Gina

I'm not sure that the pond I have will be suitable for the rather large 3D printed water feature I have in mind. Maybe I should add another pond for that - a more formal one. Or I could have a small fountain or something in the present pond. Or both I shall do some more thinking...

Yes, I know, but the trouble then is that any creature that gets/falls into the pond can't get out. What I could do is cover some of the edge but leave an exit route out of the pond. Even add something better than the ramp on the south side of the pond form.

Like most (if not all) of my other projects, this is definitely a case of "make it up as I go along" OK so covering most of this area in stone is not going to be on, so change of plan... This photo shows the stepping stones in a first try plus a garden ornament I couldn't resist - a tortoise with eyes that light up at night. Area in front of living room window I want to clear to make a patio with seating. Started clearing the patio area and putting the grass etc. round the edge of the pond. Moved the broken concrete slab away from the pond to form part of a stepping stone path to the observatory.

I think I've made a complete mess of the organisation of this blog

Placed stepping stones around the pond and towards the observatory. Amazing how things that look quite big in the shop look tiny in the garden!! Looks like a lot of this garden is going to be grass.

Just been out to the drive and carted 8 stepping stones by hand from the boot of the car to the front of the house. Now, exhausted, I'm having a rest!

Picked up 4 of those stepping stones plus two pairs of different type round ones.

Well done James - a great day's work ?

Ah yes, that's a possibility.

I do have some moss though...

Maybe I could if I had a lawn ?

Placed the three stones round the pond ? It could do with three dozen!! No, I don't think 3D printed stones would work!!

As for the Dec drive, I'm thinking 28BYJ-48 mini stepper motor with gearbox. Stride angle approximately 5.625° / 64 = 0.087890625°. It's a bit less than that as the gear ratio is slightly less than 64:1. A pixel movement is 0.002° with around a 100mm lens (105mm). I may go to 135mm FL lens so something like 0.0015°. The Dec axis is only needed for slewing to the target and 10px will be near enough (no guiding) giving a required resolution of 0.015° in the Dec axis. For the final drive a 120mm diameter disc with a 20t GT2 timing pulley will give 10:1 ratio making the motor resolution needed as 0.15°. Single stepping already gives and accuracy of 0.08° - nearly twice as good as needed so half stepping, which gives higher motor power will be more than adequate. Is this right? My brain's overheating ? LATER :- No it isn't! Didn't think so.

Well, I've found three stones - they wont go far. I have some concrete blocks though. Not as nice as stones but guess they may do the trick. Have to ask my neighbours I think.

With only 3 of the 15t pulleys in stock I've decided to go ahead and order those bits. It would be typical if I delayed and then found them gone or at least two of them gone.

Been out adjusting the back fill to get the pond to the right shape. Still more to do but it's got very warm outdoors now. The pre-formed pond shell should have an almost flat top with no kinks. That is what I'm trying to achieve but it isn't easy. Think I shall see if I can find some large stones to go round the edge of the pond. Guess I should have collected some when Gigaclear's contractors were digging the trench but I didn't. I do have some concrete slabs I can mix with the stepping stones I have in mind, to form the patio and path to the observatories.

Pond filled. More back filling with soil. Now having a rest! Some photos.

There is a very slight possibility that I might make a bigger pond to the east of the house. There is a tiny water-course (drain) running in a large pipe through my property and emerging just inside my boundary before going under the fence into the field next door. It is uphill from my current garden project and I do have thoughts of redirecting a small amount of the water into another pond and back out to the field. But that's way into the future. One thing at a time ?

A pond skater might be able to water-ski but this pond is only about 4ft x 2ft ?

Taken from living room window. Pond is level - ground slopes. So does my bird feeder - must re-plant that upright ? Another lovely sunny day with a few clouds about. I'm doing what I can before it gets too warm - 23°C forecast for today. Stopped for a mug of coffee ATM.

Oh I don't have much energy Carole! Mental energy isn't lacking but physical certainly is. I have to do a bit then have a rest then do a bit more and so on. I amazes how I had the energy to build my observatory some years ago - don't think I could do that now! That was a marathon of a job! Just had one short session at the pond - back filling and levelling. Making sure there was support under the pond form. I had to take that out and add some extra soft soil cleared of stones but I think I now have enough support under the form. It's now level and just needs a bit more back filling around the sides. I think I might add some water and let it settle.

I think I would advise contact adhesive for the corners. Mine have come undone and I added extra clamping. Large headed tacks can be useful for holding the edges - I wouldn't rely on adhesive. And I too highly recommend EPDM roofing from Rubber4Roofs.

The 80t GT2 pulley seems to be available only from the USA otherwise it's 60t (3.75:1 with 16t) so I've been looking at MotionCo who do a much bigger range than I can find on ebay etc. Only problem is that the number of sizes with 5mm bore is severely limited. They offer shims to reduce bore but I don't like that idea as it might produce eccentricity. Some available combinations give recurring fractions which I don't like. It all boils down to just one combination viz. 15t and 120t giving 8:1 ratio. Keeping to 20t for the final drive gives 25 x 8 x 8 = 1600:1 which is better than needed for a 200mm lens if I use a 0.9° stepper motor. OTOH I don't think it matters having too much resolution except that it would take longer to slew to the target. I could use a 1.8° stepper motor (which I have in stock) and still have better resolution than needed. Anyone see anything wrong with this? Or have any better suggestions? Cost £54 - including precision 5mm SS shaft for axles.

You mean three altogether including the final drive? Yes, I think that's what I shall do. Looks like Avalon have four. I have plenty of ball bearings and can soon design and make a 3D printed gearbox belt/pulley box.

One side of my observatory faces south and I made this lower. Also have a drop down end in the form of a window made from twin-wall polycarbonate roofing. I designed mine in SketchUp too. I only have one pier and want three. When I built my observatory I was less advanced in astronomy and particularly in astro imaging. I could have had a bigger scope room and smaller warm room like you. So I would advise sticking with the three piers. I know it's a lot of extra work but you won't regret it. I shall probably end up with three observatories to accommodate my three piers but two of them will not be human sized - just enough room for remote imaging. ?