JamesF

This sort of thing, though there's no way I'd part with that sort of cash to buy one:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p10961_Geoptik-Tripod-Pier-with-Wheels---holds-up-to-100-kg---Height-470-mm.html

James

I'm sure I've also seen piers with three feet that also have wheels.  Once in position, the wheels are raised to leave the pier on its feet, or the feet are lowered to lift it off the wheels.

James

I need to make a spider for a restoration project.  My current intention is to take a cylinder of aluminium and machine out four pieces to give flats that I can make threaded holes in to fix the inner ends of the vanes in place.  With steel vanes I think the outer ends could be done with just threaded rod, slotted along part of its length to accept the vane which could be held in place with a pin at right angles to the slot.  Not sure that would work with carbon fibre though.

James

4 minutes ago, Stu said:

What impact do the double vanes have on diffraction, must be increased surely?

Yes, I'd imagine you'd get eight diffraction spikes.  I'd guess, though I'm not certain, that there'd be a small loss of contrast over a traditional four-vane spider, too.

James

A "degrading memory module" may have caused the problem?  Sounds like a ZX81 with a bit of RAM pack wobble.

James

26 minutes ago, johninderby said:

Could be worse. Imagine if the computer had been made by Amstrad. 😁😁😁

They could fire the chap who made it?

James

Hellfire that's bright!  Oddly I've not noticed it from here.  Or rather, I've not noticed any obvious change in the pattern of light on the northern horizon, though perhaps it just blends in with the rest of the mess sometimes visible in the direction of Burnham and Weston.

James

Typical!  Now the cloud is starting to break up!

James

Cloudy with a chance of more cloudy, here.

James

Totally solid cloud here at the moment, but the BBC News headline gave me a laugh: ‘Ring of fire’ to sweep across the Earth.  Then going on to explain that it was an annular eclipse, but that very few people would be able to see it in full unless they live in the Arctic.

James

The weather forecast makes it look like something of a washout here, unfortunately -- solid cloud from now until showers start at around 1pm.

Hopefully others around the UK will do better.

James

I'm so saddened to read this

James

11 minutes ago, Sunshine said:

put Wonders and Brian Cox himself on the same pedestal as my beloved Carl Sagan.

I don't think this is an unreasonable view, though their work is hard to compare given the time between them and how much has changed.  I'm not into the whole "lingering stare into the distance" thing with Brian Cox for which he is often criticised (amongst other things), but actually that sort of stuff is about how programmes are presented these days -- they're entertainment as much as informing and educating and that's what the producers feel is what (some) people want.  If you talk about the passion for the science and the desire to communicate it then yes, I think they stand shoulder to shoulder.

James

Which reminds me... I must design a polar scope cover for my EQ3-2.

James

3 minutes ago, skyhog said:

That's very much arbitrary though...😉

I agree it's a pretty arbitrary distinction to make, but for me it does feel as though there's some sort of qualitative difference between being on an aircraft and on the ISS where the astronauts can't just stick it down at the nearest airport if something goes wrong, for example.  If you like, I kind of feel that on an aircraft you're just "temporarily not here", whereas on the ISS you're "somewhere else".

James

13 minutes ago, skyhog said:

It wasn't long ago I read that book after it had been on my must read list for years. It didn't disappoint. One of the most unassuming figures of the era and incredible to contemplate that level of isolation in the command module. To hear him talk of using a sextant out of the window to gain settings for guidance is unbelievable today. If anyone who is interested in the apollo missions hasn't read his book, I would strongly suggest you do. 

Absolutely agree.  It's a fascinating book, but seems to me to give an honest feel for what the whole "Moon landing project" was like for the crews of the Gemini and Apollo missions.  I had to buy my copy second-hand as it seems to be out of print now.

James

3 minutes ago, saac said:

Yes it's really about being off the planet itself including the atmosphere.  I'm watching it now , some other thought provoking quotes - watch out for the speech by Yuri Gagarin.

The bit about being able to navigate to the Moon and come back reminded me of a quote from Michael Collins's "Carrying the Fire" where he talks about the accuracy required to get home.  I think he calls it the "window of survival" or something like that.  He claims it's the same as being able to split a hair by throwing a razor blade at it from twenty-two feet, if I recall correctly.

James

It does, yes.

James

Just watching it now.

I love the quote that at no time in the last twenty years has every single living human actually been on Earth.

James

9 minutes ago, Louis D said:

A nearby city has an ordinance protecting trees with trunks greater than 19 inches in diameter at 4.5 feet off the ground from being cut down without council approval even if dead.  Generally, they require them to be moved if they impede construction.  This can cost $125,000 to $250,000 per tree and take weeks of preparation.

The unintended consequence being that lots of trees get cut down as soon as they reach 18" in diameter?

James

13 minutes ago, happy-kat said:

'feeling safer' is not the same as actually being safer.

There's a term for this: "security theatre".  Street lights are perhaps a good example.  As are many of the measures taken at airports after 9/11.  They're designed to make it look like something is being done and to make people feel more secure without necessarily achieving anything real.

Personally I'd prefer to see the money used to address the root causes of people feeling insecure rather than treating the apparent symptoms which may well just move the problem elsewhere.

James

Given the UKs apparently changing weather patterns where we can have very long periods of rain making the ground soft as well as storms with quite high winds, even during what might historically have been more settled periods when trees are in leaf, I'm surprised that more people aren't getting a little anxious about large trees growing close to houses.  Particularly, perhaps, large trees in one person's garden growing within falling distance of someone else's house.

James

I think quite possibly you should contact FLO.  It might be worth running the test for 24 hours too, so you can quantify quite how much it is out.

James

I have no hesitation in taking down some of the sycamore trees we have here because they spread like weeds.  Removing some of them will improve my view to the East a little, but will also reduce the huge number of leaves dropped into a pond which should make it more pleasant for newts and frogs.  Other sycamores I might remove just because they snuff out other trees that don't grow so fast.  There is an ash tree that blocks my view slightly to the south east, but that will stay unless it starts to show signs of ash dieback in which case I won't have any choice but to have it taken down before it becomes unsafe.

I've planted plenty of hedging and a couple of dozen trees since we bought this place though, so overall I have no guilt about it.

James

23 minutes ago, Astro Noodles said:

You're probably right. Hardly scientific. But to trail at 200mm after 20seconds, it must be out by several percent I would have thought. It may be detectable visually. A longer experiment over several days might be more obvious visually.

I did something similar with my Star Adventurer.  If I recall correctly I used a mark on the wall and fixed a pointer to the mount to align with the mark, then allowed the mount to run for 23 hours 56 minutes.  It should then be pointing back at the mark.  Using a laser pointer would probably be ideal as the mount can then be further from the wall, making errors more obvious.

It's a bit more tricky to do shorter intervals that way though.

James