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About Filroden

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    Sub Dwarf
  • Birthday August 26

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    East Cleveland
  1. I know exactly how the metre is defined today and how a prototype measurement had to be used until a definition based on nature could be agreed. What I don't understand is how you can evidence that the metre varies in different parts of the world. Pointing at what things were in the past is not evidence. And just to be clear, even the historical definitions did not allow for the metre to be different in different parts of the world. They all produced a "standard" metre which was used as the benchmark everywhere. The fact that the methodology chosen could have given rise to many different definitions is irrelevant; they chose one particular method and used that to create a standard that was universal. So what evidence do you have that shows the metre varying based on location? And you still haven't provided the evidence for how mass varies with gravity. I don't need immediate answers. I appreciate these will need research and study and am happy to wait. The answer is important to me. As a surveyor and cartographer, I need to know if I've been practising my trade incorrectly.
  2. I’m struggling to find the scientific evidence for both your statements. Could you provide links. To save you time, I’ve already checked the website of the Bureau International des Poids et Mesures and could not find anything.
  3. The EQ3 DSO Challenge

    Now that's that I call red shift! I had a go with your jpegs using PixInsight to blend luminance from one and RGB from the other plus I used it's new colour calibration tool that uses the stars actual BV to calibrate colour across the image. Hope you don't mind!
  4. The EQ3 DSO Challenge

    Mixing subs from 2 cameras shouldn't have that impact. Are you stacking all the subs together or stacking subs from different cameras then restacking the results? The latter is prone to degrading the image. But if you throw it all into the same stack and use an algorythm that weights by SNR and uses a good rejection technique then it should improve the image.
  5. Double check the back focus requirement of the flattener as Skywatcher printed the wrong figure in the Esprit 80 manual. I think they updated the PDF version online.
  6. The EQ3 DSO Challenge

    I'm not much more of an expert but open both images. On the image you want to use as base, create a new layer and make sure that layer is highlighted. Go to other image and copy it. The I think its as simple as pasting it in the other image. I'm assuming both images are identical in scale, etc. If not, they need to be aligned first.
  7. The EQ3 DSO Challenge

    Can you extract the luminance from the middle and the colour from the right and recombine?
  8. M33-Red Channel Stand Alone

    I think it’s just part of the galaxy structure. It feels like it’s on the verge of being resolved rather than being noise.
  9. Using lower iso ?

    Are you saving DSS’s auto save file? That’s the best starting point for processing then take it into your processing software and stretch from there. What processing tool are you using? It does look like you have detail there just not yet stretched to make it visible.
  10. M33-Red Channel Stand Alone

    Now that’s a lot of fuzzies! It’s going to make a great colour image. I find M33 a much better imaging target than M31. It just feels more galactic.
  11. The EQ3 DSO Challenge

    Lovely images. And 8 min exposures Another advantage of the no darks strategy...I’d have spent 4 more hours collecting darks before I could even process.
  12. Reducer Myth: Some data.

    This would only be true if both images have not been stretched with a non-linear function (not true of the original images) and the upsample method did not apply a scaling function (unknown, as I don't know what function PixInsight uses to upsample). It can only work by looking at the non-linear image. As soon as you stretch the image, you're affecting the pixel values in each image differently (even with the same pre-set STF function).
  13. Reducer Myth: Some data.

    I agree. If they were the same aperture and no change to their focal lengths, the Televue would have appeared MUCH brighter (but would have been of a lower resolution). This is where I don't agree. The extra aperture has started to achieve the appearance of equal brightness. You would have to have the TOA's aperture reach 153mm (at the same focal length) to see it overtake the Teleview in appearance. On the single, unstretched subs covering the same area of sky?
  14. Reducer Myth: Some data.

    I don't think you can stretch them with the same preset. It applies a non-linear stretch so if a pixel value is higher in one image (because of the effects of the smaller focal length) it will appear much higher in the second, i.e. inflating the apparent brightness. If you go back to the linear images and crop to the same area, can you do a sum of the total pixel values in each image? I would then expect the TOA to show a higher count by 1.66x (all things light pollution, atmosphere, etc being equal). The reason I ask about the 35% brighter is that the Teleview image should appear 35% brighter because it's shorter focal length has a higher impact than the TOA's bigger aperture by that 35% amount. This is what's breaking the whole myth. You cannot discount the change in aperture. If aperture had no effect on exposure why would we desire larger scopes? Why are we building 20m+ scopes to "see" deeper into space. If the larger aperture didn't result on more photons being collected then what would be the point? In your case, that 1" increased light collection by 66%. That's not insignificant. It's just not significant enough to combat the other effect which is the different focal lengths.
  15. Reducer Myth: Some data.

    In your opinion, would you say the Teleview looked about 35% brighter?