Rusted

The obvious improvement in colour correction was once the exclusive sphere of the triplet. However the introduction of special ED glasses has reduced their advantage. When I dabbled in geometric ray tracing one could obtain 1/10th as much false colour with a triplet. But, then only in comparison with a doublet of common glasses like BK7, F4 at longer focal lengths. The triplet APO still needed very exotic and expensive glasses at that time. e.g. Roland Christen's early 'AP' APOs. Special glasses are now much more widespread in larger aperture blanks thanks to the Chinese popularising affordable "short" APOs. Not to mention binoculars and spotting 'scopes. None of which answers your question. Triplets do have the reputation for much slower cool down. [As already discussed above.] Peter's mention of mirrors is certainly true. The ultimate "planetary" telescope in amateur sizes is/was probably still an optimised Newtonian of 12-15" aperture and longer focus. However, the corrective elements now available to combat coma are even allowing short focus, large aperture telescopes to produce superb visual images. But only in excellent seeing conditions. Like Florida? Or at high altitudes. Yet another red herring to avoid giving a direct answer?

If you are incredibly lucky you may find a secondhand lathe ex-education or from a small business going bankrupt. I picked up a good quality, British, tool room lathe on its original cabinet + tooling, ex-uni for a couple of hundred quid, but that was ages ago now. The floor pillar drill expense and wasted space was met by shelf mounting my big pillar drill into sturdy 24" deep shelving on thick ply + support pillar underneath. This replaced cheap 12" shelving with steel shelves [which always collapsed under their own weight] and holds lots of stuff in big, but shallow, 4" deep, plastic tubs from IKEA. Downside is the inability to stack these trays without using the lids. Which means double handling to reach the lower storage trays. It ought to be made law that storage tubs stack by reversing them by 180°! I moaned for years about the usual deep storage tubs before I found the IKEA. Most of my old tubs were mostly fresh air. Or far too heavy to lift! The trick is to fill all the fresh air on one wall right up to the ceiling. This leaves space on the rest of the floor for woodworking machines [saws] on wheeled stands/cabinets. These can be nested and/or packed away compactly under deep shelving/work benches when not in use. The investment in decent kit made it possible to complete my two story, 10' Ø trapezoid dome at a fraction of the cost of a commercial plastic shell. Nobody did one big enough for my 7" f/12 refractor for less than the cost of a small car.

Building a replacement for my 6" solar H-a scope. With better parts now I know what I need from months of direct, hands-on experience. H-a solar imaging has become so much a part of my daily life that it is well worth investing more funds. Still small change compared with commercial offerings in this aperture. The plywood dome already needs a strip and repaint. Or re-covering with something more waterproof. Building a shiny, aluminium, trapezoidal dome would be good from a thermal/waterproof POV. Just too visible from a distance. When I'd rather be camouflaged. Like a big tree!

2x WO Barlow of last dregs of the 'pylon' prom before the sun sank below the roof. Seeing was awful all day! But at least the sun shone. I thought it had forgotten how to!

Yes. At about 10.00 o'clock on the NE limb. Ignoring chimney total eclipses of the sun!! Pylons? Here you go:

Even after 17 hours torturing the final image on the iMPPG rack: See it and weep! Not even a pylon for added interest! 😉

You don't get bragging rights from being north of the M25 any more. Not since the fall of Hadrian's Wall.

You can nip round and fell my neighbour's trees if you have a moment to spare. Gone 11am and the daft things are still rocking back and forth in front of my rare H-a sunshine. Grr?

I haven't read any science fiction in 50 years so must bow to your obvious expertise.

Well done. I have no direct experience of CF. Only glass fibre and cloth with polyester resin. It would be humanly impossible to make your tube any uglier than mine. I was working on the outside!

iThey only need to expand access to the Internet because they have already achieved total, devastatingly invasive, advertising supersaturation with the presently available, hideously involuntary, customer base. Income, versus expenditure, is now falling like a world destroying, mega-meteorite. Though, unfortunately for most of us, not one of the Daily Express, imaginary variety. Like every other human endeavour before it, iThey has greatly exceeded the sustainable resources available. So that full desertification is rapidly approaching their balance sheets. Leading to total, global, panic and financial collapse. Before long, institutional investors will begin to realise that there really is nothing on the horizon to replace the critically damaged, advertising supported, expansion model. iThey values are entirely virtual. With nothing to convert into hard cash when the downturn comes. iThey is already running on borrowed time. Note how all the smart entrepreneurs are running with their cash while they still can? Just as smart robots are about to replace most forms of manual employment, it is highly likely that General AI will soon begin to decimate iThey workforces. Like a fleet of vast, burning dirigibles, once the gas ignites, it will quickly spread between them. To reveal there never was anything behind the paper-thin facades. Except empty hyperinflation and a heavily tattooed, fake skin. Decorated with tasteless, pixelated, pop-up, in-yer-face, advertising banners aimed squarely at the inter-lektule "lower orders." iDon't believe it? Well, if it looks like an iBargain, too good to be true, then it very probably is. Creeping iCynicism will soon make a global, Windoze, DOSS attack look more like a dodgy case of Monday Morning, man 'flu! 🥶

Isn't the same multiplicity our strength rather than a weakness? We don't usually allow a complete monopoly in any one thing. This means we can usually survive a critical bankruptcy or factory fire. Competition for survival, within any commercial sector, usually ensures progress. It usually means lower costs even if it takes time for trickle down to occur to the masses. There must have been some really leaden feet because so many businesses went bust. Communism was formerly the prime example of industrial weakness through deliberately restricted choice. Yet China took several centuries of Western technological progress and ran with our balls. Now you find Chinese names on a great many scientific and engineering breakthroughs. They produce more engineers and scientists than the rest of the world put together. Humanity constantly invents new things because it provides adequate education. It seems inevitable as previously powerful dampers, like religion and gender, are removed. Just imagine what "we" can achieve when Sub-Saharan Africa is freed from our historical yokes. Given a proper education, fed properly and relieved of the daily theft of their resources. Freedom to invent and improve is often despite crippling restrictions like hunger or gender. Petty monarchies, barons and warlords no longer control the freedom of ordinary people to imagine our future.

Without Gravely Blighted, Denmark would have no weather at all. We watch the UK weather to see what you are sending us next. Will you have to stop doing it when you are outside the EU?

I invented the universal, "girder" suspension fork for bicycles with a generous, 7.5" travel. Unfortunately it was just a geometric improvement on the existing design of decades before. Most suspension bicycles now have short-lived and/or expensive, telescopic forks. Then I invented the self-supporting, binocular steadying device for astronomy. It relied on two shaped bars with counterweights behind the wearer's shoulders to balance the weight of the binos. Sadly it only worked over a very small vertical angle and nobody would want to carry more than twice the weight anyway. Then I invented the "tunnel" tent with arched fibreglass, self-supporting poles. It looked just like the mountain expedition tent offered by Blacks of Greenock at the time. I can only assume they were mind readers.

Me confused?

And, preferably, live to tell the tale!

Have you been hacking the NASA computers again Charl?

I think Olly's speaking the same language as Gina. Try this: Google Translate

How do these low temperatures affect the PST etalon? Mine stays out in the dome, unprotected, with potential drops to -20C. Though not very often in today's warming climate. Minus single digits C are still commonplace. 26° above the horizon in midwinter? Mine scrapes past the Meridian at 11° ish!

I have to say these are easily the most incredible, solar images I have ever seen in over half a century. Bar none! As such, you ought to be amply rewarded for your incredible skills and considerable investment in time and equipment. This is not remotely a case of your needing to be flattered by your inclusion on these commercial, sales websites. Your superb results also reinforce the huge gap between your advanced processing skills and those who simply can't. [People like me.] Which is not to dimininsh your contribution one iota. Utterly amazing! Head and shoulders above the rest of we, mere mortals! Would it be churlish to suggest that the commercial vendors cannot possibly guarantee your incredible results from every sale? To use your images and animations, on their sales websites, as an example of what can seen or imaged with their equipment probably borders on false advertising. But that's just my jaded opinion. The QC of much of the equipment leaving the factories simply does not warrant comparison with your high art and scientific value.

What Sun? I thought it was just a modern myth?

We are not alone! 🤣

An internal D-ERF has the capacity to refocus the hot, unfiltered, converging beam from a large objective to cause a fire in the dewshield. Ask me how I know this? Cardboard aperture stop anybody? Flames in your dewshield? It could happen to anyone! Especially me!

Just a couple of clicks of contrast and a minus click of gamma. One has an extra dollop of colour saturation to bring out the green. All the work of free PhotoFiltre7. I've been using it for years on my landscape photos. I could never afford Photoshop. Nor spare the brain cells to learn how to use it. So I use PF7 on my solar and astro daubs too.

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