Orion 10 inch Dobsonian on Equatorial Platform, and my imaging setup.
It’s been a bit of a barren few months for observing- bits and pieces here and there, but no really good session to get properly stuck in.
The forecast for last night was looking great all through the week but gradually deteriorated as it drew closer and was looking decidedly iffy by the time last night arrived. There were a few breaks in the cloud so I decided to set up just before ten (hey- no work today! 😀 ). This was soon looking decidedly optimistic:
Swung the scope round to a clearer bit of sky near Ursa Major:
There’s a gap!
Blow this- headed inside for a drink and some cursing of UK weather. Kept checking with gradually diminishing enthusiasm every 20 minutes or so. One last look at 12:15- Wow- crystal clear! Right…
I’ve had the scope out a few times over the last few months and a few nice views, but for various reasons it hasn’t really come together into a properly decent session like this. There were some fabulous views and it was enhanced by some virtual companionship on the WhatsApp group. The thing that has me scratching my head is why the views of the nebulae were so good. I’ve been using the same equipment for a while now (14inch dob, 30mm Aero Eyepiece and UHC filter) but it’s never been close to this despite some apparently excellent transparency and sessions at darker sites. I guess just another reminder of what a capricious pursuit this is!
Away for half term at the moment and staying in close proximity to some dark skies. Amazingly, for Cumbria, there has also been some lovely clear nights- and best of all, my wife agreed we could bring some astro kit with us. She may not have expected the whole boot to be taken up with it. Good job we have a roof box for the rest of their stuff (don’t ask how many days I’ve been in the same underwear)…
I’ve had two superb evenings, so please bear with me as I’ve got a bit wordy….
27/10/19: Whinlatter Forest Park
The Clear Outside astro weather app was promising a clear night on Sunday so I managed to get out for quick recce during the day. The nearest dark skies looked to be in Whinlatter Forest Park and, whilst the main car park was surrounded by very tall trees I managed to find a side road that had been closed off after 50 yards with pretty good skies and lovely views out across Bassenthwaite Lake and towards Keswick. Arriving around 7:30pm with Sam in tow we were greeted by the view below:
Whilst this was pretty stunning, even better was the view straight up. Our little eyrie was up at 300m, and although Keswick was only 6 miles away the height seemed to take us above the outer reaches of the light dome leaving the Milky Way bright and clear across the sky. The number of stars was breath-taking: much the darkest bit of the sky was the rift running through our galaxy. My friend Ian, who happens to be holidaying nearby at the same time had arranged to join us, and I had the dob set up just in time for his arrival. I’ve bored him in the pub on many occasions with my astro obsession and so it was great that the skies obliged us with such a wonderful display. We started off with a naked eye tour, first of the main constellations and then of the brighter larger objects that we could see- the Pleiades, Andromeda and Auriga cluster all easy to spot with the naked eye (thanks Paul M for the laser pointer suggestion). Then we moved to the dob for some showpieces…
M31 – Was clearly visible with the naked eye so I just pointed the dob at it- no star hopping. Checked in the finder to make sure I had it right and there was the whole thing in the finder! Bright core, elongated shape even M32 visible. Move to the eyepiece (30mm/55x) and it’s like a photo- and clearly bigger than the FOV. M110 was just there- no effort, no AV. Dark lanes prominent. A suitable “Wow!” from Ian. Yeah- it’s always like this, honest…
M27 – Dumbbell – Like M31 I was able to put the scope right onto it, and it could clearly be seen in the finder. In the eyepiece, with no filter, both the applecore and the wider fainter sections were visible. Gorgeous.
M57 – Ring Nebula – Stuck out like neon. A glorious sight with real texture in the outer regions and obvious darkening in the centre, although I couldn’t see the central star.
M45 – Pleiades – very bright and with clear nebulosity visible in patches around the brighter stars.
M81/2 – Bodes and Cigar – Nice rewardingly clear view, although try as I might I couldn’t see spiral arms. Ian very impressed with the idea that
Ian’s kids are younger than mine, so he had to head at this point and with the temperature dropping through zero Sam retreated to the car- I had an hour before forecast cloud to go after some fainter stuff.
M33 – Surprised to see this appearing in the finder as well. In the main eyepiece it was clear as day- and with a spiral structure. I’ve had it before on M51, and flattened in M31- but here it was, laid out in an exquisite swirl across the field of view.
The Veil – I’m quite accustomed to my back garden view of this in O3- sinuous green strands against a pitch background. Here, with no filter, the nebulous regions were brighter and richer, the challenge was only picking them out from the dense star fields that crowded it. East and West were easy to spot but the central sections were harder to pick out. Popping a filter in would have made it easy, but for this night I wanted to see it unmolested, so to speak.
NGC892 – Spiral Galaxy in Andromeda – A nice pleasing streak across the FOV. Tried for some time to see the dust lane, but it was not visible to me. At home this object is not visible at all.
Stephan’s Quintet -YES! I read about this object some time ago: a cluster of five galaxies , four of which are interacting, sat above one of the arms coming off the square of Pegasus. It’s almost a ritual on better, clearer nights at home that I go and have a look and fail to see it. Well here it was. To be fair it was a faint uneven smear: but still- the light of four dancing galaxies 200 million light years away with a fifth nearby at 39 million years photobombing them. Not a bad way to finish the evening.
Oh- and I got a star trail over the Northern end of Bassenthwaite lake:
29/10/19 Castlerigg Stone Circle
Wonderful as Sunday night was, the one downside of the site was that cars coming over Whinlatter pass would sweep their full beam headlights across it. I wanted to do some imaging with my Star Adventurer so tried for somewhere equally nearby that wouldn’t have that problem. Castlerigg is a place I’ve loved for a long time. It was built 3-4000 years ago on a plateau surrounded by mountains. We’ve found no evidence of settlement at the site and it was built pre-Bronze Age- no-one really knows what these early stone circles were for but it was obviously an important and sacred site for the inhabitants of the area at that time. And it’s a heck of a place to sit and look at the stars.
It was clear as soon as I arrived that the conditions were not quite so favourable- the sky wasn’t quite as dark (although the Milky Way was still easily visible), there was broken cloud scudding across it and a pretty stiff breeze across the exposed site. I quickly discovered that the ¼ to 3/8 adaptor had fallen out of my SA as well so that put paid to any serious imaging plans. No worries with the dob in the back of the car ready to go again. From the observing log:
M45 – Pleiades – very twinkly so seeing not great, but nebulosity was clear again. A wonderful sight.
M1 – Crab nebula – quite easy to pick out even with no filter. Whilst I couldn’t see the tendrils that feature in so many images, the uneven shape was nice and clear and there was an obvious fading from the core through to the outer sections, with some uneven mottling within the object.
Double Cluster – I had planned to make the most of the dark skies and focus on fainter objects, but the double is a favourite and was clearly visible naked eye so I pointed the dob at it and was surprised to find that even clusters are enhanced by the dark sky. Just so many stars! So next up…
Melotte 20 – this is barely visible as a cluster naked-eye at home, but here it was almost as prominent as the Pleiades. Pointing the dob at it gave almost bewildering fields of stars- so densely clustered it felt as though they were joined in a net.
NGC7331 & Stephans Quntet- The view was very similar to Sunday night and good to affirm the sighting. I concentrated more on NGC7331- the closer galaxy nearby which was quite prominent and showed a bit of shape. Again- I couldn’t distinguish arms, but it was good to be able to see so much more than from home.
M81- Bodes – Tried again for the spiral arms and spent some time on it. Outer reaches were visible and definitely the shape of the galaxy was not an even circle, but if I’d tried to draw what I could see there would be no arms on it. That’ll have to wait for another dark skies trip.
NGC1499 – California Nebula – This was really tricky to make out. I could detect it more as an interruption to the brightness of the stars in the field than anything else. I tried again with the UHC filter and a sort of fibrous structure was evident, but it took a lot of concentrating and relaxing and averting vision.
IC5070 – Pelican Nebula – As I had the UHC in I popped across to this one, but it was again very tricky to make out. There’s a bright ridge running above the 2 brighter stars and this was clearly visible, but the rest of the object only appeared intermittently in averted vision. Whilst I caught glimpses of it around the field of view I certainly would not have been able to draw the shape of it.
NGC7000 – North America Nebula – It was natural to move onto this after the Pelican. The Eastern seaboard section was similar to the Pelican- hinted at, but not obvious. It started to become more easily visible around Florida and the Gulf Mexico and the Cygnus Wall was quite prominent.
At this point a bobbing white light appeared in my peripheral vision. Someone walking with a torch. I always feel quite exposed when out on my own in places like this and I sat quietly, but with heart pounding, as the light gradually made its way toward me. Then it started sweeping the field, and stopped dead when it found me. Feeling a show of confidence was in order, I waved my hand in the air and shouted out a cheery “Good evening!” as if it’s the most normal thing in the world to be found on your own sitting on an ironing chair in a freezing cold field in the middle of a late October night. The torch again started bobbing towards me and as he came closer I could see he was clutching a tripod and camera bag and was most probably a like minded soul. My visitor turned out to be Javier- a Spanish amateur photographer having a week’s holiday in the lakes.
He was very interested in what I was doing and my equipment, so I whipped out the filter and started showing him some galaxies which he was very taken with. An explanation of what he was looking at, and the distances involved caused some rather pleasing swearing and evolved into a lengthy conversation about the likelihood that the universe is infinite and whether or not the multiverse theory is a pile of nonsense (not the word used).
His mission for the night was to take some nightscapes of the stones with stars beyond, using his torch to paint them in. It’s a fun technique and I was able to join in with my camera , which are the pictures that you can see here (his results were better!).
Whilst he carried on I returned to the eyepiece as Orion was now high above the mountains and above the lighter section of sky.
M42 – Orion Nebula – My first observation this season, at was as always a joy. With the UHC filter in I sent some time just enjoying the bright bow-like “front” of the object and then, with time, the billowing structure of the nebula behind began to emerge. Reflecting on the earlier observations of nebulae that evening, there really are no others that compare to it for me. It’s just an endlessly rich and fascinating object.
NGC 2024 – Flame Nebula – feeling encouraged by the fabulous views of M42 I slid the scope up to Alnitak for a gander at the Flame nebula. I found that the UHC filter didn’t really add anything (especially as the blue/red separation it puts onto Alnitak is a bit distracting) so I took it out and found that I could still see it. Far more obvious than at home it appeared as two prominent patches separated by a dark lane. The branches that you see in images couldn’t be seen at all, but the shape was very clear as was the central dark lane.
IC434 – Horsehead Nebula- finally! This was not easy at all. Following guidance I’ve read here and elsewhere I tried with a H-Beta filter in my Baader zoom but this wasn’t showing it at all. Switching back to the 30 mm with no filter I went through the ritual of just circling the area with the positions of the local prominent stars in my mind. The nebulous bank in which it sits was quite straightforward and with time the Horsehead appeared as a notch in it, a clear area of darker sky through the brighter part of the nebula, but not cutting all the way through. I couldn’t see the famous charismatic shape but the dark cut into the nebulous bank was there, as well as some hints of the shape in the clouds beneath it (I probably wouldn’t have been able to discern those clouds but for the darkness of the HH bit).
I called Javier over, but the stiffening breeze was making it very hard to keep the scope in place and I was unable to show him. As it as 2am and he wanted to be up to photograph the dawn at 6 he announced that it was time for him to turn in. Reluctantly I also started to pack up.
Reflecting back- what a couple of nights! My first time with a large-ish dob under pretty dark skies: it will not be the last. If you’ve read this far then- thank you – I’ve had fun re-living the experience and I would finish by repeating that the old cliché about the best upgrade to your telescope being petrol is one that I now firmly agree with.
Having been away with work and other commitment through several clear nights this week I was itching to get out last night and had the kit set up before it was properly dark. I set the cameras going for some imaging then concentrated on the visual with the 14” Dob and Baader Zoom. I didn’t really have a plan, but instead spent the time wandering through Sky Safari and just going for stuff that might be interesting.
Double-double: This is a regular starting point for me- I align the Rigel and Finderscope on Vega then check out the double double to see what the seeing is like. It wasn’t the best and the sky was clearly a bit milky too, but even without the aperture mask there was clear separation on both pairs which augured well.
M13: Just a short hop down and I almost go there out of habit. A nice view with good resolution into the core; couldn’t see the propeller though. Never quite sure whether it’s the conditions or me- but I can only see it about half the time.
NGC7331 and Stephan’s Quintet: This was my first imaging target for the night and I wanted to see what I could get visually as well. NGC7331 is a nice target- quite easy to see the core, and then with a bit of time and some averted vision more of the shape becomes clear. I’ve had quite a few goes at this and always feel it’s right on the edge of my vision. I spent a long time on it last night- moving the scope, looking around the object, just relaxing and trying to let it float into view. There was definitely something there- a faint mottling of the sky. But not distinct. I have dark sky 2 trips coming up where, with a bit of luck with the weather, I’ll have more of a chance. It’ll be great to finally tick this one off.
M15: It’s a couple of years since I put this one in the eyepiece and I’d forgotten what a wonderful target it is. To me the core seemed to appear slightly below centre (so I guess above centre as I’m using a Newt)- but I’m guessing that’s an effect of local atmosphere as it certainly doesn’t appear on any photos that I’ve checked online this morning. I also tried the Binoviewers; I’m a huge fan of globs in Binoviewers- they both seem to add an extra dimension and support seeing more detail in the object; but on this occasion it didn’t really seem to add anything. No worse, just no better either.
M2: This was a nice view, but being a bit lower in the sky than M15 it was a bit murkier and harder to resolve, so suffered a bit by comparison. I probably did them in the wrong order!
NGC891: In Sky Safari this looks reminiscent of the Needle Galaxy so I was keen to have a look, but I really couldn’t see anything at all. I spent a long time on this- trying averted vision, and then dropping the magnification right down with a 30mm eyepiece- but nothing at all. Then, as I had the 30mm in…
M31/32/110: This I COULD see! Lovely to sit back on the chair and just drink it in. I find that it reveals itself in the same sequence each time. The core of M31 leaps out at you and then M32 is right there as well. Gradually some of the dark lanes appear and I then have to work a bit to get to M110. On really good nights I can see the edges spilling over the field of view, but the sky was too milky last night for that. It really is an awesome thing to contemplate: the light of a trillion stars travelling for millions of years and landing in my back garden. I hope it wasn’t too disappointed in the state of my lawn.
Caroline’s Rose: Next, and with the low power still in, I wandered up to Cassiopeia. I could see the dark lanes in this open cluster; I sort of get it as a rose but it doesn’t quite leap out and grab me.
M52: I much prefer this open cluster- not really sure why. The odd brighter star (not sure if it’s foreground) reminds me a bit of the Wild Duck Cluster- a pleasure to look at. I went back to the Baader zoom and quickly dropped back down to 8mm for the best view.
Blue Snowball Nebula – I love the colour of this, it’s great to have something that’s not grey. I can never make out any details on this, but I always enjoy the blinky thing that PNs do. This inspired me to jump across to…
Blinking Planetary Nebula- which always sounds like an exclamation to me. Strangely it didn’t blink as much for me as the Blue Snowball.
M57 – The Ring nebula. Always a favourite; I decided to try some filters and also the BV’s on this. In the end reached the conclusion that it’s bright enough that none of these approaches really added anything. In the Baader, at 8mm/206x it’s a lovely view with a darker section (although the central star was beyond me last night) in the middle and variations in shading around the ring. Always good to experiment, but in this case the simple view is the best for me.
M27- The Dumbell. In this case it really was worth experimenting. In the zoom it’s only a faint wispy thing at any magnification, and only really the apple core shape is visible. Dropping to the 30mm and it appears much more strongly, standing out a little against the star field. Popping the Baader back in with the UHC filter on it made it stand out a little further against the background, although at the expense of a little detail. Putting the Oiii filter on turbo charged this effect: in monochrome green the full extent of the object was visible against the pitch background, there was a lot of shape as well, although it was quite blurry and you could only really focus by sidestepping to a nearby star.
M71 – Nice, but quite faint and small compared with the other globs in the session.
The Moon was up now and bed was calling, but like a kid left alone with the biscuit tin I was unable to resist a few more targets. The moon itself was in a really wobbly bit of the sky so I didn’t spend too much time on that, and switched back up to Cepheus.
The Garnet Star- always a beauty, nice and sharp with the aperture mask on it.
Delta Cepheus – A nice easy split; and almost Albireo like with the contrasting colours.
Kemble’s Cascade – Too bright to find in the moonlight; no stars to hop from.
Double Cluster – A wonderful place to finish!
Right, where are those subs…
Between a busy work week, family commitments and some so-so forecasts it wasn’t looking good for astronomy this weekend, but it turned out pretty well.
Didn’t get out until about 10:30 but tried to make up for lost time by setting both the main scope going and trying out my 50mm lens on the Star Adventurer. I had high hopes for the 50mm lens- it’s another oldie (I’ve had it about 15 years), but online quite a few people are getting great results with them. Well- I’m not in that club (yet). The diaphragm only has five blades and although I stopped it down to f2.8 (it’ll open up to f1.8) all of my stars are pentagons and DSS is refusing to recognise them as stars- so no results from that. Fortunately, the main rig saved the day: I went for NGC6946 – The Fireworks Galaxy with my 200p. Throughout the session low clouds were interrupting the view, and around half the subs were lost, but the ones I did hang onto gave the result below. Over the summer I’ve picked up a second hand Canon 550d that has been home modified with a Peltier cooler and put into a metal case- it’s not pretty, but it seems to be effective. This is 13×4 minute subs and throughout this session it held the temperature down to around 7-8 degrees which I’m pleased with (a couple of degrees below ambient, my 600d usually runs about 10 degrees above ambient and is consequently much noisier). The target itself is quite a bit smaller than I’d anticipated- this is a crop of about 20% of the frame. Despite the small size- I think this is a lovely target- both for its colours and the asymmetry in the arms.
Whilst the cameras were doing their stuff I had the Dob out on the following objects:
The Double-Double- I used Vega to get the finders lined up then dropped down to Epsilon Lyra to check out the seeing. It was a straightforward split, but I could see that the transparency was not great.
M13 & M92 – I often start with these and never get tired of them. In Binoviewers at about 260x they fill the field of view and appear 3 dimensional. For me these are the only types of objects that actually look better in the eyepiece than in a photo; I love the difference in their appearance- M13’s great with lots of features, but a bit of a mess with arms everywhere, whereas M92 is compact and very neat. Just wonderful.
The Veil – I was reading a thread on SGL recently which referenced a Sky and Telescope article on The Veil (https://www.skyandtelescope.com/astronomy-blogs/explore-night-bob-king/explore-veil-nebula/) . Using this as a guide, and with an Oiii filter a 30mm eyepiece (55x) and a coat over my head I managed to explore just about the whole thing. I’m a bit prone to hopping from object to object whilst observing, so it was great to really take my time in the tranquillity of the small hours and drink it all in with nothing but the odd clunk of a shutter release and that American woman with the nice voice who commentates on APT saying “Dithering started…” softly in the background. Ahhh… a very nice dither contemplating the remnants of a supernova.
I was on the Veil for over half an hour and loved every minute of it, but decided with to move on with the Oiii filter and go check out M27. This is normally not a problem, but by this point the transparency had deteriorated so much I was unable to hop to it. Altair was the only nearby star that was naked eye visible and despite several attempts I just couldn’t find the stars in the finder to hop up to M27. Reluctant to retire I switched up to the North East to check out M31 as the skies looked better in that direction. Before I could get to it a bank of cloud blotted it out. Time for bed…
I managed to pop out briefly whilst doing other things on Saturday evening and set the imaging rig running on M13. This was a bit of an experiment: I’ve imaged M13 before, but with my guide camera on a smaller scope using the short exposure method. Whilst I was quite pleased with those outcomes (see https://roslistonastronomy.uk/catching-up-on-images) , I wanted to see how it would look with more integration time and a DSLR chip. This is 22x 4 min subs plus calibration frames and I am really pleased with it. As a bonus for the last half-hour it was running I sat outside with Sam observing the sky primarily with Mark 1 eyeballs. After a while we were both able to pick out the Milky Way running up through Cassiopeia and Cygnus despite the local light pollution. A real pleasure!
Got home from the trustees meeting last night to a glorious clear sky. On a Monday? Really?
I made an aperture mask for my dob over the weekend and was itching to try it out. The idea behind the mask is that on bright targets cutting out a bit of light and diffraction from the secondary struts should improve clarity, even though the aperture is reduced (350 to 160 in this instance).
And so after failing to resist temptation I was setup by 11:20:
Jupiter: Disappeared behind neighbors house. Need to catch it in the gap between house and apple tree 1.
Saturn: Seeing dreadful without mask: boiling away with no clarity at all. With the mask: same but dimmer. Hmmm.
Pluto: Spent ages looking for this. Definitely in the right place. Pluto formed a triangle asterism with two other faint stars. I upped the magnification to dim the sky glow and there was definitely something there. Wobbled the scope – that helped. Averted vision- didn’t make much difference. So- I’ve looked at Pluto but not seen it! Beginning to regret doing this on a work night…
Jupiter again. Behind apple tree 1. That moved quick! Damn!
Izar: At last- some success. Successively improved views moving from Baader zoom to binoviewers to adding aperture mask. In the final view the stars were pinpoint sharp and well separated with the companion showing a lovely blue.
Double double: the same experience. The 2 pairs were easily separated in all 3 configurations, but the binoviewers plus aperture mask gave the best view.
M13: Too dim for the mask, the best view was in the binoviewers- resolving all the way to the core and seemingly spherical, even though at that distance you don’t really have depth perception!
Jupiter again: Gotcha! Just before it snuck behind apple tree 2… Definitely a better view with the aperture mask- slightly dimmer but with much more clarity. 6 bands plus the GRS were clearly visible, with some detailing on the bands, plus the moons spread out as clear disks 3 to one side and one on the other.
Well worth the fatigue today!
Very pleased with the aperture mask- it’s not often an astro upgrade is almost free. It’s only really good for bright objects and with the binoviewers I had to velcro 4kgs onto the bottom of the tube to balance it- bit well worth the hassle!
Popped out for a quick session on Friday night and there was a lovely Noctilucent Cloud formation to the North, so I popped my camera on a tripod and recorded it.
The video above was using a Canon SL1 at 22mm f4 taking 265 shots between 23:49 and 00:30. I used Pixinsight for a curves tweak and some unsharp masking and then Videopad to string it all together and add a bit of music.
The red light in the foreground for part of it is me setting up the dob. It doesn’t really add to the ambience- but it led a pretty good session despite needing to do a bit of cloud dodging. Finally got the Binoviewers dialled in for some good views of the Double Double, Izar, Albireo, M29 and M57. Really surprised that at similar magnification they outperformed my 7mm Celestorn X-Cel Eyepiece- the split on Izar was really clear, and the companion was a vivid blue, wheras the Celestron had them fuzzier and less colourful. Even Saturn came out to play- and despite hugging the horizon, the seeing gave me glimpses of the Cassini division plus Titan, Rhea, Dione and Enceladus. Best of all was M13- it resolved close to the core, but with tails everywhere- it looked like a ball of wool after a kitten’s been at it!
“You’re writing a blog about a spreadsheet???” My wife has just discovered that not only have I adopted the habit over the last couple of years of sitting in the garden on clear dark nights and then making notes about it, but I’ve then been putting it into a spreadsheet and getting statistics about it. And now I’m sharing it in public. She’s giggling at me with what I hope is affection…
Last year I bought a 14 inch dob and after a few months enjoying the views and wandering through the skies I decided I wanted to be a bit more rigorous and start planning my sessions, so I started making notes on my phone of what I wanted to look at after reading observing reports on the web. I quickly moved onto recording the success or otherwise of these observations on a black notepad on my phone (to minimise disruption to my dark adjustment, although to be honest, in Bortle 5 skies it doesn’t make a huge difference), and it was a short step from there to Excel. I just spotted I’ve been doing this for around a year so I thought I’d share it, partly out of curiosity to see how it compares with others experiences…
Stating the obvious: we get quite a lot of cloud.
If it’s clear, I’m not doing family stuff and work’s not in the way then I’ll go out and observe. Altogether I’ve recorded 26 sessions. I’m pretty sure there have been more than that- if I’m observing in company I’m much less diligent about recording it. I also sometimes have quick sessions with my 8 inch for half an hour and I’m a bit rubbish about recording those too. So: 26 is roughly the number of ‘proper’ sessions where I’ve sat outside with a target list and written it down. From this I reckon twice a month is a good working average for how often I can do a ‘good’ session.
|No of Objects||149|
|No of Observations||280|
If I was a bit disappointed to realise how infrequent observing sessions are, I was quite surprised by how many objects I’ve managed to record during that period- including quite a good chunk of the Messier catalogue. I suspect I’ve managed to get through most of the easier ones. From my location, although my southern horizon goes down to a few degrees in places, I’m looking directly over rooftops and at the dome of light pollution of Burton on Trent and often the orange haze makes finding reference stars to hop from very difficult, so I’ll probably need to make more effort to get to dark sites to grow this list a bit.
I wasn’t surprised to find that there are some objects I come back to again and again, but I was quite surprised to find the Leo triplet at the top of the list, although on 3 of those occasions I couldn’t find NGC3628. M13 is less of a surprise, I never get tired of looking at it and trying to resolve as far as possible into the core. I notice that over time I’ve been less inclined towards the higher magnifications. The Double Double is a favourite first port of call, both because it tells me how good the seeing is, and also whether my mirror has cooled. Plus, I love the idea of it as a vast interstellar executive toy- with six components that we can’t see. I’m sure M42 would have overtaken all of these if it were visible for more of the year and not so subject to winter weather.
Something I’ve not done much of is logging how often I can’t find or see things. The Horsehead is conspicuous by its absence (I picked up an H-Beta filter in March, but just missed out on the HH) and I really want to see Stephan’s Quintet visually- this will need darker skies! I suspect that if I was logging more diligently the times I’ve failed to find either of those targets they’d be quite high up on the list and I’m going to start doing that. I’m also going to record a bit more about where I observe (usually my back garden) and what equipment used.
I’ve attached the spreadsheet I’ve used in case anyone wants to re-use the format- it’s pretty basic and has just sort of grown organically as I’ve added bits and pieces to it. It’s a bit of effort to keep it up to date, but I’m glad I did it as it’s been interesting to look back over it and remind myself of what I’ve seen- It’s also a reminder of how great visual astronomy can be when you’re suffering the frustration of several weeks of cloud cover.
I’m going to brush over the slightly worrying and repeated experience, of reading about targets, thinking they sound great, then finding I’ve already seen them…
After hearing about the rapid set up and simplicity of a Dobsonian mount for casual observing, I thought I would investigate how to get one as an alternative to my EQ5. Strange that these mounts cannot be bought separately, except at Orion Optics UK, where I was quoted a high price. This set me on the DIY route.
I decided that I wanted the capability to adjust the tube axially (for balancing) and rotationally (for comfotable viewing position), as with the EQ5.I also wanted easy transfer of the tube between Dob and EQ5 (no tools needed). After a week of research, I settled for a hybrid that included a features from this article: http://www.scopemaking.net/dobson/dobson.htm, The Sky at Night articles in Dec 2014 and Jan 2015 and the Orion Optics design. Originally, I was going to design the rings and dovetail bar to be interchangeable, but when a set became available I settled on a separate ring set for each mount.
I won’t go into detail about the build/assembly but show various stages in pictures. The main stages are; 1.mods to the ring set, 2.cutting, shaping and painting, 3.bearings and the 4.optional brake. Anyone who wants more detail please contact me.
1. Modify ring/rails assembly.
Trunions: PVC 160mm pipe plugs (Buildbase, Newhall, Swadlincote). Protect bearing surface with masking tape. Locate centre and fix to bar with 1/4″UNC fasteners (Pugh & Sanders Ltd Burton on Trent).
Shape and fit 2nd ‘rail’ from 10mm plywood. Fix to rings with 1/4″ csk head screws. Locate trunion on centreline in same position exactly as other trunion.
Trial fit completed ring/rail assembly to scope
2.Cutting, shaping and painting frame
I used 18mm mdf for the base and sides and 10mm plywood for the front, back, rail and accessory tray. Use plastic fixing blocks and screws to hold everything together. No adhesive needed. Take basic dimensions from the article referenced above, except width of front and back, noting that alt bearing box is not needed and friction brake needs to be included.
Mark out parts using trammel to draw circular base.
Cut with jigsaw and smooth with rasp and glasspaper
To obtain width of front and back, measure distance between trunion flanges and add 10mm.
Use plastic fixing blocks to assemble, drill through upper base and screw to frame, bolt to lower base, trial-fit scope assembly. If all goes pear shaped, use as a ‘lazy-susan’ coffee table!
Trial fit 3 feet 120° apart.
Use jigsaw and ripsaw to cut holes to reduce weight and improve appearance.
Hang from washing line for painting – 2 coats minimum. Have a coffee between coats!
For altitude bearing use two 2mm thick ptfe sheets, drilled and countersunk in centre for small csk head screw.
For azimuth bearing use 3 Magic Glides (Wickes) spaced 120° apart within 300mm circle .
Use M10x60mm carriage or ordinary bolt and M10 Tee Nut (Amazon or ebay) inserted upside down for pivot in lower base. Tighten so it will not fall out or turn when M10 Nyloc nut is tightened.
For upper bearing use 12″ vinyl record (grooves make for low friction). To form a good bearing for the bolt in the upper base use a brass10-15mm reducer plumbing fitting (Wickes) drilled out to 10mm. Secure bases with oversize washer, spring washer and M10 Nyloc nut. Tighten only enough to take up slack.
Small spacers are needed to prevent sideways movement of scope assembly. Spacers are squares of ptfe fastened with small screw and spring washer fitted between side and flange of trunion. Trial fit to to gauge the spacer size and position of spacers.
4, Friction Brake Feature – Optional
This feature prevents the scope moving if the assembly becomes out of balance, although there is the option to slide the tube axially.
Attach another strip of ptfe to top of curved section of brake. Attach small hinges between brake and side using small 90° brackets to allow screwing into face of wood – mdf will split if screwed into edge! Attach a ‘Brighton sash window catch’ (satin chrome finish from Screwfix) such that it can be released to allow the scope to be lowered into place and tightened to stop movement or lock the scope. Fit accessory tray to front and hooks to sides for clipboard, glasses etc. Extension legs can be used if elevation is low or if the ground is long wet grass. To make carrying more comfortable, fit a length of 12mm soft clear plastic hose cut lengthways to upper curve of the front.
I had great fun making this but have used it only briefly to observe the Moon and was pleased the way it moved…but I still like the fine control provided by my EQ5 control cables. Now how can I add this feature to the Dob…?