powerlord

lid is like this cross section with bottom:

Right... don't laugh.... before viewing the pictures let me outline my aims and reasoning: - I am not ready to commit to a permanent observatory yet for a fee reasons: 1. it would go on right side of garden half way up at the fence, and I'm not sure I want a big shed there. 2. with a 6 foot high fence, and a 6 foot+ high shed, I'd NEED big long piers to see over them. In the present position, I use the mounts on the tripods unextended and they work great. big piers would be a lot of work to install, etc. 3. I'd struggle to fit room for 3 mounts over on that side, whereas where i use just now I can easily. 4. Last year I fitted a round slab feature for astrophotography. It feels like that works well, BUT again, not really sure I want a permanent observatory there. So aims: - To cover the existing concrete circle so that I can leave all my mounts outside most of the time. - High enough that I could occasionally leave OTAs, etc out there.e.g. if expect to image the next night also. - Needs to be reasonably solid, waterproof. - Can leave all power cables, etc all connected rather than fiddling with 100 connections every night - Be temporary and cause no damage/changes to garden. - Be resilient enough that it should last many years if I decide not to go further So lets get the elephant in the room fed and watered - I've built it out of plastic sheeting. Specifically - Correx. This is basically cardboard, made out of plastic. 3mm thick roll, 1m high. It's tough, waterproof, doesn't deteriorate in sunlight/UV, and cheap. And the elephant is saying - SECURITY SECURITY !! Well - firstly I don't think any shed is secure. A pair of bolt cutters and you are in. 10 seconds. I don't think mine is any9 worse tbh. AND, I will be fitting wireless PIR siren alarm, AND a motion sensitive camera alarm (BLINK) which notifies my phone if there is any movement inside the observatory when armed. I feel comfortable that it is as secure/insecure as any other outside shed frankly. Plus I don't got out much. If I was going away for a week, etc - I'd take the stuff in. Right, with that out the way let me explain what I've built: The bottom section is the 1m correx as a cylinder around the slabs. the slaps sit level with the grass. I have cut a 1in deep channel around the slabs, and the correct fits in that groove. Around the correx, and supporting the weight of the obsy is ABS plastic 'slab/grass edging'. It's 'L' shaped plastic. This would usually be used along a path of slabs to seperate the slabs from the grass. It is very tough and quite rigid. By glueing this around the bottom edge of the correx, about 1in up, it sits on the slabs all the way around, taking all the weight, AND ensuring that no rain, etc can get into the obsy, since the correx is now lower than the top of the slabs. The edging is held in place all the way around with concrete bricks. At the top of this bottom layer, is another rings of the L edging, but facing up. This provides extra rigidity, but also provides the 'shelf' which the top part/roof sits on. The top part is the same idea, but on the bottom, the L edging is 30cm up from its bottom. This provides a nice amount of overlap for rigidity. The top is carved into a sinusoidal shape. When rolled into a cylinder that then provides a flat top of the 'wall', with the front 65cm higher than the back. The front is north facing. The idea here, is that it allows room for the mounts to be parked in home position with the OTAs on and still fit with the roof on. Correx is made from Polypropylene. Which is a great tough material, but tricky to glue. However there is a specialist technical type of hot glue stick that works well. I got loads of these. Everything is glued together with this: - the L edging is glued to the correx - the correx joints are glued - the roof sheets are glued The roof is joined to the top sinusoidal cylinder with 2" clipped off bits of L edging - one over 6" or so all the way around. And then sealed inside and out with T-REX waterproof duct tape. The idea is that the top part+roof sits on the bottom part. And remains there because it is supported all the way round with opposing rings of L edging, plus the 30cm lip. It can therefore, be simply lifted off, from the back to the front. At least that is the plan. Like a lot of stupid stuff I design and built I won't know if it works till I've built it. What remains to be done is the internal strengthening. This is going to be via fibreglass poles, staked into the grass around the slabs and attached to the correx with glue all the way around, PLUS thinner fibreglass rods, which will be glued and taped primarily on the underside of the roof, stopping it sagging, and giving it far more rigidity. Once that has been done, the theory is that it SHOULD be possible to lift/pry the roof off and on. It may be the easiest way to do this will be to lift it from the centre from underneath. Time will tell. Entry/Exit is made through a flap at the back in the correx. This has an internal flange all the way round made by another part of correx glued to it, larger on each side by 1". This seals it when the door is closed, keeping it rain proof. It is latched with magnets all the way around. I can get in and out there reasonably easily. Mounts can be dragged through there, or lifted in with the roof off. Inside I have power, and will be installing lighting, PIR alarm, PIR camera, wifi network switch. Right now, tonight it's empty and being tested. The forecast tonight is for 50mph winds and tons of rain. If it survives that with no fibreglass strengthening then I know it's up to the job. Getting a reliable way of removing and replacing the roof if definitely the unknown at present, but I feel reasonably positive that once sufficiently made rigid it should lift off ok. So - there you go - one observatory, built in 2 days.. out of plastic. Now I am prepared for the laughing - wire in.

very nice. is that with the asi ? I shot the same target/comp basically last night with my 6d +135. Not looked at subs yet but no way as good as that.

forecast clear all night here, so attempting a poor mans asi2600 with the 6d -orion in full. we'll see if worthwhile... obsy should be finished tomorrow - ran out of time tonight.

yeh my camera or maybe it was the efw came with a set of spacers, so ok there. anyway, tonight was not to be as somehow I found out I'd damaged two of my power lead plugs, ripping them off. 🙄 i have rigged up the 6d for the first time in ages with the SY135 for some widefield - at least no BF issues there.

yer not in ipswich are you ? its just, the houses in the background look the same as mine.

No just a random number example. It says with efw, and my 1600 for altair o. 8 it's 30.33, but i put 25 for who knows why. Zwo says 29.5 + 20mm efw. So dunno why they are saying 0.83 more. But I was way off last time.. It comes from trying to get the right things out in the dark at midnight. Duh

No bother. What I find a pain is mostly trying to work how how I can get Bf of X with the multitude of 42mm adapters I have. You know.. Its say 36..i have a 10, and a 20, but no 6. I have a 15 but no 1..i have a 21 and a 15..ah there we go. Etc.

Believe me when I say you would NOT get this part the boss. One of the (many) benefits of being single is that there is no one to tell me I 'don't need it', 'am being stupid',"am wastimg mytime'. Saying that... the downside is that I spend a fortune on useless mince and ages building nonsense. swings and roundabouts ? 🤪 stu

I will clarify that I don't need to fit in mine - it's purely for imaging. So It just needs to be big/high enough for the mounts, and occasionally the OTAs if left one (though mostly I intend to bring those in the next day) It will be ... unique... lets say. And As I said at start... I very much doubt anyone will want to copy it.. but I will share the 'build' pics. over today/tomorrow. IF I get my finger out I might get it finished this afternoon - looks imagable tonight.

Mine is a middle ground too.. I'm building it all today/tomorrow. I'm not sure it's something anyone else will want to copy, but for me, it's gonna work a treat I think. I shall leave it there, and post pics when complete. I will tell you it will be solid, waterproof, long lasting with a removable roof, power and room for all 3 of my mounts permanently setup. Oh.. and it's costing me 100 quid. stu

Trailing all this in and out at night is becoming tedious.. Observatory build in progress...

So.. does it matter ? Being as it's just such a long focuser distance, I could get focus with all sorts of spacing between the OTA and my asi533 for example.. so.. does it matter ? and yeh - I know.. why are you doing this ?? a valid question - I was just curious as to what I could capture with the thing, so humour me. stu

I've not come across this before, so apologies if it's egg sucking: https://cloudbreakoptics.com/blogs/news/calculating-back-focus-metal-back-distance assuming it's accurate I've had the totally wrong back focus with my altair 0.8x and image train for example.. so gonna try correcting it for tonight! stu

Well, after stripping the EQ6, cleaning everything, regreasing and tuning everything I've went from 1-1.5" RMS to this: 😀

Oh and if you are one of 'us' types.. and you have not got yerself a 3d printer yet - what is wrong with you man!!! I've had one for 9 years now (well still got that one, and got a newer one too) - learning CAD was a steep learning curve, but then it's awesome - any idea/invention/widget you think of - 30 mins in CAD and I've designed it and it's printing out.

ooo ultrasonic cleaner bath... I do fancy one of those tbh....

yeh, I work with folk like that "I can't do a meeting at 2pm, the're a man coming in to fit a shelf". I hate spending money on new appliances if no need - they give me zero pleasure. I've fitted 2 replacement elements in the oven, repaired my microwave twice, 2 elements in the dishwasher, repaired my washing machine, and the hot tub is on it's 3rd motor, 2nd controller, and 2nd heater after 20 years. None of this stuff is rocket science, but of all my mates, none of em would have attempted it. Don't really understand that mentality. I was 5yo when I took my first thing apart and remade it better (operation game), I could certainly repair all bike stuff by 8 or 9. It does appear to be a dying mentality 😞

thanks, yeh I think I still had the back focus a bit off to the CC so one to try next time, but certainly as far as my non star peeping eyes go, it seems no different than before!

Couldn't get any O or S out this at all, so settled for Ha, but didn't really work for me as a mono B/W, so settled for a warm orange Basically, pulled a sort of HDR high contrast version out, and used that as the green, and used the more standard stetch as red, then combined them both to get a little bit more hue variation in the highlights. 250 mins of 10 min subs in Ha with my asi1600 on my Altair 80ED with FF (400mm)

ta - didn't know there was a web version of stellarium.

Anyone have a good way of finding out what this little galaxy is called ? I can't find it on sky safari. astronomy.net plate solve doesn't name it, neither does Kstars - but Kstars does show it in the sky picures, so it does exist.

NGC4631 - The Whale Galaxy. Shot with my 150 TS-Photonic, with secondary mirror with chunk out of it, and damaged primary ( came oot ok I reckon. 274 mins of 2 min subs with asi533, with uv/ir filter. Processed in APP, Siril and Affinity Photo. stu

A later entry shot saturday night. M78. Been trying all sorts of ways to image this - tricky one. Eventually got a result with my 150 newt, and uv/ir filter on asi533, then combining a bit of Ha from a wider shot from my 80ED and asi1600. Processed in APP, Siril and Affinity Photo (with starXterminator, and a bit of Topaz denoise.

Been trying all sorts of ways to image this - tricky one. Eventually got a result with my 150 newt, and uv/ir filter on asi533, then combining a bit of Ha from a wider shot from my 80ED and asi1600