Thalestris24

Anyone?

Yes, fusion 360 creates an image of a standard thread from the McMaster-Carr database but it makes it into a real thread if you check 'Model'. Unfortunately, McMaster-Carr don't include a M42 x 0.75 thread . The only alternative I've found is to use the coil tool to create a T2 thread from scratch. If anyone knows an another way, I'd be interested to hear. I used the coil tool to create a T2 lock ring. The challenge is really to print threads precisely enough so that they mate properly and work as expected! Thanks Louise

Oh, didn't know you could do that! D'uh.. I'm still a green noob! But it still sounds like trial and error... Do you by any chance know a way of adding a T2 thread to Fusion 360? I have come across references to doing this via a file in a particular folder but I don't have the files/folders that were mentioned, so unable to take that further. Any ideas on that? Thanks Louise

Any tips re the lock ring?

Hi again Neil Not sure what you mean by 'vertical'?? Not sure what you mean by 'compensating for hole size', either! I've kindof managed it by trial and error. I have been trying to modify existing T2 stl files. I've tried designing the parts from scratch in fusion 360 but there doesn't appear to be a standard thread available for m42 x 0.75, so I've tried to do it using the coil tool. Everything is always a bit hit and miss. I scaled one part (existing stl) by a factor of x1.001 and it just about fitted! Thanks Louise ps I'm still a bit stuck trying to print a t2 lock ring properly: As you can see, it's quite thin. The best I've been able to do is make it slightly small and click push it in!

Yes, I know, thanks. It's also pointed out in the assembly guide Louise

The lenses arrived from Surplus Shed today - yay! At a glance they look ok - no obvious scratches or marks. Each was individually wrapped and in its own little envelope taped to the packing note and inside a padded envelope. Looking forward to trying them out fairly soon Louise

I came across the Sega Flux and saw it briefly demoed on YouTube. It made me think it would be really cool to project on to the ceiling and be able to fall asleep under the stars (yep, I'm an incurable romantic at heart!). Anyway, has anybody got/used one? They seem quite expensive for what they are, though. Got me thinking, surely one could adapt a led projector whilst running Stellarium? Maybe need a different lens that would give a wider projection than normal. Any thoughts? Louise

Reading some of the comments here I'm reminded of Scientific American who used to do a 'the amateur scientist' column until sadly it came to an end in 2001. I used to love reading it even though most of the experiments were beyond my ability to do, often simply because I didn't have the wherewithal - always seemed like Americans had access to so many things compared to the UK. But, anyway, I obviously never saw the contents of the column as in any way competing with professional science. It was complementary, educational, and fun, and could bring scientific principles and experiments into the sphere of enthusiasts. I think I view amateur astrophotography in a similar way. Some people have better kit than others, and some have darker and clearer skies than others. But we can all have a go and have fun and enjoyment on the way. Does it matter that I can't make images that are anything like as good as most people on here? Nah, not at all. I just like messing about with telescopes, cameras, computers, software, electronics, optics etc. I'm not in competition with anyone! Louise

Hi Ken Did you actually design the L200? I see your name appears on the sample spectra I wonder what you think of Christian Buil et al's Uvex3? I was thinking of having a go at building that originally - until Robin pointed out the lack of guiding in the basic design. However, knowing what I know now, I could incorporate the Lowspec reflective slit guiding and modify the case to use the Uvex3 layout. But I doubt I'll be trying that any time soon! The Lowspec is coming along. If I get the lenses this week I could be able to do initial testing Louise

Hi Ken I take it that curve applies to the camera - grating view? Do you manage to get away with not having to change focus within the visible spectrum? Or do you take exposures in sections? Louise

Ender 3 Pros are pretty much stock items and semi kits and rather cheap already, so unlikely to be discounted. I got mine from Amazon Louise

Hi Gina I'm trying to avoid it as much as possible! Fusion 360 doesn't have an inbuilt M42 x 0.75 thread type so, as far as I know, the only way to do it from scratch, is to make one with the coil tool. Seems to work ok but that doesn't mean the printed result is good enough to mate with a purchased component, unfortunately. There must be some dark occult spell involved... Louise

One thing about sending abroad - take note of the format of other countries' addresses (Royal Mail lists them). Always put a return name and address on the reverse of a package. As for post going to the wrong country - I've no idea how that happens! But always write countries names clearly and in capital letters. Never use labels for valuable items - use a 'documents enclosed' packing envelope instead. Louise

Hi Eric Yes, superfine in Cura. I've pretty much given up trying to print them for this project... It may be, as you say, to do with the thread start - I'll check that out when I get round to it. I have problems with my eyesight and can't see small things very well. In the meantime, I'm printing nice plain inserts so I can use metal T2 tubes instead. I think in the long run that'll probably be a good idea but nothing set in stone yet. I'll see what works Thanks Louise

Yeah, it's no problem getting T2 tubes - I bought a set off Ebay by 'svbony' quite cheap. I could use them but need inserts so they can fit in the holes in the design. I'm just trying another 3D printed T2 - if that doesn't work, I'll move to the metal tubes plus inserts. It's these two: As you can see, they are quite thick compared to a metal tube so metal tubes will need padding out with an insert but at least no printed thread involved. Oh, I've had the same problem with the Ovio slit holder... Louise

Good luck to you too, Jim! I've printed most of the parts using PLA+ - seemed a good idea at the time! Of course, filament properties vary anyway. Most of it fitted together ok but had to do a bit of filing and emery papering. I'm into the last stages now - final assembly, but I need to get over the T2 thread problems. Trouble is, very small differences prevents being able to screw things in. Now the two T2 inserts, one for camera, one for telescope, might be better served by purchased metal ones. The threads would then be fine, but the outer diameter would be too small unless I could find 'bigger' ones. Don't know if they exist off the shelf… Standard female T2s would need an extra insert but that wouldn't be too difficult to do. I slightly wish I had been able to modify the original design a bit but never mind. I'll post something in my Lowspec thread when I sort it I'm still waiting for lenses to arrive from surplus shed. Louise

I received the replacement screen from China last week. Installed it yesterday and the (new) rotary encoder works properly - yay! My 3D printing quality of life has greatly improved But I'm still struggling to get T2 threads to print out nicely - not sure if it's just shrinkage or other inaccuracies. Of course, I've tried scaling to counteract shrinkage but it never comes out quite right! It may be that I have to scale in one axis, or two axes, only? It's a bit trial and error! Louise

I'm constrained by the Lowspec design and physical layout. I think Eric @ejp1684 found the aperture stop improved the image. Perhaps it was more to do with focus. When I get the lenses from surplus shed I'll hopefully have something to play around with. I've tried to fit a larger camera lens but there's no room really. Of course, I'll post my findings. I'll obviously do some basic tests without a scope first. Louise

Sorry Andrew, didn't mean to be short before - was a bit distracted at the time. I think Simspec recommends slightly larger lenses but they are difficult to fit in physically. My collimator lens fl should match the slit distance ok. I've read (well, skimmed ) Philp Massey's paper on astronomical spectroscopy . The Lowspec design has given the collimator lens a diameter of 24.5mm and fl of 125mm - that gives it a focal ratio of 125/24.5 = ~f 4.9. However, the original collimator lens aperture apparently gave blurry images and the lens holder was changed to mask the lens down to ~12.75mm giving a fr of ~9.8 (f10 in round numbers, and I understand that worked better. I'm probably going to use my f6.96 apo so I'll probably have to change the mask to give a bigger diameter of about 18mm. It's all a learning curve and I'll have to see what works best with my setup. I'll be pleased if I can get it working at all! Regards Louise

Yes, I know

The Lowspec design uses 25.4/1" (collimator), 30mm (camera) and 12.75/0.5" for the guide lens. They seem quite small diameters, in some respects. Louise

That's quite a long fl - 190.5mm, and 42mm dia? 😮 Is it a doublet? Btw surplus shed are offering random discounts over this weekend! Their doublets are usually only $7.50, but pot luck, of course. My ones might come tomorrow but could be held up in customs for all I know... Louise

I have an old Olympus C-770UZ compact with optical zoom (UZ = ultra zoom!). Only 4MP but an actual ccd! I think it has a lens of about 17mm diameter but it would be a shame to break it apart. I've not used the camera in many years. I put one of the old batteries in it, switched on, and it powered up! No card though - I think it uses an obsolete type. Oh, found a card in the case - a 512MB XD card. Anyway, I put it back into its soft case and it can sit and wait for when someone comes along to do an inventory of my belongings ha ha. No commercial value. Louise

Nothing of interest to me but thanks anyway! Louise