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!!!

With the current weather I have not been able to set up the repaired M25C for any imaging and I am aware of the days ticking past with nothing new to add   Still, this gives me a little time to sit down and plan the next phase of the mini-WASP array.  Unfortunately the mini-WASP will not be up and running for this winter, looks more likely that this will now be a winter 2011 first light.  I didn’t get the decking and concrete pillar base in ready for the observatory and I think it will now be spring next year before I get that part done, so this winter it will be Hyperstar III imaging only (which is no bad thing).  Got a few nice projects noted on the whiteboard – now I just need the weather to play ball.  Having said that, it is this time of the year that I have had a 3-month imaging break due to the weather on more than one occasion!

Returning to the mini-WASP project – this will need to go into its own observatory dome so that I can run both the Hyperstar III and mini-WASP systems at the same time.  The first phase of the mini-WASP will use 2 x Sky 90 scopes together with two of the new Starlight Xpress M26C one-shot colour cameras.  A Megrez 80 and SX guide camera will occupy one slot of the mini-WASP array for the guiding.

In phase II (unknown date!) two further Sky 90s and M26C cameras will be added to the two remaining mini-WASP ports and the Megrez removed altogether.  One of the Sky 90s will have an OAG (SX) for guiding.  So the final mini-WASP system will be a four Sky 90, four M26C system giving a field of view of 6 x 4 degrees (that takes into account the frame overlap) a sampling of 3 arc seconds per pixel and 40 megapixels of data per sub download (36 megapixels of non-overlapped data).  I think the final system will produce some quite impressive images

I went over to what I thought was going to be a “dark” bit of the forest around 10:00 p.m. last night and got worse sky glow on the horizon (from Southampton) than I get in my back garden.  So the wife and I reccied another site about 3 miles away for future use and this one was quite a bit better – although there was the possibility of the odd car headlight giving low-level glare.  Anyway – came back home and set up in the garden again for a night of Perseid imaging.  It’s amazing that with a 180 degree FOV fish eye lens you can still see meteors that you don’t manage to image (usually because they run along behind the house – they have to have intelligence!).  Imaged for two hours and didn’t notice that it had got cold enough for dew to form on the fish eye lens, so the second hour’s imaging was a complete waste of time.  Visually, the display was reasonable but nothing particularly special – I seem to feel the same every Perseid session, I think I’m expecting a display from “The Day of the Triffids” and instead I get little more than you would expect on any dark, clear, Moonless night.  Not sure why I bother really.

After a completely overcast day the cloud began to break up around 5:00 p.m. and now (9:00 p.m.) it looks like we might actually have a reasonably clear night.  Whooppeeeeeeeeee – I’m off over the forest with the AstroTrac Canon 5D and 15mm fish eye lens to grab some Perseids   There was just too much light pollution from the street lights in my back garden to do a proper job with this setup, so I’m going in a nice large flat field right next to our allotments to hopefully get some dark sky imaging.  I’ll report on the outcome of this evening’s efforts tomorrow – provided it stays clear long enough to get started.

Today it was brought home to me just how dangerous it is to work on your own in this imaging business.  Tom How is a local guy and an imaging expert, and we only recently realised that we hadn’t met up for (too many!) years.  So Tom popped over to Brockenhurst this morning to see what I had been up to in the intervening years.  Tom also educated me about darks, bias frames and flats, something he has spent a lot of time on getting properly sorted out on his system.  It was when he showed me the bias frame from my M25C that he immediately knew that something was wrong with the camera – there was a large top-to-bottom gradient.  As I’ve never looked at a bias frame before it meant nothing to me.  However – it did kick me into action – and the long and the short of it is that (after mailing Terry Platt) it looks like the Peltier cooler is open circuit.  I have no idea how long the CCD hasn’t been cooled, but I suspect it goes back to when the power supply gave up the ghost a couple of years ago!!  Blimey – Noel and I have been turning out some pretty nice images without a cooled CCD.  We were getting a bit cheesed off with the hot pixels mind you – and I was very surprised (after having used the H9C for a few years) that I couldn’t do a decent job on CTB1, the supernova remnant in Cassiopeia.  Now we know why!!  So it is a trip up to Starlight Xpress ASAP for some surgery on the M25C and hopefully we’ll see a big leap in image quality brought about by some decent chip cooling!!  If Tom hadn’t popped over and pushed me along to see about bias frames and the like I would have carried on in ignorance.  This is the risk you run if you work on your own in this technologically demanding hobby

Testing out my all-sky imaging rig ready for next week’s maximum in the Perseid meteor shower.  AstroTrac, Canon 5D MkII camera, Canon 15mm fish-eye lens and Canon electronic shutter controller.  You might just make out a faint Perseid bottom left in this image.

I intend taking the rig over to a dark spot in the Forest next week provided we get the clear skies.

Last night I managed to grab the frame to the right of the Cocoon nebula – whilst at the same time getting some ultra-wide-fields of the Perseids using the Canon 5D MkII, 15mm fish-eye lens and AstroTrac.  Anyway – I quickly bolted the Cocoon right hand frame on and what do I find?  In order to get all the dark nebulosity in the region I also need the two frames off the top and bottom as well!!  Talk about a go-deeper job.  Well at least we all know what this summer’s mega-project will be.

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!!

I am using a Bryan Mumford Time Machine and the high speed flash gear from http://www.highspeedflash.com/ to create some visually stunning images of water collisions – an example is here:

Some spikes added to the highlights using Noel Carboni’s plug-in  So this water drop collision took an exposure time of 9-millionths of a second, and the beer can pinhole camera project used a 6-month exposure time – that’s over 12 orders of magnitude difference in exposure time!

Why is there so much cloud at night recently when it’s been relatively clear through most of the day?  Well I have the AstroTrac ready and set up with the new Canon 5D MkII and the Canon 15mm fish-eye lens so that I can take some whole-sky pictures (the 5D and 15mm fish-eye gives me a full 180 degree field of view so I can get horizon-to-horizon shots).  So that’s why it’s cloudy   Don’t forget we are also in Perseid season (that’s the main reason I’m ready with the AstroTrac), and although we won’t be getting any Moon problems at the height of the shower, we can’t guarantee clear skies on the main nights, so it’s fingers-crossed time again, as usual.