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About kbrown

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  1. kbrown

    3D Printed Spool Holder (off topic)

    Yes, I felt a little silly for printing a print for the printer to be able to print better prints :D Anyway. The accuracy of the prints is a variable. It depends on the printer itself, the diameter of your nozzle, the layer height, the shapes you're trying to print and the orientation of the object you're printing to name a few things that'll affect the accuracy. For example with a large nozzle the tight corners will be more rounded. This may or may not be a problem. With higher layer height you loose some detail too. And of course the more detail you want, the slower it'll print. But with some care you can get around these problems. This was all printed at 0.2mm layer height (including the internal and external threads) with a 0.4mm nozzle. Took a little trial and error to find suitable tolerances for the threads to work smoothly. In practise I had to model the tolerances into the threads before printing. Same goes for the hole/shaft diameters where the bearings go. My printer seems to be fairly accurate on external diameters but internal diameters end up a tiny bit too tight so I have to factor that in in the model too.
  2. Okay, not directly astro-related but since there's a few of us using 3D printers here I though I'd share this with you. I essentially got tired of failed prints due to some cardboard spools (namely Realfilament) not rotating properly on the non-rotating stock spool holder of my Prusa i3 Mk3. The fails were mainly due to excess force required to pull the filament off the spool causing the extruder gears to slip and sometimes the filament just didn't go past that point at all or momentarily. The print (extrusion) just either stopped prematurely or there was bad layer adhesion here and there weakening the finished print. So I decided to design and print a spool holder with tapered bearings. The holder will sit on the "roof" of shelf I have my printer on so it's not going to cause any vibrations to the printer frame either. Here's what I came up with:
  3. kbrown

    DIY Refractor

    I'll definitely look into that one at some point. Just ordered a 0.6mm and 0.8mm E3D V6 nozzles. Should help a little...
  4. kbrown

    3D printed Solar Tracker/Compass

    I like it. Has that sort of retro feel! What filament is that light brown one you're using for the main bits?
  5. kbrown

    DIY Refractor

    Just checked the times from the gcode files. The front tube was 21 hours, back tube 15 hours and the middle bit 8 hours. Yes, I definitely should get a bigger nozzle as well. At the moment I only have 0.4mm, 0.25mm and an experimental 0.15mm, which I haven't tried yet. These were printed with the 0.4mm one and 3 perimeters which is one above the default (slows things down too).
  6. kbrown

    DIY Refractor

    Thank you! I've only had one proper imaging session with it so I can't really say for sure. Didn't notice anything worrying though. Even my dew heater worked okay wrapped around the printed tube. I can't remember the exact printing times but the front and the rear sections took about 24 hours and the centre bit less than 10 hours.
  7. kbrown

    Tripod Tray (on steroids)

    Thanks guys. Yes it's not the best solution but it's not the worst either. Mine is the SLIK 504 QF-II. It came with a video head which I have removed completely as that was the main source of flexures. I've attached the Star Adventurer wedge directly to the height adjustment centre pole which I always keep at its lowest position to minimise any remaining flexures. I may even look into permanently fixing the pole in this position somehow. Here's what the original tripod looked like:
  8. kbrown

    Tripod Tray (on steroids)

    As some of you already know I've been recently concentrating on getting my smaller DIY refractor in a usable state. I already can use it with my DSLR but ultimately I'd like to be able to use it with my Atik 383+ and QHY5L-II mono cameras and my (DIY motorised) filterwheel. Ultimately I'd like to also motorise the focuser on the scope and be able to control that via INDI like I've done on my 10" newt in the past but that's something for the future. All this of course presents some additional challenges especially when trying to keep everything reasonably portable. Would be great to be able to fit everything in a single large rucksack. This thread will be mostly about building a tripod tray for my old SLIK camera tripod I'll be using with this scope. The tray will be a platform for things like a Raspberry Pi or similar for running the INDI server for the cameras, filterwheel and gps plus a power source for all of these and dew heater(s) etc. Here's a rough idea I'm thinking of at the moment: The green parts I've already printed. The white parts (three of them, one of them hidden above to show what's going on) form the tray itself. The reason why it's split in parts like this is that I intend to 3D print them to keep the weight down but due to limitations of my printer I can't print the whole thing in one go. Most of the tech bits and bobs and wires I'll try to hide under the tray.
  9. Here's the first few proper tests with my recently finished DIY refractor. More on the project here. At the moment I'm only able to image with my unmodified Canon 6D. Was surprised how well it actually did. The plan is to be able to image with my Atik 383+ with LRGB and NB filters. Some more work is required though before I can do so.
  10. kbrown

    DIY Refractor

    Do you mean baffling? I didn't put any in this scope but I did add flocking material in front and behind the lens in the cell and in the dew shield (not in the pics) and also inside the focuser tube. Since the objective lens is now fully AR coated and the main tube is black, I didn't feel there was any need for additional baffling.
  11. kbrown

    DIY Refractor

    Thank you. Indeed I am pleased. Will take me a little more work to get it usable with my Atik and Filterwheel. Shouldn't be too hard and the result should be even better. Indeed I did get the focal length from PixInsight's Photometric Color Calibration which said it is ~497mm. Not too far off from my 500mm guess :)
  12. kbrown

    DIY Refractor

    Finally got to test this thing properly. Here's Andromeda shot with my unmodded Canon 6D attached to the scope with the field flattener. I cropped the original image to 3k x 3k then resampled down for web. There was only tiny bit of vignetting in the corners of the full image and everything was in focus. The polar alignment or balance was probably a little of as the stars are no quite round. Other than that I'm pretty pleased so far
  13. kbrown

    Artificial Star from a led light torch

    Thanks Chris. I did start wondering about this after my last post. I then had a look at the hole I made under a USB microscope and it actually wasn't even all the way through. The light was just shining through a very thin layer of plastic so this is another downside of just using plastic -> it might not be opaque... Anyway carrying on with my experiments I pushed a needle through the plastic just enough to feel the tip on the other side. I then took a piece of 1mm fiber optic and pulled it slowly under heat to thin it out as much as possible. Took a few attempts but I managed to get it hair thin in one end. I then pushed the fiber optic through the hole and cut and sanded it flush to the front of the cone. This resulted in a very round light dot. It's just a bit too big now after all my attempts. I'll probably try the same again but with a thin sheet of aluminium or brass like you suggested in front of my 3D printed cone.
  14. kbrown

    Artificial Star from a led light torch

    Had a go at it indoors with my diy 70mm refractor. The light was only about 4-5 meters away so I don't know if this tells me anything useful other than I've got dust in my optics . I had to add an extension to be able to go both sides of focus. Took these images through a 10mm EP with my phone. Guess the chromatic aberration seen here is typical for an achromatic objective... 1) Inside focus 2) At focus 3) Outside focus
  15. You could have it printed for you. For example here: https://www.3dprint-uk.co.uk/

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