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Fo_Cuss

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About Fo_Cuss

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    Nebula

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    Home engineering, understanding the relevant fundamentals - otherwise, pretty much everything.
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    Aude FR

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  1. I understand. However, at a fundamental level, the best prospects have been achieved. I would certainly modify my baffle assembly method, for a second attempt ... but that's normal when prototyping. The most important aspect is that the scope epitomises 'the black abyss of nothingness'. Consequently, I am of high hopes that, whatever colours are presented to the lens ... these will have the best chance of being recorded. Hahaha ... probably too much blue (I'm led to believe). Anyway, we will all see, soon enough. For a project of this scale; there is no point in hi
  2. Yes, it is a good image of the moon Expectations for my scope performance are very high. It is now 90 f/1000, flocked, baffled, and damped at each interface. Initial confirmation testing, produced very encouraging results - remarkable focus capability, with images now in full colour. However, we will see what we will see...
  3. The scope (generic refractor 60 f/700), at that time was in fairly original format, with a few minor improvements and Omni Plossl's ... but still not at all ideal (with a poorly ground crown). I'm fairly sure that Venus was out of focus - ie. operator error. It was our first stargazing attempt, and with such a wobbly scope ... gaining focus was problematic. The moon ... it was classed by the astronomer sites as being 'unviewable', due to its proximity to the horizon (on that date and time). We had a crack at it, because it was there in plain site. Venus (if that's what it wa
  4. From this consensus, it is likely to be the case that most of the gains to be had, are closest to the eyepiece. For my scope, I have gone for all out elimination of stray light, to the extent of creating a cone of flocked baffles down the tube. It is currently in an unfinished state, but I have had a scope at terrestrial objects, and found that the images are now highly colourful (as compared to being previously dull and washed out). I have found that all flocking material does reflect some light, particularly at very fine angles (skimming across the surface). Conse
  5. You may be right. Sadly ... I was quoting the Wiki opening paragraph, which annoyingly takes a different view to your own. https://en.wikipedia.org/wiki/Airy_disk Let us not forget that Wiki has a long and proud history of being incorrect Either way, delving a little deeper is never a bad idea. 1. R Nave - I would suggest starting here, because the subject is explained in an extremely simple manner, referring to a diagram: He doesn't specifically state 'best focus', but rather : "that is the best that can be done with that size aperture" ... (best focus?)
  6. If you can't get hold of recommended flocking material... In the meantime, you can get experimental Acquire card, or rigid plastic sheet, that will self roll to the interior of the scope. If initially, it doesn't perfectly self-roll ... you can train it, by rolling the material into a slightly smaller diameter. In this way, when it springs out, it will grip to the tube. Once you have cracked this setup phase, you can experiment by apply different materials to the transport material. Find a light to point your tube at, and look down the other end. See which materials
  7. Ahaaa! The mystery of the rings of light, around stars, has been solved Here is Polaris (the earlier image after denoising): I was reading a paper by Roger Ceragioli, discussing how he observed Sirius B with a 145 mm refractor. In it, he described using an aperture mask, as recommended by double-star observers such as W.R. Dawes. "It alters the diffraction pattern of stars from the normal bull's-eye pattern to one in which a bright star shows the Airy disk, but with the diffraction rings mostly suppressed." Boom! Further research indicates that the diffra
  8. Baffle Assembly & Testing Preparation We can cast our minds back to January, when the final roll of the Baffle Transport Mechanism was completed. The BTM had been put on the back-burner, in the hope that the lighter gauge inox sheet would offer an easy 'self roll' option. It didn't! All the effort would have had to be reproduced. Surely easier, the second time around, but even still.... The task was enormous, and the challenge hadn't changed. In fact, it was worse, because the first attempt was begun under blissfully ignorant conditions (perfect wh
  9. Flocking like a pro ... before getting baffled Stray light absorption I tried Black 3.0 on the inside of the scope tube. The problem is that it doesn't perform that well with 'low angle' glancing light. Rather than being absorbed, the photons merely bounce off the surface. It is excellent for small difficult areas (so it is definitely worth having, and using). However, for the tube section; material flocking will absorb a greater proportion of the photons. Having said that; the 'bouncing bomb effect' still persists... Hence, for those who are wanting to create a sco
  10. OTA Assembly Three pairs of clearance holes were drilled, equidistant around the 60mm - 100mm adapter. The surface around these holes was severely abraded, using a grinder and emery cloth. Six nuts were to be bonded over the holes, so each was also roughed up. Six screws were wrapped in cling-film, prior to the nuts being assembled over the cling-film. In pairs, two part epoxy was rubbed into the abraded surfaces of the adapter and nuts ... enabling the nuts to be bonded to the adapter. When each pair of nuts was sufficiently cured, the s
  11. Pan Handle Hahaha! What else do I call it? The scope pans and tilts, and ideally needs a handle for both operations. This one deals with the panning operation, so ... it's the 'pan handle' Sourcing the material One really needs a recycling centre that allows exchange. Bring something in, and take something out (for repurposing). This 'life balance' pays dividends (is it a game?) It has got to the stage, where I now expect my needs to be fulfilled. There was a beautiful 'big' piece of angle iron in the centre of the skip. It was there just to tempt me
  12. Tilt Damping Washers & The (perfect) Spindle Bearing Tilt Damping Washers Easily and quickly made, once the leather has been staked out. A new blade in the Stanley knife, is best for tough hide. Then a hole punch to suit the clamp screws. The (perfect) Spindle Bearing This requires PTFE sheet - 0.4mm should be ideal, assuming the sloppy play in these bearings is universal. Determine the bearing circumference, and height. Cut the strip of PTFE short in circumference, by 2mm ... and short in height by 4mm. Wrap the PTFE inside the bearing tube
  13. Horizontal Azimuth Damping Pan Gauge Two extra spindle clamps Horizontal Azimuth Damping Do you remember those old leather boots that you threw in the back of a cupboard? ... it's payback time Top right ... you can see where the leather was removed. This is strong hide leather, 2mm thick. While you are at it, remove the tongues ... they are 1mm thick. The leather appears to be in an unusable condition ... but this all changes, when washed and scrubbed in warm water. Stretch the leather pieces out on tenta-hooks (or cable clips ) L
  14. The Azimuth Mount - Created Anew ! Someone is watching over me It must be the case, because I fell upon some beautifully soft, box section mild steel. Oh ... I needed it, as I was going to use angle iron (which is a different beast altogether). Just thinking about it, makes me thankful. I could cut it like butter with a hacksaw, or jig saw. Here it is being cut, after marking out : The plates cut, drilled, and formed : What's the formed curve for ? Hahaha! A moment of madness, when I thought " c'mon ... add some form over function " I
  15. A daft error - Misaligned lock shaft clamp So there I am, examining, and thinking about the azimuth mount (what a heap of....) I'm actually considering how best to reinforce the slanted 'U'. With the scope being extended, there will be an increased 'twisting' force, centered just above the lock-shaft clamp. The primary force will be along the scope clamp centre line ... but this will passed to the legs of the 'U' ... finding the weakest point, which is the horizontal centre line of the legs. Obviously, the rigidity of these legs must be increased ... but we
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