saac

Found this offering of the Prague clock on Etsy. Looks like it is laser cut from birch ply, may give you some inspiration. 

Jim 

https://www.etsy.com/uk/listing/1594994603/prague-astronomical-wall-clock-unique?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=prague+clock&ref=sc_gallery-1-2&pro=1&frs=1&referrer_page_guid=f743a6e6641.a89e442282fdfd6ed5f4.00&plkey=9a86244c7e89e4c68bfb1e8529da184c80c3c1db%3A1594994603

17 minutes ago, maw lod qan said:

The only thing I do know for certain is my waist line is continously expanding!

Something I sadly have in common and it aint due to cosmic dust  

Jim 

7 hours ago, FrankRyanJr said:

Starting around this time, I've been asked every year for the last 30+ years from at least one person what is the best scope to buy someone for Christmas/Holidays.  Usually the budget is around $250 so I have a stock answer! 🙂
No.1 rule: Do not buy them a hobby killer!

I'm interested in hearing what others think of my take on it. 
In short (the long is below) if they are new to astronomy I simply recommend binos and a book. I know, it sounds hella boring but I've seen so many times kids and adults getting gifted scopes that literally destroy any interest they had. 

(YT vid)
Don't gift 'Hobby Killer' telescopes for Christmas! Do this instead...
https://youtu.be/Gvrb65AfJuk?si=NAyxm17GTLZJ5rUj

I take the opposite view especially if the telescope is a gift for a child.  As an 8 year old I received my first telescope at Christmas, it was one of the Tasco refractors and came with a tripod and some accessories.  It really had little to praise in terms of quality or performance but it offered something far more important. It offered  "possibility" and it fired my imagination well beyond the limits of its limited optics.  I spent fruitless hours in the back garden searching the heavens for something extraordinary and I enjoyed every minute of; it enriched my passion for science and engineering. Fast forward some 50 years, a career in engineering now education and I am still searching the night sky, sometimes with a little more success.  A telescope for a child is a completely different proposition than a telescope an adult may consider, adults have a fraction of the imagination of children. For me at least,  a £250 telescope is not a hobby killer it's a door to possibilities that could stretch far beyond that Christmas morning.

Jim 

These researchers put the amount of cosmic dust (micrometeorites) gained each year at around 5000 metric tonnes.  No doubt that will come with a fair margin of error. If that were distributed evenly across the surface of the planet what thickness (increase in waistline) would it represent?  This reminds me of the number of angels dancing on a pin head puzzle or maybe even a Fermi question; best contemplated with a few whiskies  

Jim 

https://www.scientificamerican.com/article/antarctic-study-shows-how-much-space-dust-hits-earth-every-year/

37 minutes ago, globular said:

Gravity does a good job of keeping stuff on Earth, but a faint stream of lightweight gasses, mostly hydrogen, helium and oxygen, is continually escaping from the fringes of our atmosphere. (Particularly dense near the poles, where gas ionized by the sun flows out along the magnetic field lines.)  Several hundred tons of mass escape to space every day, significantly more than what we’re gaining from dust (which is about 40 tons per day).

Yes but gas infall or outfall I would think is not really the cause of accretion of material on the surface and hence does not contribute to any change in radius. It contributes to change in mass for sure but not dimension.  Again any increase will be of insignificant orders of magnitude against the radius of the Earth but it is an interesting academic question. 

Jim  

I do believe a known amount of cosmic dust falls onto the earth each year so in theory I guess the radius of the Earth could increase (very very slightly).  I suspect in practice most of what is gained is redistributed by our ever increasing dynamic weather system.

Jim  

26 minutes ago, pipnina said:

I have often been told by Scottish family that "england is flat" and to be fair I think a lot of it is compared to scotland. But devon/cornwall certainly seems hillier than most places I've been to. Certainly the Scottish family were surprised when they came down and this part of england was not flat haha.

I think we call those bumps  

Jim 

37 minutes ago, Mr Spock said:

As soon as it's dry outside, I'm going to dig a large hole. The flooding seems to be related to rain rate rather than the total amount - in this case 9mm per hour. The water does drain away but quite slowly. If I can provide a place for the deluge to go temporarily it should stop the flooding.

I can't access next door's drain as there's a wall in between properties. As next door is much lower than here the rainwater must be going there somehow as there's nowhere else it could go.

It doesn't help that there's a number of springs in this area which have been built over.

What you need is a soak-away MIchael.  Ideally these would drain to a functioning drain but they do not need to.  Basically dig a hole and fill with gravel - you want fairly chunky grade.  Builders of new houses would often use the rubble from the build.  If you can cover the top of the rubble pile with some geotextile (at a push an anti  weed fabric would suffice) this stops soil slowly silting up the rubble, then re turf/surface. You are effectively creating void into which the water will drain - it will then slowly seep away over time but it should alleviate the surface flooding.   If you want a more modern solution you could use these prefabricated crate systems. 

https://www.drainagepipe.co.uk/soakaways-membranes-c-18/?keyword=soak away crate&matchtype=p&device=c&campaign=S_|_PRO_|_Soakaway_Crate_(p)&gad_source=1&gclid=CjwKCAjwkY2qBhBDEiwAoQXK5fgMYPpJNDcDy7Uis8AgXOen9tEJK3WeF73snoCFbKKQnKhDmsPD1hoCQccQAvD_BwE

Jim 

No expert but would an IR cut filter help.

Jim 

Just catching up on the Sky At Night Question time edition, I think it aired early October.  Delighted to hear that Prof Chris Lintott has been appointed as Professor of Astronomy  Gresham College London.  Reading through the notice on Oxford University Physics Dept web site it gives some information on the public (free) lectures that Prof Lintott will be delivering over the next year as part of his responsibility. Not sure if our London members are aware of this but I'd imagine that these would be worthwhile considering if you are local.  Looking at Gresham College site itself they appear to upload these public lectures which is really cool.  More details below. 

https://www.physics.ox.ac.uk/our-people/lintott

https://www.gresham.ac.uk/watch-now/faster-light

Jim (envious up in Scotland) 

I really like that @Scooot; you've certainly caught some of the feinter gas cloud and to my eye your background processing is spot on.  I like the way you have a depth to the blue hue in the centre, my attempt at the moment is showing the same intensity throughout and less surrounding cloud. I need to catch a lot more data  

Jim 

To be fair for all of its apparent complexity WBPP doesn't really take that long to get a reasonable working understanding. Like @Ouroboros, I really like the way you can simply point to one folder and it identifies and collects all the relevant files.  Running time can be long, some people have reported 11 hours plus for certain heavy jobs  - crikey I don't think I have ever collected enough data to warrant that    It is a great question though, exactly what difference do these different programmes make? For a bit of a giggle I had my ASIR stack some subs the other night when I was reconfiguring my setup for winter, nothing to lose experiment.  As with the ASI Air in general, its stacking routine is the most delightfully simply process to watch, totally intuitive and it's fairly quick. As for the results, well to be honest, I thought the masters it produced were actually very good. Certainly though, if I ever manage to pull off several hours of subs (blooming weather) I'll be sticking to PI and WBPP. 

Jim 

Guys at some time in the next few decades there will be a real likelihood of  a permeant presence on the moon. Who knows, maybe with the possibility of a having a week long holiday on the Moon - oh those dark skys, day and night!  Knowing our luck though the neighbours will have their security lights on. 

Jim 

I really like the framing you have on that, it gives the sense that you are falling into the nebula. The subtle colouration is excellent. Well done. 

Jim 

I bought an Esprit 120 ED from FLO earlier on in the year with no problems whatsoever with delivery.  The packaging, in terms of protection offered, could not really be any better. The scope itself was housed in a hard shell case, itself foam lined and heavily cushioned with a number of internal points of support. The hard case was then packed in two external carboard cartons with the inner carton again being padded with cushioning foam inserts. Optically checked before shipping and absolutely perfect on receipt.  I'd have no hesitation in doing the same again - funds permitting of course  

Jim 

@blinky I've never added scripts to my Pix Insight but I'm now getting to the stage with my processing that I'm looking to have a go with some. Would you be able to describe the broad brush strokes of how I go about it? Thanks in advance. 

Jim 

2 hours ago, tooth_dr said:

Cheers Jim. Another friend just text to say he thinks he has some 100mm or 150mm flanged iron pipe left over from a job so could be in luck.  I’ll know tomorrow when he checks sizes. 
Currently have no vibration issues that I’m aware of in the dome. No wind on the scope is one of the big advantages of the dome 

That sounds like it would work. I just went out and measured mine, it's 150 mm x 150 mm and it is as I thought earlier 6mm wall thickness. The top flange where the mount adapter is attached is a little thicker at 8mm - most likely because that is what plate off cut was available.  I image remotely too, as well as the odd bit of visual work at the pier and I've never noticed any vibration concerns; my obsy walls are pretty high,  so good wind protection all round keeps the scope out of bother. It's been there close to 10 years now I think; the only thing I have changed was to recently reposition it and lower it to accomodate a new Esprit 120 for clearance with the roof closed.  It was actually quite a good move as I had always thought it was originally a little too tall, certainly for visual - either that or I'm too short . It was easier to lower the pier to sort that one out  

Jim 

46 minutes ago, inFINNity Deck said:

There is less risk of vibrations if the pier widens towards the base. Here is my tubular pier:

The tube is 250mm in diameter, 3.4m tall, weighs about 350kg and stands on a 0.80m diameter base-plate. It is held at this base by 16 M12 anchors, not bolted down, but clamped in between nuts below and above the base-plate to minimise stress on the chemical anchors.

Nicolàs

Did you have a visit from the weapon inspectors after you took delivery of that - it has the makings of a super gun   That is a cracking pier👍

Jim 

Vibration is not the issue that it is often made out to be , all structures will vibrate. What is important is the decay time, neither a box section nor and H beam of typical height suitably secured to the base would have a sufficiently lengthy decay time particularly if the observatory is used remotely for imaging.  Like the need for a cubic m  foundation these design characteristics take on legs  

As for wind, it is more likely to have an effect acting on the telescope itself rather than the pier; so as long as your observatory walls are offering some shelter from the wind I would not be overly concerned.  Have you had any vibration concerns on your existing pier, I would imagine the dome keeps it very well protected from wind?

Jim 

Here's mine.  I had it fabricated and installed by a local agricultural blacksmith.  Basically square section tube, I think 6 mm thick with the base and webs welded on. 

Jim 

3 hours ago, tooth_dr said:

Looking to erect another pier, currently trying to source some metal pipe.

As an alternative could I use a section of H iron?

 

Cheers!

 

 

An H beam would work fine but may give you more work in attaching the pier plate, but certainly doable. 

Jim 

35 minutes ago, Gfamily said:

I believe the film (not necessarily the best film ever, but one of many people's top 5) is available on the Channel 4 Catch Up service for the next few days. 

Spoiler for the Film Name under this link

ETA - Ooops, accidentally given away that it's associated with a film. 

Good spot, guess what I'm watching tomorrow    I agree, not the best ever and a bit dated perhaps now, but it does have a cult following.  I think the soundtrack makes it. 

Jim 

This is my new setup with the Esprit 120; despite some clear nights recently I'm still waiting for an opportunity to get it into imaging mode but I've had some very pleasing visual sessions.  Spent today raising the observatory floor and putting down some new carpet tiles. Had to race to get it finished against our impending Red weather warning deluge (NE Scotland) !  I'm starting to think that I should have tanked the observatory !  Thankfully, although we get some localised flooding in the garden,  there have been no leaks or water ingress around the observatory itself  - fingers crossed.  

Jim 

It's like the universe knows we are watching and is conspiring against us.  We need to stop looking for a while then sneak  a peak  

Jim 

The full size versions are absolutely stunning, amazing detail.

Jim