Bukko

Hi All, I know how much we all like these questions, so here is another one. My son wants to get back into astro imaging with a small rig. The plan is to also get an 80mm frac and some associated bits. Since I moved to France, he has lost access to my toys. Anyway, his choice was the EQ5 Pro and I mentioned the new EQM-35. They are similarly priced with similar payload capacity and both within his reasonable budget. He is space limited and we should also consider weight as the system will need to be transportable. There is no need to go to a HEQ5, I have one here used for my WO 110 frac, which will possibly be his upgrade path, should the need arise. I have searched for info from users of the EQM35, but there seems to be little out there. Our current thought process is the advantage of the 35 is weight and being a newer design, hopefully has improvements over the much older 5 pro. Perhaps even the axis are not as sticky as all the other SW mounts seem to be... BUT we do not like the exposed drivetrain. One piece of info gathered suggested that the 35 needed to be adjusted to reduce backlash and the open gears made this simple. We don't think the modular feature will be helpful, but he does have a DSLR so dropping that on should not be ruled out. So are there any EQM-35 owners out there who could help us make a decision either way? Many thanks, Gordon.

Nice capture. And well done on the early start !! I have been frustrated with focussing on a DSLR; mine is a Canon and the newer STM lenses seem to have lowered the importance of manual focus leading me to waste a lot of time... The image posted looks reasonably sharp with the expected star drift. Getting it on your EQ5 and tracking will sharpen the stars and make them a lot brighter too. The meteor does not look over-bright, so the camera settings are fine, but have a look at the same exposure time once you are tracking... Often the sharpness will drop off towards the edges amd it is a great test of the lense.. Gordon.

BTW... share my building thread with the house management team as proof how More than Reasonable your proposal is... 😀 Might help... Gordon.

The lights from your neighbours place is terrible. They do realise thieves are more likely to go after a lit place than dark? Anyway. Prize for the most stupid statement/question of the day will be coming my way very soon... I assume you have spoken to them about your pastime and invited them round for drinks and talk about the effect their lighting would have on your pastime? You are entitled to dark skies and they need to find a way to compromise; when the nights are clear, they agree to switch them off for you. perhaps. In France, it's easy. They love scotch, so I keep a few bottles to lubricate the wheels of progress... I really do hope there is a solution that stops you throwing thousands of pounds at a screen.. Good luck with them. Gordon.

For your Plan A... I would not worry too much about rust on the inside - there is enough metal to last for decades. So long as it doesn't fill with water that is. Once built, it is easy to pour some paint into the pier and then roll it around, the paint will coat the inside and any excess will pour out. Simple. Gordon.

It's not the end of the world... Good news you do not need access from inderneath, the easy thing to do is to drill the holes in the plate to attach the adapter then tap them. Fit the adapter to the plate and screw them together. Mark the threads that protrude then cut them back a couple of mm's too short. You don't need more than 8mm of threads to secure the mount to the pier. Then weld the top plate to the pier, remembering to take care around the North position for the mount... Does this make sense? Gordon.

We had a warm spee here the other week and the ambient got up to around 40 degrees C.. The warm room was far too hot, even though it is thick wood and insulated roof. The domes were much nicer place to be - the white colour seems to make a big difference and the concrete floor acts as a bit of a heatsink. The domes do not have any A/C in them, there is a fan drawing air into the dome and a de-humidifier in each one also . The Scopedome includes a humidity sensor so I will be using that to help me learn when and what to use to manage humidity. SO to answer your wuestion, I do not yet know the effects of the high temperatures on seeing conditions. We ate reasonable inland and nightime, the temperature does drop quite quickly. As of yet, I have not had time to get back and finish the installations, as the terrace over the garage and pool room was leaking badly. Working on that has drained my energy, but hopefully this is coming to an end in the next week. When I get back on it, the plan is to get the mount connected to the PC and playing nicely with the dome. I need to get the mount polar aligned and the OAG focused to match the main camera. THEN I will be able to get first light on the system (The system has run before, only the dome and interface is new) THEN I get to start working on the second dome. Everything in this one is new so I do not want to have to de-bug two systems at once. Gordon.

The skypod did OK with its limitations. A very reasonably priced dome, compared to alternatives available. I was struggling with it, as my scope was bolted down and so it was difficult to find a single ideal point to secure the pier and so with the planned move when I retired, it had to go. The Scopedomes are in a completely different league for design and build quality. I am STILL working on the terrace - almost done, the sub-structure is repaired and now watertight and I am 75% finished laying new tiles. Then need to grout them and then get back to the obby... The weather here is glorious, but too hot to lay concrete, screed and adhesive. A lot of this needs to be done in the evenings... I need to go back to work... for a rest !!! Gordon.

Sounds terrible. The green stuff was fine and makes me look windswept and interesting !!

It's actually not bad; tastes like beer, looks nothing like beer !! And makes for an interesting conversation picture... Gordon.

Hi Ahmed, Do you need access under the mounting plate to secure the mount (like a Skywatcher..) or does the mount secure directly to the top of the adapter ? If the former, then some sort of access will be required. Either, as you say, a rats nest, or you could cut a piece out of the pipe to allow room for a nut and washer. If the latter and no access is required, then the mounting is easier. If you take a look back on page 1 of my build, 2/3 down the page is a picture of my mount on a pier. The 3 studs are threaded into the pier top with another plate holding the adapter and the NEQ6. Once the mount is attached to the pier, I can reduce the height of the rats nest to just 3 or 4 cm, so reducing any issues with that method. This was the easiest method to do, as the pipe is 20cm bore and very heavy walled ( 8 or 9 mm thick). Hope this helps.

Lovely job... Impressed with the care and attention on the shiplap too. For me, what made all the diffrence in the world was getting the roofing finished on my warm room... It was like a real big milestone reached. Good luck with the interior. Gordon.

Hi Ahmed, The air duster should work, a single can should be enough. Before injecting the resin, check how deep the stud goes. If it goes too deep, then try and drop something down to set the height above the surface. A bit of wood should work. I would not fill it with that much, maybe 25% would be enough. When injected, press the stud through the resin. If it does not start to ooze out the top, then lift the stud out and inject a bit more. Try not to catch too much air in the hole though. I found rotating the stud as it goes in helps also. I am sure you will get the hang of this very quickly Good luck, Gordon.

Glad the pour went well. I would give it two weeks before drilling, just to make sure it has cured fully. The hardest part I found was making sure all the dust is out of each hole before injecting the resin (I have a small air compressor) and making sure enough resin was pumped in to completely fill the hole when the stud is pushed home, without overdoing it and running out... Every stud had extra resin come out of the top of the hole, so I knew they were full. If you plan to secure the pier directly to the concrete, then make sure you can clean off all the excess... The stuff I used cured within 30 mins and that is actually not a lot of time to confirm everything is good. Gordon.

Hi there. I know Pittsburgh can get pretty cold in winter, so it would be best to make sure the hole is deep enough to remain stable. However, what's the worst that could happen? The footing moves slightly and you would need to go back and re-align the mount? Is the rebar another requirement for managing the frost? With thoughts of removing part of it in the future, rebar does mean the concrete breaker you need to hire gets a whole lot bigger... The maximum future payload weight of 90lbs is similar to one I am doing now and I would guess the current mount would also be upgraded to suit? So the top plate of the pier needs to be thought out a little too. On your current questions, the easy stuff to use for "shuttering" the concrete above ground is the cheap shelving - plastic covered chipboard. Just needs cutting into 4 pieces and screwed together (DO NOT GLUE..) After a day or two, simply knock it off with a smallish hammer. It will not stick to the concrete very well and so no issue. My last shutter I made them too long so they overlap at the corners and after unscrewing one corner, they came off really easy. For the pier... Pittsburgh is in engineering and steelmaking country. I would expect there are a hundred fabrication shops that could weld up a pier to suit at any height you need. Probably a 2-day turnaround... For half the price of one ready-made... Be worth a look... SGL is loaded with builds, have a good look around, I am sure most of your questions are answered somewhere in the threads... Good luck, Gordon.

From a practical point of view, I used to have a 12" Newt in a Skyshed pod. It only has an internal diameter of 1.8m (0.9m radius) and it was tight and just about workable. Increasing the radius by another 20cm would be more than enough, plus your space is square, so giving even more room to work in than I had. Unless you are planning on holding events with more than a few people sharing this space, you will be fine. Gordon.

Hi Ahmed, if it helps you for Saturday, I had some sand delivered lunchtimee todasy for my terrace work... 1.95 tons, in a big trailer... It's mid-30's here and humid and we* had to unload into buckets and transfer it to the worksite... Took all afternoon, but it is considerably more than you will have to deal with, so as your plumber buddy next door says, it should be OK. * normally this would be a BLUE job, but as I could not really do this on my own, I managed to persuade Mrs Bukko to help. Bless her. Anyway, good luck on Satgurday, looking forward to the pix. Gordon.

Dave is probably right - your studs are 30cm long and you would bury 20cm of it in the concrete. That is probably enough to hold without needing any of the extra things we have been discussing... I would still try and put a bend on them; I am surprised your aintenance department doesn't have access to some heat, a big vice and hammer... I am guessing from what you said they work with big pipes and they must sometimes need slight adjustment to fit... But if you do put them in straight, then allow the concrete a week to harden and gain strength before trying to pull down the pier on them. Just in case... Good luck Saturday, Gordon.

Ask 10 different people, get 10 different answers... A single washer should be enough, if the surface is flat. If not, then its best to pack the lowest point with another washer. For what it's worth, I secured my piers between nuts and washers; from the ground up, there is a nut, then a washer.. Then the pier, then another washer and finally a top nut. I know there is no technical need for the pier to be vertical, but from an engineering point of view, it is important. The pier can be levelled on the four bottom nuts. then the top four can be used to tighten it down. It really does need to be a minimum distance and pull it down tight. Two spanners for each corner, hold the bottom nut still and then tighten the top one. All I added was some sand/cement mortar under the pier to improve the rigidity of the system. Hope this helps. Gordon.

Perfect. Gordon.

Be careful trying to bend this stuff in a pipe bending machine... It is pretty strong and often high tensile so if the machine is for copper, then it might break. If designed for bending steel and is hydraulic, then no problem. Hopefully they know what they are doing. If in any doubt, have them warm it up and hit it with a hammer in a vice. Gordon.

From my picture, the plan was to bury the lot in the concrete. The hexagonal shape of the nuts improves the resistance to breaking free and the stud pulling out. The washers would also improve the adhesion to the concrete. The idea was to replicate the purpose of bending the stud. Fixing the pier to the studs is another matter. You would be extremely fortunate to get a perfectly flat concrete base. Even if you did, it would be worth considering the possibility that the pier baseplate might distort during welding... As Dave said, he maintains a small gap between the pier and the concrete, where I chose to fill the space with grout. There is always more than one option... Gordon.

Here is a snap of a piece of M16 studding with some nuts on it. I fitted some big washers, kind of how Mark was commenting on adding some square washers. Hope it helps. Gordon.

I know bending M16 bar is not easy, it will take a bit of heat and a big hammer in a vice... Probably a very good reason people go for the M12 option. Alternatively, if you get a decent pack of M16 nuts, you can simply lock them together in pairs and embed them in the concrete. This will hold more than enough for you to tighten the pier down. Let's say 3 or 4 pairs of nuts per stud unless someone has a calculation that says more or less is required. Good luck hand mixing that lot. for sure, it will count as heavy work, which is supposed to be good for you. Please let us know how it goes !!! Gordon.

I don't think it matters which type of studbar you choose - stainless or plated... There is a good cost saving going for plated, so I woud have no problem with that. The only minor issue is the plated bar will rust where it is cut. If you get two lengths and cut it down to make the 4 ties, keep the uncut end above ground and it will be fine. This really does not need to be complicated; there are loads of good ideas on how to make it look good, but I guess it depends on how much effort you feel the need to go to... For me, having some of the stud showing adds a certain industrial look to it and I actually think it looks good like that... Gordon.