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pleiades

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About pleiades

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  1. You are welcome Eric! About Miyauchi 100mm collimation screws, must be inside the binoculars below eyepieces as APM 100mm binoculars. It's not very difficult to align them. You just have to open one eyepiece at a time, adjust screws and cover with the eyepiece again to check the alignment. I am not sure if you will lose the Nitrogen filling. Any way the best thing will be to give us a report about it, and take and upload here some pictures, to help others.
  2. Hi Themos! I'm glad you are trying a comparison between different methods and test them. I had experimented with laser beams for collimation in various ways, and also in the manner you describe. Try it out and when finish tell us about the results, so I will describe my experience with laser beams in the past, and the effort for conditional alignment through them.
  3. Some binoculars like Fujinon, use 'eccentric rings' for collimation. Some older, use screws which lay inside the prism compartment. Find the adjustment and the fix screws. More: But usually at most binoculars the adjusting screws are outside of the barrels.
  4. Where the adjusting screws are? Pick up a little the outside material to uncover the screws. Use a jeweler's screwdriver. Celestron Skymaster Helios Quantum 4 United Optics BA8 (Helios Apollo, APM HD, TS Marine, Oberwerk Ultra etc) * Do not touch the screw marked with the yellow circle. Image on top, the screws on Vixen Ultima 9x63 Nikon Action (hex key, Allen key) Bresser 10X50 (Lidl) As you can see most binoculars has the screws in the same position. Do you have more pictures to upload?
  5. I'll just try to add here my experience from tripod ball-heads. I don't feel very comfortable with any handle on the tripod head any more, and I stopped using them. Especially I didn't like that it is near my chest, face, or I had to reverse the handles. Reversed, was difficult to control them. For long time I am using Vanguard SBH-300 & SBH-250 ball heads. Both are very good and easy to use with all binoculars. Can handled from 10X50 to APM 100 45 deg of 7.5 kg aiming to the zenith. With the appropriate tension on the 3 control knobs, work very smooth like fluid heads do.
  6. Excellent article and wonderful pictures! I don't remember if I have seen something so nice written on the Internet.
  7. Steve, Manfrotto's specifications are for 4,5kg. Usually I load up to 2,5 kg with easy. I also have tested it, with 4,5 kg and was OK. But I have never observed all night long with this weight to see if there are weaknesses . I believe if somebody wants to load a little heavier than 4,5 kg can improve it, using a metallic blade to support more weight, like this in the picture.
  8. Hi Alan. At summer I usually spend some weeks near the sea and I like to observe sometime all night long. Trying different set-ups of tripods, parallelogram with tripod and weight, monopod etc, and after some years, I have reach a conclusion and I use a Manfrotto Double articulated arm and a beach lounge chair with success! - The articulated arm: 396B-3 Manfrotto 396B3 Double Articulated Arm, 3 Sections - with Camera Bracket - I also use a Super clamp to securely mount it on the chair: Karlu Photographic : Manfrotto Super Clamp 035 [035] - £22.46, Bowens, Colorama, Interfit & Lastolite Pro Dealers - and a ball head for smooth movements. Because of the lounge chair inclination I observe at zenith with no pain at neck. And no more tripod, weights and heavy equipment. Map, red light, and you are ready for hours of effortless observation. And a sleeping bag just for a short nap under the stars, later!
  9. I can confirm that it also works with inkjet transparencies. It took me only one minute to cut the outside with scissors. Brilliant idea! Thank you again Steve for the advice
  10. First I like to thank you Steve for the great idea you have to use inkjet transparency!!! I didn't tried it yet but this was my purpose when I first asked if we can find any improvements in the procedure. Collaboration is a great thing. Yes, you have right. As I can see if we want to test with a street lamp must be hundreds meters away and strong, so to be as crisp as it can and create spikes. But never will be as good as a star. Those are good news! Your description is very accurate Steve. Of course because I am a little "sensitive" with miscollimation and usually I spend hours in observation, I am trying to fix also small misalignments to avoid fatigue. But this is something personal and everybody can have different tolerance in miscollimation. To tell me how easy is the conditional alignment with the "crossed Bahtinov" technique will be a precious information. For me is easy to align my binoculars this way, and I hope also to be for you all. As regards the name I thing you have already found a descriptive name better than I can! Mark, Peter (Psychobilly) has right. I use Bahtinov mask when I test binoculars. Before some days I tested an Helios Quantum 4 20X80. I found a matter with the width of focus, and was not easy to tell if I was at the right focus for the test. Using a Bahtinov the problem solved easy. Thank you all for the time you have spend already to this. I will be glad if somebody else will try it and review it.
  11. Thank you for the warm words! I hope you will find the time a cloudy night to make 2 masks from paper and review it on another clear night. I have to know if you propose some improvements, or if it was easy for you too to find miscollimation and/or fix conditional alignment. Try it, you will not regret it.
  12. Good question! Because I observe stars, usually I test collimation with stars. But for just checking the method here, of course you can use an artificial star as far away as you can, or farther a pinpoint strong street light, or farther away a star. The only thing we need is the light source to be bright enough to create spikes. In any case at the end check with a star. But to adjust collimation definitely use a star.
  13. Easy and simple! Never thought about this. I suggest to include a lot of info like this in your site Steve, which is difficult to find elsewhere. Thank you for the tip.
  14. Hi David, I don't know if there is an accurate method without opening the binoculars and measure the light path through prisms. Anyway to create a Bahtinov mask for this test, it is not necessary for the focal length to be very accurate. So for a general measurement, we can measure A) the length from the center of objective to the eyepiece. Then measure approximately the length of light path through the prism. (Must be something around 90mm for 8X40 - to 130mm for 20X80. Divide the light path through the prism length by the glass refractive index of 1.57 i.e. for a 130mm/1.57=82.80mm. When these two measurements A) + added together, is the total focal length of the binoculars. I have to repeat here that the accurate number is not necessary. And unfortunately, I don't know an easier method to measure the focal length in binoculars. One more example A) measurement is 160mm for a 10X50. is 100mm/1.57= 64mm A+B=224mm this is the focal length of those 10X50 binoculars. I hope I didn't make it very complicate. @Moonshane @Rik Thanks
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