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Dave1

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About Dave1

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    Astronomy, Motorcycles, Theology, Philosophy , Music.
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    Dorset, UK

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  1. Hi folks, I'm having a clear out of astro items I no longer use. In this thread I will offer up for sale eyepieces I don't need anymore. There is a mixture of .965" eyepieces and 1.25" eyepieces. Most of the eyepieces for sale are Orthoscopic and most of the 1.25" eyepieces are Circle T one eyepiece is Circle V. The 0.965" eyepiece simply say Japan, on them, which I'm lead to believe means they are Circle T. There is one 2" eyepiece for sale which is GSO Superview 2" ERFLE 50mm ( Classic ERFLE 5 lenses in 3 groups ). I have one GSO Super Plossl 32mm. The Super Plossl 32mm the rubber has a
  2. Won't allow me to edit original post. This telescope is now SOLD.
  3. What AZ mount do you have? (edit, just read the bit where you state which three AZ mounts you have, ignore the question ) My Altair Sabre 2 as delivered to me had bad stiction on the AZ axis. The solution was to take it apart, clean what very little grease there was off And I regreased liberally with Halfords Bikehut Teflon Grease. Never had a problem again. These mounts really are quite simple, don't be afraid to get stuck in, if you are competent with tools. Dave
  4. I think where the confusion comes is the mix up between angular airy disc size and linear airy disc size. Like in the link John posted. If you compare the linear airy disc size of F7.5 to a telescope of F15. The F15 linear airy disc size will be double the size airy disc. That's according to Sedgwick. But don't ask me to do the math! David
  5. I've read a few different websites on this subject. That has to be one of the best well written easy to understand explanations I've ever read. Great share John, thumbs up from me. From my understanding. Comparing like for like aperture, at the same magnification the slower telescope has a bigger airy disc. Which is definitely an advantage for planetary viewing. David
  6. Still for sale, if anyone is interested?
  7. If you click on this link https://stargazerslounge.com/topic/341473-takahashi-starbase-80/?do=findComment&comment=3832402 you can see all the tests that have been done by Wellenform, which is who APM Markus Ludes in Germany use to test there telescopes. And Wolfi at Wellenform really knows his optics. This test was done on behalf of the French astronomers. It has a Foucault test, Diffraction test, Wellenform report technical conclusion, Strehl ratio achieved in specific light rays F, E, D, C. Going off of the tests the French had done by Wellenform, these are not cheap entry level optics,
  8. It means to draw/sketch to paper what you can see at the eyepiece. Can be just a normal HB pencil, charcoal pencils, or colour pencils. Easier to start of basic though. You tend to see more details on the disc as you sketch. Sketch doesn't have to be fancy. The below is an example when the seeing was very good, even though Jupiter was below 30 degrees. Note north and south are up the written in the wrong places. That was drawn using a 80mm F15 telescope. In this photo of the sketch you can see north temperate belt, north equatorial belt, festoons coming off the north temperate belt, dark
  9. Yes I'd like to buy this telescope, but not at the moment. Bank account needs to recover. I really like the Scopetech 80mm F15. The Foucault test, strehl ratios for different wave lengths, and spot diagrams are very good to excellent. Agreed a 4" F15 needs a serious mount, and any bigger must definately have a big mount. I might have a John Owen 6" F12 doublet coming my way. Thankfully I have the mount for it ! David
  10. A good 3-4" telescope can show a good amount of detail, if you practice and get your eye in. The more practice you get, the better. The more details you will see. One way to increase your observation skills is to sketch at the eyepiece. David
  11. Well some more eyepieces arrived today, to add to my collection of 0.965" eyepieces. From left to right. Takahashi Ortho MC 7mm, Pentax Ortho 6mm, Takahashi Ortho MC 5mm. Have to say they all look impressive build quality. And I can't wait to test them on Jupiter along side my CZJ O-10 which I haven't used yet. David
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