We are just about to enter the longer evenings where we can once again return to getting some decent quality deep-sky images.  To be frank, it never really gets dark enough to do good work for all of June, and most of July.

So this month, as we are still effectively in summer, with the summer triangle overhead, our object is (as usual for August) something in Cygnus.  That something is the bright star Sadr, the central star in the constellation – and as you can see from the accompanying image – it is completely surrounded by emission nebulosity – so this is a nebula image for a change.

Again – considering the deep-sky image as a whole – just a mass of red (emission nebulosity) can look very boring.  It is much better if you can break up the monotonous red region with something interesting – like a reflection nebula [NGC6914] which lies a little north of the current region.  In the present case I have broken up the red monotony by placing the bright star Sadr in the centre of the frame.  This must have also impressed the APOD guys as this image made APOD for January 4th 2007.

Sadr is the supergiant star Gamma Cygni and the two “winged” regions to the left of Sadr form the Butterfly Nebula IC1318.  Above and left of Gamma Cygni are the stars forming the group NGC6910.

Gamma Cygni lies at a distance of only 750 light years, while estimates for IC1318 and NGC6910 vary from 2,000 to 5,000 light years.

So there’s plenty more than just a uniform region of red in this image

We’re coming up to my favourite imaging month now -for the first time since May we get decent dark skies that will yield us the best quality images.

So until September – clear, dark skies

This month’s deep sky object is a Globular Cluster, this time M56 in Lyra.  Why?  Because I really like Globular Clusters with a Milky Way background – and this is what the M56 region offers us

M56 lies at a distance of 31,000 light years and shines at magnitude 8.4.  It is pretty small at a mere 7 arc minutes in diameter, so it would benefit from focal lengths in excess of 1,000mm – but having the Milky Way background makes this a good region for wide field imaging as well.

As usual with star clusters, we don’t need very long subs, anything from 3-5 minutes will be fine.  And if you want to get a nice glassy-smooth noise-free image at the end you will want to aim for around 80 – 100 subs in total.

As with all deep-sky portraits – the framing is all important, what other objects lie in the same frame to give the image that WOW factor?  In the case of M56 it is the Milky Way background that does this.  So a reasonable sub exposure length together with a nice large number of subs should yield a very impressive star image.

Fortunately, the evenings are once again starting to get slightly longer.  It’s still far from ideal for deep-sky imaging, but we have to feed the withdrawal symptoms somehow, and things start to improve by leaps and bounds once we get through next month.

So until August – clear skies to you all!!

As per usual, the skies simply don’t get dark enough this time of year for me to bother imaging deep-sky objects.  I will probably try to get some ultra-wide-field Milky Way shots using the AstroTrac and the DSLR this year – but the deep-sky kit will be mothballed for the month.

So it’s the usual, clean out the observatory, if you have a fibreglass dome wash off the last year’s worth of algae slowly turning the surface green.  Regrease your mount and check all the fastenings are tight.  Maybe give the optical train a good blow if you’ve got any dust bunnies, and check the collimation.  Not a bad time to get the polar alignment really tuned in well, you can spend several nights on this if necessary, you’re not losing good imaging time.

This year I will use this month to really push ahead with the mini-WASP array construction.  I am aiming to have the basic setup installed in a new dome by the end of this month – we’ll see!!

Until July – clear skies, even if they’re not particularly dark ones

The imaging object of the month for May 2011 is a Messier object, Spiral Galaxy M106 in Canes Venatici.  I particularly like this galaxy and have imaged it several times – it looks to me like a piece of celestial “Mother-of-Pearl” – quite beautiful colouring if you manage to get deep images of this one on a clear (good seeing) night.  M106 is about 22 million light years away and shines at magnitude 8.3 with dimensions 18.6 x 7.2 minutes of arc – so reasonably large.  Even so – this one is better imaged with much longer focal lengths than my 405mm using the Sky 90 with reducer-corrector.  I would recommend focal lengths in excess of 1000mm and sub-exposure times of around 10-minutes with the usual minimum of around 50-60 subs.

The evenings are now getting shorter and this is the last month of imaging (for me at least) for a few weeks now.  Make the most of any clear Moonless nights we get this month – we’ve got a while before we can grab some deep-sky photons again.

Until June – clear skies!!

Our April Fool’s Day imaging object of the month is Abell 1656, the Coma Galaxy Cluster!  Abell 1656 is a massive cluster of galaxies in the constellation Coma Berenices (Berenice’s Hair) and is over 2-degrees in diameter!  Nearly everything you see in the image below that is not obviously a star is actually a galaxy.  With over 650 galaxies in the cluster, Abell 1656 is one of the densest collections of galaxies in the entire sky.

The giant central elliptical galaxies, NGC 4889 on the left and NGC 4874 on the right, lie some 300 million light years away, and they are both around 250,000 light years in diameter – about two and a half times bigger than our own Milky Way.  Strangely – NGC 4874 is a strong radio source, while NGC 4889 is not.

In the Sky 90 at f#4.5 I prefer to use pretty long subs for faint fuzzies, often around 10-minutes per sub.  With the usual rule of at least 50-subs for a smooth image, this means investing around 8-9 hours total imaging time on this one – but it’s got to be worth it!  Where else are you going to get an image with so many galaxies in a single frame?  Clearly this will be more than one night’s work, and I would suggest that it is probably worth coming back to this one year after year to keep adding more data and detail to this amazing region of space.

Until May – clear skies to you all!

Our deep-sky objects for March 2011 are a pair of open clusters that sit nicely in the field of view of most imaging setups – these are M35 and close-by NGC 2158 in Gemini.  M35 (also labelled NGC 2168) has a diameter of 25′ and shines at magnitude 5.1 at a distance of 2,800 light years.  Nearby NGC 2158 looks a lot smaller at only 5′ across, but that’s due to NGC 2158 lying 6 times further away than M35.  The main stars of M35 are distinctively blue, while the stars making up NGC 2158 are clearly old and red.  This colour combination makes for a great deep-sky image if you can get both objects in the FOV.  In oder to pull out faint little NGC 2158 it is probably best to go for slightly longer sub-exposure times, I would try for at least 5-minute subs at f#3.5, and again go for at least 50-subs in total – an imaging time in excess of 4-hours is therefore required.

One of the nicest open-cluster pairings in my opinion – give M35 & NGC 2158 a go this month (weather permitting) it will make a great addition to your portfolio if you don’t already have it

Until next month – clear skies to you all!

Our imaging object for this month was discovered as recently as 1980 – yes you read that correctly – this cascade of stars was first listed by Lucian J Kemble in 1980!  Living in Alberta, Canada, Kemble came across this cascade of stars whilst observing in Camelopardalis with a pair of 7 x 50 binoculars.  Kemble wrote about his discovery to Walter Scott Houston at the Sky & Telescope magazine and Houston wrote about the discovery and named it Kemble’s Cascade – the name stuck.  There is an added bonus with Kemble’s Cascade, at the end of this string of stars is a beautiful little open cluster – NGC 1502 – which greatly adds to the “sparkle” of images taken in this region.  Kemble’s Cascade is BIG – you need a short focal length imager to get the whole thing in the field of view – I struggled to get the whole asterism in the Sky 90 diagonal where the FOV is 3.33 x 2.22 degrees – so the Cascade plus the cluster extends to over 3 degrees, which is pretty big.

Usual formula for star pictures, shortish subs, around 3-4 minutes at f#3.5 and as many of them as you can get.  For a smooth image you need at least 50 subs so we are talking about a total exposure time around 3 and a half to 4 hours, which is typical for a bright deep-sky object.

So there you have it, a deep-sky asterism discovered and named as late as 1980 – it shows you what can be done!  At this point I would like to put in my claim in for Greg’s Charm Bracelet.  Greg’s Charm Bracelet is a huge loop of stars that has the Double-Cluster hanging like a sparkly charm from the South East end of the bracelet.  What is strange about the bracelet (and this probably goes for Kemble’s Cascade as well) is that it leaps out at you in either binoculars or a low magnification telescope – but you can hardly make it out on star maps or planetarium programs.  I am not sure why the eye-brain combination makes the stars in the bracelet stand out so strongly when clearly they aren’t all that much brighter than many of the surrounding stars.  Anyway – enough of Charm Bracelet’s – Kemble’s Cascade is the imaging object for this month, and the image below got Noel and me an APOD as well, so the NASA guys like this object too.

Until March 2011 – clear skies to you all!

Happy New Year to you all – I hope the hangover from last night’s celebrations isn’t too bad

The imaging object for this month is one of the most famous supernova remnants, and the first entry in Messier’s catalogue – it is M1, the Crab nebula in the constellation Taurus.  This tiny object, only measuring 6′ x 4′ (that is arcminutes note, 1/60th of a degree) is also labelled as NGC 1952 and lies around 6,500 light years away.  Firstly, being so small, you really do need a longish focal length to do this object justice.  My 400 – 500mm using either the Sky 90 or the Hyperstar III is simply too short.  It has amazing colour and detail and would do well with narrowband imaging – the incredible Hubble image of this object is I believe one of the highest resolution images taken of any deep-sky object – and it shows!  Although we cannot possibly compete with Hubble on this one, we can get as many narrowband subs as we can at high sampling (I would suggest you sample at around your local seeing limit).  You can see from my image below that you can still get quite some impressive detail even with short focal length imagers, and you have the added bonus of seeing the Crab in context – a lonely object in a fairly barren region of space.

So we start the New Year with an astronomical bang   The last few months of 2010 were amongst the worst (weather-wise) that I have known at the New Forest Observatory – let’s hope we get some better luck at the beginning of this New Year.

Until February – clear skies to you all!

I always have a lot of trouble with my imaging at this time of year as there are so many great objects up there to be grabbed and I can only concentrate on one at a time.  Auriga is in competition with Orion for my attention every winter as Auriga is also teeming with lots of goodies to image.  Although Cassiopeia is chock-a-block with open clusters – Auriga comes in at a pretty close second as far as I’m concerned.  This December’s Imaging Object of the Month is the beautiful open cluster M38 in Auriga.  It is pretty large with a diameter of 15 arc minutes and shines away at magnitude 6.4.  M38 lies at a distance of 4,200 light years (so it is pretty close) and it makes a great capture in a longish focal length instrument where you can nicely frame the region.

M36, M37 and M38 are all open clusters lying quite close to one another in Auriga and it is well worth bagging the lot if you get enough clear skies.

As per usual the formula for imaging this one is a resonable focal length, 3 to 5-minute subs, and as many as you can get.  In the “old” Hyperstar days I often took 100 subs of an object as my sub-exposure time was typically just one minute.  Although the images did not have great depth, they were glassy smooth, and were perfect for clusters and single bright star images.

Well – the next Imaging Object of the Month will be in a New Year.  So, Happy New Year to you all and let the long dark imaging nights continue – for just a little bit longer

For November’s Imaging Object of the Month I have chosen one of my most favourite objects of all – the open cluster NGC 7789 in Cassiopeia.  Open Cluster?  This amazing collection of stars looks pretty much like a huge globular cluster measuring a massive 25 arc minutes across and blazing away at magnitude 6.6.  This open cluster was discovered by Caroline Herschel in 1783 and it lies just 3 degrees south west of Beta Cassiopeiae.  NGC 7789 also contains an amazing object as can be seen in the image below which is an animation of 2 frames taken around a year apart.  Is it an alien interstellar beacon, or perhaps a nova?  No, it’s WY Cassiopeiae an amazingly variable, variable star undergoing a magnitude change from around 7 at its brightest to around 14-15 at its dimmest – what a contrast!

As NGC 7789 is almost the diameter of a full Moon you can get away with slightly shorter focal lengths on this one, and I have managed to grab a nice image of this region using the Takahashi Sky 90 at f#4.5 and 405mm focal length.  Usual prescription for clusters, shortish subs (from 3 to 5 minutes maximum) and lots of them to get the depth and smoothness that this object rightly deserves.  It also makes sense to take two images of this object – one at WY Cass’ maximum and one at minimum, it really is a highly impressive variable.  Or why not image every clear night you can get throughout the whole cycle for a very unique recording of this star?

We are now well into the long dark evenings, astrophotographer’s heaven – let’s just hope the weather Gods look favourably upon us and provide us with crisp, crystal clear evenings for our imaging.

Until December’s IOM – clear skies – and happy imaging to you all