Cassiopeia as you will know is open cluster central – but do you know that there is a region THICK with open clusters (6 of them) AND it has a fantastic supernova remnant as well?  Use your scope’s GOTO to go to NGC7790 or NGC7788 in Cassiopeia – get a decent field of view – and take a very long total exposure with long subs – you won’t regret it.

This special area was first brought to my attention by Eddie Guscott in his Practical Astronomer magazine [August 2008, pages 22-24] in a great little article called “Six little clusters, all in a row….”  The six little clusters comprise King 12, Harvard 21, Frolov 1, NGC7788, NGC7789 and Berkely 58 moving from north to south through this region.  It wasn’t however the “Six little clusters, all in a row” that caught my attention in the black and white image on page 23, what was that amazing object just making an appearance at the top of the page??  There was a semi-circular region of nebulosity, obviously part of a great circle of nebulosity – but what was it?  A little detective work showed that this was CTB1, a beautiful supernova remnant, brilliantly imaged by Steve Cannistra – I wanted this one!!  No problem – I have the Hyperstar – I can image ANYTHING – especially faint stuff, not actually true.  Even though I took very long sub exposures, and extremely long total exposures – I just couldn’t pull out CTB1 – even with Noel’s superb processing skills.  Why?  Because this one is getting close to my skyglow limiting background.  O.K. no problem – stick in an H-alpha filter and have another go.  Yes I did this, and found the problem with narrowband filters and low f# optical systems – they don’t go together!  O.K. no problem again – just get one of those wideband H-alpha filters and go for it again.  Well yes but the huge increase in bandwidth means you sacrifice a lot of contrast – and to be honest, you don’t actually gain a lot by going down this route with the Hyperstar system.  So what is to be done?  The only answer I have is to one day put the f#4.5 Sky 90 back on with a narrowband H-alpha filter and do the thing properly, but that may be a LONG time off.  Until then, just look at this rich region of open clusters – and better still – get imaging them.

The accompanying image is a mosaic of 3 Hyperstar III/SXVF-M25C frames and measures something like 3.5 x 24 degrees.  Sub-exposure times with the Hyperstar III went to over 10-minutes (!!!!) equivalent to over an hour with the Sky 90 – and total imaging time would be in excess of 20-hours.  One of my more impressive deep-sky imaging failures.  Why not see if you can do better and grab a really nice image of the little-known and rarely-imaged CTB1?

Until October – clear skies and happy imaging!!!

Imaging conditions steadily improve as we proceed through August and once again reasonably dark skies can be had in the late evening – the only problem being if you have a day job to get up early for the next morning!!  Day jobs notwithstanding August sees the real beginning of the new imaging season and as we’re still in summer it’s the summer constellations that we’ll still be interested in.  Cygnus again (same as last month) but this time a beautiful nebula rather than the open cluster we saw last month – this time we’ll look in some detail at the Cocoon nebula [IC5146].

The Cocoon nebula itself is a beautiful little emission nebula some 10′ x 10′ in size at a distance of around 3,300 light years.  But it is not just the nebula that is interesting – look at its surroundings!!  This one lies in the rich Milky Way and there’s yet another bonus – look at those dark nebula streamers billowing out from behind the Cocoon – it looks like the Cocoon has blundered its way into this Milky Way region of stars from the right, pushing stars out of its way as it travelled through and finally came to rest.  This amazing dark nebula is Barnard 168 [B168] and is one of the northern sky’s most visually stunning dark nebulae when viewed through a low-power instrument.  It is also large!  The accompanying image is a two-frame Hyperstar III mosaic measuring some 4 degrees across – and it still wasn’t a big enough FOV to capture the full extent of B168!

Now go back to the Cocoon nebula again – and look at that amazing stream of stars coming out the top of the nebula looking like some celestial whale head blowing sea water out of its blow-hole – incredible!

This region demands a LOT of exposure time AND a huge field of view as well.  It is well worth the time and effort to put together a nice mosaic of this area to capture the full richness of the region.  For my Hyperstar III/SXVF-M25C setup I recommend 5-minute subs to get some real depth to the Milky Way stars, and as per usual, at least 4-hours per frame, preferably 5-hours to give around 60 subs for a decent stacking and good signal to noise.

I will almost certainly go back to this one to get the third frame off to the right to get a little more of the amazing B168 into the final image.

Until September, when we WILL be getting those darker skies – clear skies and happy imaging!!

With virtually no imaging for the last 6-8 weeks we enter July where at least the skies start to get a little darker in the late evening.  It is still not great conditions for imaging though and you will note a slight degradation of image quality during July compared to the pitch-black skies we get over the winter.  Never mind!!  Dust of the telescope, fire up the mount and let’s get some imaging underway.

This month’s object is open cluster M39 in Cygnus.  Not too surprising we are looking at a Cygnus object in July, but M39 is pretty much overlooked by imagers – perhaps because it is noted as being a “very large, very poor cluster, very little compressed, of 7th – to 10th- magnitude stars” – not exactly a great advert for M39 is it?  But then you put some imaging time on this one and get a little depth and you realise that although large and sparse it is a very colourful cluster.  Being large [30' diameter] you need a decent field of view, and the Hyperstar III with the SXVF-M25C camera with its 2.4 x 1.6 degree field of view is almost ideal for imaging this object.  Clusters as we know need less sub-exposure time, and we have the bonus that we can also work on them when the Moon is about.  For the Hyperstar III at f#2 I typically use 3-minute subs on clusters, and for the Sky 90 at f#4.5 I often used 4-5 minute subs.  However, as with any object things simply improve with total exposure time and I always like to get an absolute minimum of 4-hours on an object – even a cluster.

Give M39 a try – open clusters in general are often overlooked by imagers, yet they have so much to offer.

Until August – Clear Skies, and happy imaging!

It’s imaging dead time again as we enter the summer months and it never really gets dark at my latitude.  Time once again to do all those chores which we don’t bother with when we’re getting on with the real work of imaging.  So, if you have a nice white fiberglass dome, now is the time to bring it back into pristine condition by washing off all the collected murk of the last year and maybe finishing with a bleach rinse to keep the green stuff at bay a little longer.  If like me, you have your dome on wooden decking, now is the time to give your decking the Sadolin treatment to keep it rot free for another year.  Check that the interior is still waterproof and that the sealant all round the base is still o.k.  If not, remove all the old sealant with a blunt knife and reapply new stuff.  Vacuum out and dust the interior of your observatory and remove any unwanted inhabitants that have taken up residence.  Finally, if you do not have your computer connected to the Internet in your observatory, take it indoors and get all the updates loaded up.  Also load up any new software that you might have acquired during the past year and check it all works indoors before taking your computer back outside to your observatory again.  Check all your wiring and see that nothing is chaffing as your telescope skews across the sky.  Finally check that the earth leakage circuit breaker functions correctly – we don’t want to lose you out in the darkness on a cold winter’s evening.

Well we have to suffer this month, and most of next month before it becomes too unbearable and we go out at silly hours just to get an image – any image.  Hang on in there, just need to brave it out for 6 more weeks

The imaging object for this month is actually a pair of objects lying in the constellation Ursa Major.  M97 also known as the Owl nebula is a lovely little planetary nebula, so named as it has a pair of dark round spots in its green interior which look like a pair of Owl’s eyes.  It is very small at only 170″ in diameter and it is also quite faint at magnitude 9.9.  Close by there is another Messier object, a small spiral galaxy M108 which measures 8.7′ x 2.2′ and is similarly faint at magnitude 10.  Normally a long focal length is used so that there is a reasonable image scale for the Owl nebula, but if both objects are to be captured we need to work at shorter focal lengths.  In the accompanying image the focal length is much too short really to bring out the two objects well, but it still seems to work by showing them in their largely barren environment.  Surprisingly a couple of other “smallish” objects also do well in large field images including the Crab Nebula and M13 the Great Globular Cluster in Hercules.

At this time of the year we find Ursa Major near the zenith so we benefit from the best dark skies from our site and also minimum atmospheric interference.  M97 and M108 still need plenty of exposure time however, like any object, and a minimum of 4 hours using 5-minute subs is recommended for either the f#4.5 Sky 90 system, or even the f#2 Hyperstar III scope.

We are now being forced to start imaging at indecently late hours as summer approaches and if like me you have a day job you are approaching the end of your imaging season until later in the year

April brings the Ursa Major/Canes Venatici objects into a good imaging position.  Our Imaging Object of the Month this month is the interacting galaxy pair M51 known as the whirlpool galaxy.  M51 lies 15 million light years away in the direction of the constellation Canes Venatici.  Although M51 is pretty bright, there is a great deal of fine structure and also some close-by faint fuzzies that will only be pulled out by using long subs, and many of them.  What’s particularly nice about M51 is that nearby there is a very handy 8th magnitude star which is perfect for autoguiding on

A smaller field of view (than I can manage) is better for this object, and this is true for most galaxies come to that – so this is not a particularly good subject for either the Sky 90/M25C or the HyperstarIII/M25C – however I still can’t resist imaging it whenever I get the chance (along with M101, and M81/82).  The accompanying image was taken with the original Hyperstar and the SXV-H9C one-shot colour camera, giving an FOV of roughly 1 x 0.75 degrees – still too big really!  I found that the C11 with the f#6.3 reducer and the H9C camera gave just about the perfect FOV for M51 which filled the field of view very nicely if placed along the camera’s diagonal.

Until May, clear skies to you all!

This month’s imaging object is a single star shot – this time I’ve gone for Regulus in Leo.  A nice bright star central to an image can make a spectacular picture, and Regulus is no exception.  Taken using the Sky 90 and M25C with 4-minute subs and a couple of hours total exposure time, this is the sort of result you can expect.  However – what I didn’t expect was to see a trace of the dwarf galaxy Leo 1, which looks like a tiny wisp of a cloud right next door to Regulus!  This was pretty much unexpected and I believe it is due to the superb contrast provided by the Sky 90 – I can guarantee that I wouldn’t be able to see Leo 1 in a similar Hyperstar III image.  It would be interesting to know whether you can pick up Leo 1 using reflectors and CCD cameras with Regulus providing it’s own unique form of  ”light pollution” in this region.

Recipe for a Regulus/Leo 1 image – good dark (Moonless) night, high contrast imager (refractor), moderate length subs, but lots of them – and possibly some good luck

Until April’s IOM – clear skies!

I still find it very strange that this large, bright reflection nebula does not have a “popular” name.  To me it look like a cauldron of boiling liquid oxygen, so I shall call it “the Cauldron”.  M78 is a beautiful reflection nebula in Orion, and you can see from the accompanying image that it lies very close to Barnard’s Loop.  As you will know, Barnard’s Loop is faint, so to get this showing up in the image it is a good idea to collect some narrowband H-alpha data.  The reflection nebula although appearing to be narrowband blue is in fact broadband blue (due to scattering of a broad band of short wavelengths of light) – so M78 doe not benefit from narrowband filters.  However, you can see that the whole area is also permeated by dark dust clouds, and to get these showing up at all in your image you need lots of exposure time and long subs.  This image is a composite of H-alpha data taken with the Sky90/M25C, RGB data of M78 alone taken with the original Hyperstar and SXV-H9C, and finally the main part of the template is Hyperstar III RGB data with its 2.41 x 1.6 degree field of view.  You can see that by framing the subject (M78) off to the right of the FOV you can bring in the edge of Barnard’s Loop over to the left which makes for a more interesting image.

Usual formula for a nice picture – lots of subs – long exposure time for each sub – and add some good deep H-alpha data to capture the faint Barnard’s Loop.  At least we still have long nights to do this stuff, soon the clocks will go forward and it will be back to no imaging before 9:00 p.m.

Clear skies until our March edition of IOM.

First of all Happy New Year to you all!  I won’t say let’s hope for better imaging weather this coming year as so far it hasn’t been anything to write home about.  Moving on.  This month’s Imaging Object of the Month is the beautiful Jellyfish nebula in Gemini.  This is a very difficult time of the year for imagers as there is so much up there in a good imaging position right now, including all the stuff in Auriga and of course Orion and Monoceros.  IC443 is pretty faint and does well with the addition of narrowband data to the RGB, especially H-alpha and S-II.  IC443 is also BIG – you can see from the accompanying image that the rather large FOV of the Sky 90/M25C combination (2.22 x 3.33 degrees) is just about perfect for the region.

This image took a LOT of work.  This is 3 hours of RGB, 9 hours and 40-minutes of H-alpha, and 3 hours and 40-minutes of  SII giving a total exposure time of 16 hours and 20-minutes – and it could have easily done with the same again!!  So the message is, lots of time, add narrowband – and perhaps make this your winter mega-project if you can manage to keep away from Orion

Clear skies until February!

Well, not exactly the Douglas Adam’s cluster as that would look like the number  ”42″ – whereas this open cluster in Orion bears a striking resemblance to the number “37″ and is therefore known as the 37-cluster.

The 37 cluster, NGC2169 lies around 3,000 light-years away in the constellation Orion.  Being a fairly bright open cluster we can get away with short 2-3 minute subs, and we can also get away with a short total imaging time of just a couple of hours.  You get a lot more back for your short investment in time than with many other deep-sky objects.  A little digital processing on your data (Noel’s enhance star colours helps a lot here) and you will end up with an incredible figure  ”37″ appearing like a Neon display in an otherwise unimpressive star background.

Just a short amount of time needed to bag this one – so you can move onto the many other gems of Orion in the same evening and grab some more data

See you again in the New Year, have a good Christmas, and let’s hope that 2010 brings us some better imaging weather than we got dished up in 2009!!