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Tonka or otherwise 🤔

The wheel housing. The wheel sits inside a cut out from 100x47 (4x2) just bigger than it's profile. This housing then sits between two of the wall posts and held in place with a pair of heavy screws. If at some point I need to do any maintenance on the wheels I can just remove the housing without having to dismantle the obs to get at it.

Pleased with progress this morning. I had most of the components cut out to shape yesterday, just had to cut the housings in the ridge board this morning so things could begin to get assembled. I joined the rafters to the ridge board in the workshop and carried that out as an assembly. Then built each of the side assemblies, carried them out, cl;amped them in place and lifted the rafters onto them. The roof frame over the door is different to the others but that will only get done once the track and wheels are in position and I can fit the frame clearances to the build. I'll try and cut the track and make the wheel housings later today as they can be done in the workshop should the rain return... I served a 4 year apprenticeship in woodmachining too many years ago to think about now before changing to photography. I like to keep my hand in with wood although timber of this size not often!

Made a test rafter assembly this morning - that was OK so I've now made all the components for the other rafter assemblies (6 total). Now need to work on the ridge board. Photos show it without the wheels/track in place so finasl height will be about 25mm higher (1 inch) ! The long horizontal piece is just there to clamp to while I check around to make sure it sits on guide lines.

More shiplap added today - few shorts to finish the fixed part of the build + the bottom row all round...

Two days off then back to work on the obsy today: braces, DPC, some of the moisture barrier and one wall of shiplap. Need to modify a length at the bottom - reduce it's width and cut a drip groove in the bottom edge. Hopefully do some more tomorrow...

I have a helper to keep the rain running off the obsy site... (Boris!)

Well I had to make a model to confirm that the extension rail support would work. Built to a scale of 1cm to 1 inch. Photo 1 shows the extension in place with a locking pin in place Photo 2 shows the two parts with the joint part closed Photo 3 shows effectively what sticks out from the rear wall of the obsy Photo 4 shows the joint closed with the locking pin - no aluminium plate (there would be an aluminium plate on both sides of each extension frame(2)) Photo 5 Joint part closed The Obsy end wall is a piece of OSB in the model - will be shiplap on final build The aluminium plate also shown as OSB but will be Aluminium for the build.

OK decision made (for me), SHMBO separate extension frames it is. I've been looking through lots of ironmongery catalogues but apart from some gate hardware nothing really fitted the requirements so I've come up with what I feel will be a solution: The fixed part of the rail and it's support timbers will extend slightly (100-120) from the end of the obsy rear wall each side. Ali corner plates fitted each side of each extension frame will have a 16mm brass pin inserted through to link the extension with the fixed wall. The bottom of the extension leg will sit in a socket to take the initial weight of the extension frame while the pin is inserted. A socket is formed by the ali plates and track timbers at the top to align the extension track with the fixed track. Hopefully the sketch will help. I'll do a better job of the drawing or a mock-up at a smaller scale

Made up the door end frame, put a few temp screws through the bottom rails of each so I can take the clamps into the dry. I'm still trying to decide on whether to run permanent long tracks or to terminate the tracks at the end of the obsy and add on extension rails when I need to open up. I did this on a previous obsy and it worked well - jury out at the mo 🤔 Next stage on this is the dig out the central area below the concrete block level ready for a water barrier.

Rain stopped play for the moment - progress so far today... Just put in place and held with a couple of clamps. The track support rails are odd bits of 4x2 placed for effect - the proper ones will be 4.3 Mtrs so the roof can extend past the end of the lower fixed wall.

Made a start on the sleepers today, cutting half-lap joints and adding (taking away!) a bevel to aid water run-off. Then clear up the created mess... Into the workshop now to make some layout poles ready to start marking out and cutting the frame timbers.

Block work foundations are down. Woodworking now 👍

Not blaming FLO in anyway - it's beyond their control. Lisa and Grant keeping me updated. Timber arrived today. All the sheet material went straight in the workshop to keep it dry. All the rest is treated so no problem there. The postcrete is wrapped up with the barrow on top. Mix of 47x100 (4x2), 47x75 (3x2), 100x200 (4x8) and the shiplap (behind the stack) is 125 x 19 (5x¾) coverage is 119mm (4½)

CEM60's still delayed...

Roof definitely.

That's the thing Gordon, I'm imaging only (well 99% anyway as I have aa 10 inch Dob for visual) and work remotely from inside the house so no need to worry too much about tripod legs. Just need the mount so I can finalise the internal measurements ([removed word] on iOptron… fingers out)

That depends on the tripod and in my case the need for flexibility. The Tri-pier is incredibly ridged and will sit on a concrete foundation isolated from the observatory building. My observatory will offer the quick usability a chance clear night might offer but I also want to go to location with a wider horizon and a pier in that situation is useless.

Not happy

👍 ??

Tom - There is a bigger version at nearly twice the price... Timber and ironmongery all ordered and due to arrive early next week. Hence the bad weather. Found a softish spot when working on the foundation trench so I'll hammer some broken paving slabs in to it - plenty of those.

If you have your guide settle distance set to zero or one (which it seems to default to) and a long settle time, SGP will sit there until those parameters are met before beginning a sequence, same between frames. I set my time at 3 sec and the distance to 0.6 (or 6?)

The good thing about curved vanes is the reduction/elimination of diffraction spikes. As for depth the depth is needed at the central boss where two fixing points can be used to stop twisting and the third (forming a triangle) at the tube wall.

Correct James. I've chosen to use a mixed pier/tripod to give me some flexibility should I take the scope to a location with a wider horizon. The feet of the tri-pier will locate in holes in the obsy so when things are returned the re-alignment of the PA will be simpler, the tri-pier will have its leg/column height set to maintain the leg spread. It's VERY SOLID!!! Currently waiting for a couple of material quotes to arrive from local suppliers. Not ordered the wheel/tracks yet either...