Maybe tomorrow evening might be clear according to the forecast.  I'm not quite sure about the remote focussing, might have to increase the downwards pressure to hold the lens straight.  Won't really know until I get it up on a mast outdoors.  Not that I've got remote focussing working yet!  Pouring with rain ATM

Added HAT to RPi and stepper motor driver for remote focussing, started up RPi and re-compiled the Astroberry DIY driver for focus only.  Then ran

gina@asc:~$ indiserver -m 100 -vv indi_asi_ccd indi_rpifocus

In KStars/Ekos started INDI and got everything running.  Remote focussing is working   Currently using separate power supplies for the RPi and motor driver but I'll connect to the buck converter and run everything from one PSU shortly - I'm taking one step at a time due to the problems I've been having.

Focussing on a terrestrial view is made difficult because of the narrow depth of field with this very wide lens.  I have attempted best focus on the trees in the middle distance as the far hills are too misty.  It should be easier at night with nice pinpoint stars (or even the moon).  A variation of 50 ticks in the focuser is noticeable so the scale seems quite reasonable.  This corresponds to a few degrees of rotation of the lens.  Power is now from a single bench PSU using the buck converter.  I havn't  fixed the Wi-Fi yet - this is working with wired LAN.

Here are a couple of images - screenshots from the KStars FITS Viewer.

Now have the casing on and ASC on the pole and hooked on the guttering.

Raining again so had to bring the ASC in.  If it clears up later I'll pop it back out an see if I can capture some stars.  I need to get the lens cover motor working and all the code set up appropriately.

Printed and added the top dome to the lens cover and cleaned it up.  Printed in opaque ASA this seems to let a negligible amount of light through so I think it will be suitable for taking darks, at least at night, as well as keeping rain out when closed.  The next job is to write the code that controls the stepper motor that opens and closes it.

GPIO assignments.

// Lens Cover Motor Hall Switches
#define IN1 RPI_BPLUS_GPIO_J8_29	// GPIOO5  Open
#define IN2 RPI_BPLUS_GPIO_J8_31	// GPIO06  Closed

// Lens Cover Motor
#define IN1 RPI_BPLUS_GPIO_J8_16	// GPIO23  DIR
#define IN1 RPI_BPLUS_GPIO_J8_18	// GPIO24  STEP
#define SLEEP RPI_BPLUS_GPIO_J8_22	// GPIO25  SLEEP

        // step on
        bcm2835_gpio_write(STEP, HIGH);
        // wait
        bcm2835_delay(STEP_DELAY/2);
        // step off
        bcm2835_gpio_write(STEP, LOW);
        // wait 
        bcm2835_delay(STEP_DELAY/2);

if (bcm2835_gpio_lev(Hopen) == LOW ) 

This is probably the last image of 2017 as it's raining now.

Actually, the rain stopped and the sky cleared a bit just before midnight and I was able to capture an image a couple of seconds before midnight and another 3m into 2018.  There are a few raindrops on the lens.

HAPPY NEW YEAR everyone

BBC Weather forecasts clear for most of the night tonight but Clear Outside is not so promising.  Also strange with Clear Outside is that it shows 100% moon yet show tomorrow as Full Moon with 99%.  But in any case the moon is up for the whole night so I don't expect to see many stars even if the cloud stays away.

Raining again!!!

Rain has stopped and the clouds are clearing but the only things visible are a bright moon, reflections from it in the lens and terrestrial objects!  No chance of seeing any stars!   At least, not unless a dark cloud covers the moon.

I also seem to be having a problem with the remote focussing, which was working fine yesterday.  I think the top cone which is attached to the lens and rotates with it may be catching on the main casing.  I might make a new one with more clearance.

Brought the rig indoors to check the focussing and I've found the problem - the gearbox in the stepper motor is broken - a couple of teeth broken on one of the gears so it would move one way then stop.  I guess the cone caught on the casing.  The problem with these little cheapo stepper stepper motors is that the gearbox contains tiny nylon gears that won't take the torque the stepper itself is capable of producing.  I shall just have to make sure nothing can jam up.  I could increase the gear ratio to give more torque available to turn the lens.  I think I'll change the gear ratio anyway as the focussing speed is rather fast - accurate focussing needs 10 ticks or less and with a standard rang of 10,000 this is rather small.  Of course, this can be changed in the code but a higher gear ratio would mean less affect of backlash in the gearbox.

Lens gear 25mm radius 25 teeth - pinion 12mm radius and 12 teeth.  Total spacing = 37mm.  Gear ratio 25:12.  This gives a ratio of about 2:1 and for roughly double, juggling the figures gives pitch circles of 30mm and 7mm radius with 30t and 7t (ratio 4.3:1).

These little 28BYJ-48 stepper motors are really too cheap for anything other than really light duty.  After all, what can you expect for just a pound!!  Yes, that's all they cost.  I think the focuser problem may not be the top catching but could be its inertia.  It might be alright if it was just turning the lens.  I'm going to sleep on it.

I have some NEMA14 stepper motors I bought for my various clocks and one of those will just fit between camera and casing.  Better would be NEMA11 ones which are smaller.  Trouble is suppliers seem to be still on holiday as the earliest delivery is 15th January   I think I would feel happier using one of these for the lens cover too as the gears in the 28BYJ-48 are so fragile.

28BYJ-48 stride angle = 5.625° /64 = 0.087890625°  NEMA11 with 1.8° and 16x microstepping = 0.1125°.   10 steps of  28BYJ-48 corresponds to about 8 steps of NEMA11 so comparable for focussing.

I have ordered a couple of these :-  Stepper Motor Nema 11 1.8°10oz.in 0.8A 28HD1411-02 CNC Router KIT Bipolar UK

I'm thinking I might put further hardware construction for this project on hold until I get more suitable parts.  The price of 28BYJ-48 stepper motors has rocketed so replacements will cost a lot more - almost as much as NEMA11s!  I don't think they're worth it except for projects where the load is guaranteed to be very light and space/weight is important.

Found a smaller stepper motor but at twice the price :-  Smallest Nema 8 Step Motor 1.8deg Bipolar 0.2A 1.6Ncm/2.3oz.in 20x20x28mm 4-wire

The NEMA 8 stepper motor has arrived and it's certainly very small, as expected.  It would be nice for the lens cover but not sure it would be strong enough - I'll have to experiment and see how much torque I can get.  At least for that it doesn't need microstepping so the full power is available.  With 16x microstepping I reckon it would be inadequate for focussing.  But there was only one available anyway.  I have a NEMA 11 on order for that.

Having had the ASC outdoors a bit I have been having thoughts about the lens cover.  So far I have been bringing the rig in when it rains then going outdoors to see if it's stopped and then putting the rig back out if it has.  Replace the "moving the rig" with the opaque lens cover and the same problem remains - ie. when to open the cover.  So I have another idea - replace the opaque cover with a transparent dome   OK so no dark frame provision but the hot pixels don't change so taking one dark will be sufficient.  This could be done by just covering the lens during testing at night.  The dome would only need to be off when there are nuisances like moon or flood light causing reflections in the dome.  There would be no worries of running the ASC overnight unattended with the dome on.  This could give me the best of both worlds.

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...

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.

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

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

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...