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Stub Mandrel

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Everything posted by Stub Mandrel

  1. Stub Mandrel
    Thanks Vlaiv I had another go using more or less that approach, although they had all be given the same stretch in Fits Liberator.
  2. Stub Mandrel
    I found this, which is rather unfair on the MPCC as increasing the back focus should bring it to the same as the others (which are all possibly spaced a bit too far):
  3. Stub Mandrel
    Those shapes are definitely coma, shaped like the reflection of light slanting into a mug of tea! Exacerbated by poor collimation which is probably why they all point pretty much the same way.. Have you got a coma corrector?
  4. Stub Mandrel
    I can see that being an issue. Planets and the Moon are always a good standby when conditions are tricky.
  5. Stub Mandrel
    I've got some decent data for the two ends of the veil nebula. As you can see my first crude attempt is a bit iffy, although I can align it OK. What's the best way to proceed? I'm cautious of spending ages on one approach when I could have taken an easier route. How much processing should I do before I combine the images? Should I combine as individual layers or combined into RGB images? I have Ha, Sii and Oiii for each half, all the same amount of data and reasonably consistent ( more moon and better flats for the second session). Here's my crude first attempt:
  6. Stub Mandrel
    Should have a 12V power adaptor.
  7. Stub Mandrel
    Deliveries from China have been shot to hell by Covid, so most importers are working on long lead times. They are generally rather frustrated as demand for hobby equipment is booming...
  8. Stub Mandrel
    That made me curious, here are my counts since January 2014. I only really started regularly in 2015, and many of my early attempts went undated. 2014 - 3 (actually quite a few more) 2015 - 40 2016 - 43 2017 - 42 2018 - 66 (12 nights in June alone!) 2019 - 41 2020 - 18 to date There's tendency for me to push my luck if things have been thin (so I might a short hour or two's window for some planetary or lunar) , and to run out of steam if there are long periods of good conditions. My only blank month is February 2017. But on the whole, a consistent 40 days a year of actual imaging (not opportunities).
  9. Stub Mandrel
    Try downloading CCDinspector
  10. Stub Mandrel
    Two completely new versions, right from the 'bottom up':
  11. Stub Mandrel
    There's a lot of threads here and on cloudy nights but no obvious resolution. I'm going to reduce the dynamic range of a flat by half and see what happens. I've tried a star reduced version and done another round of selective colour (followed by reducing saturation). These are worthy experiments as I want to add the eastern half as a mosaic, then I will have to reprocess the colour of the whole image. But better do some work for a bit...
  12. Stub Mandrel
    Other than stretching, the top one is pretty much as it fell out of stacking. For the others I've done selective colour but nothing else. I'm not happy with the flats, I'm getting 'ASI1600 flat overcorrection syndrome' - described by many and it seems never solved. If today goes according to plan I will take a new set as I haven't touched the setup.
  13. Stub Mandrel
    Hopefully this is the start of a new mosaic. My new 33mm spacer seems to have come up a bit short as there some poor star shapes in the corners. Printing a new spacer an extra 0.5mm thick. Really not sure what's right. The lovely green bit at bottom left in the first image seems to be an artefact. I still can't get a 'muddy yellow' in my hubble... I'm interested in which colours folks prefer, and why.
  14. Stub Mandrel
    Good stuff!
  15. Stub Mandrel
    Here's one, there will be cheaper on eBay I guess. https://www.amazon.co.uk/Micro-Third-Olympus-PL10-PEN-F/dp/B083JHLVXL/ref=sr_1_1?dchild=1&keywords=olympus+em10+t-ring&qid=1595872226&s=electronics&sr=1-1
  16. Stub Mandrel
    They are very fussy about spacing, try moving it outwards in steps of 0.5 to 1mm, if the coma is more or less away from the centre. A small amount of tilt will become insignificant when adjusted spot on.
  17. Stub Mandrel
    You could use a depth micrometer or the tail end of digital calipers to measure how high the lip is compared to the surround. Obviously the paint finish will limit the accuracy.
  18. Stub Mandrel
    Hi, hope you don't mind, I took a screen grab of your image and pasted it as an image in Photoshop. I cropped off the dotted line, created a mask to exclude the galaxy and ran gradient exterminator. This balanced the background colour to a neutral dark grey. Then I applied a flattened S-shaped curve to brighten the faint parts fo the galaxy (but not the very darkest bits) while not blowing out the stars. You need to experiment. Then I ran an 'increase star colour' action 2 or 3 times. It coudl do with noise reduction and tweaking to smooth the background, but you get the idea. It's worth you persevering with your original data, 99% of the hard work is processing!
  19. Stub Mandrel
    I think I'll have a go at my unconventional 'floating mod'... kill or cure!
  20. Stub Mandrel
    Sorry Michael, The autofocus mechanism is all before the mirror; removing the internal filter does not affect the autofocus mechanism. This is the fundamental reason why you need to make a correction. You said a clip filter could work - it most definitely won't help with autofocus. I've found the Baader filters and they are too costly given the risk of breaking the camera. My main question stands... what distance do I need to reduce the shims by - not having the original filter I can't estimate it and the only figure I could find assumed a thinner filter was used to replace it.. ... but I've been given an idea by this discussion: slightly reduce the height of the mounting pillars, insert a rubber grommet, and treat as a 'floating' sensor adjusted by trial and error.
  21. Stub Mandrel
    No... the autofocus isn't affected by removing the sensor glass as it uses the image reflected up to the pentaprism. If you use a clip filter the focus point will change to compensate so the sensor image will still be out, compensating glass needs to be behind the mirror.
  22. Stub Mandrel
    I will revisit them both, but in a few days with fresh eyes.
  23. Stub Mandrel
    Good point... it need to be a=bout 1/3 of the filter thickness, can anyone tell me what that is? I doubt it as it would be in front of the mirror and affect the autofocus as well. It needs to be behind the mirror. Hmm.. problem with a filter is that for another £20-30 I could get an unmodified one..
  24. Stub Mandrel
    There are three pairs of screws around the base of the focuser. Loosen the larger locking screw and tighten or loosen the small adjuster and re-tighten the locking screw. If you do this with cheshire eyepiece you have eliminated tilt when it maintains collimation throughout the movement of the focuser. Tilt should show as the mirror centre spot drifting away from the middle of the view as you move the focuser over its whole range.
  25. Stub Mandrel
    Portrait version with just 30 subs.
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