AllSky Camera (astronomy)

thingiverse

This is a versatile housing for an All-Sky camera that can accommodate any 1-1/4" body "eyepiece" type camera from manufacturers like Altair or QHY and so on. The lens focal length is optional, but the best choices are probably 1.8 to 2.1mm focal length (offering 180-150deg FOV respectively). Note that this design requires an optical acrylic dome of some sort, the one used here is sold at a modest price by Orion as a spare part for their own AllSky camera. It's worth using a high-quality dome like this to get the best image quality possible, a cheap dome will cause distortions and probably reflections too. The seal can either be made from a dual-row of 3mm O-rings (I have made my own like this using cut lengths super-glued together). The seal part shown here can also be printed using TPE flexible fillament (shown above in white) and that seems to work well also. There are two electrical connections provided - the first is the necessary USB connection, and in this design I use a pair of wedge blocks (keyed) which when placed around the cable (USB A-B) it can be pushed into the rectangular opening in the side and will provide a reasonably weather-tight seal without further work. Using silicone sealant would be more effective but probably not necessary. Use a small cable tie on the inside part of the cable to prevent it being pulled out. The round hole will accept a 2.5 x 5mm socket for connecting an external 12v supply to an internal heater. You can make your own here using nichrome wire or resistors - or even a commercial dew-band if you like, and the suggested power output would be around 5w (this is something of a guess!). The internal heater is needed to keep misting or dew forming on the outside of the dome, the heater is to be placed in the lower section (beneath the camera plate) and the warm air will rise through the holes and circulate around the inside of the dome. Where I am (UK) I've found the heater is essential on almost every night I've used the camera, if I forget to power the heater it will soon dew up! In addition to the heater I also keep some sachets of dessicant inside. I'll update this with material sources later... This was my source for the dome used here: http://www.scsastro.co.uk/catalogue/orion-allsky-camera-replacement-acrylic-dome-5857.htm?term=dome Print Settings Printer: Wanhao 4S Rafts: No Supports: No Resolution: 0.2 Infill: 30 Notes: Designed to be printed without supports, I use ABS for this job apart from the top weatherseal which is TPE. Care needs to be taken assembling the dome retaining ring to the main body, 12 screws are specified to provide even pressure all around but tightening must be done incrementally working your way around the ring several times. The ring is best printed with high infill (80% or so) for strength. Using either the printed TPE seal or a pair of 3mm O-rings the retaining seal should be compressed all the way down into contact with the main body of the casing. That will ensure the best chance of a 100% weather seal (it has been effective for me even in driving rain!). Addendum: You may need to chamfer slightly the inside/lower edge of the retaining ring. This is a close fit on the perspex dome and difficult to specify the exact shape needed. I have 4 of these domes and they vary a little with regards to the fillet at the bottom edge. I use a de-burring tool (designed for de-burring metal) to do this in a couple of seconds, you should really get yourself one of these anyway as it's a way quicker/easier/more-precise method of removing unwanted edges etc. This is the sort of thing I'm talking about: http://www.amazon.co.uk/gp/product/B00NVPMV5I?keywords=de-burring%20tool&qid=1456888129&ref_=sr_1_1&sr=8-1