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About Demonperformer

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    Red Dwarf

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    51-ish N; 1-ish W
  1. Cluster buster 18/2/18

    Nice report, but I thought the butterfly cluster was M6 in Scorpius?
  2. M37

    Yes, very nice, Alan.
  3. I've found a trip for my baby telescope

    Do that and the skies will be unseasonably dark and clear ...
  4. I've found a trip for my baby telescope

    I reckon the clouds will be just about the same.
  5. Filter technical data

    Thanks, Stu. It is a filter that blocks part of the spectrum, but I am trying to work out what it is going to do to the rest of the spectrum. The intention is to darken objects which are bright, but want to know what it will do to everything else.
  6. Thoughts on these CLR and Ha filters

    My first thought is: when dealing with ebay Caveat emptor (in spades!). I don't know the make specifically, but my caution-question would be: What are you hoping to do with them? Looking at the graph for the Ha filter, it isn't really a Ha filter as you will see the term used on SGL (for narrowband imaging, which have a 3-10nm bandwith). It is more a 'block everything below about 640nm' type filter, which is what any good red filter would do ...
  7. DSLR Flats with a Huion Light Panel

    My simple answer would be: if the histogram is in the middle, don't worry about it too much. Yes, the prevailing wisdom seems to be 1/3 to 1/2 (from the left) and 20k-30k ADU. But I have also seen posts that suggest that the histogram should be as far to the right as possible, WITHOUT clipping the data (reaching the far right hand end), as this increases the dynamic range. Truth is, I don't have a good enough grasp on the theoretical to say if this is right or not. At the end of the day, the only way you can tell if they are working or not is to apply a real set of flats to a real set of lights. But it sounds as if you should not be too far out.
  8. Filter technical data

    Just want to make sure that I am understanding what they are saying. If I have a filter, the technical data of which states "Max. transmission: 50%", am I right in thinking this means that, for an object that emits the entire spectrum evenly (yeah ... "spherical chicken in a vaccuum"!), I would need an exposure of twice the duration with the filter for the object to appear as the same brightness in the resultant image as an image taken without the filter, in otherwise identical conditions? Or does it mean that the transmission at peak-transmission is 50% and other bits of the spectrum are a lot less? Or something else ... ? Thanks.
  9. M45 - Glowing Gems

    Yes, but I would approach it the other way round. Personally, I really dislike diffraction spikes on stars and would seek a way to reduce those on the brightest stars rather than worry about the ones on the dimmer stars being too small. Just my personal opinion. Which in no way should be seen as a diminution of my other comment that it is a nice image. You have captured a lot of very faint stars in it.
  10. M95, M96, M105 and friends

    My guess would be 300s [sorry ... couldn't resist ... and let me be the first to confess I have done the same thing on numerous occasions]. On the image itself, I think it is a refreshingly different approach compared to many images of the triplet.
  11. Cone & Fox Fur wide field

    Excellent detail. Spiky ... makes me think of ice crystals forming on a window in winter ...
  12. A beautiful transit!

    Need to upgrade my sct to 14" ... and my skies to Brazilian! And I still wouldn't be able to produce images like yours! Excellent capture.
  13. M65 + M66

    I have enormous admiration for those who can produce sketches like this. Well done.
  14. M45 - Glowing Gems

    My personal opinion is the smaller the better. Nice image.
  15. Mars