Gina

I'm using grommets for the pressure tube and 7-core cable. These seal fine without any sealant. The water tubes go through printed pipes as part of the base which are smaller than the OD of the tubes so these fit tightly and also seal fine. The dome has also sealed well with no sign of a leak. The problem areas are the main flange and the USB cable. I could cut and join the USB cable then it can go through a grommet and solve that problem.

I do have a lathe but can't get at it ATM.

Ordered an O ring - arriving tomorrow. 130mm x 5mm Rubber Sealing Oil Filter O Rings Gaskets Black

Just tried to separate the casing parts at the flange and it's stuck solid most of the way round. So much so that the casing has broken trying to prise it apart!! OTOH the seal for the USB cable, also apparently well sealed with lots of sealant is leaking profusely. Looks like I need to change the design completely.

Yes, no doubt that would work - I'd be surprised if it didn't but I'm surprised silicone sealant didn't work. Bit final though - to get inside any time in the future, if a problem arose, would mean breaking the casing.

No, I haven't and can't see any advantage. The printed parts are not leaking. It's between the parts of the flanges. The flange surfaces are perfectly flat from being printed on glass with good extrusion so that there are no grooves between filaments. The mating surfaces are like a mirror. Maybe just grease would work better that sealant. Or perhaps a greased paper gasket - works for engines.

Been testing the ASC casing for leaks. Still leaking from flange joint in spite of using a copious amount of silicone sealant! ? I'll try printing a gasket in TPU next. I have some thick grease I can use with it.

Young??? Wish I was ?

Bolted the casing top to the base - 8 M4 bolts and nuts through the flange with silicone sealant between. I'll leave a while to set before applying pressure. Yes, I did remember to include some silica gel bags (3).

Base and camera parts assembled and wired up. USB cable sealed to base and camera tested. Unfortunately, when I tried to test with the ASC control electronics I found a short on the supply. Disconnected everything but the RPi and powered that separately but it didn't work - no red power light and no activity. Seems to be dead. Tried another RPi with the ASC SD card and the camera is working. Because the RPi hardware is different the WiFi doesn't work (WiFi setup depends on the MAC address of the WiFi unit) so I'm using Ethernet. I shall need to sort out what's wrong with the electronics otherwise I'm ready to bolt the top to the base using sealant and see if the casing is airtight.

Of course I wish you luck ? I haven't enjoyed binocular vision for a number of years due to muscle imbalance (my right eye points slightly outwards) which has got worse over the years. It was correctable when I was young by prism in my glasses but now it's beyond optical correction and also non-operable. Also, quite severe astigmatism means observing is not good anyway and one reason I concentrate on imaging. My brain produces 3D images if I'm walking or driving due to motion - the same way as hens do by moving their heads back and forth. I guess a suitable optical system with cylindrical lenses to correct astigmatism plus a mirror or prism system to bend the light beam inwards could be used to enable me to use a binocular telescope. It would be horrendously expensive, of course! Or would it?? I guess an old pair of glasses could provide the cylindrical component then a modified diagonal for the right eye. My right eye is still good optically.

Does a binocular telescope actually give a 3D view of a planet or is it just that you get the extra light compared with a telescope of the same size with a binocular eyepiece? I wouldn't have thought that tiny separation, compared with the distance of the object, would give actual 3D viewing but I'm happy to be corrected on that.

OK, I'll check that out tomorrow.

I thought petroleum jelly attacked rubber.

Problem!

Great - luvvit

Been having lots of problems with the Z drive - very noisy and tending to stall one side or the other even at quite a low speed - so decided to dismantle the Z drives and see if I could find the problem. Tested the threaded rods for straightness and they are fine. One problem is that the printed Z carriages have warped and the wheels are loose on the Z rails. So I shall need new Z carriages anyway. From what I can discover and discussions, I think the main problem may be the accuracy of alignment of the threaded rods with the nuts on the carriages. To make alignment easier and save myself a lot of work I think I may add more cash than effort and order some ready made parts. I would want two sets - one each side. There are other useful parts too such as top and bottom plates that hold the rods precisely in ball bearings but aluminium parts are quite expensive at £10.50 each (so 4 off would be £41) and I think 3D printed ones would be good enough. This is a system designed for precision in CNC machines and with the taller gantry plates just the job for the Z axis. Firstly though, the smaller and cheaper gantry plate. C-Beam Gantry Plate £11.00 The double gantry plate is longer that the standard one which is only 60mm between wheel centres and would give better resistance to twisting. C-Beam Double Gantry Plate £16.50 C-Beam Linear Rail – Cut To Size £13.62 I'm already using NEMA23 stepper motors for the Z drive so it all fits.

Printed parts finished and tested for fit. All the tubes and cables disconnected and separated from the previous base.

Base printed successfully and now printing the conical mast coupling.

Decided to go for a flat gasket for the main flange. But instead of using another flange on the mast coupling I'm going for a vertical joint with four horizontal screws to hold the ASC onto it. The casing top is fine as it is but the base and mast coupling have been redesigned as shown below. Underside of the base - top is flat.

Can't see it being a problem. I use Linux Mint on my desktop machine and Ubuntu MATE on RPi. I think the desktop would be easiest and my desktop has USB3 whereas RPi is only USB2. In fact I have two ASI1600s. I also have ASI174MM, ASI178MM, ASI120MC-S and the ASC uses an ASI178MC.

Found the leak - the main flange joint between casing top and base. I shall have to improve that. Silicone sealant doesn't stick to PETG. I think I'll try a groove in the two parts filled with a TPU O ring. A lot less messy than silicone sealant too. OTOH the only perfectly flat surface possible on 3D printed parts is where they come off the glass print bed. That is what there is currently between the flanges. Maybe some closed cell foam rubber as a gasket.

OK so it's back indoors!

Went out to the observatory and painted the joints with soapy water. The cap of the air reservoir bottle leaks but then I had a thought about the ASC itself and squeezed the tube to that to seal it and eliminate loss of air from the ASC and pressurised again. This time it took a lot longer for the pressure to fall, so there is air loss somewhere in the ASC casing. Guess I'll bring it back indoors for investigation.

Started thinking about this again following the successful night's imaging with my ASC and the Milky Way coming more and more into a favourable position in the sky. I need to sort out better focussing I think and the mounting wants to allow clear airflow in and out of the ASI1600MM-Cool camera. I may make up a dew heater for the lens rather than using the warm air for the camera cooling. I bought a batch of 3W ceramic resistors for the ASC and have some left.