Yawning Angel

Hiya, thanks for the links I’ll devour them a little later! The roof will be coated in a liquid applied membrane by Sika. It’s especially suited to awkward shapes, flat roofs and areas subjected to flex. This is one of the demo displays :

Some minor progress today in the baking heat. Dug the pads out for the ‘shed’ base, or rather chipped out. Clay and builders rubble under turf, so it was pickaxe work. Ordered the SWA, the corner blocks and concrete and started on the pier’s foundation pit The gazebo was the only way to make any use of the day ?

Looking really good!

Thanks James, I had thought I might run a high level cable, I can go over the patio via the existing pergola, then underground to the Obs. Clay soil and 4 weeks of no rain in making any spade work 'interesting' Very useful! I will be doubling up too, so even with the wall thickness, I should have that same edge...now I will make sure it's in the plan, to remind me I'm finding SketchUp invaluable for this job. Being able to slide the roof and see the clearances has really helped. Next step is to get the pads in and the pier block dug out then poured Don't worry, there will be pictures ?

After a frustrating winter with glimpses of the night sky few and far between, I’ve decided to try to join the ranks of amateur observatory owners to try and maximise my opportunities. So, inspired by @Astrokev, @JamesF and other recent builds I have permission from the missus (!) a space and SketchUp - what can possibly go wrong?? The plan is a 50/50ish roll off with warm room, weighing in at 2.4m x 4.2m and scraping in just under 2.5m high. Scope side is 2.4m square with the remainder given over to the warm side. The rails will extend over an area I can’t put posts in, so they’ll be supported by diagonal braces back to the main structure (this needs adding to the drawing) The all important roof is intended to be a ‘flat’ roof design, having about a 2.5% fall from the rolling side to the warm. Waterproofing will be liquid applied - I’m lucky in this, as i work for the manufacturers, so there is some expertise to draw on - not to mention staff discount ? Work-in-progress plan look like this: And the plot, taken looking north (warm room to the left, scope to the right) So I get North, East and round to South. The is already 3 core 2.5mm SWA buried, so power should be ok. CAT5 might be an issue, as all routes go under the patio. I’m hoping to get powerline networking out there, otherwise a solid WiFi setup should be manageable, as the house isn’t too far away. Should be a fun summer!

Could upgrade to C24 grade timber for the roof....or even swap out for oak on select parts, giving more strength for the same dimensions ?

If you're thinking of tackling welding yourself, then maybe borrowing or hiring a gas axe if worth it? It'd make short work of the Owl's nest - and the larger bolt holes if you're careful

I’m planning to use a liquid applied roof coating, which is flexible enough to cover heat expansion and flex in structure as the roof moves. Plus, anything it touches it sticks to ?

Hiya Kev, I've been following your build with interest - very nice work! It's my plan to put a similar build together this year. One thing I'm struggling with, and you may have solved in your design - how are you weatherproofing the horizontal seam between the rolling roof and the southern end, when it is closed?

That is absolutely glorious! Pops right off the screen whilst giving an impression of boiling motion. Lovely composition too, with the right side constrained by the clouds, and the left open to the void so your eyes fall into the centre

All the parts in my imaging train are ZWO, right up to the reducer, and it didn't all work correctly without some messing - hang in there! Keep the OAG as close as possible to the reducer. I strongly suspect it's lightpath is currently too long. My test should help prove that Before you sack the supplier - Do you know, or can the supplier confirm, the backfocus distance for the Scope / Reducer? Someone earlier mentioned it might be 73.5mm? My napkin maths says you're currently at maybe 91mm with the spacers after the reducer and the that ZWO adapter in place. (My estimates - your spacers look like 16mm or so, the Prism is 9.5mm insider the OAG, The turret is 33mm, adapter is about 20mm, SX backfocus is 12.5mm = 91mm) Looking at these rough numbers, you might get away with just dropping the spacers from the reducer, if you can. Otherwise, swapping the 20mm adapter for a slim one will bring it into the ballpark. It looks like it'll come together, in principal at least :-)

Aha, got it now. The light path to both sensors needs to be the same length, as governed by the focal reducer / scope spec . Looking at the photo, the 1600 is much closer to the reducer than the SX (my blue arrows). You might be assess this roughly like so (in daylight): Rack the focus in, as far as it will go to start Remove (unscrew) the adaptor, marked in red Extent the OAG prism turret down into the light path until it's basically flush with the top plate Hand hold the SX to the top plate of the OAG Move the focus out and see if you can get anything - it'll be hit and miss, but you should spot a roughly focused image It that works, you can look at replacing the adapter with a slim T2 to C mount...I linked one back in the depths of this thread :-)

Rodd, before you send it back, could you snap a photo of the imaging train please? There may be something easily identifiable that is not being picked up purely off descriptions

The distances are purely from the spec sheets. Can you grab a photo of the setup, please?

This should do the job, and for only 4mm TS-Optics ultra low profile T-2 to C-mount adaptor length only 4mm, T2-CS

The OAG comes with a 5mm T2 spacer, then T2 to 1.25” adapter for a nosepiece. My mistake when building it up was to include the nosepiece adapter, it adds far too much. Looks like it needs a T2 to C adapter where I’m using the 5mm T2, unless the Lodestar has something hidden for T2? One with the nosepiece (too long) one without (just right)

I’m running the ZWO asi1600 with both their OAG and Filter wheel, asi120mc guiding. It all stacked up correctly, although it’s a close thing on inward focus travel! For my own sake, I documented the setup, so maybe this could help. Note the back focus of the 120mc is 12.5mm