Jovets Observatory build

[Ivor]

Thanks for the installation images it had crossed my mind I'd only seen both your set-ups in the dark, they're really helpful and the youtube link is excellent very enlightening. I'm really not convinced about creating a large nest of any sort and having watched the clip it confirms it. Mark in your solution did you cut a bolt to size, place the plate on the mount and then fasten it to your pier?

On reflection I think my solution isn't hugely better than bolt option and the hole could be a lot smaller all I need to be able to do is get a ratchet spanner underneath unless I take Mark's approach (if I've guessed correctly).

One does start to wonder whilst working it out at what point is it too anal?

Off topic: I've been wondering for a while is it a 40+ ( I include myself in this group) thing to call them videos? I just asked my 14 yr old daughter and she wasn't much help.

[MarkS]

I haven't really got room for a spanner in the gap underneath because the bolts holding the blue adaptor plate to the big disk protrude underneath.  So I centrally bolt the EQ6 mount onto the blue adapter plate and big disk while it's off the pier then lift the whole assembly onto the pier in one go and tighten it down.  I don't overtighten the central bolt because it needs to be possible to perform the Dec adjustment.

You'll also notice the EQ6 is not mounted centrally on the pier - I'm pleased with that decision because it gives the scope far more clearance and extra imaging time beyond the meridian.

Mark

[Ivor]

I had noticed in particular it is offset to the north, did you find polar alignment a challenge?

The normal in a circular observatory is to offset the pier south, so to do what you've done I'd have offset the pier even further south to keep the mount position slightly south of the centre of the observatory (I hope that makes sense) I'm not sure that is viable for me with the way the floating floor is supported.

I need to get the plate made, was yours made with mild steel and how thick was it?

[MarkS]

It was mild steel 13mm thick.  I sent the company this jpeg created from a Word document:
http://www.markshelley.co.uk/webdisk/pierhead3.jpg

They quoted me for the work and charged me £25 + £10 delivery for each one.
These were the guys: www.rsjsteelbeams.co.uk

Mark

[MarkS]

Have you made any recent progress Ivor?

[Ivor]

Yes, I'm writing it up, should post something today. The thing that pays for it all is getting in the way at the moment.

[Ivor]

4th November
Last weekend I didn't manage to progress very far, I mortared the lintels onto the footings and filled the pier pit to 500mm below ground level. To work out where to place the posts on the lintels I drew template around metal ring.




10th November
After weeks of preparation and fine tuning this weekend was the big push, everything was pre-cut and prepared so it was a test to see if my calculations were all correct. On reflection I've made a few wrong choices on the sheet material, I originally planned to use 6.5 and 11mm thickness throughout however during the build it become apparent that this wasn't rigid enough for the larger sections so I've been forced join a number of sheets together. The ring for top of the walls was made of three sheets two 6.5 and one 11mm, which I fasten together with screws and wood glue. I staggered the joints of each circle but still keeping them within 700mm of each other so the three joints were braced between two posts and to prevent them from getting in the way of the castor placement.





To build up the frame I first made up the four sections for the footings and then attached the cross beams joining them together, with a hammer bash here and there the frame came together and I was pleased to see that all outer dimensions are within 10mm of their target. In addition the tops of the posts are level and I won't need to add any shimmies to bring the height up. Achieving this with DIY grade tools has proven painstaking, having a cutting depth of only 100mm on the mitre saw plus trying to keep the wood flat and at right angle to the blade is challenging. I'm pleased care and attention has paid off so far.

[MarkS]

If the observatory doesn't work out, you could put a liner inside and have a nice deep splash pool for the Summer!

[Ivor]

That's an idea maybe I could make some further adaptations and a create a thunderbirds telescope coming out of the pool.

[Carole]

Made some good progress there Ivor. 

Just wondering how you are going to fix the floor as the cross beams are at different levels presumably because the brackets were in the way. 

Carole

[Canadian Roger]

I'm really enjoying this thread, and not just because another amateur is realizing the dream of a home observatory (although that's part of it).  I like seeing the design considerations that are made due to location and weather, and how people solve these issues.

A fellow I knew in Arizona was mostly worried about the 35degree Fahrenheit swings between day and night.  The need for ventilation was at odds with trying to keep snakes and scorpions out.

I have to be concerned about the ground freezing solid for a few months.  I also have to worry about the local wildlife, but in my case it's a skunk that tried to make it's home underneath the raised wooden floor (it was not fun the night I realized where the little bugger had made it's home). 

A very good friend in the Atacama desert in Chile has to worry about the dust: there's a good proportion of volcanic glass in it, and it's incredibly fine.  There's a fair bit of salt in it, too...all in all, it's not very friendly to fine optics and electronics. 

So, I'm looking forward to more updates, and hoping the weather doesn't stop you from working outside.

[Ivor]

Just wondering how you are going to fix the floor as the cross beams are at different levels presumably because the brackets were in the way. 

Carole

Good spot, you are right about the cross beams the current ones will be only used to support the structure. I am planning to add additional cross beams slightly in from the frame to support the floor.


Glad you are enjoying the thread, I have to admit I find it difficult to decide which bits to put in and which to leave out as a lot of it has been thinking up until now and attention to detail. Wildlife for me is more likely to be hedgerow creatures so I need to make sure I protect the cabling, the mice chew through just about anything.

After this weekend work will die down and I've got to take mandatory leave between now and the end of the year so hopefully I will get most of it done by the end of November. The last two really technical bits are the pier and the roof, I hope to complete them next weekend so I can put the walls up.

[Rick]

Wildlife for me is more likely to be hedgerow creatures

Main problems round here, wildlife-wise, are usually foxes (and badgers?) digging holes and chewing things, squirrels getting in under the roof, and slugs and snails getting into things (with a side order of fallen leaves, which do a great job of helping timbers rot if they get a chance). There's sometimes the slight risk of the neighbours' cats getting locked in, too...

[Mike]

In other words, don't bother, concrete over your entire garden, it's safer. Plus you have somewhere to rest your tripod !

[Ivor]

In parallel to the physical build I have been writing an ASCOM dome driver using an Arduino, I now have C du C sending basic commands to the Adruino and displaying them on an LCD. I'm now trying to work out the best motor and drive wheel combination which is a little difficult as I don't know the force required to move the roof which I estimate is less than 50kg and will rotate on 6 ball castors. The top max slew rate for the EQ6Pro is 3.4 degrees/sec which equates to 71mm travel per second for the dome. Where it's not necessary to have the dome keep up with the telescope it would be nice to get close. I haven't looked yet but I'd like to at least have the dome be able to go the same speed as the ISS so I could have option to image it in the future.

I've seen a NEMA 23 used in one observatory and it appears to pack a punch for it's size but I'm not sure how to decide which specification to use for mine both from a dome and arduino view point. The majority of the Arduino stepper motor drivers go up to 2A so I've been looking at motors below that rating but I'm not sure what calculation to apply to make my choice.

I spoke to a chap at the company below and he recommend this model, but I don't understand why.

https://www.motioncontrolproducts.co.uk/products/2/6/nema-23-60mm-high-torque-stepper-motors/

Any advise gratefully received.