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Piero

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Everything posted by Piero

  1. Quick solution,for the time being they are on top of the nylon pins. See video.
  2. Absolutely! The problem is not really the lack of contact between 0 and 5-ish Deg of altitude. The problem is the difference in support that the mirror receive from the bottom. The point is that even if the mirror is supported by all pins of the triangles (all pins touch the mirror), this does not guarantee that the mirror is well supported. If the pins touch the mirror at the same time at the same altitude (0deg ideally), then the support is expected to be identical or close enough.
  3. Very low altitude, probably 5 degrees. You need to raise the telescope very gently. I laid down with the mirror box above me, and then pulled it towards me very gently, raising the telescope. The video shows this. The mirror touched the pins of the 2 lower triangles, but the telescope needed to be raised another bit before the mirror was supported by the pins of the top triangle. Adding 1 pad reduced this gap, although there is still a little gap left.
  4. John, here is a photo of an original Glatter sling attachment. As you can see, it is attached to a roller which can slide up and down according to the mirror plane. Together with the velcro strips, the sling remains in place and in the correct position. It's a great design really. The sling does the job, not the person who needs to assess the correct mirror height. Also, that design prevents the sling to squeeze the mirror (and therefore astigmatism). My telescope also works, but this just because of the wood platform holding all the components (mirror, sling attachments, etc). Still in
  5. Thanks Gerry. That's an interesting idea as it minimise the amount of strips, and therefore potential side effects from these. I should do the same. At what angle are these two cruces attached to the mirror? Thanks John. Yes, in my telescope the collimation bolts adjust the alignment of a wood base on which lay the triangles, mirror, sling attachment, sling and edge supports (for safety). This is not generally the case though. In almost all mirror cell designs I've seen, the collimation bolts move the triangles up or down. I think the range can be up to 1 inch
  6. Further tests on the Glatter sling cable. There are several ways to install a Glatter sling. Here I will focus on the 180 deg (or "U-shape") installation. There are a few important aspects to pay attention: the sling must be placed slightly below half of the mirror thickness (see "h" in figure). The exact value can be obtained here http://www.cruxis.com/scope/mirroredgecalculator.htm . For my telescope, this is 17.75mm. the sling must be attached with some vecro stripes, so that it remains in place. These stripes should be minimal in order to avoid
  7. Personally, I would upgrade the telescope rather than getting a coma corrector to be used with that telescope. Then, yeah, at F5 I would use a coma corrector, especially if using eyepieces with 70 Deg AFOV or more. Not everyone, and here on SGL very few, would though.
  8. Looks good! Are the plastic covers open at the bottom? P.S. I also keep the small ladder and ramps in the living room, although these are stored in a corner and barely visible (as they are covered by the dob!).
  9. Looks great! .. and I second what Stu said above.
  10. Thank you! i think it is important to be sensible and accept some compromise. If partners have their own space and hobbies, then we can have ours, respectfully, without causing arguments. in my case the living room is rather large so keeping the telescopes there is not an issue. Actually the opposite, as they make it feel less empty. The other side of the living room has almost only things of hers.
  11. Great scope, Paz! F7 Is a nice focal ratio for refractors as colour is well controlled and wide field views are possible. I know you said that you don't plan to use 2" EPs, but a 30mm like the APM UFF weighs about 550g and can offer you slightly more than 3 deg of sky, which is great for scanning the milky way. Just a comment of course.
  12. I agree! More seriously, the shroud is on to minimise dust going to the mirrors. Taking the telescope outside takes a couple of minutes, as I don't need to assemble it. Once outside, I leave the fan on for 30m-1h, sometimes also while observing. Taking the Tak outside is also a quick process. My lovely girlfriend has never complained about the telescopes in the living room. She actually said that they look beautiful there. Her mother was a bit shocked by the size, but I assured her that I won't store larger telescopes in the living room.
  13. When an eyepiece undercut is a problem, I use some black tape (the type that is used by electricians) to make the barrel flat. That's it.
  14. With that focal ratio, I wouldn't get anything longer than 31mm focal length. If money is a concern, I would go for a 24mm 82 deg (e.g. Explore Scientific). Alternatively, 31mm TV Nagler, 26mm TV Nagler (second hand market), ES 30mm 82 deg), APM/Lunt 20mm HDC 100deg. If you really don't mind the cost, you could consider a TV Ethos 20mm. Many people love it. Personally, I'm very happy with the APM UFF 30mm.
  15. Hi @foffof, I have both the 3.4mm and 2.4mm Vixen HR on Sale, if you are still interested.
  16. That's quite a long wait! Glad to hear that it's all working well.
  17. Great report Gerry! I was out with my dob on the 30th Dec. Really pleased with the views of M42 and other targets. Also glad to hear that the pushfix adapter is working well with you.
  18. When an eyepiece weighs more than 1 pound, I personally prefer that the barrel is 2". It feels safer on the focuser to me. Having the whole eyepiece set with the same barrel size also eliminates the need of reducers.
  19. +1 for the wheelbarrow handles! My 12" f6 has them too. It is a pleasure to take the cannon outside and inside easily.
  20. As part of my equipment reduction, I'm selling the following items: Vixen HR 3.4mm (like new) £200 Vixen HR 2.4mm (like new) £200 1.25" Lunt Herschel Wedge (prism, ND filter, and wedge housing structure like new. Locking screw requires tapping and threading. Hence the discount) £80 SOLD The Vixen HR are the best eyepieces I have ever owned. A few members on CN matched them with the Pentax XO. No light scattering and incredibly sharp. In my opinion colour tone is neutral and sits in between the Docter UWA and my Zeiss Zoom eyepieces. Eye relief is comfortable if spectacles
  21. I used the milk carton solution on the central bolt for smoothening the az axis of my SW 8" dob. It works well. Off topic, but something similar can be done to improve the movement of the thumb screws adjusting the secondary mirror.
  22. Interesting thread and I agree with the points raised so far. I bought both new and used in the last years, and never had a problem with items bought in the second hand market. Sometimes, selling can be frustrating though. I find a bit irritating when I advertise something at a honest price and buyers still want to make offers (e.g. large discounts or £5/£10 discounts to cover the shipping costs). Thankfully, most of people just accept a "no", but some can be rather persistent. I remember a member who repeatedly sent me PMs saying that I would never have sold my items at that price,
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