ChrisLX200 Posted November 8, 2016 Share Posted November 8, 2016 I think last night my problems were due to it being really cold, -3.5degC, so even with the heat rising in the case the dome itself remained cold. More heat would have fixed that I think, but there should have been no moisture inside anyway. This is the metal casing I'm using so perhaps the 3D printed one would lose heat more slowly.. ChrisH Link to comment Share on other sites More sharing options...
SkyBound Posted November 8, 2016 Share Posted November 8, 2016 When you have your ASC running all night what exposures do you use, and what length of time between exposures...I see you seem to use 30s and 60s exposures, what pause time in between...?? I will be using an ASI120mc for my ASC. Link to comment Share on other sites More sharing options...
Gina Posted November 8, 2016 Author Share Posted November 8, 2016 I'm mainly using 60s exposures with 1s pause between though the download time produces another several seconds gap between exposures. Link to comment Share on other sites More sharing options...
ChrisLX200 Posted November 8, 2016 Share Posted November 8, 2016 I just run mine continuously, with the Moon up I use ~10sec exposures, on a dark night 20sec. I save as PNG files then use VirtualDub to create an AVI (H.264 compression to save space). That's using SharpCap, but in the past I've used FireCapture to create the AVI directly - no PNG files. However, SharpCap has superior Dark Frame handling using a library of saved Master Darks, with FireCapture you have to create a new (single) Master Dark each time you start - something of a disadvantage if running remotely because of the need to cover the camera. ChrisH Link to comment Share on other sites More sharing options...
Gina Posted November 9, 2016 Author Share Posted November 9, 2016 I seem to have a problem - can't connect to the ASC I'll try powering down to reset (again). Link to comment Share on other sites More sharing options...
Gina Posted November 9, 2016 Author Share Posted November 9, 2016 Found the problem - it's not drawing any current so the power connection has failed up top I'll take it down tomorrow and take a look. Not doing it tonight even though the rain has stopped. Don't think there will be any DSO imaging tonight anyway but I would like to have had an "eye on the sky" We've had heavy rain and strong wind today and the rain hasn't stopped long. Pointed my torch at the dome and it's well and truly fogged up. I'm thinking a sealed enclosure might be a good idea. Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Just taken the ASC down and brought it indoors - a shower of wet rained down on me as I unscrewed the bracket holding the mast Had to change my jumper! Opened up the box and not only was the dome wet inside and out but there was water in the bottom of the box that hadn't drained out. Found the power problem too - one of the wires had pulled out of the plug and the latter was half out of the socket. CONCLUSION :- This box/case is a disaster!! Just hope the contents are still working! I shall have to wait for everything to dry out before applying power again. Don't know how all that wet got inside the box - must have got up under the dome I guess even though there's a 6mm overlap of the dome over its retaining ring and such a close fit that it needs prising off. OK so it wasn't actually sealed but I didn't expect wind driven rain to be forced up into the dome and down inside. I don't believe it was due to condensation as there was far too much water in the box for that! And I thought this was a finished project!!! Link to comment Share on other sites More sharing options...
hughgilhespie Posted November 10, 2016 Share Posted November 10, 2016 Gina, Surely you remember the special Devon 'falling upwards' rain. We get a great deal of that variety here in North Devon!! This is rain that just laughs at 'waterproof' and giggles when you mention IP67!! Fingers crossed for the soggy electronics. Regards, Hugh Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Yes, it could have been the "falling upwards" Devon rain - I quite agree! Stripped all the parts out of the box and everything is dripping in wet Raspberry Pi, HAT, buck converter and camera assembly all running with wet!! Just hoping the camera is alright - the other stuff isn't too expensive to replace. If the camera turns out to be duff I'll try the ASI185MC instead - much lower resolution and less sensitive but might be adequate for just seeing if there are clouds. I'm now looking at the design of a cylindrical casing that I can 3D print in ABS. I think I would be wasting my time trying to waterproof that rectangular box. I'm thinking in terms of arranging a seal and clamp arrangement for the dome which has a rim for this purpose - it's a genuine replacement dome for a commercial ASC. I have rubber sheet left over from trimming my observatory roof that I can make a seal out of. Don't know whether sealing the casing totally is going to be possible yet but another possibility would be to attach it to the tubular mast and take the power cable down inside. Link to comment Share on other sites More sharing options...
ChrisLX200 Posted November 10, 2016 Share Posted November 10, 2016 That's disappointing for you Gina, but if the only joint is the base of the dome I gues it's no mystery where it got in. A printed seal in that flexible stuff should do the job? ChrisH Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Ah yes - good idea - hadn't thought of that - better than the hard rubber roofing sheet But no, not the only joint, there's a joint in the case where the lid fits onto the base. In this case an upside down box with the lid used as the bottom of the enclosure. A good fit with a lip but with the wind blown rain we've had lately that could also have been an ingress point. With the amount of wet on top of the camera I think it got in round the dome though. I thought I was lucky to find a box just the right size but should have known there would be a downside!!! There's no substitute for a properly engineered custom case I guess. Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Shouldn't take me too long to design and print a case but it won't be ready for tonight I don't think. For one thing the appropriate printer for this is my middle one the "Pilot" and that's out of commission ATM but could be fixed tomorrow with some new parts. Link to comment Share on other sites More sharing options...
ChrisLX200 Posted November 10, 2016 Share Posted November 10, 2016 I would offer the suggestion to spray the electronics with ACF50 in any case - I'll swear electronic boards would work under water after a coating with that stuff In fact, I think my USB hub literally DID work with the electronics submerged for quite some time, when I finally noted a problem with it and brought it inside for a look it was full of water - it just poured out. The mount cover was leaking and dripping into the USB ports on the top. I dried the thing out and amazingly it still worked (albeit one of the 7 ports had failed - which was how I noticed the problem in the first place). I'm uncertain how long it continued to operate under those conditions before one port failed. ChrisH Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Thanks Chris - I'll see if I can get some of that Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Taken you advice and ordered some - should be here Tuesday. Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Now printing the dome sealing ring in that rubbery stuff. Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 This is what I have in mind for the top of the box. I may add some supports for clips to hold the dome in place. Probably three of them. Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 To make room for the electronics without making the casing too big I could offset the camera to avoid the wasted space on the opposite side from the electronics. Whether it's really worth doing this is a moot point. Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 I have an alternative to the offset camera idea - take the HAT off the RPi and connect with a ribbon cable so that the RPi can go one side and the HAT on the other (or some other board in place of the HAT). Link to comment Share on other sites More sharing options...
Gina Posted November 10, 2016 Author Share Posted November 10, 2016 Actually, the HAT is overkill as I'm no longer using the stepper driver and using only three data connections to the GPIO pins plus the +3.3v rail. The +12v, +5v and Gnd connect to the buck converter which also connects to the RPi power input. There is no actual Gnd connection used from the RPi as the Gnd only applies to the 5v and 12v supplies for the Peltier TEC cooler and the dew/raindrop heaters. I can use the HAT for other applications. Link to comment Share on other sites More sharing options...
Gina Posted November 11, 2016 Author Share Posted November 11, 2016 Here is the design for the box bottom or main part. Link to comment Share on other sites More sharing options...
Gina Posted November 11, 2016 Author Share Posted November 11, 2016 I shall be making up a new circuit board as the HAT is going to be "repurposed". This will contain the circuitry for the cooler control and the two heaters plus their connectors. A small piece of stripboard will suffice for this. These are the circuits - one for the cooler and two for the heaters. Link to comment Share on other sites More sharing options...
Gina Posted November 11, 2016 Author Share Posted November 11, 2016 I've worked out a way I can make the casing parts small enough to print on my UP Plus 2 3D printer - this means I can leave getting my Pilot printer working for now, though I have the parts to fix it (hopefully). Instead of having the longest section as part of the bottom I can make it part of the top with the conical part to the mast having a short cylindrical part at the top. Link to comment Share on other sites More sharing options...
Gina Posted November 11, 2016 Author Share Posted November 11, 2016 Cooler and heater circuit nearly finished. Link to comment Share on other sites More sharing options...
Gina Posted November 12, 2016 Author Share Posted November 12, 2016 Top part of the case printed plus dome seal and bottom support plate. I have yet to add mountings for the RPi and other bits. Link to comment Share on other sites More sharing options...
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