Exmoor under dark skies

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. 

Zeacombe House Caravan Park
Zeacombe House Caravan Park on the edge of the national park

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.

Ioptron tracking EQ mount and Canon EOS600D
Ioptron tracking EQ mount and Canon EOS600D

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.

IR filter
The world through an IR filter

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.

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.

Andromeda region
Andromeda region, Cassiopia to the left

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.

 

 

A break from the norm

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.

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.

IMG_20190802_133810
IOptron tracking mount and Canon 600D DSLR

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.

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.

Picture saved with settings applied.
NGC7380, The Wizard Nebula Ha

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.

 

 

78 days later

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.

IMG_20190721_010819
Veil complex, Cygnus

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.

IMG_20190721_004053
PHD2 Guiding
GPUSB Adapter
GPUSB Adapter

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.

IMG_20190721_004145
APT capture software

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.

Pickering's Triangle Ha
Pickering’s Triangle Ha

Still no good, but the bee’s love it

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.

Summer time, is it realy.

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.

UK cloud cover
UK cloud cover 16.06.2019

Finally finished M51

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.

M51 COLOUR
M51 Colour
Green Filter
Green Filter
Blue Filter
Blue Filter
M51 Luminance
Luminance Filter

First time with colour filters

Up until last night, I have only used narrow band filters with my ZWO asi1600mm Pro Monochrome camera, mainly because during the winter months the majority of imaging is of nebulous objects, with the milkyway high overhead there is a vast number of these deep sky targets to choose from – now that the long nights are over, it’s the turn of the galaxies to occupy the imagers time. However narrow band imaging shows little on these distant islands of stars, only Ha really picks out the star forming regions and then only on the closer galaxies, this means that galaxy imaging is done with wideband filters, Red, Green and Blue, I decided to image M51 the Whirlpool galaxy in the constellation of Canes Venatici, below the handle of the Big Dipper, changing from my narrow band filter wheel to my colour filter wheel only took a few minutes, however the focus position was way off – luckily it was outward focus travel that was required as my narrow band filter focus position leaves me with only 2.5mm of inward focuser travel remaining. I managed 45 x 300 second exposures giving me 3.75 hours worth of data with the red filter. I now need to do the same with the green and blue filters and combine the three mono images in Photoshop to create a colour image, I will then use the Ha filter for the star forming regions and add this data to the image followed by a luminance for detail. The forecast looks good again for tonight, when I’ll use the green filter – this is the only disadvantage to using a  mono camara, you have to use multiple filters to create a colour image but the result is far better than using a colour camera alone.

M51 Red filter
M51 Red filter

Something at last

It’s been a while since my last post, nearly 4 weeks in fact – a combination of poor weather and other commitments including going away in the campervan to Cornwall when we had that glorious 4 day bank holiday weekend has kept me out of the observatory, I could hardly say to my better half, sorry dearest we’re not going away this bank holiday – the weather is just too good. Anyway I have finally done some imaging, addmitedly over a couple of nights and on a very dim target – PK219 + 31.1 or Abell 31 or Sharpless 290 – this is a very dim and ancient planetary nebula in the constellation of Cancer it is slightly larger than M27 the Dumbell nebula  ( mag 7.5 ), though much much dimmer at mag 12.2. The image below is the culmination of two nights imaging, totaling 5 hours exposure time ( 30 x 600 sec ) in Ha, to be honest I think that 2 or 3 times as long is needed, it is brighter in OIII but that will have to wait until there is no moon around.

pk219
PK219 +31.1 in Ha

I also took the opportunity to check if my collimation efforts were any good or not, I centered the telescope on Pollux, β Gemini the brightest star in that constelletion and took a 60 second exposure, thankfully the collimation I did on the 8 inch RC was nearly spot on with only very small adjustment required. the exposure showed that while the stars in the image are round in all four corners, the vignette or uneven illumination was slightly off centered to the left of the image and only very minor adjustments to the secondary mirror is needed, the two bright patches to the right edge of the image is Amp glow from the camera sensor this would normally be  removed with dark frame subtraction when processing.

Uncentered Vignette
Uncentered Vignette and of course microlens reflections

This Uncentered vignette is only a problem if a bright star is in the field of view ( otherwise it is removed by subtracting flat frames ) as there are none around PK219 I’ll leave the final adjustment to a later date, below is the same image with a gradient map applied to make it easier to see, lots of clear skies needed, fingers crossed.

Gradient mapped
Gradient mapped image

Clouds and rain once again

Just typical, I re-collimate my main imaging telescope and ever since then the weather has been typically British for April, clouds and rain. The forecast for the coming week is not good with more of the same unfortunately. The days are getting longer and the period of astronomical darkness ( when the sun is more than 18° below the horizon ) is getting shorter, Orion is pretty much out of view for me now so I’ll have to wait till later in the year to get more data on M42. However I want to get a closer look at the Leo triplet of spiral galaxies M65, M66, and NGC 3628 – at my telescopes native f8 focal length, come on blue skies.

Leo triplet
Leo triplet of spiral galaxies M65, M66, and NGC 3628. WO72mm Megrez f6

Collimating the 8 inch RC

After discovering that my 8 inch RC was out of collimation ( read previous post ) I thought I’d run through the steps needed to re-align the two mirrors. The first thing to do is to dismantle the focuser end of the telescope to gain access to the primary mirror, this was because when I washed the mirror I had to remove the centre light baffle tube – this has a thin rubber O ring that needs to be seated correctly on the baffle, if not then the mirror will not be secured in place properly and will have a certain amount of play.

Remove the top and bottom Losmandy plates and the Radius blocks from the focuser end only, undo the two remaining cross head screws and gently lift of the mirror housing, do not drop and place on a flat surface. Unscrew the centre baffle tube counter clockwise and check the rubber O ring ( do not touch the mirror ), it has to be sat in the groove and not on the threaded portion of the tube. Re-assemble the telescope in reverse order.

The Howie Glatter laser collimator I use is quite expensive costing about £200 with attachments, but it is the only reliable method to collimate these RC scopes because of the two Hyperbolic mirrors, Newtonian telescopes on the other hand have a concave primary and a flat secondary. Now the safety bit, Never look directly at the laser beam or eye damage and blindness may result.

Insert the collimator into the focuser and only just slightly tighten the focuser thumbscrews so that it turns freely in the focuser without being loose. using the tight beam attachment that screws into the end of the laser, get the red laser dot of light onto the secondary mirror centre spot ( it marks the centre of the secondary mirror and is essentialy a paper disc with a hole in the middle just like a ring binder reinforcing ring. do this by adjusting the primary mirror collimation screws ( there are three sets of two screws and work in a push/pull fasion ) only make small adjustments to get the laser on the spot, this can be seen from the front of the telescope and looking at the reflection of the secondary in the primary.

When you have the laser in the centre of the spot or ring, you then look at the reflected laser spot and see where it falls on the white disc at the end of the laser, you will probably see two red dots this indicates the misalignment of the secondary to the primary, move the outer red dot to cover the centre red dot by making small adjustments to the secondary collimation screws arranged in a triangle around a larger centre screw.

When this is done it’s time to change the laser attachment to the Holographic ring projector, this as the name suggests projects a series of concentric rings down the telescope tube to the secondary mirror, these are then reflected back onto the primary and then out of the end of the scope tube and onto a white surface ( a wall or large piece of white card, or in my case the side of my fridge ) this is for fine adjustment to get the rings concentric with the shadow of the secondary in the middle of the rings, the actual proccess will take two or three iterations of the above procedure until finally no adjustment is needed and you can swap between the dot and the circle attachments and the laser spot will be on the secondary centre spot and projected circles will be concentric.

Only fine adjustments are needed and the proccess can be time consuming and also frustrating as these telescopes seem to be on the tipping point of going out of alignment, especialy if you forget where you were in the procedure. Lets hope I got it right, you can only know when you take an image, any remaining misalignment will be instantly obvious as the stars in each corner will be different shapes.