A few hours of clear sky made imaging comet C/2017 T2 (Panstarrs) possible, the comet was discovered at 20th magnitude in September 2017 when it was 9.3 au ( 1 au is about 93 million miles ) from the Sun, it is now 1.5 au from the Sun and at approximately 10th magnitude. it can be found in the constellation of Perseus, this makes it currently circumpolar, meaning it does not set from UK latitudes.
The comet can be seen to move againts the background stars over a series of exposures, this is how they are discovered – an image is taken, then another of the same patch of sky a few hours or days later – anything that seems to have moved position is either an asteroid or a comet, comets tend to have a fuzzy appearence to them, as they approach the sun they warm up and produce a coma.
I took a total of 20 x 3 minute exposures through a clear filter, only this time instead of guiding on a star, I guided on the comets bright nucleus itself, this stops any elongation of the comet due to exposure lenght, this gives an hour of image data, but when you add dithering between images this gives 75 minutes from first image to last. After processing the images twice, once for the stars and once for the comet, then combining the two images together to give this final image.
Some of the tail was lost in processing the final image, if you look at the animated image you can see faintly the extent of the tail towards the left of the picture. Hopefully ( weather permitting ) I’ll get another chance to image this as it gets brighter on nearing the Sun.
After weeks of cloud, rain and wind, months of the rudy stuff actually – the sky cleared just after midnight on Christmas eve, ten minutes into Christmas day the roof on the observatory rolled back once again, the telescope was set up and aligned, the ZWO asi1600mm Pro camera was cooled to -20°C, the Flame nebula in Orion was targeted and imaging was begun. I captured 15 x 300 second exposures through the Ha filter of NGC2024, this star forming region is about 1300 – 1400 light years away and lies close to the star Alnitak – the easternmost of the three stars in Orions belt, it shines energetic Ultraviolet light into the Flame and this knocks electrons away from the huge clouds of Hydrogen gas that reside there. when these electrons recombine with the Ionised gas the clouds glow in Ha light.
Then as the Flame got too low ( no pun intended ) in the sky to image any longer, I swung onto NGC2264, the Christmas tree cluster in Monoceros, well why not, it’s Christmas. This star forming region and emission nebula lie about 2700 light years from us, the NGC2264 designation refers to the star cluster and the nebulosity including the Cone Nebula and the Fox Fur Nebula, again I captured 15 or so 300 second exposures through the Ha filter.
Then for something completely different, Imaging M101, the Pinwheel Galaxy in Ha, This galaxy is in the constellation of Ursa Major, the Great Bear and is located at the imaginary top point of an equilateral triangle with the stars Alkaid and Mizar, it is a face on spiral galaxy at a distance of 21 Million light years from us and has a large number of H II regions, many of which are very large and bright. H II regions usually accompany the enormous clouds of high density molecular hydrogen gas contracting under their own gravitational force where stars form, H II regions are ionized by extremely bright and hot young stars, hense imaging it through the Ha filter, I had to increase the exposure time to 600 seconds, so only managed to capture 8 images before it started to get too light, but you can see clearly the H II regions.
The forcast is again not good for the coming week, but boy was it good to have a proper imaging session once again, not just the odd hour or so…… Wishing you Clear Skies, a Merry Christmas and a Happy New Year.
After a day or two longer than four months the sky cleared, for a bit anyway and I did some imaging, that’s crazy – a third of a year between imaging sessions because the sky is cloudy, raining or the air is misty or foggy or just plain rubbish. It’s December and I’ve been in a Tee shirt for heavens sake, anyway back to the imaging, I chose IC405 – The Flaming star nebula in Auriga.
To capture my images I use a nice bit of software called Astro photography tool, it will control the camera, focuser, filterwheel as well as guiding and has a host of usefull features such as bahtinov focus assist and Plate solving to name just a couple, and as with most software it has regular updates when new features are added, great. I started using APT with version 3.52, updating when a new version comes out and during the four months of doing nothing I’ve updated to version 3.81, so last night was the first time using the new version, this update has native support for ZWO cameras and when I connected the ZWO asi1600mm Pro camera I use, naturally I selected ZWO camera from the select camera type window, all good.
Before the update the camera was controlled by the ASCOM driver, ASCOM is the industry standard for astronomy software and it ensures that image aquisition, planetarium, guiding and other astro software are compatible and work together, however some ASCOM drivers are limited in their user adjustability and so camera manufacturers have started having their own native drivers with selectable options, again all good.
I managed to capture five shots of IC405 before ( yes, you guessed it ) the clouds rolled in, so while I waited for them to go away I processed the five images I had, for this I use another bit of software called Deep Sky Stacker to stack the images together after subtracting ” Dark frames ” so as to remove noise from the image, these dark frames I have stored in a Dark Library. first you have to load your images as light frames, then add your dark frames taken with the same camera, same exposure, same binning factor and at the same temperature This is not a problem as I always run the camera at -20 C ( camera noise is very dependant upon camera temperature ), when it’s done you have a nice image to work on in Photoshop for example. However DSS threw up the message that the images and darks were incompatible ?, upon checking the image data for the lights and darks I noticed that the image sizes were different by 4 pixels and this was causing the incompatibility, the image size of the asi1600 camera at 4x binning is 1164 x 880 pixels, this was the size of the darks, however the lights had an image size of 1160 x 880 pixels ( 4 pixels narrower ), how could this be as both the lights and darks were taken with the same camera ?.
APT ZWO asi driver
APT CCD ASCOM driver
It turned out that the native ZWO driver was causing the problem, when I switched back to the ASCOM driver and took an image, the image size was again correct at 1164 x 880 pixels, I’ve informed Ivo at APT and I’ll keep using the ASCOM driver till a fix is sorted. Anyway heres the result of four months worth of waiting, an uncalibrated image made from 5 x 5 minute exposures. Oh and by 11.30pm the sky had still not cleared so I called it a night.
Yes, hard to believe that more than six weeks have passed since I have imaged anything, and I mean anything, meteor showers clouded out, possible imaging sessions ( according to the weather forcast ) not coming to fruition because the weather forcast was wrong, drizzle, wind, rain, wind, torrential rain and more bleeding wind and rain. on a few occasions the weather has been fine during the day only to become cloudy as the evening wears on. I have treated the observatorys wooden walls, moved the spiders out of the observatory again, hoovered the floor of the observatory, cleaned the optics of the telescope, filters and the camera – in short everything I can do short of any actual imaging; and the weather remains for the week ahead wet and windy. The word bored really does not reflect how I am right now, so to alleviate the boredom I have been messing around imaging smoke, yes I’m that bored, it is quite simple to do really.
Set up a DSLR camera in a dark room, pointing and manually focused at a black mat surface ( large piece of cardboard sprayed mat black ) about 2 feet from the card, have the camera on a long’ish manual exposure of up to 10 seconds and have a seperate flash gun at 90° to the camera at about 2 feet distant from the card but level with the card, now this is the important bit – using black electrical tape cover the flash leaving a very narrow slit in the middle of the flash, you will need at least 3 layers of tape to block out the rest of the light from the flash, you only want to illuminate the smoke not the whole room and not the card. light an incense candle and start the exposure , now trigger the flash and stop the exposure, you will need to do this several times and if all is well you should have some pictures of smoke curls and whisps, trial and error is the only way to get it right.
Then all you need to do is add a starry background and play with the saturation in Photoshop or whatever software you use and hey presto, you have made your own nebula in the comfort of your own home.
I have, for some time wanted to do some wide field imaging under the dark skies of Exmoor , with that in mind my partner Julie and I spent the bank holiday weekend at Zeacombe house caravan park, West Anstey – just 3 miles from the edge of Exmoor national park, just over an hours drive from where I live.
We spent the first day relaxing after setting up camp, in the sun that moved through a beautiful clear blue sky – and I was looking forward to some imaging using my Canon EOS600D and the Ioptron tracking EQ mount, it’s only a small mount but is more than capable of handling my camera and any lens I care to put on it – unfortunately as the sun began to go down the clouds rolled in, and stayed in for the rest of the night, along with the rain.
The cloud and rain had cleared the following morning, leaving behind a thick mist that soon burned off as the Sun got higher, before breakfast we took a walk around the local area, lots of fields and not much else – you would definitely need a car if you lived around here, but it would be worth it just for the view across the landscape, stunning. I tried out my new 58mm Infra Red filter for the camera and the world looks very different when viewed through this wavelengh of light.
This time, as the Sun began to set the sky remained clear, even though I was only going to use 3 minute unguided exposures through an 18mm lens the mount still needed to be polar aligned, and I was getting impatient for Polaris, the Pole star to appear – it is not as many people believe, the brightest star in the sky, it’s not even among the twenty brightest stars in the northern hemisphere so I had to wait for it to get dark enough to find it. Once the mount was polar aligned I had to wait for night to fall ( I did get quite a few fellow campers showing an interest in what I was doing, this was mainly because I was staring up at a seemingly empty northern sky – but none wanted to stay up for the fun to begin ) , all the while watching for clouds to drift over, none did and I began imaging. First off I imaged the Cygnus region as the milky way runs right through it and I was hoping to catch a late Perseid meteor as the peak of the shower was clouded over, I did see a couple of meteors but none through the area I was imaging.
Imaging at last
Cygnus region, Lyra and Milky way
After taking about 20 exposures I moved to the Andromeda region, this time I only managed to get 10 exposures ( I briefly shone a torch onto the hedge and tree behind it during one exposure for effect ) before a wall of mist rose up obscuring all but the brightest stars and even those vanished as the fog got thicker, everything including myself got wet it was that dense, there was no chance of doing any more imaging so I quickly put everything away and went to bed about 1 ish with damp hair but happy to have done something. once more the following day was bright and clear I got up late just in time for a full english breakfast before we headed back home.
I hope to do more of this type of imaging when I go away and the Ioptron mount is ideal for it, I think I will need a better lens though.
Almost at the end of a week and a bit holiday, been a busy time too. Julie and I took a trip to Woolacombe, North Devon on Thursday – for a friends 7th wedding anniversary, this involved setting up camp in the ” Party field ” to use as a base to explore the surrounding coastline, did a bit of body boarding at Woolacombe ( the water was warm ) as well as Mackerel fishing from a boat out of Ilfracombe. Music, BBQ’s and drinks around a campfire in the evenings made for a great few days among friends.
Camping in the party field
here come the clouds
here come the clouds again
Evening shenanigans continue
I also took with me a small IOptron tracking mount and a Canon 600D DSLR so as to do some wide field astro imaging, and the weather was promising during the day time with glorious blue skies the whole time we was there, but come the evenings was a different story, the clouds would roll in without fail and stay until the next day when they cleared away for another fine day, just beggars belief, we made our way home on Monday a pair of happy campers.
The Wednesday and Thursday however was more favourable and I finished off the Pickerings Triangle, capturing the OIII and SII data on Wednesday night. I had a play about with the data, combining it into different colour channels to get very different results.
Pickerings Triangle HOO
Pickerings Triangle HOS
Pickerings Triangle SHO
Thurday night was clear for only a couple of hours and it was the turn of the Wizard nebula, NGC7380 in Cepheus, I had to use 10 minute exposures on this target and only managed 9 exposures in Ha before the sky clouded over but it was enough to process an image.
I’m not sure which of the Pickerings Triangles I prefer, but I’m leaning towards the HOO version, any thoughts would be most welcome.
No – 78 days later is not the tittle of a new post-apocalyptic horror film directed by Danny Boyle, it’s the number of days between last nights imaging session and the 5th May, when I imaged M51. It was clear enough last night for a few hours of imaging with the Ha filter, the waning moon has little effect on imaging with this filter and the target was Pickering’s Triangle in the Cygnus, Veil complex also called the Cygnus Loop supernova remnant. this is a cloud of heated and ionized gas and dust at a distance of 1470 Ly, the remnant of a supernova that exploded about 8000 years ago.
The imaging session was marred only by the GPUSB adapter that is used for autoguiding dropping out, this was caused by its USB connection, not surprising considering the time between sessions, unplugging and reinserting the plug sorted the problem. The adapter uses optocouplers to electrically isolate the computer from the telescope, eliminating a possible source of electrical interference.
I also had to think how to aqiure the image in the first place with the APT software, it had been that long since I had last used it.
I managed to capture 19 x 300 second exposures before it clouded over again, not quite enough to stack together for my liking – but stack them I did and to be honest its not as noisy as I thought it would be. Hope I don’t have to wait as long to get the OIII and SII data to give this object some colour.
And this blog seems to be turning into a weather moaning thing, and with good reason – the rain has gone, the temperature is too hot and yet I have not had a single night that has been any good for imaging. Broken cloud, haze and high altitude wispy stuff, in short rubbish. On the “every cloud has a silver lining” side of things, beside astrophotography my other hobby is bee keeping, and the bee’s have been loving this non astro weather, they have swarmed twice – one main swarm and one small cast. Both of these swarms I have luckily been around to rehive them, after collecting the swarm, I prefer to let the bee’s walk into their new home – by puting a cotton cloth covered board leant up against the entrance to the new hive and pouring out the bee’s onto the base of the board, the bee’s will instantly start to walk up the board and into their home, this way you can keep a look out for the queen ( big long fat tapered bottom and long legs ) as she makes her grand entrance. The main big swarm however decided to decamp on a day that I was attempting to remove honey from the hive, so it turned out to be a long hot day wearing a full bee suit – the outcome of this is that I have gone from one hive to three and extracted over 60lbs of honey and lost a few pounds in sweat to boot. So I’m at the moment looking onwards, but not however upwards.
More than two weeks have passed with no imaging being done or even the remotest thought of attempting to image because the weather just won’t allow for it, clouds, rain ( the wettest June on record ) and wind but mostly cloud. When I was a kid, I would be outside all the time in the summer because it was hot and sunny, spending the evenings outside in the garden with my Tasco 60mm refractor looking at the stars, moon and planets, I would stay up all night tucked into a sleeping bag on a camp bed watching the perseid meteor shower moon or not – every year, and in the winter, the cold crisp frosts would not stop me going out with my telescope under clear star filled skies. Now the sky is just, well not to put too fine a point on it, it’s Crap and getting worse. Global warming is real, anyone can see it is – if they can be bothered. When extremes of weather are the norm, if you ask me it’s already too late to do anything about it.
I finally got around to adding the Green ,Blue and Luminance data to finish processing M51, the Whirlpool galaxy, I did not get a chance to capture the Ha data, this can be added later, that’s the beauty of digital imaging, you can always add more data.
This colour image is created by combining ( I use Photoshop ) the Red image data with the following Green and Blue images, these are added to the colour channels of a new image of the same height and width, this provides the colour image, the Luminance data provides the detail and is added as a luminance layer.