2 for 1

January 11, 2015 by grahamrob in AstroBin, Deep Sky Objects, Imaging and tagged DSO Imaging, Gemini, Star Clusters | 1 Comment

Whilst I know of Gemini I have limited knowledge about this constellation that, like Monoceros, starts to play a more prominent part in the night sky here after 10 pm at this time of the year. Located immediately above Monoceros and north east if Orion, Gemini is Latin for twins and its asterism appropriately forms two stickmen whose ‘heads’ are formed by the stars of Castor and Pollux, also suitably twin brothers from Greek mythology.

At the western extremity of Gemini, beyond Tejat Posterior (which means back foot), just above the ‘left foot’ of the upper stickman, lies the open cluster M35. Located at the heart of the Milky Way and 2,700 light-years from Earth, M35 is formed of some 2,700 young stars of between 100 and 200 million years old. On the same clear, cold evening I recently photographed the Rosette Nebula, I also produced an interesting image of M35 with good colours, including some yellow-orange stars.

Because of its short focal length, the relatively wide field-of-view of the William Optics GT81 can be both a good and sometimes a bad feature, depending on the size of the object being viewed. From experience so far, it seems that the scope and DSLR camera produces good to fair resolution for objects down to about 5 arcminutes. Whilst objects below this size can be identified, the power of the scope and sensitivity of the camera sensor can usually only show the presence of such features without providing useful detail. However, at other times this set-up is perfect for wider but still detailed images that sometimes lead to me other, unexpected objects in the same picture. The image of M35 is just such an example.

At the time of imaging, the less-than clear initial RAW images from the camera, with a dark blue hue from the CLS light pollution filter, nevertheless indicated that M35 was nicely positioned at the centre of the picture, with good resolution of the component stars. However, it was evident that there were also some other bright features away from the M35 open cluster which I had not anticipated. Notable amongst these was what seemed like a pale yellow smudge to the immediate west, the importance of which only became apparent after stacking and post processing.

M35 & NGC 2158 Open Clusters WO GT81 + Canon 700D (unmodded) | 15 x 120 secs @ ISO 1,600 & calibration

M35 (Centre) & NGC 2158 (Lower right) Open Clusters
WO GT81 + Canon 700D (unmodded) | 15 x 120 secs @ ISO 1,600 & calibration

It turns out that M35’s neighbour, 20 arcminutes to the south-west, is no less than NGC 2158 – another cluster. To the eye NGC 2158 seems to form an attractive, golden globular cluster. In fact it too is an open cluster but located more than 9,000 light-years beyond M35 and at 2 billion years, is much older. As they say, with age comes beauty, and I find this feature to be the more interesting of the two, all the more so as I was not expecting to see anything there, instead I got 2 for 1.

Raising the bar

January 5, 2015 by grahamrob in Deep Sky Objects, Equipment, Imaging and tagged DSO Imaging, Nebulae, telescope | 8 Comments

My short astroimaging journey has been marked by a number of challenges, which looking back can now be viewed as important steps and achievements that have made it all worthwhile.

First trying to get a recognisable astronomy picture of anything using a compact camera: widefield on a tripod or afocal through the telescope eyepiece. Afocal imaging was surprisingly difficult to do well, even when using a camera clamp. Eventually I managed to obtain a crude photograph of the Orion Nebula, which nevertheless showed its colour and the Trapezium star cluster. Whilst basic, at the time I was very pleased and found the capture of the nebula’s light itself something of a seminal moment for me; using a basic compact camera, it had been possible to reveal hithero unseen colours and nebulosity. I wanted more.

M42 The Great Orion Nebula
Afocal image | February 2014

Next, with the objective of achieving basic images of other iconic astronomical objects, I adopted two paths using (a) an astronomy webcam, and (b) a DSLR camera. At this stage I had added RA and DEC motor drives to my EQ3-2 mount, which then allowed the telescope and attached camera to track the desired object and thus achieve longer exposures required to improve quality and detail. However, this set-up was still quite basic, with exposures of no more than 20 seconds possible without producing star trails. Furthermore, finding the desired objects and focussing remained quite difficult.

M45 The Pleiades Canon 700 D DSLR + 150PL Newtonian relfector + x2 Barlow |February 2014

M45 The Pleiades
150PL Newtonian relfector + EQ3-2 mount + Canon 700D + x2 Barlow |February 2014

Mars 150PL Newtonian reflector + EQ3-2 mount + ZWO ASI 120 MC webcam + x2 Barlow | May 2014

The breakthrough came in June 2014 when I acquired an AZ-EQ6 Mount, which when properly aligned significantly improved tracking accuracy and thereby extended exposure times of up to 180 seconds; for various reasons this was not easy to set-up properly and took some months to master. At the same time I also obtained a William Optics GT81 apochromatic triplet refractor telescope which, in combination with the mount, held the prospect of even better astrophotography.

Since then I have slowly been trying to, (i) learn how to use all the various facets of the new equipment, and through this (ii) to improve the quality of my images and tackle new, hitherto unseen features. I have made good progress with the equipment in recent months, although there is still much untapped potential. However, improved imaging is now revealing the otherwise inaccessible world of Deep Sky Objects that is nothing less than incredible, exciting and very rewarding.

M57 Ring Nebula, close-up with polar alignment. Canon 700D | 24x30sec @ ISO 1,600

M57 Ring Nebula
William Optics GT81 + AZ-E6 GT mount | Canon 700D | 24 x 30 secs @ ISO 1,600 | September 2014

M45, The Pleiades or Seven Sisters star cluster Canon 700D unguided | 26 x 90 secs darks/bias/flats @ ISO 800

M45 The Pleiades or Seven Sisters star cluster
William Optics GT81 + AZ-EQ6 GT mount (unguided) + Canon 700D DSLR| 26 x 90 secs darks/bias/flats @ ISO 800 | October 2014

The Orion Nebula October 2014 - the secondary feature in the top left corner is another nebula, M43. Orientated with equatorial North up and East to the left. Canon 700D unguided | 20 x 90 secs + darks/bias/flats @ ISO 800

M42 The Orion Nebula
William Optics GT81 + AZ-EQ6 GT mount (unguided) | Canon 700D + field flattener| 20 x 90 secs + darks/bias/flats @ ISO 800 | October 2014

At this time of the year it is necessary to grab every opportunity possible for imaging and so it was last Monday. With the new, waxing Moon dominating the sky until about 10.30 pm and the probable onset of dew, or worst still frost sometime after midnight, the window of opportunity was likely to be limited and cold. As it turned out, when I started to set-up and align the equipment at 9.30 pm it was a balmy 4^oC, which subsequently cooled to less than 2^oC by midnight and -1^oC when I packed up after 2.00 am. However, the relative humidity during most of this time varied only between 75% and 78%, thus delaying the onset of dew and eventually frost until shortly before 2.00 am.

The wonderful Orion constellation still dominates the sky at the moment but having recently ‘discovered’ the Monoceros constellation, I wanted to continue to get better acquainted with some of its exciting objects as well as something new in Orion. Shortly before Christmas I managed to image my first Monoceros target, NGC 2264 or the Christmas Tree and Cone Nebulae. Whilst pleased with the outcome of this seasonal object, the image suffered from noise and some lack of detail arising from the pre-dominance of Ha-light which my unmodded camera is unable to record – note to Father Christmas, modified DSLR in 2015 please. I was concerned that my next object might suffer from the same problem but in the short imaging time I had available, was determined to improve the quality through better alignment, more subs and longer exposures of 120 seconds at ISO 1,600. The result was excellent and, I believe, shows how far I have come with astroimaging since my earlier afocal photographs just over one year ago. Practice + perseverance + patience = results (sometimes).

The main target this time was the Rosette Nebula, situated to the south west of NGC 2264. This giant molecular cloud of hydrogen gas consists of four nebulae (NGC 2237, 2238, 2239 & 2246), some 130 light-years in size with an open star cluster at the centre – NGC 2244. At about 5 million years old, these superhot stars are young and still being formed, with a brightness estimated to be some 400,000 times greater than our Sun. It is the energy and light from these stars that excites and illuminates the surrounding Rosette Nebula, which itself dominates the image.

NGC 2244 Rosette Nebula
William Optics GT 81 + AZ-EQ6 GT mount (unguided)+ Canon 700D DSLR| 30 x 120 secs @ ISO1,600 | 29th December 2014

Amongst various definitions, a rosette is the French diminutive of rose. It is also an award given for achievements. I’d like to think that this image captures both of these definitions – as a beautiful red, rose-like nebula and my personal award to mark a another milestone in my quest over the past year. A rosette may also typically be awarded to the winners at a show jumping or similar sporting event – in a comparable way, it’s now time for me to raise the astroimaging bar higher in 2015.

Reflections – 2014

December 31, 2014 by grahamrob in Astronomy holidays, Comments, Deep Sky Objects, Equipment, Imaging, Solar system, Viewing and tagged DSO Imaging, La Palma, Moon, Nebulae, Saturn | 1 Comment

2014 has been my first full year of astronomy and I thought it would be useful (for me) to recap, thereby hopefully providing some encouragement and momentum for 2015. It’s been a good year which I have enjoyed but it only gets a little easier, slowly, and I can see many challenges ahead.

JANUARY TO MARCH

At the start of the year I was still getting to grips with my original basic equipment, purchased in 2013 as an introduction to astronomy to see if I liked it: EQ3-2 mount, Skywatcher 150PL telescope and two basic Plössl eyepieces and Barlow. Though good, the shortcomings of the equipment quickly became apparent even for modest viewing tasks, so I soon made some important additions. In no particular order these were: RA and DEC motor drives, a Telrad finder and two better quality, wide-angle eyepieces. All of these items made a noticeable improvement to my astronomy and eventually my growing interest in astrophotography.

As a result, at the start of the New Year I decided to purchase a Canon 700D DSLR camera, which has since opened up a whole new world, literally. I have considerable SLR experience and had been using a compact digital camera for some years but the need to understand and use the technology embodied in a DSLR for astrophotography is, as they say, a whole new ball game.

At this stage, my approach to astronomy was to try and learn the basics first by using basic equipment, thereby understanding the nuts and bolts of astronomy before moving on to more technical processes and software driven equipment. Moreover, I hoped such an approach would provide a good, long-term foundation of knowledge to undertake more ambitious tasks one day; walk before you run.

Although a member of the Flamsteed Society, its location at Greenwich does not lend itself to regular, on-the-ground astronomy from which I might otherwise learn first-hand from other members. Unfortunately more local clubs are also absent, so the learning curve has been steep and mostly personal and hands-on, though I must recognise the extensive and generally excellent help gleaned from the internet and various astronomy blogs, noteworthy of which has been Stargazers Lounge. I have often been disappointed by some of the retailers who, in my experience don’t relate well to customers and / or provide clear, helpful guidance or adequate aftersales support. My interpretation is that they consist of persons who have probably started astronomy shops as an extension of what was previously a hobby and often lack the commercial and personal skills required for such a business. Thankfully there are exceptions and it is they who I shall return to with my business in the future, whenever possible.

Date	Object*	Feature / Name
Feb	Jupiter	Afocal Images
	Moon	DSLR mosaic
	Greta Orion Nebula	Afocal Images

*Record of photographic images taken in 2014

APRIL TO JUNE

By now I knew I wanted to pursue astronomy as a hobby and, in order to fast track my learning process and experience the subject at a higher level, I undertook a one week astronomy course at the private Tacande observatory in La Palma. The equipment there was outstanding and so was the night sky and guidance provided by the owner, Joan Genebriera. Afterwards I was hooked and my aspirations were sky high, literally.

Virgo Group – Galaxy Supercluster| Canon 350D from Tacande Observatory, La Palma

Returning from La Palma brought me back down to Earth, however, undeterred I felt it was time to try my hand at webcam planetary imaging. On the face of it easy but, as usual, looks can be deceiving. Online advice indicated that it was possible to adapt and rig-up an old webcam for such purposes but my attempts to do so using a spare Logitech webcam only ended in misery. I therefore decided to bite-the-bullet and purchase a more suitable, off-the shelf one. The Holy Grail for entering webcam imaging is apparently the Philips Toucam but alas it is no longer made and finding one second-hand is very difficult. I therefore soon realised that it would be necessary to purchase a new webcam and, furthermore, it made sense to get one which was specifically made for astrophotography, the theory being it would work out-the-box. As a result I purchased the ZWO ASI 034 MC colour webcam but, despite my best efforts was unable to get a picture and decided to visit the retailer in person, determined to find out if it was me or the camera; as it turned out it was neither.

The first problem turned out to be the camera software SharpCap, which despite assurances, would not work with the camera. Next, for reasons I still don’t understand, the alternative FireCapture software would also not work until a more up-to-date version was downloaded. Notwithstanding, it also became evident that the camera would not work through a USB 3.0 port – though at the time this was not specified anywhere in the accompanying literature. Finally, with the camera plugged in to the USB 2.0 port and the up-to-date version of FireCapture, it worked! Getting to this point took me countless hours at home, a long trip to the retailer (who was very helpful) and then still some 2-hours to get it working. So much for working out-the box! This again seems to be a feature of astronomy.

From this and other experiences with equipment, software and manufacturers I have concluded that the world of astronomy is fraught with unnecessary problems often arising from just inadequate advice (see previous comment). It is assumed, by others: manufacturers, retailers or more technically minded astronomers, that the user will possess similar skills to make things work but, as many /most of us are newcomers this is, to say the least, an unhelpful assumption. I have therefore learned that the internet is your friend. Through the use of various online sites and blogs, other astronomers have given their very helpful and often not inconsiderable time and advice, for which I am eternally grateful.

Whilst this was all happening at the retailer, I took the time to review the camera I had purchased more closely and at the last moment decided to exchange it for the inevitably more expensive ZWO ASI 120 MC version, which unlike the 034 MC version can be used for autoguiding – I hoped futureproofing the purchase, time will tell. It is interesting to note that the current version of this camera (a) comes with different software and (b) has been upgraded to work with USB 3.0 – well why wouldn’t it in the first place, as most computers now use this specification? This suggests to me: did they really think about the camera’s design and operation properly at the beginning? However, following this breakthrough using the webcam for imaging was still to provide its own problems, which I am still grappling with.

SW 150PL x2 Barlow & ZWO ASI 120 MC

Using the ZWO ASI 120 MC I first started imaging Saturn, with some success. However, using the EQ3-2 mount to find, focus and image was very difficult, especially when I tackled Mars. In this case the size of the planet makes all the aforementioned issues even more difficult but, after lots of attempts I managed to get an image – altogether with plenty of room for improvement but satisfying nonetheless. I subsequently discarded the webcam in favour of the DSLR, with which I am more comfortable and due to the lack of suitable, mostly planetary objects through the summer period. With the return of Jupiter in recent weeks and the prospect of using the ZWO webcam for autoguiding, I have returned to using it again but given the time that has since elapsed, I need to relearn its use all over again!

At this point I had concluded that I wanted to pursue astronomy and astrophotography. I was also drawn inexorably towards astroimaging DSO objects; they provide numerous, albeit more difficult targets at all times of the year and I have found their combination of otherworldly beauty and science fascinating – I am now on a slippery slope that I feel will last for years! The implications of this conclusion and based on what I had learned over the preceding year about my basic equipment had only one consequence, I needed better equipment. There are astronomers who will say this hobby can be done cheaply, frankly I don’t believe it. Even buying second hand and generally making-do, the need for another piece of equipment never seems to stop – ask my wife.

Resigned to this course of action and the inevitable extensive analysis of what equipment was best suited, I reached a conclusion of what equipment I needed surprisingly quickly, though still prevaricating over innumerable makes and models available. In the end I purchased an AZ-EQ6 GT mount and William Optics GT81 FPL3 triplet achromatic refractor. I could have shaved £400 to £500 off the cost by purchasing other very good but cheaper makes and models but the WO is a beautifully tactile piece of obviously very well made equipment, which is a pleasure to own and use. I had originally intended to purchase an HEQ5 mount but on taking the long view (no pun intended) and considering the superior and critical payload capacity decided to move up to the EQ6, which then became the AZ-EQ6 GT for its superior belt driven mechanism and even better payload.

Date	Object*	Feature / Name
April	M104	Sombrero Galaxy
	M1	Crab Nebula
	M3	Globular Cluster
	M84	Lenticular Galaxy
	M95 & M96 Group	Spiral Galaxy
	Virgo Group	Supercluster of Galaxies
	NGC 4435/38	The Eyes (Nonet) Galaxies
May	The Moon
	Mars
	Saturn

JULY TO DECEMBER

The absence of good astronomical darkness approaching the Summer Solstice at the end of June and onwards until later in August, makes imaging difficult at this time of the year. Furthermore, the summer skies are generally less interesting and altogether provide limited opportunities. As a result the one object remaining, that hopefully dominates the sky at this time of the year, is the Sun. It was therefore time to start solar astronomy.

Given the obvious dangers I approached the task carefully, getting a made-to-measure Baader Astro Solar filter for use with the Skywatcher 150PL. Rightly or wrongly, at this initial stage I decided to use the 150PL as I figured the larger, open design of the Newtonian reflector would help cooling. The result was fascinating, with sun spots and general surface granulation clearly visible. However, the set-up has two drawbacks: (i) the resulting FOV is small and requires six or more images to cover the whole of the Sun, and (ii) such a filter only produces a view of white light, not allowing the more spectacular features evident at a other wavelengths, such as prominences, to be viewed. For this a considerably more expensive solar telescope or highly specialized filters are required – such is the fascination of our local star I can see the time I will want to pursue this branch of astronomy further.

Sun Mosaic
SW 150PL + Baader Astro Solar Filter + Barlow x2 | Canon 700D DSLR

Having since used the new equipment for nearly six months now I have no regrets – you get what you pay for. However, as usual there have been problems to overcome. The mount is very solid and was a real pleasure to use but from the outset I have faced one big problem – polar alignment. With no view of Polaris or any of the northern sky, as my house is in the way, combined with restricted views to the south, east and west due to adjacent housing and trees, the only options were drift alignment or the polar alignment routine that I latterly discovered in the SynScan handset. For the moment the SynScan method has become my preferred technique but it can still be problematical, as it is quite fiddly and often the stars chosen by SynScan are not always visible e.g. it is not uncommon that at times all the alignment stars provided by Synscan are located in the northern sky and cannot be seen because of the aforementioned problems. However, I am getting better and with diligence and patience can now get to within 30” or less of true polar alignment, which has allowed exposures of up to 180 seconds. I have tried drift alignment a few times but have difficulty finding suitable stars on the horizon, as I basically don’t have an horizon! Going forwards I am considering the use of Alignmaster software, which looks very useful for this purpose, though the lack of a northerly view might still be a problem. In addition, I hope the ultimate goal of autoguiding should further enhance tracking accuracy even without perfect polar alignment – we shall see.

The second problem initially encountered was achieving an image when using the William Optics field flattener / focal reducer. Try as I may, I could not get an image with the William Optics GT81 + field flattener + camera combination and after a few evenings trying became desperate. How could it be so difficult? All this money for top-end equipment and not even a lousy image, let alone a good picture. With the help and encouragement from members of Stargazers Lounge, I had another go. This time I was more diligent with the set-up and at first using a very bright, easy to see star, was at last able to achieve a camera image and good focus using a Bahtinov mask. In a nutshell, the problem was that the point of focus is very, very critical, just a fraction of a millimetre out and the image disappears. Now I know this it’s quite easy but nobody points this out, least of all the manufacturer or retailer, who provided little to no instructions – I am learning this is also something common in the world of astronomy, which I find quite unacceptable.

So, after some weeks of trials and tribulations, the new equipment is mostly working very well and I have been able to successfully image a wide variety of objects. There’s plenty of room for improvement but I have obtained some enjoyable and often quite exciting photographs. Now for the next challenge, which has just started: computer control and autoguiding.

NGC 6960 AKA The Witch's Broom Canon 700D | 20x90 sec + darks.bias/ flats @ ISO 800

NGC 6960 AKA The Witch’s Broom
Canon 700D | 20×90 sec + darks.bias/ flats @ ISO 800

With DSLR or CCD / webcam imaging, processing is at least equally important as the original image capture. In the later part of the year I have therefore also started to tackle this dark art. Whilst compilation software such as Deep Sky Stacker and Registax requires some understanding to set-up, it is with post-processing that the final image can be made or lost. As a result I am using the extra time indoors to try and master the various techniques, with mixed success.

I should also note that during this period my elder daughter, Alison, persuaded and then helped me set-up this website. It has proved a useful discipline for organising my thoughts and images. I am very grateful for her help and have surprisingly enjoyed recording my astronomy endeavours. Although intended as a personal record, I note from the underlying website provider that it has been read far-and-wide across the world – 36 countries this year – which is also gratifying. I would love to hear from anybody via the WTSM site: questions, what are you doing, comments & feedback etc?

Date	Object*	Feature / Name
July	M57	Ring Nebula
	M13	Globular Cluster
	M15	Globular Cluster
Aug	M27	Dumbbell Nebula
	M31	Andromeda Galaxy
	M11	Wild Duck Cluster
	ISS	International Space Station
	NGC 6888	Crescent Nebula
		The Sun
Sept	NGC 7000	North America Nebula
	NGC 6960	Western Veil Nebula & Witch’s Broom
	NGC 7380	Wizzard Nebula
	M31	Andromenda Galaxy
	IC 1396	Elephant’s Trunk Nebula
	M2	Globular Cluster
Oct	M45	Pleiades Open Star Cluster
	Uranus
	M33	The Pinwheel Galaxy
	NGC 6992	Eastern Veil Nebula
	NGC 6995	Bat Nebula
	M42 & M43	Great Orion Nebula
	NGC 7320	Stephen’s Quintet (Galaxies)
	NGC 7331	Deer Lick Group (Galaxies)
	NGC 7814	Spiral Galaxy
Nov	NGC 1909	Witch Head Nebula
	IC 434	Horsehead Nebula
	NGC 2024	Flame Nebula
	NGC 1973/75/77	Running Man Nebula
Dec	M1	Crab Nebula
	ISS	International Space Station
	NGC 2264	Christmas Tree Cluster & Cone Nebula etc.
	NGC 2261	Hubble’s Variable Nebula
	NGC 19818	Open Star Cluster
	NGC 2244	Rosette Nebula
	M35	Open Star Cluster
	M78	Reflection Nebula

Goals for 2015 are:

Transfer the mount to EQMOD computer control – I have already linked the equipment indoors, together with Cartes du Ciel, but have yet to use it outside live.

Upgrade camera control software – again I am already trialling Astrophotography Tool (APT) indoors, which looks good and provides lots of flexibility, though in some ways I still like the EOS Utility software, which uses more simple and therefore reliable control choices.

For astrophotography this is the Holy Grail and, if successful, should enable significantly longer exposures and thus better detail and sharper images to be achieved. At the time of upgrading my equipment in the summer I also purchased a William Optics 50 mm guidescope – all I need to do is get it working! This will require two further pieces of software: (i) Push Here Dummy or PHD, which is responsible for controlling the interaction between the guidecope and the mount, and (ii) Astro Tortilla, which undertakes a process called ‘plate solving’, whereby using actual pictures taken at the time of set-up, it then recognises the section of the sky it (the telescope) is looking at, identifies the object in the field of view and using this information ensures that the telescope (and thus camera) are pointing exactly towards the chosen object by iteratively interacting with the other guiding software. As a fan of the KISS principle, I must admit to being somewhat intimidated by all this but am assured by others that it is not so bad to use (famous last words) and once up and running, will have a major impact. We shall see!

Even at this stage, I can already see the need for additional equipment. With numerous Ha-emitting nebulae a modified DSLR camera is beginning to seem essential and probably a more powerful computer for image processing. I am sure this list will grow as the year progresses.

All-in-all, I am pleased with my progress during the past year, with a noticeable improvement since acquiring the new equipment. There have been more highs than lows and, I suppose, that’s a result in itself. It is very exciting when you first see Saturn, Jupiter or Mars and then image them but I have discovered that my metier and main enjoyment comes from DSOs, in particular nebulae. I find their very nature beguiling; beautiful to view, challenging but very rewarding to image and scientifically fascinating. I am therefore sure that in 2015 they will remain my main targets but, notwithstanding, there are many other objects worthy of attention, including in the UK a partial eclipse of the Sun in March.

Watch this space!

Orions Sword. Top to bottom: NGC 1981 Open Star Cluster, NGC 1973/75/77 Nebulae, M42 & M43 Great Orion Nebula & the binary star Hatsya. WO GT81, Canon 700D + FF | 30 x 120 secs + darks/bias/flats @ ISO 800

My picture of the year: Orions Sword. Top to bottom: NGC 1981 Open Star Cluster, NGC 1973/75/77 Nebulae, M42 & M43 Great Orion Nebula & the binary star Hatsya.
WO GT81, Canon 700D + FF | 30 x 120 secs + darks/bias/flats @ ISO 800

It’s Christmas Time

December 24, 2014 by grahamrob in Deep Sky Objects and tagged DSO Imaging, Nebulae | 4 Comments

Being that time of the year and with my new interest in astronomy, the possibility of imaging the Christmas Star seemed like a good idea. However, looking into the matter it becomes apparent that there is much controversy over what the actual object might have been: a star, a supernova, a shooting star (meteor), Venus or Jupiter etc. Furthermore, it even seems that we don’t know for sure when Jesus was born. Apparently due to an error by a Church cleric hundreds of years later, it is thought the birth could be up to 4 years later than believed and almost certainly was not on December 25^th! This is all news to me and makes a timely image of the night sky difficult but then, on a rare clear night last Friday, I turned the telescope and camera on NGC 2264 in the constellation Monoceros, or the Unicorn, itself within the Orion arm of the Milky Way Galaxy. Situated on the Celestial Equator to the east of Orion and above Canis Major, Monoceros is something of a new name to me. Considered a ‘modern’ constellation, since being discovered more recently than many others in the 17^th Century, it turns out to be abundant with many exciting objects. But at this time of the year it has to be NGC 2264 or the Christmas Tree Cluster which is most worthy of attention.

At first, whilst the images from the camera looked very promising and the ‘tree’ showed up well, it’s equally interesting partners were nowhere to be seen – notably the Cone Nebula and Fox Fur Nebula. Notwithstanding, following more aggressive processing adjustments they appeared, albeit smaller in my image than expected and very noisy. Technically, lessons arise from this: (i) whilst the William Optics GT81 is a great telescope with outstanding optics, it is a small telescope, and only the very largest features will fill the image (ii) in this case and probably more importantly, in order to achieve an acceptable signal to noise ratio, only longer exposures will work – I am currently working on this, with the goal of starting to autoguide as soon as possible in the New Year. Furthermore, the nebulosity is mostly Hydrogen Alpha (Ha) emission type, which my unmodded sensor therefore responds to poorly due to its inbuilt UV/IR filter; something else to deal with in the future.

Notwithstanding, I am still pleased with the result which in the end does show most of the main features, albeit with plenty of room for improvement; I also know how but getting there will not be easy. For obvious reasons the star of the show (no pun intended) is the Christmas Tree Cluster. The bright star at the bottom of the picture is Monocerotis 15 or S Monocerotis, which forms the tree’s ‘pot’ and is a quadruple system of four brilliant white stars. A little confusing, the view we get from earth of the ‘tree’ is upside down, so the following image has been inverted and is before post-processing, so as to make the stars that form the outline of the tree more clear.

NGC 2264 Christmas Tree Cluster - inverted to better show the 'tree' shape i.e the top is south

NGC 2264 Christmas Tree Cluster, before post-processing and inverted to show the ‘tree’ shape i.e the top is south. The large, bright star, 15 Moncerotis, marks the base of the ‘tree’.

However, the Christmas Tree Cluster is only part of NGC 2264’s glorious nature, most notable of which is probably the Cone Nebula. Located below (south) of the Christmas Tree, the Cone Nebula is a towering, triangular shaped column of cold, dark molecular hydrogen gas and dust, which appears to be flowing out from the young stars located close to the top of the cone. Some 2,200 light-years distant from Earth and 900 light-years further than the Orion Nebula, the Cone is quite small in the original picture but is in fact 60 arc seconds or 40 light-years in size!

NGC 2264, actual orientation: Cone Nebula at the bottom, Monocerotis 15 at the top with the Fox Fur Nebula to right but not clear, outline of the main stars and numbla defines the (invered) Chriostmas Tree Cluster WO G T81, Canon 700D + FF | 30 x 120 secs + darks/bias/flats @ ISO 800

NGC 2264 (actual orientation): Cone Nebula at the bottom, Monocerotis 15 now at the top, with the Fox Fur Nebula to the right but not visible. The outline of the main stars and associated nebulosity defines the (upside down) Christmas Tree Cluster – 15 Monocerotis is now at the top.
WO G T81, Canon 700D + FF | 30 x 120 secs + darks/bias/flats @ ISO 800

Map of Cone Nebula

Also included in the NGC 2264 region is the wonderfully named Fox Fur Nebula, so called as it is said to look like the head of a stole made from red fox fur. Combined with the aforementioned Ha light issue, my equipment cannot do this feature justice at the moment but, using an image from elsewhere, when viewed close-up (and you get your eye in) it is a very convincing feature.

Fox Fur Nebula

In addition to the above, NGC 2261 or Hubble’s Variable Nebula is worthy of mention. Located nearby to NGC 2264 this fan shaped nebula is illuminated by the star R Moncerotis.

NGC 2264 Christmas Tree Nebula shown by red box. Lower arrow points to the Cone Nebula, upper arrow indicates location of the Fox Fur Nebula. NGC 2261 Hubble’s Variable Nebula shown by red hexagon.

NGC 2261 Hubble’s Variable Nebula, illuminated by R Monocerotis star

Altogether there are more than seven nebulae to be found in this region of the sky, which has turned out to be something of a pleasant surprise to me and will be revisiting once I can achieve longer exposures and deal with Ha light better. The constellation of Monoceros is also itself something of a surprise, with the prospect of some other great images that deserve further attention in the New Year – can’t wait for Christmas to finish.

Sunset at Fairvale Observatory on the evening before the Winter Solstice

Sunset later the same day at Fairvale Observatory, the evening before the Winter Solstice

Lace up the Nikes

December 2, 2014 by grahamrob in Deep Sky Objects and tagged DSO, DSO Imaging, Orion | 2 Comments

There is no doubt in my mind that the Orion Constellation is the most spectacular of the year and right now comes into imaging view at Fairvale Observatory at about 11pm, about the same time the waxing Moon disappears over the horizon; for once the timing is perfect. So before the presence of the Full Moon later this week rules out astrophotography, last Saturday evening provided an excellent opportunity.

The more I look at the Orion Constellation the more there is to see and image, as well as some other attractive objects that will be around until at least the New Year and in some cases well beyond. One lesson I have learned early on with astrophotography is the need for good planning: what’s around to image? when is it in the best location i.e. near the Meridian? what equipment is needed and is it working? set it up in good time and ensure good alignment. Given the aforementioned favourable conditions and the arrival of Orion, my list of objects this month is considerable:

Early evening: M32 Andromeda Galaxy & NGC 1499 California Nebula.

Late evening / midnight: Orion Constellation – NGC 2024 Flame Nebula, IC 434 Horsehead Nebula, M42 & M 43 Great Orion Nebula, NGC 1977 Nebula, NGC 1981 Emission Nebula, NGC 1909 Witch Head Nebula, SH 2-276 Barnards Loop, SH 2-264 Angelfish Nebula, M78 reflection nebula and more. Other – M1 Crab Nebula, Hyades (Taurus), M77 barred spiral galaxy and Jupiter, which together with its four moons is also looking very nice after 1 a.m. at the moment.

With such an array of possibilities it can be difficult to know where to start but having recently achieved good images of the Great Orion Nebula and the Flame and Horsehead Nebulae, the next target was an easy choice – it had to be NGC 1977, which with the William Optics GT81 field-of-view also takes in NGC 1981 and M42, three for the price of one!

Orion’s Sword. Top to bottom: NGC 1981 Open Star Cluster, NGC 1973/75/77 Nebulae, M42 & M43 Great Orion Nebula & the binary star Hatysa.
WO GT81, Canon 700D + FF | 30 x 120 secs + darks/bias/flats @ ISO 800

There is so much going on in this photograph that merits attention. The view encapsulates all the major components that form Orion’s Sword, notably from top to bottom: the open star cluster NGC 1981, the star Theta Orionis C in the Trapezium cluster – itself within M42 and the star Hatysa (Iota Orionis), which forms the tip of the sword. Obviously M42, The Great Orion Nebula dominates the scene but two other major features are worthy of attention too.

Orion’s Sword – detail

The aforementioned NGC 1981 is an open cluster of about 20 stars located 40 light years closer to Earth than M42. But it is what’s between M42 and NGC 1981 that was my main target this time: the reflection nebulae of NGC 1977 and related NGC 1973 & 1975, AKA the Running Man Nebula, so named because it looks like a running man! The three nebulae are illuminated by the blue light shining from young stars that are forming within each area of nebulosity, which are separated by dark zones of interstellar dust in the form of a man running – not unlike Eadweard Muybridge’s pioneering photographic images of motion taken at the end of the 19^th Century, I am sure he would have appreciated the analogy.

NGC 1973/75/77 The Running Man Nebula (rotated – North is left)

Eadweard Muybridge’s photographic studies of a running man, late-19th Century

The Horse & Flame

November 26, 2014 by grahamrob in AstroBin, Deep Sky Objects, Imaging and tagged DSO Imaging, Nebulae, Orion | 2 Comments

With the full moon early in the month and some truly awful weather, I have been unable to get out at Fairvale Observatory since October 31^st! Notwithstanding , this has been an opportunity to spend time learning more about the dark art of processing, which can sometimes be more important than image capture itself, so is hopefully time well spent. Apart from the usual assistance of Mr Google, I have purchased the excellent online ‘book’ of Jerry Lodriguss, Photoshop for Astrophotographers – which I am slowly working through, and watched the equally excellent YouTube tutorials by Doug German on the same matter. It is often said that a picture is worth a thousand words, and Doug’s tutorials are probably the easiest and most accessible way into the use of Photoshop for astrophotography – I also enjoy his dry sense of humour. Finally, I am currently trialling Russell Croman’s Gradient Exterminator, which is intended to remove the external light gradient that inevitably creeps into even the best of images; it’s early days but I think I like it – it’s tricky to use and Doug German’s video tutorial is very helpful in this regard too.

The extended absence of clear night skies for astronomy also benefits subsequent viewing as the sky has changed, in this case a lot. We have now moved on to winter skies, which are best exemplified by the constellation of Orion here in the northern hemisphere. I was initially successful in imaging the iconic Orion Nebula early in October but only by getting up very, very early. At Fairlvale Observatory it now comes into view at about 10pm and after 11pm can be imaged. With clear skies finally arriving last Sunday evening, albeit accompanied by very cold temperatures, I was finally able to get out again – this time to spend more time with Orion.

In my ignorance, what has surprised me about Orion is the extensive presence of spectacular nebulae throughout the constellation: M42 Orion Nebula, M43 De Mairan’s Nebula, NGC 1973/5/7 The Running Man nebula, M78 between Alnitak and Betelguese etc, etc. But, I had also somehow overlooked the ‘Horse & Flame’, located above the Orion Nebula nearby the lower end of Orion’s belt: Mintaka – Alnilam – Alnitak. In close proximity to Alnitak (a triple star), which with an apparent magnitude between +2.0 and +4.0 is a problem for imaging, the sky is full of spectacular nebulae – notably the Flame Nebula and the iconic Horsehead Nebula. Having latterly learnt of their presence in the same part of the sky, I had to try and image them.

The Horsehead Nebula is a cloud of interstellar dust and gas that, as a result of it’s density, appears dark against the surrounding red nebulous ‘curtains’. The resulting shape looks like, well a horse’s head and has therefore become an iconic and well known image. However, located on the other north-eastern side of Alnitak is perhaps the real star (no pun intended) of the show, the Flame Nebula – NGC 2024. A combination of dark gas and dust with glowing hydrogen gas, energised by ultraviolet light emitted from Alnitak. Such is the form of these materials that the resulting effect is that of a burning flame. I was therefore thrilled that after my enforced indoor sojourn to be able to capture the Horse and Flame (sounds like a pub I’d like to visit!) together in one beautiful picture.

The Horsehead and Flame Nebulae. The Horse is located directly below (south) the large bright star Altinak triple star which forms the eastern end of Orion's belt, about half way down the image, sticking its 'head' into the red curtain nebulosity. The Flame is just to the left (east) of Altinak. WO GT81, Canon 700D + FF | 28 x 90 secs + darks/bias/flats ISO 1,000 | Photoshop processed + Gradient Exterminator

The Horsehead and Flame Nebulae. The Horse is located directly below (south) the large bright Alnitak triple star which forms the eastern (left) end of Orion’s belt, about half way down the image, sticking its ‘head’ into the red curtain of nebulosity. The Flame is just to the left (east) of Alnitak.
WO GT81, Canon 700D + FF | 28 x 90 secs + darks/bias/flats ISO 1,600 | Photoshop processed + Gradient Exterminator

The Bat

October 29, 2014 by grahamrob in Deep Sky Objects and tagged DSO Imaging, Nebulae | 1 Comment

It’s Halloween time of the year and I don’t like it. My problem is that in the UK this used to be a minor event, treated as a bit of fun for some and ignored by most. However, it’s been given the North American makeover and pumped up as a big deal, mainly on commercial grounds. Grrrrr!

Less seasonable has been the weather, which thankfully continues to be warm and sunny with occasional clear night skies. Hooray! A great combination enhanced further by the appearance of winter astronomy objects and since last weekend’s change of clocks 1-hour backwards, darkness from early evening. What’s not to like for the astronomer? Starting at 6 pm I was therefore able to spend more than 7 hours on Monday night imaging a procession of DSOs as they approached and passed the meridian. Moreover, I achieved almost perfect alignment and for the first time was able to obtain good exposures of between 120 and 180 seconds; had I tried I suspect even longer periods could have been achieved.

First off the rank was the Veil Nebula, part of the even larger Cygnus Loop, a massive supernova remnant. Located about 1,470 light years away and between 5,000 and 8,000 years old, much of this this emission nebula is not in the visible spectrum and what is is feint and difficult to image. I have already obtained a good photograph of the Western Veil of the nebula, also known as NGC 6960 or the Witch’s Broom https://watchthisspaceman.wordpress.com/2014/10/04/the-witchs-broom/ . Now with such good conditions and my best ever alignment, I decided to turn my attention to the Eastern Limb, or NGC 6992 and NGC 6995.

Cygnus Loop (Veil Nebula) in untraviolet light. Image area of the Western Veil highlighted by red box.

Cygnus Loop (Veil Nebula) in untraviolet light. Image area of the Eastern Veil highlighted by red box.

Using the new CLS light pollution filter and 30 x 120 second exposures, the resulting image from the camera immediately showed the full extent of this magnificent object, even before processing. Post processing the feature really comes to life, with large billowing waves of nebulous ionized gas and interstellar dust. The brighter, right-hand side (northern) of NGC 6992 trails off to the left (southerly) section of NGC 6995, also known as the Bat Nebula – well it is Halloween!

Eastern Veil Nebula – NGC 6992 (right) & NGC 6995 (left).
WO GT81 + Canon 700D & FF | 29 x 120 secs + darks/bias/flats @ ISO 1,600

NGC 6995 AKA The Bat Nebula (look carefully and you’ll see him!)

The Witch’s Broom

October 4, 2014 by grahamrob in Deep Sky Objects, Imaging and tagged DSO Imaging, Nebulae | 2 Comments

With polar alignment and tracking now working quite well, I have been hunting around for potential new targets before moving on to the next challenges of computer control and auto-guiding. Within the constraints of my limited sight lines, light pollution, weather and a rapidly encroaching full moon, I decided to tackle the somewhat elusive Veil Nebula. Although the apparent magnitude of 7.0 is not unduly challenging, the delicate nature and low surface brightness of this very large ionized gas cloud can make it difficult to image.

Located in the Cygnus constellation, the Veil Nebula is a very large but feint supernova remnant about 1.400 ly from Earth that exploded between 5,000 and 8,000 years ago i.e. quite recently. The Veil Nebula, Cirrus and Filamentary Nebula usually refer to those parts that can be viewed, the rest of the feature not being in the visible spectrum; the Veil is one of the largest, brightest features in the x-ray sky. So big is the Veil that various sections are recorded as separate NGC numbers: 6960, 6992, 6995, 6974, 6979 and IC 1340.

Located close to the binary star system 52 Cygni, the classic view is of the Western Veil or NGC 6960, AKA the “Witch’s Broom”, “Finger of God or “Filamentary Nebula”, which spans across 35 light-years and I therefore set out to photograph. Following the recent success of the North America Nebula I undertook a test shot at the same settings: 90 seconds at ISO 1,600. However, the resulting picture looked excessively washed out and so changed to 90 seconds at ISO 800, which seemed to work better – though you never really know until the late stages of post-processing. Despite forecasts to the contrary, the cloud rolled in after just six shots but two hours later and still tracking, the clouds parted leaving a clear sky and just enough time to take another twenty shots.

Initial processing was not encouraging. Truth be told there’s still a lot to learn with this part of astro-imaging but, with some difficulty and courtesy of Mrs G, a good image of the Witch’s Broom was eventually teased from the data.

NGC 6960 AKA The Witch’s Broom
Canon 700D | 20 x 90 sec + darks/bias/ flats @ ISO 800

Focus is everything

August 7, 2014 by grahamrob in AstroBin, Deep Sky Objects, Equipment, Imaging, Uncategorized and tagged DSO Imaging | Leave a comment

FOCUS: The state or quality of having or producing clear visual definition – Oxford English Dictionaries.

Splashed the cash and got the equipment, done the reading and asked all the right questions on the astronomy forums, got a clear night, time to catch those images – what can go wrong? Having recently purchased and got a new AZ-EQ6 mount and WO scope working OK visually, it was time to embark on my new DSO photographic quest. Not for the first time I unfortunately underestimated just how difficult this astrophotography is; forgetting that I’d already battled before to image with the Newtonian 150PL using both the DSLR and ZWO webcam (more on that another time).

This time the challenge was using the new WO Field Flattener http://www.williamoptics.com/accessories/flattener6A_features.php. So – set up scope, align mount/scope, find object, centre and visually focus. Then attach the field flattener (FFL) to the DSLR and slide directly into the focus tube, focus and take images – easy? No! Even now I am not sure what went wrong but after three evenings and numerous questions on the Stargazers Lounge forum (SGL), I was completely unable to get a clear picture through the camera, let alone an image. Initially I just thought the set up was wrong (whilst all the WO various equipment is excellent, none of it comes with instructions. I am told this is par for astronomy but, when you are forking out this kind of money I find that quite unacceptable) or I needed yet another piece of equipment to achieve focus (surprisingly the ‘expert’ dealer from where I bought it wasn’t even sure on this!), spacers perhaps? By now I was very concerned.

Another clear warm night soon came and with perseverance low and behold a result. This time I was much more meticulous: visually focusing on the bright star Arcturus, then switching to the DSLR + FF. Using the Canon EOS Utility and Live View, with the ISO set very high I was at last able to see something on the screen, which with very fine adjustment came into focus as a small, very bright dot. Placing my other recently discovered brilliant invention, the Bahtinov mask http://en.wikipedia.org/wiki/Bahtinov_mask

over the objective lens I was able to refine the focus perfectly:

Now carefully transferring the scope and refining the position via Live View I was ready for a serious attempt on my first DSO, M13 The Great Globular Cluster in the constellation of Hercules:

WO GT 81 + FF 10x16sec at ISO800

Bingo + what a relief! Like my first crude afocal image of the Orion Nebula last year, getting the picture was exhilarating. OK it’s not brilliant and I have seen the image in numerous publications and online but, it was mine, having captured those photon’s which had been travelling for the past 25,000 light-years on my camera, just outside my back door. WOW!

http://apod.nasa.gov/apod/ap120614.html

I hope to improve on this one day, once I have mastered all the other software, guidescope etc but I doubt I’ll feel quite the same next time. In the end, focus was everything, it is very difficult to achieve and only goes to show just how difficult this astrophotography is but after the light spent so long getting here, the least I can do is focus it right on my camera sensor, which requires a fraction of a millimeter accuracy.

Later on the same night I also captured M57, the Ring Nebula (more another time). Apart from refining this process (which I can see will take what ever’s left of my lifetime) my next ambition is to capture a galaxy out my back door, I can’t wait!