Room With A View

February 12, 2015 by grahamrob in Comments, Imaging, Widefield Imaging | Leave a comment

The International Space Station is an amazing achievement and I consider the people who fly in the ISS to be very lucky.

From time to time the ISS flies over Fairvale Observatory and last Christmas Eve was such a moment when, travelling at just over 17,000 mph about 250 miles above Earth, I managed to get a picture of its trail in the sky.

ISS flies over Fairvale Observatory 24th December 2015

ISS flies over Fairvale Observatory
24th December 2014

Yesterday US astronaut Terry Virts currently onboard the ISS tweeted this fantastic picture of the British Isles from his vantage point above Earth, set-off by the Aurora Borealis to the north. Thanks Terry and good luck.

Orion in Perspective

February 6, 2015 by grahamrob in Deep Sky Objects, Equipment, General Astronomy, Imaging, Widefield Imaging and tagged Orion, Photography | Leave a comment

Perspective:

The appearance of objects relative to each other, as determined by their distance from the viewer, or the effects of this distance on their appearance – The Free Dictionary.

Noun: The art of representing three-dimensional objects on a two-dimensional surface so as to give the right impression on their height, width, depth and position in relation to each other – Oxford English Dictionary

I have just finished an Open University MOOC (Massive Open Online Course) on Orion, which it has to be said was mixed in its content and quality. Notwithstanding, the course provided a useful basic understanding of objects in the Universe, particularly Orion, how they related to each other and as a whole. Through my professional experience I am used to viewing and understanding objects in 3D, all the more so since computer modelling has provided a tool with which to visually illustrate such spatial shapes and relationships. Although it is obvious that such relationships also describe the astronomical space in which we exist i.e. the Universe, and commonly describe the location of stars and other heavenly bodies by their distance, RA and DEC, I have seen very few of these objects visually modelled for common asterisms or constellations.

The constellation of Orion is probably the main feature of the winter night sky and it is certainly my favourite, particularly when looking at its rich content: M42 the Great Orion Nebula, the Running Man Nebula, the Horsehead and Flame Nebulae, M78, Barnard’s Loop and many more. Sadly after more than 4-months imaging these objects for the first time, Orion is now starting to rise very early in the evening and by 11pm is well past the Meridian – it will not be long before this magnificent feature will be gone for another year, until on the very early mornings of next October it will reappear again, can’t wait!

With my new found interest in astroimaging I have almost exclusively used a DSLR camera and focused my attention on DSO features, using a telescope and GoTo mount, somewhat neglecting the use of the camera for basic widefield photography. Apart from the attraction of playing with my new toys, I was put off by the lack of a suitable camera attachment and a wide angle lens; because of the inherent crop factor associated with the cropped digital sensors employed in most DSLR cameras (except very expensive full frame cameras), the real focal length of a camera lens will be extended and hence the field-of-view narrowed – in my case with a x1.61 crop factor, a 50mm lens operates at an apparent focal length of 80mm! However, using the top off an old camera tripod I recently I managed to jerry rig the camera onto the GoTo mount, thus providing tracking and enabling longer exposures. It’s only a start but there is great promise in such photography, as seen on this excellent website, and I intend to pursue more of these images with a better way of attaching the camera and decent wide-angle lens when I can.

As a result, on Christmas Eve I obtained my first reasonable image of the whole Orion constellation, which with better exposure shows the detail, beauty and context of the numerous DSO items contained within and images previously noted.

The Orion Constellation Canon 700D | 27 x 10 secs @ ISO 1,600 & calibration | 24th December 2014

The Orion Constellation
Canon 700D & Telephoto 200 mm | 27 x 10 secs @ ISO 1,600 & calibration | 24th December 2014

In the early days of my astroimaging about 12 months ago, I found focussing something of a challenge but, with the assistance of the wonderful Bahtinov mask and Live View on-screen computer focusing, I thought that had become a thing of the past, unfortunately not! Guided by the infinity mark on the camera lens for focussing, I set out to image some of Orion’s more elusive nebulosity, in particular Barnard’s Loop, with which I am fascinated – its enormous size of some 10^oor 600 arcminutes and complete absence from ordinary view are both intriguing, exciting and challenging. I had tried to photograph this feature before, which completely envelops Orion’s Sword and extends up towards Betelgeuse, but to no avail. With my bodged but useable camera set-up I tried again two weeks ago. This time the problem was once again focussing; it turns out that with widefield astroimaging using a standard camera lens, infinity does not necessarily mean infinity, as there is some leeway either side. The out-of-focus images that resulted could therefore not be stacked but, using a single image, calibration and extensive post-process stretching in Photoshop, Barnard’s Loop was finally revealed and even Lambda Orionis above Betelgeuse and Bellatrix, albeit very noisy and out of focus. Notwithstanding, I am pleased with this enticing glimpse and will return another day to rectify the problems.

The Orion Constellation & Barnard's Loop (up / north is left) AZ-EQ6 Mount + Canon 550D & 200mm Telephoto | 180 secs @ ISO 1,600 & calibration | 22nd January 2015

The Orion Constellation & Barnard’s Loop (up / north is left)
AZ-EQ6 Mount + Canon 550D & Telephoto 200 mm | 180 secs @ ISO 1,600 & calibration | 22nd January 2015

Since my first decent image of the Great Orion Nebula on a very early morning at the beginning of last October, I have had hours of fun and some frustration imaging various parts of the Orion Constellation. But despite my new familiarity with the Orion constellation, 3D modelling and, I’d like to think, good spatial awareness, I was still pleasantly surprised and impressed by this wonderful 3D video of the constellation produced by the Space Telescope Science Institute for NASA and used during the aforementioned Open University course, which really does put it all into perspective: The True Shape of Orion.

Busy Bees

February 1, 2015 by grahamrob in AstroBin, Deep Sky Objects, Imaging and tagged Cancer, DSO Imaging, Star Clusters | 1 Comment

Cancer AKA the Crab, is the dimmest of the zodiacal constellations and generally lacking in notable objects except, at its centre, lying almost on the Ecliptic just 600 light-years from Earth, M44 is one of the closest star clusters to the Solar System. More engagingly, M44 derives its alternative name from its appearance as a swarm of stars dancing actively like bees i.e. the Beehive Cluster. Its Latin equivalent, Praesepe means hive, manger or crib.

At 600 million years old its dancing stars must be considered quite youthful compared to our Sun’s 4.5 billion years and are thought to have been created from the same, very large molecular cloud as Hyades in the constellation of Taurus. An open cluster of some 1,000 stars, M44 spans 15 light-years across or about 1.5^o. A few but distinctive yellow-orange tinted red giants stand out, scattered amongst the brighter hot blue stars, making an attractive image, one I expect to return to during the next three or more months as The Crab shuffles westwards across the night sky before giving way to views of a Spring and Summer nature.

M44 The Beehive Cluster
WO GT 81 + Canon 550D & FF | 20 x 120 secs & calibration @ ISO 1,600 | 24th January 2015

Flip Flop

January 29, 2015 by grahamrob in Deep Sky Objects, Imaging and tagged DSO Imaging, Gemini | 2 Comments

Another night, another lesson learned, the hard way.

A good, clear sky on Saturday meant the prospect of a long and productive imaging session before the frost came down. Whilst Orion has now moved to early evening, the light pollution from Gatwick airport to the south is bad at that time, so I’ll grab what I can but later is better when the light pollution starts to subside; from experience I presume they start to turn off the airport lights gradually from about 10pm, so that by midnight the sky is noticeably darker and much better for astronomy – though nothing like a true dark sky. I therefore look more to the south east at about 8pm to line up potential imaging targets for about one to two hours later when objects will be located at their best position, towards the Celestial Meridian and preferably high in the sky; such a location reduces the thickness of the atmosphere and improves tracking accuracy as the telescope’s angle with the object is less extreme. At the moment this means something in or around the constellation of Gemini and later at night Cancer; Canis Major, Pupis and Hydra also fit the bill except for one critical problem, they are too low in the sky and are mostly obscured by houses and trees, grrrrr!

Having imaged three, mostly easier objects earlier in the evening, at about 10pm I then turned my attention to something more challenging. Though large at some 100 light-years in diameter, the wonderfully named Jellyfish Nebula in the Gemini constellation (not far from the M35 open star cluster), with an apparent magnitude of +12 is quite faint and would be difficult to photograph. Notwithstanding, my first test image showed it was already in my field-of-view, though as anticipated faint, which I then set about adjusting to optimize its position within the frame before starting imaging. In this regard two bright, dominant stars flank the nebula – to the left or East, Tejat Posterior and to the right or West, Propus – thus assisting on screen identification and the approximate position of the nebula on the camera’s sensor.

At this time the nebula was very close to the aforementioned Celestial Meridian and it was clear that during a 1-hour imaging run would actually cross the Meridian, thus requiring a so called ‘Meridian Flip’. When setting-up the EQ-mount and telescope at the start, it is essential that they are aligned parallel with the Celestial Meridian in order that the mount and scope will then exactly track the movement of the night sky during subsequent viewing or imaging. However, due to the physical nature (internal gears) and resulting constraints of the mount and tripod, as tracking proceeds from east to west and eventually encounters the Celestial Meridian, it is necessary to carry out a Meridian Flip, manually or automatically. Such a flip requires that the mount and thus telescope and camera are swung from the west side of the tripod to the east, thereby ensuring that in continuing to track the object as it proceeds westwards they do not come into contact with the tripod.

Using the guide stars of Tejat Prosper and Propus to mark the East and West limits of the nebula and expecting the bulk of the other associated nebulosity to extend upwards, I positioned the stars towards the bottom of the frame. However, the nebula had by now crossed the Meridian and the telescope and camera was switched (flipped) to the other side of the mount before I completed framing. In-so-doing and, in my defence operating in the dark, I had overlooked that as a consequence of flipping across the Meridian, the camera had been inverted. Oblivious to this change of the camera’s attitude, I continued to frame the stars and thus hopefully placing the nebula towards the bottom of the image, when instead I should be moving them towards the top of the frame as the camera was now upside down. The result was that the final image unfortunately misses some of the associated nebulosity, though thankfully not the Jellyfish itself.

IC 443 The Jellyfish Nebula with Propus to the left and Tejat Prosper to the right after inverting the camera. As a result much of the considerable interstellar cloud illuminated by interaction with the nebula is outside the bottom of the image. WO GT81 + Canon 550D + FF | 20 x 180 secs @ ISO 1,600 + calibration | 24th January 2015

IC 443 The Jellyfish Nebula, with Propus to the left and Tejat Prosper to the right after a Meridian Flip inverted the camera before framing. As a result much of the interstellar cloud illuminated by interaction with the nebula is lost outside the bottom of the image.
WO GT81 + Canon 550D + FF | 20 x 180 secs @ ISO 1,600 + calibration | 24th January 2015

The Jellyfish Nebula is considered to be the remnant of a supernova that took place between 3,000 and 30,000 years ago and is now interacting with surrounding molecular clouds. Like similar supernovae such as M1 the Crab Nebula, the Jellyfish also harbours a neutron star within, indicating a collapsed stellar core. The main Jellyfish is some 100 light-years across and 5,000 light years away from Earth.

IC-443 Jellyfish Nebula, correctly orientated Propus is now to the right.

The denser, though still delicate nebulosity of the main ‘Jellyfish’ feature, is located immediately east of Prospus but most of the entire field between the two aforementioned stars and an equal area above is also occupied by extensive, though more faint nebulosity – it was this which was lost in my final image due to the framing error noted above. Even with the new modded camera and 180 second exposures at ISO 1,600, the sensor has struggled to capture all the light but I am fascinated and pleased nonetheless with the result. A better image of IC-443 AKA the Jellyfish Nebula will have to wait until I am able to undertake much longer exposures, which I hope to do one of these days soon. In the meantime, I will be more aware of the Meridian Flip and its associated problems.

Seeing Red

January 24, 2015 by grahamrob in Deep Sky Objects, Equipment, Imaging and tagged DSO Imaging, Orion, Photography | 2 Comments

It was towards the end of last year I realised what I was missing in my images. Hydrogen alpha (Ha) is a deep-red spectral line created by energised hydrogen gas, with a wavelength of 656.28nm, such light is a dominant feature of emission nebulae. However, terrestrial cameras are made with an infra-red (IR) filter placed over the sensor in order to achieve the red-green-blue colours that typify what the human eye see as life on Earth. Unfortunately by filtering out some of the red wavelengths this has a negative impact on DSO astroimaging, as it will block the aforementioned Ha light. The result is that imaging such Ha features with a DSLR camera, as I have been doing with a Canon 700D, can significantly reduce the colour and even detail – in some cases where Ha is the principal light source the camera sensor may almost completely fail to register the object at all.

I had been aware of this problem from the outset when I purchased the Canon 700D but decided to make-do in order to see, (a) how I got on, and (b) if I even liked astrophotography. Nearly one year on and maybe I made a mistake then but I also enjoy using the camera for terrestrial photography. Here’s the catch: to improve the camera’s sensitivity to Ha it is necessary to remove the IR filter, to become what is then known colloquially as a modded camera, however, in doing so the camera becomes useless for terrestrial photography. Removing the IR filter allows more red light wavelengths to reach the sensor and, as a result, terrestrial pictures then acquire an overall pink-red hue! There are some ways round this but, as always with implications – but it was now clear I needed a modded camera.

There are three basic ways to ‘restore’ a modded camera for terrestrial use:

Adjust the custom white balance – each time the white balance needs to be set manually, depending on the type of prevailing light and subject. It will work but, in my opinion, makes the process of day-to-day photography something of a chore and certainly reduces the scope for spontaneity, something I like when I am out-and-about photographing.

Restore the colour balance during post-processing – basically this requires adjusting each photograph individually using processing software, such as Photoshop, to remove excess red that is reaching the sensor without the IR filter.

Use an OWB (Original White Balance) filter – like the CLS light pollution filter I already use, this filter fits snuggly in front of the mirror / behind the camera lens (if fitted) and essentially acts like the original IR filter that has now been removed for astrophotography. Although quite expensive, this is by far the most convenient solution but there’s a problem: the back-focus section of the standard Canon EF-S lens I use is too long to accommodate the filter. An EF or other manufacture’s lens would overcome this problem (at further expense) and I was about to go down this route when serendipity paid a visit.

Not to be taken literally, but sometimes I would rather be lucky than smart. Whilst researching the aforementioned issues and seeking out other possible solutions, such as purchasing an already modded camera, I registered on the excellent Astronomy Shed forum and posted a question on how to deal with my problem. By the next morning, together with other advice on how to proceed, my attention was drawn to a Canon 550D for sale that had just been posted on the forum that very moment. Furthermore, the price was good and the seller would modify the camera for a small charge; it requires a degree of expertise to carry this out but, as a professional photographer with an interest in astronomy, the seller had undertaken this successfully many times before, though I obtained references to be sure. Therefore, after a few online exchanges, I became the new owner of a modified Canon 550d camera, together with some other bits and pieces – leads, intervalometer and a Canon battery grip.

Apart from the fact that this was a good camera, at a good price, it had one other very useful attraction – it is a close relation of my other camera, the Canon 700D (about three years older in development terms) and thus I immediately knew my way around and, furthermore, all my existing accessories would fit. Like I said, I had just got lucky – in more than one way. It’s early days but, with a clear sky last Friday and plenty to image at the moment, I just had to try it out and was not disappointed.

Rosette Nebula
WO GT81 + Canon 550d (modded) + FF | 15 x 120secs @ ISO1,600 + darks/bias/flats | 16th January 2015

The evening’s targets were Comet Lovejoy, The Rosette Nebula and the Great Orion Nebula, of which the latter two showed off the camera’s new capabilities best. The difference was there to see immediately with the images straight out the camera and stacked, with a noticeable increase of red colour present. The benefit after post processing is perhaps more subtle but, I suspect, will become more apparent when I move on to objects where Ha is more abundant, such as NGC 2264 AKA The Christmas Tree Cluster & Cone Nebula, which when imaged just before Christmas showed just what I was missing – a shortage of red light and thereby significant detail of these beguiling astronomical objects. Hopefully this issue will now become a thing of the past and in the future I will be literally seeing red, for all the right reasons.

M42 & NGC 1977 After DSS stacking only
WO GT81 + Canon 700D (unmodded) + FF | 15 x 120secs @ ISO800 darks/bias/flats

M42 + NGC 1977 After DSS stacking
WO GT81 + Canon 550D (modded) + FF | 5 x 120secs @ISO1,600 + darks

The above stacked, pre-post processing images are the same objects shot with unmodded (Canon 700D) and modded (Canon 550D) cameras, showing a marked increased in red light using the modded camera following the removal of the IR filter. Below, the same images after post-processing.

Final, post-processing image from unmodded camera

Final, post-processing image using modified camera

Lovejoy Part-2

January 18, 2015 by grahamrob in General Astronomy, Solar system, Viewing and tagged Comet, Solar system | 1 Comment

I first became acquainted with C/2014 Q2 Comet Lovejoy just before Christmas and have since been keen to obtain my own image of the object from Fairvale Observatory; at the time I was fortunate to obtain a photograph of the comet from a fellow astronomer in La Palma. Despite the comet reaching its best positon on January 7^th, some 44 million miles from Earth and with the apparent magnitude (brightness) improving throughout January to less than +4.0, unfortunately nature and life prohibited me from attempting this task: Christmas, New Year, travel, bad weather, full Moon etc. A couple of clear skies did present a good visual sighting through binoculars but no image.

Last week, on Thursday evening, I eventually got my first opportunity but due to very strong winds (hence the clear sky) was unable to even set-up the equipment. The following evening a cold but clear sky again occurred and this time I took my chance.

Photographing and processing a comet is not straightforward. Since my last post, Comet Lovejoy has tracked west (to the right) of the Orion constellation and at the time of imaging was located just above the western end of Taurus, before it passes west of Pleiades on 19^th January. The first problem is therefore obvious – it’s travelling very fast, about 82,000 mph. Fortunately Livecometdata.com provides real time information on the comet’s journey, which is both impressive (how does it do this?) and very useful. Inputting the real time RA and DEC location data into the SynScan handset, the mount slewed straight to the comet, which was just off-centre of the field of view. And thus I had my first, proper live view of a comet – fantastic! Now for the tricky part: how to get an image?

I had already posed this question on Stargazers Lounge and had a number of useful suggestions. Of course, whilst the mount tracks the celestial sphere, the comet is making its own way through the sky, which is not the same path as the stars seen from Earth; I believe it is possible to track the actual comet but that’s too difficult for me. Therefore, it is necessary to err towards lots of shorter exposures to avoid blurring; the longer the exposure the more likely it is the comet’s tail can also be captured in the image but it is a fine line between achieving this and blurring. In the end I took two sets of images at 20 seconds and 60 seconds – probably too cautious but I was happy with the result and will be better prepared for my next comet, whenever that is.

Then came the next obstacle – stacking and processing. I had not thought about this before but in the world of stacking, the software is unable to distinguish the comet from stars. As a result it is necessary to identify the comet in each light frame by manually tagging it; at this point I regretted taking x40 exposures! Deep Sky Stacker will then stack using one of three procedures which basically prioritises either the comet or the stars or a combination of both – I chose the latter. As usual post processing in Photoshop is then used to improve the final image.

C/2014 Q2 Comet Lovejoy WO GT81 + Canon 550D (modded) & FF | 40 x 20secs @ ISO1,600 + darks | 16th January 2014

C/2014 Q2 Comet Lovejoy
WO GT81 + Canon 550D (modded) & FF | 40 x 20secs @ ISO1,600 + darks | Fairvale Observatory 16th January 2015

Whilst I am very excited to have successfully photographed Comet Lovejoy, I was less than impressed by the stacked image and actually prefer the original. Processing comet images takes the dark art of processing to a new level and I feel I’ve only reached the learning foothills so far.

Lovejoy will be in the sky for some weeks to come as it tracks across Andromeda and Perseus during February and into Cassiopeia in March. Whilst the best may be almost past, I certainly hope to follow its progress and, subject to conditions, might even attempt to image it once again before it continues its 8,000 year orbit into deep space. However, for now I’ve got my comet and am well satisfied – I will spend the intervening winter days practicing my comet stacking.

Comet Lovejoy WO GT81 + Canon 550D & FF | 15 x 60 secs @ ISO1,600 + darks| 16th January 2015

Comet Lovejoy
WO GT81 + Canon 550D (modded) & FF | 15 x 60 secs @ ISO1,600 + darks| Fairvale Observatory 16th January 2015

The Eyes Have It

January 17, 2015 by grahamrob in Deep Sky Objects, Imaging and tagged DSO, Orion | 1 Comment

Before the cloud rolled in the other night and already successfully imaged the Rosette Nebula in Monoceros and M35 in Gemini, I decided to turn my attention once again towards Orion – it’s addictive! Having previously imaged M42 the Great Orion Nebula and other features of Orion’s Sword, the Flame and Horeshead Nebula, Orions belt and a basic widefield image of the constellation – alas without Barnard’s Loop and the Anglefish Nebula – it was time to tackle some of the more elusive objects.

This time the challenge was size – less than 6 arc-minutes overall and located nearby to Alnitak – the reflection nebula M78 would be difficult for my telescope. Whilst the mount was well aligned and I was confident the GoTo software would accurately point towards the chosen target, as is often the case, the original image was not promising. However, after stacking and some delicate post-processing, the nebula became apparent. Peering out of a hole in a misty patch of interstellar dust were two ‘eyes’ formed of 10^th magnitude stars, thus illuminating the nebula.

Section of sky located just above Alnitak – not promising but look closer.

At this magnification further detail is not possible but nonetheless, the image is intriguing. M78 (NGC 2068) is the brightest (+8.3 magnitude) portion of the dust cloud which also includes NGC 2071, NGC 2067 and NGC 2064, all (just) visible in the image. Together with the Flame Nebula, all these nebulae are associated with the LDN 1630 molecular cloud, part of the larger Orion complex. I’ll need something like a 10” or bigger scope to reveal better detail but at the end of an already successful night, the image was pleasing – I look forwards to looking into those eyes again one day.

M78 (top left) with NGC 2071 (lower right)
WO GT81 + Canon 700D + FF | 15 x 120 secs @ ISO1,600 | 30th December 2014

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