PeterW

16 minutes ago, sorrimen said:

Down in Plymouth today but no luck with clouds in the way. 

I wondered @sorrimen, I did have a quick look about in case you were doing some outreach. 

Peter

Went to the park, could see down to a little below 9degree, mistiness inbound. Nothing apart from a few stars that just stayed put. Nice and chilly, great wide view of the Hyades with the ol 7x35 and the sound of deer bashing antlers (I did check they were plenty far enough away).

Wonder if anyone else got lucky.. maybe in more southerly and warmer climes?

Peter 

Looks like the slightly delayed launch means the clouds are going to kill of @Stua chance. That 100miles buys me more time, but stuff will be much lower. What’s the betting that no-one sees this from the UK…. Anyone predicting sighting astro phenomena in the mass media always ends up dooming the event 😞

Peter

3 minutes ago, Stu said:

I’m in the garden, good horizon from here but clouding up a bit 🤬.

Anyone know how high it will be? @Captain Scarlet we need some of your maths ability here!

I think Magnus has gone to bed with a hot chocolate, nothing to see apart from what he can view on the live stream.

Peter

Not very from the BAA predictions… like less than 10days and heading southwards at speed, you’ve got 100miles or so on me. More detail on the predictions at different times, with some elevation estimates would have been useful. 
 

peter

Why the on screen data in psi and Fahrenheit….hope we’re not going to see any imperial-metric issues… previous flights were from the US where they tend to use there archaic old units….

Predicted drop just after 11, @Stu you’re a bit closer, you got a reasonable south westerly horizon? I could go to the local park but after the recent Mercury-in-trees fun I think it’ll be too low…. How far away can you see the light of a big firework… it’s not in the scale of Elons?!

Peter

I’d expect they’d want to lift it up as high as they they can… so hopefully above any los(ish) level wetness… of course if there are any thundery clouds out there they’ll want to give them a wide berth. So looks like you won’t see anything… clear in London, but probably too far away to see.

peter

@Captain Scarlet looking right up its backside as it shoots away from you… at the very least if anything goes wrong it’s heading AWAY from you! Let’s hope the clouds keep away and see what you can spy!

Peter

OK, made a variation of a prism modded daytime red dot finder (mainly for daytime use). https://www.cloudynights.com/topic/854410-better-rdf-sighting-ergonomics-with-a-bed-glasses-prism/
 

Peter

Yes, sort of “un finished” photons from earlier in the process contaminating the nice green ones you want. The whole process is temperature sensitive, hence these ones die in the cold, the new simple direct emission ones give you what you want immediately and should be less temperature sensitive. (I make an LED change between orange and green with the help of liquid nitrogen… expect a laser diode would behave similarly, but might just break it).

peter

Diode pumped solid state lasers, most of the existing green ones are actually 880nm(ish) IR diode pumped… this causes an and containing crystal to lase at 1064bm, which is then doubled to 532nm. So you’ve got IR in there you don’t want/need that should be filtered out so that the end user only gets the green that want. Without a spectrometer you won’t know the balance of visible to invisible power. The “cold proof” ones that are emerging (seem to be 515-520nm) are direct diode ones that only emit the exact colour you want… no IR, no doubling etc. 

Peter

For SI prefix geeks, there are a few new ones just been internationally agreed - UK proposed. https://www.npl.co.uk/si-prefix

I would certainly hope that none of the new ones are needed for laser specification.

Peter

I’m about to build a mod for a daytime led reticle finder for angles use, based on a forum post, might help in this setup too. I’ll be attaching to a 127mm mak, so same sort of geometry.

Peter

Yes, 1mW is intrinsically safe, 5mW is generally safe unless you try to damage yourself and any more is additionally risky. I am sure you could use a 1W laser as a pointer, but I wouldn’t want to be within at least a few miles of it. Don’t risk yourself or others, <5mW is plenty.

Peter

Welcome. Loughton Astro society who meet in Theydon bois run talks and observing and could be worth joining. Escaping further into Essex should provide some better skies.

Peter

<5mW max, avoid generic low cost online retailers as I got one that was dangerously over powered once. Find a company who can assure you of the power you’re getting.

ideally you want a 520nm direct green (not a dpss 532nm), the reason being that the latter will die when cold, the former are new and cold proof (allegedly. I plan to make my own multipurpose pointer when I   Do some CAD design).

power it with lithium batteries as they are cold resistant too.

As always, be careful who uses it (ideally only you), where you point it. Avoid it shining on things that could reflect back to you or planes/animals etc. Be safe.

I used mine to help a friend find objects in their dob from a light polluted location, worked a treat:
 

Peter

If you want quality of view then get a 1.25” wedge. I compared my wedge to several people with different white light filters and it provided a much more detailed view.

Peter

APM sell 7x50 that are very close to the Fuji, but cost a good deal less.

Peter

Well done!  Need a very low horizon to catch them.

Peter

DO NOT get a binoscope/binoviewers or your eyepiece collection will breed like rabbits! I am not an eyepiece collector, but I now have a drawerful. I agree with Al, but if your scope have the same focal ratio then you can share them… otherwise just add a longer/shorter one as needed. You certainly don’t need to have a “full set” of any eyepiece brand/series… they overlap too much.

Peter

You might need bins and a low horizon… good luck!

Peter

Been cloudy for ages and soon to return that way, popped out and just managed to get a low enough W horizon to catch Venus before it set, Mercury just naked eye a little higher behind a tree… with Saturn, crescent moon, Jupiter and mars stetching across the sky. Great sight, worried I’d not get to see Mercury this elongation, much lower than I’ve previously seen it.

Peter

… hope you bought en eyepiece the right size for your hole saw…

Peter

I use a very extended extendae blade knife…. But probably do a much worse job than the alternatives.

peter