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Adam J

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Everything posted by Adam J

  1. Adam J
    In general I don't think that you would use both dark flats and bias at the same time, in so far as I am aware you use one or the other and for CCD's the choice is BIAS. Using both might be tripping APP up a little.
  2. Adam J
    Honestly no, not that one anyway. I will admit that I am going by his TV appearances mostly, but he seems to spend most of his time saying the same thing in 50 different ways, so that if you got it the first time it gets annoying. I am a physicist myself so perhaps I am looking at it with a different perspective to the masses mind you. Honestly now sure but I do know he did not believe in quantum theory so maybe not. Adam
  3. Adam J
    Brian Cox ? the BBCs expert in dumbing it down. You would be better off with Hawking I think.
  4. Adam J
    Welcome to imaging with a Newtonian, did you really think that it was going to be as easy as a ED80? Now imagine doing the same thing but needing to be more accurate in colimation due to using a much larger sensor. I think that if you are mostly after perfect stars then you are better off with the ED80, but its a slower scope so you wont get the faint stuff in the same detail or as fast as you do with the 130PDS without longer integration. I would be happy with what you have here. How was your tracking it looks like you might have had some drift across the image as a whole? The only other thing I would note is that the most likely reason that you are getting different results between the two colimation devices is that they are being held differently by the stock 2inch clamp as discussed before. Adam
  5. Adam J
    I would expect it to do quite well not quite so well as a heq5pro but better than a eq5 and much better than a eq3pro. In Ra the gears have more in common with the heq5 than the eq5 or eq3.
  6. Adam J
    Problem is that with only two screws you will get tilt also as you tighten up the corrector. I added a third screw to get even pressure around the barrel and stop it from tilting. You also have to tighten them evenly in small amounts like with the head gasket on a car . Same procedure with the colimation tool or you will tilt that. If none of that then as above check the primary mirror clips.
  7. Adam J
    Exactly. Screwing it too tight, although I have only seen an example that was with a baader click lock. The optics are very snug to the metal barrel. Adam
  8. Adam J
    Yes. I have also seen an over compressed coma corrector cause this. Adam
  9. Adam J
    A couple of my recent efforts with the 130PDS the top one is a Bi color of the heart consisting of 70x240s Ha and 70 x 240s OIII using my ASI1600MM Pro and 5nm Astrodon Filters. The Second image is 100 x 30s Lum and 40x 30s RGB per channel on M42. Thanks for looking, Adam
  10. Adam J
    which way is gravity pointing in respect to the image taking camera orientation into account? How are you attaching the camera? Just the original two thumb screws? Have you checked the tension / preloading on the draw tube? I would say this is tilt but need to know the above to be sure. It would have to be quite bad to cause issues like these on such a small sensor. It cant be spacing alone or you would have the same problem in all three corners. Adam
  11. Adam J
    Consider placing a washer between the secondary screws and the holder. The holder is alu so the screws dig in after a while making adjustments difficult.
  12. Adam J
    Depends on what camera your using. Smaller the pixels the harder it is to track. SO..I suspect that some people who find it works perfectly well for them are probably using a large pixel camera such as a 450D (5.2um) , a 1000D (5.7um) a 6D (6.54um)....etc. On the other hand with a ASI1600mm pro and 3.8um pixels, pushes a unmodified HEQ5pro and your better off with belt mods if you want to consistently get round stars. Adam
  13. Adam J
    I still think that with your size of sensor you will have no issues with the Baader MPCC MkIII you wont see much difference with the more expensive corrector on the 130PDS its more about if you want to get that F4 scope in the future along with a larger sensor. But I do understand you wanting to future proof your purchase.
  14. Adam J
    Did you decide which CC your going for in the end?
  15. Adam J
    I dont use a heater, I do use a dew shield. It has to be very high humidity 85% before I have problems and that is usually associated with poor transparency anyway. I have only had it dew up once this year and I suspect that was because I needed to remove the dew shield to refocus with the mask. I think that some of this is to do with using a obsy though and I do remember it being worse before I got the obsy. I would see how you get on with a dew shield before you go to the trouble of adding a heater to the secondary. The most important mod is that you, cut the focuser tube (unless you get the ES corrector). Adam
  16. Adam J
    Are we talking about this one? https://www.teleskop-express.de/shop/product_info.php/info/p1151_TS-Optics-70mm-f-6-ED-APO-Refraktor-mit-Carbon-Tubus.html This was a year or two back and it may have been the older glass with FK61. However the one I linked is not fpl53. Am not convinced fpl51 is much better than FK61. I imagine you would still get some CA if the ZS71 is anything to go by.
  17. Adam J
    A friend got the TS carbon tube ED and I can tell you that the CA is horrendous.
  18. Adam J
    Any data cable worth its salt will be sufficiently well shielded that a power cable wont effect it. Just think of the cluster of cables behind most PC's.
  19. Adam J
    Problem is that the perfect focus position in the center of the image is not the same as that on the edge of the image. So assuming that you focus on the center perfectly the edge may well still be within your critical focus zone.....but its much close to the edge of that zone than the center, hence the coma issue in the corners. As such I would argue that its possible that a smaller temperature change than 6c will show in the corners of the image, but as I noted above maybe not in the center star FWHM. I guess the way I understand it is that the Airy disk is not the limiting factor in resolution. For example the Daws limit for a 130PDS is something like 0.8 arcseconds from memory. My pixel scale with the 130PDS and the ASI1600mm pro is about 1.25 arcseconds per pixel. Adam
  20. Adam J
    Do you focus with a mask? I can certainly see the change from the start of a session to the end if I start at 7pm and end at 4am..a refocus every 2 -3 hours is certainly worth while to me. The second thing is that the place you see it is not so much in the FWHM but the correction of coma in the corners of the image. I note that as my focus drifts the corner stars become more egg shaped as the coma corrector only works in the far corners with perfect focus. Some people actually focus on a star offset from the center of the image to mitigate against this. Finally its worth while mentioning that such fine changes in focus are much more apparent on my small pixel mono ASI1600mm pro than they will be if your working with say a Canon 6D at the other end of of the pixel size scale. Adam
  21. Adam J
    Ill disagree with you that you would not have to refocus a 130PDS between 15c and -10c insulation or not. In fact I would say that adding insulation to the tube will just prolong the cool down time of the scope something that is not desirable at all. I see differences in focus over only 2-3 degrees of temperature drop. Hence why everyone purchases expensive auto focusers. I think that most of these CF tubes are around 5mm thick so there you go.
  22. Adam J
    The carbon fiber is not for stiffness its for superior thermal expansion properties that means you hold focus better. Many premium scopes use CF such as the ES Comet hunter.
  23. Adam J
    I think that the biggest factor is the larger flat field that can cover a full frame camera.
  24. Adam J
    People who cant colimate a newtonian and dont like diffraction spikes. Its got to be said thought that this is all without the use of even a premium 4 / 3 element coma corrector etc. My personal thought on the matter is that a premium edition of the 130PDS with premium focuser and a carbon fiber tube would sell very well, I would buy one at any rate.
  25. Adam J
    The tube will not fall out if that is what you are worried about, it is physically impossible. You just have to make sure that you have tightened the thumb screws sufficiently and it will not move. I hang a ASI1600MM pro and wheel from mine without any fear.
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