PeterW

Rkas is defunct. Ewell go out when they can, also observe from nonsuch school. Guildford are also quite active, check their webpages for info. Also there is Walton AS as well who meet in Esher. http://www.waltonastrogroup.co.uk/ The skies out in north surrey aren’t amazing, but a definite step up from urban London. The South Downs can really quite dark. Peter

Phew... you know what I mean! Peter

I checked two commercial units and got 0.1-0.2mm accuracy for a range of dimensions in all axes. Mostly better than 0.15mm. Though the first layer thickness offset, slight “elephants foot” and small holes underside were all present and can be accounted for in the car or fettled away. Given the size of the material creator (nozzle diameter, layer height, laser spot size etc) is much bigger than this we are not likely to be able to improve much. “The professionals” (think aerospace companies) always add stock and machine dimensions and fittings where they have specified tolerances or care about the roughness affecting fatigue performance. Good luck in your quest, but I am not sure how much better it is worth hoping for. Peter

Gavs is either a Photonis Intens or a Harder Gen3, both white phosphor, both high res and with gain control. The harder appears to be a wee bit better on nebulae, but both do a fantastic job. Peter

The human eye has actually greater quantum efficiency than the intensifier (IIRC), but the intensifier has a much wider bandwidth of colours it is sensitive, so you see more. It’s essentially blue blind, the photonis is supposed to be better in this regard, but the judges are still out about reflection detection as some reflection nebulae have a bit of emission in confusing things. There are second hand systems out there that can show much of this stuff... not as well as our illustrious new NV innovators, but plenty cheaper. Gain control is the one thing the new systems have that’s very desirable. As long as you avoid the gen1&2 which don’t offer enough benefit to be worth really using. More spec is more better of course. Many people express an expectation of price drops, but I wouldn’t put money on that happening unless the US dropped its export restrictions and the US manufacturers went nuts expanding their markets. Also the expectation of performance improvements, again there has been very gradual improvements but nothing huge (some mil specs have actually been lessened), like camera sensors we are probably near as good as we’ll see. For those wanting to find stuff in the dark the longer spectral windows of thermal are the place be, rapid spec improvements and price drops. Peter

Good luck, generally the newer and higher spec the better they take filtration that helps to improve the view and make nebulae more visible. I’d gut a long pass filter (eg680nm) and get away from the worst of the light pollution to show more stars and then look to try a wide hydrogen alpha filter (12nm maybe). I don’t know the relative sensitivity or spectrum of the tube so you’ll have to report how you get on. PEter PS for low(er) cost NV I’d recommend the secondhand market for Gen3. Stuff does come up as hunters move to thermal.

The usual measure of NV effectiveness is the expletive count when you first let someone see expansive nebulae or a profusion of stars. It’s analogue tech too, just some special materials and a voltage across them. PEter

Sort of, if you are shortsighted, sitting at the back of the stadium and left your glasses at home..... Peter

Live.... move the scope by hand, does the image change instantly and smoothly? If it streaks it’s not live. At least CN isn’t dominated by Malincammers as it used to be, more balanced now.... taken a decade for NV to become “mainstream”. Peter

@vlaiv NV gives you a live view in an eyepiece... no wires, no stacking delays. Can appear essentially like an enhanced naked eye view, unlike what some people claim. I’ve watched over many years NV has been kicked about as a minority activity on various forums. Those of us who have tried just enjoy the views and are happy to share. Peter

Biscuit! peter

I have it on good authority that the 28” Greenwich is apertures down quite a bit... impressive looking.... but!! at one dark site I visit, we have 5 red light radio mast... gives us a quick indication of cloud cover! PEter

Very quick run with the 70mm and stock 18mm ep under urban skies and scudding clouds. M35 was very nice with delicate chains of tiny stars, more impressive that the Pleiades (possibly as they were behind a tree). Also got hints of M1, which was a pleasant surprise. We’d to design a finder bracket for them. AZ3 working nicely, probably bring a chair out next time. PeterW

Anyone know what happened to John Walls 42”, https://www.britastro.org/node/12262 Peter

Collected from work, compact, but solid. Going to be fun using these in the daytime with wide field eyepieces. Need to sort a carrying option and some finder mounting. PEter

New 70mm APM on an AZ3 modified many years back with a Beacon Hill simple bracket and weight bar for my old ST120 which would not balance when used at altitude. Balances fine, need to add a Reddot/laser finder. Nice tight stars with 18mm and 13mm ep. Bought for daytime usage… as a two-eyed spotting scope, for which I use a lighter tripod as they’ll be pointing horizontally. Peter

Stu seems to be stand on his own when I’ve met him.... ? Peter

Stands up on its own.... impressive! peter

Skye? Those numbers are almost “down a mine” dark! Peter

About 18.8 best, though just noticed the shield on the nearest streetlight has fallen off... reported! 21.few at the dark sites I don’t get to often enough. Peter

I keep my IS bins is a pelicase, more worried about knocks than dust. The supplied softcase isn’t any good for keeping them protected. Enjoy the views, surprised myself recently how nice the stars are in my 12x. PEter

Spare monopod quick plate to enable quick swapping of binoculars. Don’t seem to be available online?! Made it a bit thicker for stiffness. Peter

Machines exist from several suppliers, desktop metal, HP, digital metal, markforged that are “lower price”. Wait for Shapeways and imaterialise to use them and then you can get them to make them for lower prices. Laser sintering requires post processing almost all the time. The above machines need post sintering. Peter

A cleaning tank and uv/heat post cure box are recommended. Big prints need more costly machine, though photocentric in the U.K. have some lower cost clever machines. There is lots of resin development as well as filament development. Peter

Impressive, we had only a very heated plate and a very hot end and our peek trials were not great. Peter