Oh, I thought the rim centre was going to be a bearing point but I just realised the bolts to the brackets. It's still an amazing looking set up!
Do the rims roll in any particular material to protect the timber?
Looking back it looks like a strip of mild steel but I'm both blind and stupid!
Probably nothing this sort of weight (I don't have a working crane) but I've often used the yellow tongue from flooring to act as a bearing/sliding surface which removes risk of wear and is easily gotten and replaced.
Do you have a permanent smooth concrete area to roll it out on?
Sorry, I always over design everything and I'd have to have a lead base so it was counterbalanced at all times, that or outriggers. Then again, I have a sloping, uneven yard and struggle to roll a welder on a stand without it rolling off (40Kg MIG welder).
Oh, I thought the rim centre was going to be a bearing point but I just realised the bolts to the brackets. It's still an amazing looking set up!
Do the rims roll in any particular material to protect the timber?
Looking back it looks like a strip of mild steel but I'm both blind and stupid!
Probably nothing this sort of weight (I don't have a working crane) but I've often used the yellow tongue from flooring to act as a bearing/sliding surface which removes risk of wear and is easily gotten and replaced.
Do you have a permanent smooth concrete area to roll it out on?
Sorry, I always over design everything and I'd have to have a lead base so it was counterbalanced at all times, that or outriggers. Then again, I have a sloping, uneven yard and struggle to roll a welder on a stand without it rolling off (40Kg MIG welder).
Just outside the garage door there is a hardstand area where I do my imaging and observing from. I wouldn't want to wheel it much further than that haha, the thing weighs a lot.
The trunions sit on HDPE pads (2 per side) the pads are 10mm thick and seem to ride pretty well. The hdpe might not be quite as slick as tpfe but it feels pretty acceptable to me, I might put a bit of soap on the trunions to try make the movement an little slicker. It isn't that it is sticky now, just the scope being so heavy makes the movement a one hand job instead of one finger job, oh the travesty.
Overall I am very pleased with the build. Only drawbacks at this stage is the insane top-heavy nature of a tall mount like this, one must be very careful when moving it and moving around it. It does also seem to take a second or two to settle as the moment arm is so long, I guess any sufficiently long instrument suffers with that same problem.
The trunions sit on HDPE pads (2 per side) the pads are 10mm thick and seem to ride pretty well. The hdpe might not be quite as slick as tpfe but it feels pretty acceptable to me, I might put a bit of soap on the trunions to try make the movement an little slicker. It isn't that it is sticky now, just the scope being so heavy makes the movement a one hand job instead of one finger job, oh the travesty.
I think bearings or teflon (sorry, PTFE) grease on the pads would make movement easier but you need that bit of resistance if you want any chance of sighting any target I would imagine, unless motors and gears were involved. I'm guessing once that weight starts swinging it takes some stopping?
The resistance stops the unit running away from you when adjusting the RA.
Quote:
Overall I am very pleased with the build. Only drawbacks at this stage is the insane top-heavy nature of a tall mount like this
Hence my mention of outriggers or heavy lead base. It's good you have a decent area to roll it though, that makes it much safer with the design and the height probably couldn't have been avoided with the length of the scope itself?
The build is extremely impressive!
Were I to own my own place and I had something extremely heavy I could leave on a more permanent mount but required moving to my viewing area and I had a decent concrete area to move it around I'd go rails. But my son is an absolute train buff (or was) and there would be a driven rail system designed whether I wanted it or not and, I'd go with it.
Indeed, I concur. A more permanent installation is the endgame. This dob style base is only meant to be a temporary solution until I can mount it on an eq mount. The ASA DDM100 is in the pipeline but will be a few months away at the very least.
For a temporary solution this base serves a purpose and it seems to be sufficient for the time being. Ultimately a permanent pier setup is the goal but that will be a work in progress and span the foreseeable future.
For a temporary solution this base serves a purpose and it seems to be sufficient for the time being.
For a temporary solution what you have done is beyond impressive!
Is that Ply you've used or particle board/MDF?
I couldn't see in the images, if particle board/MFD basic PVC wood glue is great to seal it to weather proof/make it weather resistant for dewy nights. If ply that is of minimal importance but the PVA glue is still good on edges. It can be mixed with water and painted on with a brush and dries clear.
I have no idea why I'm telling you this, with what you've just built I'm sure you know.
For a temporary solution what you have done is beyond impressive!
Is that Ply you've used or particle board/MDF?
I couldn't see in the images, if particle board/MFD basic PVC wood glue is great to seal it to weather proof/make it weather resistant for dewy nights. If ply that is of minimal importance but the PVA glue is still good on edges. It can be mixed with water and painted on with a brush and dries clear.
I have no idea why I'm telling you this, with what you've just built I'm sure you know.
Haha yeah all good, it is 26mm chipboard with laminate on both sides, from an old stock stand shop fitting from a bookshop. The edges have been painted with 2k epoxy resin mixed with black pigment, as are all the glue joins along with a healthy amount of biscuits for good measure. Recycle what you have was the name of this build... so I used what I had laying around and built the mount for $0.
Ok... I am not an incredible story teller nor am I able to embellish details to keep one on the edge of their seat as I regale my experiences. I have never written an observing report either so I have no idea of the format or what things to talk about. Having said that I am sure there are some who would be eager to know what this scope is like so I shall try my best, here goes.
Let me first preface this evening with the weather report... dismal would be fitting. I had just finished a 12 hour shift but I am extremely keen to try this thing out, the cold, wind and incessant
sucker holes wouldn't get count me out tonight.
I have to move the scope out of the garage onto a carpark area made from that old pea-gravel bituminised stuff, even though a few short metres is all that is required it is painstakingly nerve-racking wheeling this thing around. The 60kg tube mounted so high is precarious to say the least, traversing small bumps feels like driving a monster truck over a pile of wrecked cars. It takes agonising minutes to move into place, the scope must be tilted up and down to clear various low-hanging obstructions like the garage door, roof rafters etc... this thing is big.
Once in place the wheels are locked, I make sure they are all facing outwards to maximise the footprint as much as possible. The movement is actually incredibly smooth, I am very surprised I was able to build it right the first time and have it move with the perfect amount of stiction. Although the movement is sensational, the settle time... well not so much. The moment arm on this tube is huge, and being such a heavy scope it really is under-mounted in it's current form, a 3 second settle time I would say. I doubt there would be a solution for this short of fabricating a 200kg steel base somehow. The 2800mm focal length is quite long, objects move through the field of view quite quickly so you need to constantly bump the scope, then wait the settle time and bump again, not ideal.
I only observed for around 30 mins to get a feel for the scope. I am using one of Denis Levatic's incredible bino viewers and a set of Docter/Noblex 12.5mm eyepieces. If you were ever on the fence about binoviewers I thoroughly recommend you seek out Denis and purchase some... they are simply the best.
The sucker holes were so bad that I would find a target, get focused and then get whited out, try again somewhere else. I was eventually able to dial the focus, get both eyepieces focussed in the same spot and try to find some stuff. Being f10 it was noticeably dimmer than my 16" f5 dob, some targets were much more difficult to find but I guess it is pointless comparing the two as they are vastly different instruments.
I have to say though, this lens cell is incredible, the stars are as sharp as a tack. As round as one could hope for across the field, no discernable colour fringing, no colour aberrations whatsoever, no spherical aberrations, no coma, nothing, it is literally perfect. I was able to clearly see the stars change shape and size based on seeing conditions, whether an appropriate cool down time would have changed this I don't know, most likely.
I viewed a few targets very briefly, fighting through the clouds and inclement weather was a struggle. This scope really will be a planetary and double star beast, Rigel and Acrux both split so much you
could park a bus in-between them. I don't know much about double stars or how those two pairs sit on the proximity scale but it was no challenge even in the slightest to discern the two pairs.
Omega Centauri looked sensational but dim, I could see the atmospheric turbulence much more noticeably on the globular cluster. The whole thing was wobbling like a desert mirage because of the field of view was full to the brim with stars. It only just fits in at 224X... I probably should have tried some lower power eyepieces first.
Ergonomically the scope is very cool, I have the folded tube slightly off center to the scopes main axis. This means I can move the binos either side of the tube axis and get many different angles to suit your head placement regardless of altitude. I think this feature will really shine once the scope is equatorially mounted, I cant wait. Only downside to being able to move the bino so much is that it changes the way you perceive movement, up is left, right down... then you go the other side, left is down, down is right etc, no easily learnt pattern as the mirrors are always in a different spot.
Well that is my first impressions, thanks for sticking with me. Hopefully I can get better at observing reports in the future instead of where I am now. "Stars are little white dots and round"
(please note the pic attached with the clear skies was not tonight, in no way shape or form was the weather that good)
Haha yeah all good, it is 26mm chipboard with laminate on both sides, from an old stock stand shop fitting from a bookshop. The edges have been painted with 2k epoxy resin mixed with black pigment, as are all the glue joins along with a healthy amount of biscuits for good measure. Recycle what you have was the name of this build... so I used what I had laying around and built the mount for $0.
Much respect Luke, proficient with timber and metal. Not many people can do that, I've had experience and training with both to a higher level with metal.
I was wondering about the rolling it in and out and did mention something. Here's a probably stupid question, I'm full of them (or was it full of it, I don't remember), could you put some sort of slip on outriggers with small casters/wheels which wouldn't have to actually roll on the ground?
Much like a lazy axle on a truck, if the unthinkable was to happen an extra measure of security whilst moving the unit and easily released and removed once in position?
A double timber V set-up which easily removes but gives extra protection in both axis while rolling the unit across the yard , any tilt and the wheel offers immediate support.
They could slip into some c brackets and be locked in place with a t bar threaded bolt (welded T across the top), it would be an extra minute or two to fit them and remove them again so you don't trip in the dark but give a lot of peace of mind and be reasonably simple to do,
Or a set of set in place rails done with 5mmx25 flat and joined with welded angle across between the rails so the angle gave a wide footprint, dyna-bolted down with welded flat bar (cut angle) on outer edges of flat, it's a lot of work, much like a mini rail, they use flat and box section for rails, even 3mm flat because it's easy to radius if necessary but that only works if you have one place to place the unit till you get your pier and mount. The wheels could be turned out of large-ish pulleys off washing machines or dryers. Damn, if you were closer I'd be offering to be over there welding it all up for you and setting the rails on or in the concrete, I'm beyond intrigued!
I have a set of relocatable rails I made with some 2" angle screwed to some old 4x2 timbers, it helps me get my heavy compressor up and down the steps at the shed and has been used for multiple other purposes. It also served to assist getting the 300+Kg lathe off a box trailer and into a shed before lifting the lathe with an engine crane onto it's stand I welded up. I rolled it down the rails on some pipe (aha, now I remember where my round 50mm 7075 aluminium went.
Welded flat between two lengths of 2" angle gives you a flat surface with minimal frictional resistance for the casters to roll in safely at minimal cost.
I was wondering about the moment with such a long tube and had mentioned a lead weight at the base.
Still, it must be the most AMAZING experience when it's in operation and very satisfying to think you did it all yourself. You deserve a lot of credit for what you have achieved.
