Gina

The motor control system is pretty much complete so the firmware is next. The Arduino sketch is simple - just a loop watching for the various data input conditions. The RPi firmware will be a modified Astroberry Board INDI driver. The GUI panel shown in Ekos will have 3 buttons for Open, Close and Stop. Lights associated with the Open and Close buttons will indicate the progress of the movement - off, moving, finished and fault represented by colours - grey, yellow, green and red. The Stop button light would normally be grey (off) and green for Stopped.

Photos of finished observatory and HERE (Posted May 16, 2015 ).

Took the observatory apart again - well, some of it and took out large pulley with fixing bolt and cover. Now have it indoors ready to design and print a new cover. Stuffed a lump of polystyrene packaging in the gap the keep the rain out until I get the new parts installed.

Well, modifying the camera seemed a good idea but I think it's fraught with problems and I don't want to destroy a £300 plus camera. So guess I'll just sort out why the focus motor isn't working, finish the current build and see it the damp stays out.

I've tried woodfill, in fact I was part of the trial for rigid.ink Woodfill. It was "interesting"!! Certainly difficult stuff to print with.

No but I've used rigid.ink ASA. Found it very similar to print as ABS. Supposed to be more resistant to UV than other plastics but can't say I've had any problem with white PLA.

Yes, I agree about ABS wanting a warm chamber - the tendency to curl and lift off the bed is indeed a big problem. I'd forgotten that - been quite some time since I used ABS.

PLA is the easiest to print with. ABS makes a horrible and poisonous stink and really needs a fume cabinet. I have gone right off it! PLA is produced from sustainable natural resources and is biodegradable so it's the "green" option. PETG is my next choice. It's stronger and more flexible than PLA. However, even printed PLA is very strong and suitable for the majority of projects I would say.

I can get the ASC camera sensor down to -20°C with a single stage Peltier TEC. This reduces the thermal noise quite effectively. The cold side of the Peltier TEC is applied to the back of the camera casing with the hot side water cooled. I have the feeling that I could get the temperature even lower if I could cool just the imaging sensor chip. Also, it should be possible to keep the lens above dew point like it is with a proper cooled astro camera. I can get the sensor in my ASI1600MM-Cool cameras down to -35°C without any dewing problems with the lens. One reason may be that the camera casing is on the hot side of the cooling system and slightly warm. If I could get the lens held by a metal casing attached to the hot side of the Peltier TEC I would only need to desiccate that casing and not the whole ASC. OTOH there is still the question of sealing the chamber.

With all the cloud and rain, I'm thinking about other projects that are high on the list including this one. I'm really not happy with the current design. Cooling the whole camera and with it the lens seems ridiculous. I would have considered an ASI375MC-Cool had ZWO not stopped making them and only applying cooling to larger sensors. Smallest ZWO cooled camera is now the ASI 183MC-PRO USB 3.0 Cooled Colour Camera at £800 which I can't afford - not that I could afford the ASI375MC-Cool at £100 less. The 183 has a 1" sensor whereas a 1/2" sensor is big enough. I have experience in cooling a DSLR sensor with a cold finger and was wondering if I could do the same with the ASI178MC camera in my ASC. I have taken the camera apart and the sensor is on a separate PCB and this has a small rectangular hole through which the rear of the sensor chip can be seen. One problem may be that this hole is smaller than the sensor image area. Another is that the main PCB with USB and ST-4 connectors is being prevented from coming out of the casing by the two connectors, otherwise it's loose. These two problems may mean just cooling the sensor chip is not practical. I don't feel too happy cutting a slot in the camera casing for a cold finger with the main PCB in situ. If I could have got the main PCB out I could have dispensed with the casing.

Same here - nearest astro club is a long drive.

Camera with new brackets and 135mm lens all mounted on dovetail bar together with focus motor and gears. Photos will follow when I've found out why my DSLR camera has stopped working!

Now printing the second camera support bracket.

I love Aardman Animations too.

I thought I had imaged Orion very widefield before and at last I have found it. This is what I want to get more data on later.

I'm also planning a very wide view in Orion with Barnard's Loop.

Later on when Orion is up at a sensible hour and the moon is out of the way and we have a clear night, I want to imaged the region around the Horse's Head including the Flame and Orion Nebulae. This would be with either 135mm f2.5 lens or a pair of 200mm f4 lenses.

This screenshot from KStars shows how the Heart & Soul Nebulae fit into the fields of view of the 105mm lens and the 135mm with camera rotated.

Now printing a new focus motor bracket to allow for the focus sleeve being further out on the 135mm lens. The focus sleeve on the 200mm f4 lens is the same diameter as the 135mm f2.5 and the same new focus bracket will work with both. For the dual imaging rig I shall use two of the single rigs side by side on an aluminium plate which is then bolted to the dovetail bar.

Brought the imaging rig indoors in a gap in the rain ready to swap to the 135mm lens and make new camera mounting brackets that will allow the camera to be rotated. Currently printing the 135mm lens focus gear.

Found the problem and fixed it. Needed PTFE tube to guide the filament through the Precision Piezo Z probe where there was a fair sized cavity. 2.85mm filament is stiff enough but 1.75mm collapses.

Something isn't right - the filament is jamming, so I'll have to take extruder & hotend apart again and see why.

Removed the umbilical holder from the X carriage and started unwinding the spiral wrap. Soon found the break in the heater wire, just a few inches in. Repaired it by stripping off the insulation, twisting the ends together and soldering followed by covering with heat shrink sleeving (previously threaded onto one part of the wire). Put everything back together and printer is now working again. Now printing focus gear for 135mm lens.

Did a quick continuity check with the DMM and found one heater wire in the umbilical was open circuit - broken somewhere. So I'll unwind the spiral wrap and replace the wire (or repair it, depending on where the break is).