Gina

ASC in its casing showing the focuser.

Clouded right over now. Oh well... I shall need to look at the standard focuser code and alter it. ATM it starts off at zero and will only go positive - "focus outwards". It loses the current focus count when disconnected then when switched back on the software thinks the focus count is zero and will only go positive ie. will only focus one way. So I have either to arrange that it saves the current focus position of is able to go negative as well as positive. There is "Parking Mode" where the focuser is moved to the zero position when disconnecting - provided the Disconnect button is used rather than just cutting power. But then the focus must be adjusted after starting up as the focus position isn't held, though I guess you could write down the focus count and go back to it. None of this is exactly "user friendly".

Some more, gamma reduced to 20, WB adjusted. It could do with the camera cooler on. Probably sort that out tomorrow. Dew heater too though no dew ATM.

Stopped raining and some clear sky The focus is not quite even across the field - it may need some pressure applied to the lens thread tho stop the slop. Settings :- Exposure 10s gain 240 gamma 50 (1.0). No dew heater and no camera cooling.

This screenshot of the KStars Fits Viewer shows camera on the table and focused of the mess of wires. If it stops raining I'll put the casing on and hook it on the guttering and test it on the distant lights or if I'm really lucky, stars.

Connected everything up and ran all the firmware/software operating the focuse resulted in the motor just twitching so I checked the connections and the NEMA 14 is NOT connected as per RAMPS so I had to extract a couple of the connector "pins" and swap them over. Now to try again... That's better - remote focus working

Here is the full focussing system (except for plugging in the motor cable). Pinion printed in TPU flexible filament for easy attachment to motor shaft.

Found the lens Now checking the gears - slight adjustment needed.

Prints are fine Need to find the lens for testing! No, it hasn't turned up yet.

Not sure how much plastic this could print at a time - maybe I should cater for 3Kg reels of filament Mind you, that would be a very expensive print!! And what if it failed near the end

Gears designed and now printing.

Now designing the gears for the focuser. Distance between centres = 49mm so I think I'll make the gear radii 40mm and 9mm with 40t and 9t ie. mod 2.

That works fine - focus motor fits perfectly

The NEMA 14 motor is a tight fit and the mounting plate has needed slight alteration. The motor moving slightly outwards and a mm taking off the underside of the plate to make the motor fit. This screenshot shows the model as for printing - upside down.

I've ordered some shaft couplers that I'm going to try as XY drums. See if they fit the motor shafts closely enough.

Focus motor mounting plate - also centres casing onto camera.

NEMA 14 mounting - M3 on a 26mm square. 22mm x 2mm raised round part.

Guess what I've lost now... The lens Doesn't stop me working on the ASC but does affect testing!! Oh it'll turn up in due course, when I'm looking for something else. And no, it's not in the box of 3D printer parts...

Here are photos of the XY frame (Z carriage) in the main frame from above. Second photo includes the print bed heater.

No - I'm not thinking of building a hang printer at this time But it's an interesting idea

Apart from astronomy, it's clocks, weather stations and 3D printers that fascinate me most. Anyway, it's 3D printers in particular ATM. Been thinking about that "hang printer". I think my workshop, when it's cleared out and "re-furnished" could be used for one of these Apart from the rather complex geometry, I can't see many problems. But I wouldn't want to be limited to PLA and would therefore want a heated print bed. It's difficult to see any way of producing a very large heated bed without spending a small fortune though a 600mm square one would not be out of the question. The 400mm square silicone heater pad I'm using in my Giant printer cost £87.50 - 300mm square are a lot cheaper eg. 300x300mm Square Silicone Rubber Heater Pad w/ thermistor 220V 300W Four of those would be affordable at £136. 6mm Aluminium 5083 Sheet Plate blanks profiles ANY SIZE CUSTOM CUT Free shipping 600mm square costs £113 10mm Aluminium 5083 Sheet Plate blanks profiles ANY SIZE CUSTOM CUT 600mm square costs £175 inc. carriage. My 3D printers would be roughly doubling printing area with each model :- Mini 200mm square = 40,000 sq mm (Reference) Titan 300mm square = 90,000 sq mm (80,000) Giant 400mm square = 160,000 sq mm (160,000) Hang 600mm square = 360,000 sq mm (320,000)

From looking at the design of the casing top, I think I may have gone a bit small on the 60mm dome. 70mm would have been better but we shall see - might be alright. The 3" dome I already have still shows a few scratches and scuff marks after a thorough clean CLEAR PERSPEX ACRYLIC DOME 70mm Diameter with 10mm flange

I have another change of plan too. I've decided against having the top of the casing rotating with the lens. Although this provides best protection from rain if an unexpected shower should arrive with the lens cover open, it causes a lot of problems and now with the lens cover replaced with a transparent dome, it will be unnecessary to have the lens sealed to the rotating top casing - it there is any possibility of rain the dome can be on. If I go on to produce a cloud sensor, the dome could be put on (closed) if open for imaging. With a fixed casing top I can change the arrangement for opening and closing the cover/dome. The stepper motor can be mounted on the main casing top and its casing can be part of the top. I think I shall be able to use the two NEMA 14 motors I originally bought for clocks for both focussing and operating the dome. I can use the NEMA 11 stepper motors currently on order for my clocks. This means the delay in waiting for delivery of stepper motors is avoided

There are clear acrylic domes available in various sizes but only 4" stated as for CCTV cameras from the UK. There are different sizes of JMX domes like the 4" one I got before but in smaller sizes, available from China. I might order one to use later but for now I've ordered CLEAR PERSPEX ACRYLIC DOME 60mm Diameter with flange to try. If it causes distortion I could use it just to determine cloud or rain and open it for imaging. Decided to order JMX 2.9 Inch Acrylic Indoor / Outdoor Cctv Clear Camera Dome Cover Security Camera Housing. Arriving 24 Jan - 2 Feb. It might not seem that the difference between 4" and 3" is not that much but windage is determined by the square of the diameter and weight by the cube.

Now I have a choice of domes - basically, 2", 3" and 4". On checking, the 2" dome is too small (smaller than the lens). I have a 3" dome that has a few small scratches and two brand new 4" ones. A 3" dome would be ideal - big enough yet not too big, 4" domes would be a lot heavier and liable to catch the wind when open - probably alright closed. A 4" dome would certainly need a reasonably powerful stepper motor though gearing is possible. I'll look for 3" domes I think...