a tripod and fitted a 50mm f/1.7 lens. I took several photos of the teapot asterism (at ISO3200, 6 seconds exposure), hoping against hope to capture both M6 and M7 in the shots. When I got home I was very pleasantly surprised to find that I had been successful.
By 12:45 the sky had darkened in the south such that the teapot asterism was now clearly visible to the naked eye.
I then returned to my Dob, hoping to see the globular clusters of M69 (near the base of the spout), nearby M70 and M54 (near the base of the handle). I had success with each object: M69 and M70 were both faint fuzz balls, M54 was rather brighter but smaller. I then turned my attention further east with M55 in mind. I rehearsed star hopping with my bins a couple of times so that navigation with the Dob was straightforward. Looking through the eyepiece there was the mighty, but faint, globular cluster of M55.
In the combined sessions of 17th June and 24th July I saw all the southerly Messiers for the first time from this country - and from a latitude close to that of home. These viewings gave me the satisfaction of having seen all Messiers from a latitude of 53 degrees or higher.
So that is my story of the southerly Messiers.
I wonder what tales of frustration and success other observers can share about their experiences seeking out these low-lying objects, especially from UK latitudes?
Re-processed - Trifid Nebula in Sagittarius ( Messier 20, NGC 6514 ) - new PhotometricColorCalibration toolBy MikeODay
Re-processed 12th August 2017 using the new PhotometricColorCalibration tool from Pixinsight.
This function seeks to adjust the colour balance of the image by plate solving the image and comparing the colour of the stars in the image with the colour values for these stars as stored in various databases.
( please click / tap on image to see larger / sharper )
Trifid Nebula ( M20, NGC 6514 )
I manged to capture another 60 odd 240sec images in late July to add to the data I captured at the end of June ( Trifid Nebula WIP )
Trifid Nebula in Sagittarius ( Messier 20, NGC 6514 )
( please click / tap on image to see larger and sharper )'
and a crop of the main part of the nebula ...
I am quite pleased with how the colour balance turned out - especially the colours of the stars ( my goal has been to get the colours of the stars as close as I can to how they would look with "daylight" whitebalance and no light pollution / sky glow).
"High Dynamic Range" ( HDR ) image of the Trifid Nebula - built from exposures ranging from 1/8 to 240 seconds in duration.
Size: 52.2 x 35.5 arcmins.
Centre: 18h 2 min 30.8 sec, -22deg 57' 37.7''.
Orientation: up is -88.2 East of North ( ie. E^ N> ).
Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ).
Corrector: ASA 2" Coma Corrector Quattro 1.175x.
Effective Focal Length / Aperture : 1410mm f4.7.
Skywatcher AZ Eq6 GT.
TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 .
Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels).
Blue Mountains, Australia
Moderate light pollution ( pale green zone on darksitefinder.com map ).
12 sets of sub-images with exposure duration for each set doubling ( 1/8s to 240s ) all at ISO800.
Calibration: master bias, master flat and no darks.
Integration in 12 sets.
105 x 240sec main image.
5 each for exposures 1/8 to 120sec - to caputure highlights.
HDR combination using Pixinsight's PixelMath function.
Observation 25-26 July 2017
Date: 25-26th July 2017 @ 19:50 – 2:30AEST
Equipment: 14” Skywatcher GOTO Dobsonian, Televue 31mm Nagler T5 , Televue 17mm Ethos, Televue 11mm Nagler T6, Televue 2X Powermate, Baader Neodymium, Baader Contrast Booster, Astronomik UHC filter.
The first thing I noticed from the beginning is that there was more sky glow than I would like, it was quite obvious that the seeing won't be perfect.
I keep hunting for maximum magnification and detail on planets so before observation I re-collimated the Dobsonian from scratch.
This time I put a white piece of paper behind the secondary so it was easier to see if the secondary mirror is circular and centered.
Second step was to use the laser to collimate but noticed that when I touched or span the laser, its reflection changed, so using it is pointless without first collimating the collimator (what da?) and proceeded to use the Cheshire.
As a final step I tweaked the collimation on Saturn and a nearby star.
Saturn: Saturn looked soft and fuzzy. The Cassini division was barely hinting itself in and out of a shade like apparition on the outer edges of the rings.
There were 5 soft moons around it, but I knew that the seeing was too poor to properly test the collimation tonight.
After a disappointing start tonight when comparing to my hope and expectation, while observing Saturn at 150X, at 20:40 (iPhone time, 20:38 "Star Walk" time) a bright satellite flew past and through Saturn. The flyby was not slow but wasn't as fast as a shooting star either. When checking for satellites on the "Star Walk" app, it turned out to be "Envisat".
It is rare views like this that make a view memorable and special, by adding a bit of action to the scene.
After seeing that Saturn looked quite soft and with the considerable amount of sky glow, I wasn't expecting to get the best views so I took the lazy approach to observing tonight and, after accurately star aligning the scope, selected the objects above 40 degrees in order from the "Deep-Sky Tour" option on the SW14 hand controller.
Lagoon Nebula (M8): M8 was visible the same as I saw it last time I was observing and as before the sky glow killed all of the fine detail that I saw back in May. Again the main part of the nebula was visible, the dark lane was there, with a hint of structure with in it, as well as the faint nebulosity around the main “Lagoon” coming into view at 50X and 100X power. During dark nights, there is a lot more visible, especially detail wise within and around the nebula, but unfortunately tonight, that was washed away. As with most nebulae, the best way to view this nebula is by using the UHC filter.
Omega Nebula (M17): At 50X and 100X the “Swan” is easily visible, along with some of the outer nebulae coming into view faintly around the “Swan”, particularly behind it. Higher magnification, 200X, the structure and shading was once again very easily visible within the Swan head and body. The use of the UHC filter is a must on this nebula to see all of the details. Still a lot of detail is visible for such a bright sky glow seeing condition.
Eagle Nebula (M16): The "E" shape was quite easily visible, not as obvious as during a darker night but still visible among the stars in and around the nebula. I’m very sure that at 200X magnification and using the UHC filter, I saw the “dark pillar”, the middle one out of the “Pillars of creation”, the one with “squiggle” at the bottom of it in the photographs. At 100X there was a quite obvious dark shading where the dark pillar is situated.
At first I thought it might be wishful thinking and talking myself into believing that I’m seeing hints of one of the pillars, as the seeing and transparency conditions are not the best, but the more I looked in the area, the more I was seeing a distinct elongated darkening at the correct spot, just under the two brighter stars within the nebula.
Pavo Globular Cluster: The Pavo Globular is a very nice looking Globular cluster. At 200X it looked like a typical globular except that it has, what looks like, more brighter individual stars sprinkled at the foreground with the Globular shimmering behind it, a few scattered stars at the edges and one particularly bright star toward edge at the top left.
This Globular is not as big as 47Tuc or the Omega Cluster but at higher power, it looks just as nice and interesting. This Globular is definitely in my top 3 Globular Clusters to view to date and I will make the effort to image it hopefully in the not too distant future.
Butterfly Cluster: An open star cluster with a bright orange star within that drew attention to itself. At 50-100X magnification it sits nicely within the FOV of both the 31mm Nagler and 17mm Ethos. The Butterfly Cluster is a medium sized open star cluster and with the orange star glowing within it reminds me of two other objects, it sort of resembles the cluster within the center of the Rosette nebula with a touch of the orange jewel from the Jewel Box cluster in Crux.
Trifid Nebula (M20): The nebula was surprisingly easy to see tonight considering the glow, but the dark lanes are easily visible, within the easy to see with direct vision, “Trifid”, the double star in the center is easily split and the blue nebula haze is quite easily visible to the right of the “Trifid”. The best way to see M20 was at 100X and 200X magnification and using the UHC filter, although the wide angle view with the 31mm Nagler did give a nice contrasty view of the nebula floating in space, with the wide angle, it was like looking out of a space craft port hole.
Comparing the view of the Trifid Nebula to how I saw it from a dark location through the 8", it looked about the same, so not bad for seeing the same view but from a much brighter and worse seeing condition sky.
Globular (M4): M4 is quite a small Globular cluster in Scorpius near Antares on the eastern side. This globular needed 200X magnification to resolve its core into granulated stars.
Globular (M5): Another Globular Cluster picked from the SW14 deep sky tour hand controller. This Globular is quite bright and looks quite nice in the eyepiece, definitely a considerable amount brighter than, for example, M4 and M80.
This Globular looks tightly packed at the core, where the granulation is visible at 100X very easily, and less dense sprinkling of stars at the edges.
This Globular Cluster is a worthwhile object to observe during a night of observation.
Wild Duck Cluster: This cluster is something different, heaps of stars quite tightly packed, looking almost like fireflies rather than wild ducks. There was the shimmer visible through it which gave it a “being alive effect", it is a good sight at 50X and 100X magnifications. As most objects, this one would really benefit from a dark transparent sky to have the "fireflies" as sharp pin points of light since tonight it sort of looked soft focused.
Globular (M2): Another small globular needing 200X to resolve stars at the core, this one seemed tightly packed. I just had a quick look and moved on. Maybe I should have studied it a bit longer but initially it resembled M4 and other small globulars.
Globular (M22): M22 is a bright Globular Cluster in Sagittarius. The Sagittarius and Scorpio constellations have, by the look of it, a lot of different types of Globular Clusters.
M22 is almost as impressive as the Pavo Globular cluster, it is almost as bright and big as the one in Pavo which places it in close position four of my favorite globulars to date.
At 100X I saw a dense core with less dense randomly sprinkled brighter stars at the outer edges.
Definitely worth a visit.
Globular (M28): M28 is another smallish Globular, not too dim, and a bit bigger than and not as faint as M4. This Globular looks good at 200X.
Southern Pinwheel Galaxy (M83): Tonight the view of the galaxy was disappointing at best, all that was visible tonight was the glow of the core, no spiral arms were visible at all at any magnification, 50X-200X. Not even the “S” shape coming through, simply the sky was not transparent enough and I guess it didn't help for it to be getting quite low toward the west.
Saturn Nebula: As the last time I looked at this planetary Nebula, it was a fuzzy greenish oval, looking almost as if it's always out of focus, only knowing I was focused by the stars near it. 300X needed to see a decent size, but still looking like a featureless oval that is poorly focused, UHC filter didn't help either.
Looking at the Hubble image is obvious why it is looking out of focus. It is a planetary nebula within a fainter more diffuse nebula with a bar structure flowing through it, so at a lower resolution, fainter monochromatic view, the more diffuse nebula flows into the central nebula resulting with a fuzz oval view.
Helix Nebula: The "Eye of God" initially looked like a smokey oval which was quite hard to see with no central star and initially only showed dimmer fuzzy center.
I stopped observing at about 23:00 because I wanted to see the Helix Nebula higher up in the sky so I decided to comeback to the Helix later.
I left the scope tracking on the Helix Nebula for almost 2 hours, and returning at 01:30 when it was much higher in the sky, I was pleasantly surprised that it was still in the FOV... not center any more but still in the 100X magnified Ethos eyepiece FOV.
Using the UHC filter the smokey ring was much easier to see than before, when it was lower in the eastern horizon. The smoke ring was defined with a dimmer center, the top and bottom parts of the ring were noticeably brighter with the central neutron star visible when using averted vision.
Some of the main stars that I remember in the image I took a while ago were also visible there around the smoke ring. The view in the 8" did not reveal as much detail even though I tried to observe it in a darker sky condition. Not bad for what I saw during a milky bright sky. I was under the impression that there was little or no difference between the 14" and the 8", but after seeing the difference in the Helix Nebula, perhaps I was wrong, and just have the wrong idea of what 3X light gathering power really means.
I wonder how it will look under a dark, crystal clear sky.
The view without the UHC filter made the central neutron star just barely visible with direct vision, along with the stars around the nebula but the nebula was a lot less obvious, still hinted at some nebulosity, but the structure was not discernible.
Under a darker sky I'm sure the view will be staggering.
M80: Much like M4 except a little bit fainter. M80 is near Antares on the other, western side. This Globular Cluster needed 200X to resolve the sprinkling of stars that seem to be more sparse at the edges.
M9: This is a small and faint Globular cluster that needed to be magnified 200X to see any granulation through it but it is still small when comparing to The Pavo Globular Cluster, M22 or even M4 or M80.
300X was needed to see it at a decent scale where it was still a fair bit fainter than the other globs I observed tonight but at this power it had quite obvious star separation visible in the form of granulation all the way into the core.
Neptune: At 150X Neptune was a tiny, pale blue disc not much bigger than the bright stars near it.
There is no hope to see any detail in the atmosphere of Neptune so any more magnification is pointless, plus the atmospheric conditions wouldn't allow for it anyway, but it was a tighter point of light than last time I targeted it. It also was a lot higher in the sky.
Seeing was quite poor tonight coupled with a lot of obvious sky glow visible to a level where the sky looked milky when dark adapted, resulting in loss of contrast and transparency causing fuzzy views and lack of details. The poor transparency was particularly visible on the brighter nebulae such as M8. The poor seeing also made it impossible to tell whether tonights careful collimation helped the ability to get crisp detail at above 400X magnification.
As night went on, the condition improved slightly but still nowhere near the best seeing conditions which I experienced in May. The slight improvement in seeing conditions, along with being higher in the sky, might have been the reason for the increased details and features that I saw on the Helix Nebula after coming back to it 2 hours later.
Looking at the objects I bagged tonight, most of the them, by far, were Globular Clusters so I guess tonight was a "night of the Globular".
After not expecting too much due to the seeing and taking the lazy Deep-Sky Tour option tonight, I did get a few nice surprises, namely the Helix Nebula, a possible pillar of creation in the eagle and a few nice and bright Globular Clusters, few of which I saw for the first time.
I noticed Pegasus/Andromeda at 02:30 as I was packing up and so I tried to find M31 with the binoculars but it was too low in the north, in the direction of many street lights that washed any hint of it away... I guess I'm situated to far south.
If you read this novel of ramblings of a astro-nut to the end, thank you and congratulations.