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Thalestris24

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Everything posted by Thalestris24

  1. It's ok - I sorted it. Problem was caused by loose rollers under the bed. Thanks anyway Louise
  2. Maybe not completely out of focus but made worse by the reflection. I adjusted the focus and used a translucent plastic sheet as a diffuser. I think the focus is still off a bit. CWL? My focuser on the Lowspec is dreadful... I hate having to use it. I'll definitely have to reprint the slit assembly. I'm tired - going to bed now. Thanks for your help. Louise ps Working in my living room I can't keep dust out - can but try and keep it to a minimum. All the optics have dust on it...
  3. I set the grating back to normal mode but it looks completely out of focus now. Surely it should still be in focus or close to it? Louise
  4. I think this one is maybe a bit better. I took the slit assembly out. I noticed that when looking through from the illuminator side that the bottom of the slit was being cut off! I've taken the illuminator out so this image is without it. Bin 1 this time, just the illuminated wall, 15s. There is still a tendency to cut off the very bottom. It's looking like I'll have to try reprinting the slit holder body... Another thing I noticed from looking through from the illuminator side is that if tilt the assembly such that I'm not looking through the slit itself, I can still see the cfl bulb. Maybe this is what's causing the ghosting? Maybe it's not an issue with a less bright source. Louise
  5. Oh, I see what you mean now. I mentioned I had problems with the slit to Paul earlier. Louise
  6. Here is 30s exposure, bin 1 (cropped), 30s exposure As well as the ghosting/reflection there is an obvios difference between top and bottom. I'm wondering whether the grating is not vertical ie leaning at the top or bottom towards the camera. Louise
  7. Hiya It's not stretched but it is bin2. I'll do another with a longer exposure. What does that mean - 'not aligned with the grating grooves'? Louise
  8. Hi Ken Vignetting could be a problem - I'm not sure. I just took this image of the zero order (20um) from the camera. It shows up the reflection problem very well. Do you think it's something to do with the reflective slit? I've tried masking off both sides of the slit with some card but it doesn't make any difference. So it must be something else... Louise
  9. Oh ok - I have the modified holes now. I've tightened/loosened the spring. The main problem is that I can't get a smooth movement. I count that as a small problem since I basically leave it on the 20um slit at the moment. Do you think I might have a problem with the slit illuminator part? I reprinted it to match the modified holes. I'm trying to take an image of the zero order at the moment but can't seem to focus on it - it's 'optically' rather distorted with ghosting even against just my illuminated wall. Something is amiss - I just don't know what. The focusing mechanism is very stiff which doesn't help. Louise
  10. That's a very clean line! I'm envious... Is that also a 20um slit? How come it doesn't show the slit angled ends? (Clearly visible in mine). My holder mechanism doesn't always place the slit vertically and in the same/right place. I'll try imaging the zero order as well. Louise
  11. Here is CFL spectrum, taken with the 183M, bin 1, 1s exposure, 20um slit. I think it's a bit sharper than before. There is still some widening / blurriness at the bottom (=top?), as seen above. Louise ps I've bought a Nitrogen spectral tube. I just need to put together a power supply to try it. I think they 'strike' at 2kV but I'm unsure what they normally run at. Maybe a fluorescent tube ballast could be used? I think they strike a 1kV pulse but then drop down to below mains voltages. If anyone has any experience of using spectrum tubes and knows how the power circuit works, please let me know!
  12. I think this is about the best I can do(after tightening) though it doesn't look right, It seems to 'flare' towards one end - maybe that's to do with the light source - a cfl? Anyway, after dropping it again earlier, I have try and get the camera attachments back on the body... Louise
  13. I've set up a mini guide scope and camera. This is the first slit image I took: Doesn't look good, and maybe overexposed. This is an image after attempting adjustment: Better? Adjusted focus and reduced exposure. I have terrible trouble trying to decide on focus or not. Any idea how I might get rid of the ghosting / multiple images? Is it caused by the reflective slit? Louise
  14. Looks very unappetising to me! I cook mostly plant-based food but don't have any need to make it into shapes! Louise
  15. Oh ok. I'll bear that in mind! Thanks Louise
  16. I have a small 45 deg mirror that I made before I'll try a finder first and see how I get on - I'd rather do that than hunting around for the zero order. Will post my result . Louise
  17. Ok. Hmm... I'd have to take the grating out to do that - or maybe I could just use a mirror. It's 2:30 am here now so I'm turning in for the night! Thanks Louise
  18. Um, I meant how best to adjust the collimation lens? When I try to get the best focus it's not been easy to get a sharp image so was wondering if that might be due to the position of the collimation lens? Maybe there's another reason... Thanks Louise
  19. Hi Ken How are you? Um, not really. Having put the Lowspec back together after it fell off the scope, I've been struggling to get a clean calibration lamp spectrum. I changed the Atik over to a qhy183m which is much more sensitive and easier to use. But I've been getting a lot of 'ghosting' with the image. I've been trying to improve the calibration source by putting it in a holder with a slit. It doesn't seem to help if I diffuse the source. Not done anything with it today. I've been struggling with adjusting the focus also. Can you remind me how I check collimation? Is it by counting the number of pixels from the illuminated slit? Thanks Louise
  20. Ideally you need to test the focus on a distant object. If during the day then maybe a couple of km or more - but you will still have to make a small adjustment to then focus on stars/infinity. The Moon is always good if you can see it! Louise
  21. It may do - I couldn't say, I'm afraid. You need something that will have the right optical length so that you can get focus via the prism. I've no hands-on experience of fitting or using an oag. I take it the oag is for a long focal length scope? Louise
  22. Hi It looks like the fitting is t2 rather than the usual 1.25". Maybe you can remove part, or all, of the t2 barrel and fit a t2 to 1.25" adapter? hth Louise
  23. Well it looks like tightening the under bed rollers seems to have fixed both problems - wobbly bed and loose adjusters. If so, I won't bother with new springs just yet. Doing a quick test print. I don't have anything big I need to print at the moment. I have been thinking about reprinting the Lowspec lid so might do that in the near future Thanks everyone for all your help, advice and ideas! Louise
  24. Now then, it looks like I have to go back to the assembly/bed adjustment... My bed is wobbly - I always thought that was normal - d'uh. Having done some research, it looks like I need to adjust the rollers. I think I probably also need to do something with the springs but must get the fundamentals right first! Louise
  25. Ok, I tried tightening up all four nuts. However, that leaves the nozzle about 8mm above the bed... The vertical home position of the nozzle is fixed by the position of the microswitch. I can't see any way to move that up so I'm pretty much back to square one. Looks like the only way to get the right height is to loosen the springs again. Louise
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