Mr H in Yorkshire

50 minutes ago, dlavall said:

It might be overkill

Engineers would call it safety margin. Think of the money and time to install a less powerful motor, discover it's limitations then install another one.

I just remembered why I thought of making the platform upper as a a Dob base - it lowers the COG of the whole mass. I never went any further so I don't know how significant that would be in terms of drive torque needs, I just thought it would be a bit more stable.

That all sounds logical. My son has a 12" Dob, I proposed to make him a platform but he was not particularly interested. I had planned to make the platform upper a replica of the actual supplied Dob base, thus the Alt sides and Az swivel would be integrated into the platform, onto which the scope could be placed.

6 hours ago, dlavall said:

Like you said, If I do I can always add weight to the base of the rocker

You may have understood my suggestion. What I had in mind was to add the maximum anticipated weight at the design/construction stage. The torque and power demands are then predictable. Then when observing, as you add or change a component (eyepiece whatever), add back or take away the same weight from the base. I picture the weight as thick slices of lead, say 500 grams each. Is that clearer, does it sound feasible?

If you expect to add components at various times, would it help/be too complicated to design to a theoretical maximum, add that weight physically to the moving base (as removeable part-weights) and then you have the flexibility to remove the nearest amount each time you do add a component.

Just to say thanks for this, just enjoyed a lazy wake up to a fascinating presentation.

This may be of interest, https://astro-gadget.net/gadgets/control-of-telescopes/dobsondream8

I have used these (minus the attachment hardware) on my 'drive to' motorised binochair (q.v.) and can fully commend them. Service and delivery was good, communications and advice was superb. Aleksander has moved the company to the west of Ukraine and seems to be operating as normal. 

21 hours ago, John said:

I think we will need to sort out repairs

Too bad I live in Yorkshire, I'd be more than willing otherwise. Sounds like you will be up and running soon, good timing just as the night are lengthening.

Cheers

Wow that is one massive base, my query was not well expressed, but I expect the answer is simple. I wondered how any floor vibrations would be isolated, but if the floor doesn't touch the base or column directly then no problem.

1 minute ago, Mandy D said:

Does this not make it even more important to do something about the present problems?

I am only a binoculars/naked eye observer so not grossly affected, but the entire amateur imaging community will surely be impacted, and as for professional (ie very expensive) work, they are suffering already as I understand. Having said that, the cavorting bright satellites quickly cease to have any novelty and become just a distraction.

I wonder to what extent the probability of a satellite collision catastrophe is increased? All our existing technologies produce regular environmental disasters, is that to be extended to space (beyond the existing space debris issue)?

If recent decades of evolving hi tech gear is anything to go by*, these zillions of satellites will be obsolete and replaced by another technology surprisingly soon. Only the damage will remain. *Think cabled router internet replaced by wifi, tape recordings > cassettes > cd's > streaming, 'Squareials' > other satellite dishes, the list is long, the piles of landfill deep.

41 minutes ago, John said:

I was up at the observatory a few days ago.

I am very pleased that your Starchair topic can now see the full light of day, it was too good to be buried . That equipment is absolutely amazing and I will be following progress keenly. Did I ask, what would you do about maintenance or repair if ever it was needed?

enthusiasm for tinkering but in the daytime I fix Bicycles 

Sounds perfect!

Have you cast the column into the base slab? Any concerns about vibrations?

Now you've done it. Three weeks of solid cloud.

Looks wonderful, if only the real thing could be made so easily!

21 hours ago, bosun21 said:

I discovered I didn't include the tent pegs

You aren't the first, you won't be the last. When doing my field work geology mapping in North Wales I found I had made that mistake. I was able to improvise from some barbed wire. Flexing short lengths back and forth to fatigue break them was time consuming but then I bent them into 'staples' and forced them into the ground, they worked quite well!

Welcome, I am an avid binos fan, I've worked my way up to 20 x 100's but they need a specialised mount, 7 x 50 are an excellent choice but all viewing benefits from a stabilising mount.

I thoroughly recommend a book too, one of the best is 'Binocular Astronomy' by Stephen Tonkin. ISBN 978-1-4614-7466-1 This contains all the info about binoculars as instruments and a set of detailed maps.

5 hours ago, Mark2022 said:

A bit of tongue in cheek never harmed anyone

But easier to misunderstand than straight dialogue.

2 hours ago, Mark2022 said:

I am what most would term a full blown "Conspiracy theorist" and  find this thread fascinating but, unfortunately, due to 'rules' and the wish not to offend anyone,  I must, essentially, shut up. 

In defence of SGL policy, free speech is not constrained, you can state your daftest/most sensible ideas as you so wish, and some might be offended and disagree. My experience is this is all permissible as long as the language used does not itself get offensive. What is constrained is subject matter, especially religion and politics, because these lead, inevitably, to controversial and increasingly heated remarks, which is emphatically not what SGL is about. 

At the age of about seven I was aware that there wasn't the slightest reason to think that a God, any God, exists, that there are ghosts to be frightened of or anything at all supernatural, or anything as daft as aliens and UFO's. Why would anyone who sees the astonishing wonders of the the natural world, the real world, from a drop of rain on a leaf to a supernova, waste their time on such unnecessary and futile/foolish thinking.  Anyone with any scientific awareness, any awareness of accumulated knowledge and ongoing investigation, of curiosity and rational understanding, will have an existence replete with delight and wonder.  Only a day ago I was with my grandchildren travelling over Greenhow in Yorkshire, a high hill in an open landscape where we could clearly see the cloud base. I put it to them 'why do the clouds form way above us, and what would life be like if they always formed right down to the ground'. They were silent for a short while then with real excitement and insight they started  describing how different life would be under those circumstances. It was a sublime moment.

21 minutes ago, maw lod qan said:

The one thing I know for absolute certainty is when one lands in my yard, I won't be taking a gun out to greet them!

Without trying to cause offence, I'm always amused at the hubris the USA has over this matter. What's to say UAV/UFO's wouldn't first go to say Bangladesh, or Lichtenstein or Guatamala?

13 hours ago, John said:

No problem if that can be done

I have handed the disentanglement job over to Stu, I really think the Starchair deserves it's own place, especially if progress reports are to be added in future. It is an amazing piece of work - and I think I can speak with authority on that. The inventor's fate is a bit of a mystery but there are snippets that suggest he suffered ill health. What would you do about maintenance or repair on yours?

In the meantime, I wonder if you have a manual for the beast or otherwise know what the drive rates are in AZ and Alt, and how they are controlled. Are the drives continuously variable from star tracking upwards to fast slewing? I ask because I am currently working on a more sophisticated version of my 4-bar binochair and I have now completed the Az drive. By chaining a 12v electric drill and an extra ex-drill gear box I have speeds from 1 full revolution in 80 seconds (more fairground than astronomy) down to 0.25 degrees per second which will be good for centring  targets in the 2.2degree FOV of my intended 150mm 35x binoscope. I will post all this in due course.

On 26/06/2023 at 17:40, John said:

My astro society were recently gifted this amazing setup

Hi John, your introduction of a sub-thread about the Starchair is interesting but I think it could do with a separate entry. Anyone searching for info on the Starchair will likely miss this if it's embedded in a different topic and that would be a pity. Unless you object I will ask a moderator to do that. Cheers.

On 26/06/2023 at 17:40, John said:

My astro society were recently gifted this amazing setup.

Wow, that is one hell of a benefactor.

@munirocks So sorry, for some reason I did not see your post.

Yes the balance is important and is preserved by the footrest, and the more open but fixed angle of the knees is actually quite a lot more comfortable that without a rest, I did try both setups. Without the alt drive attached to the seat I could actually move the chair in alt simply by lifting or lowering my legs!

2 hours ago, Carbon Brush said:

Sorry to drift off topic

No problem, and I get the counterfeit rubbish angle, but who can resist the bargain gizmo at 1/10 the price you would expect pay! Before you think that's me BTW I am being as sarcastic as I can manage. Just for amusement sake I once bought a cable stripper from a pound shop, got home, picked some unchallenging cable, got my wife to watch the result. It had the mechanical strength of wet paper, we both fell about laughing - it was worth the pound for the jollity.