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About digital_davem

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    Star Forming

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    South east London

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  1. Hi I'm after a Mak 127 OTA, keeping missing out on ebay auctions. I don't need a mount. However, you're a long way from Bromley where I live. If I offered £150 to cover insured postage, would you be prepared to wrap the OTA in a load of bubble wrap and stick it in the post?
  2. Re: True FOV v Apparent FOV again

    Hi digital_davem,

    Out here in the Arabian desert, one can feel a bit astronomically isolated! I was out camping in a beautiful area of rocky and sandy desert last weekend. Amazing because recent rain had led to a brief sprouting of grass and the Bedouin had brought their herds of camels into the area to graze. I set up my small refractor on top of the huge dune we were camping on only to see clouds beginning to obscure the view!! Out here, clear skies are the norm, (but you do have to be careful when the wind whips up the sand and dust). I did get some nice views of Jupiter at least. A (photographic) friend queried when I explained that I was changing to an eyepiece with wider AFOV. I trotted out the stock answer about the difference between TFOV and AFOV, but quickly ran into difficulty when he persisted in asking why!! French philosophers used to say if you keep asking why about six times (or ten... can't remember!) you always run into God!!!

    I loved your questioning thread on this topic a couple of years back... By the end, I think you were theorizing that a telescope objective optic (lens or mirror) may produce a maximum illuminated circle. That the real difference between EPs with different AFOVs was how much of this maximum illuminated circle they could usefully use? With better quality (more expensive) optics and size, their field stop could be set wider giving the wider fields of view? Did you ever get to the bottom of this? Could you summarise your current understanding of the 'real' difference between TFOV and AFOV for us relative newcomers who still struggle!

    Thanks again

  3. Given the amount of slop, i wont be locking them at all. Still don't understand why there so much movement. I don't think k the gears in this thing would be much use in a clock or watch....?
  4. When the locking clamps are unlocked, is the worm drive doing anything - it feels like it is bypassed.
  5. Makes sense. So the movement is in worm drive rather than the main bearings?
  6. Hi I'm not sure what to do with the counterweight on an alt az (it's kind of obvious on an EQ) so I screwed the bar into the top mount and put the weight in the middle. It does help - now I can nudge with the clamps unlocked reasonable smoothly and it doesn't drift under the scope's weight. It's very usable like this. I still don't really understand why such a huge mount isn't rock steady, though. There should be zero movement with the clamps locked. Given that a simple cheap camera ball head is completely steady within its weight limit it doesn't say a lot for SW's quality control.
  7. Very nice, looks exactly like my Prinz 660 before I refurbished it. They can easily be upgraded to use standard 1.25" eyepieces by swapping the visual back. Someone should preserve this classic...
  8. Hi Knighty I wish I could be so sanguine as you, but my experience has been very disappointing. Example: observing Jupiter. I line up the planet in my finderscope and lock down the mount. Jupiter in smack in the middle of the eyepiece view. I then adjust the focuser - the resulting movement is enough take the planet entirely out of the field of view of the eyepiece. Or when "nudging" with the clamps unlocked I position the planet right in the centre of the view, then let go of the eyepiece and it jerks to some other position. It can end up anywhere in the field of view, usuall
  9. Hmmm... the only reason I bought mine at all was because of the problems I had with previous mounts and the assurance that the skytee would fit the bill and would be "rock solid"....
  10. Hi I got my Skytee just over a month ago and have had a small problem with movement of its axes. Basically, there is about 1mm of play in both the main axes with everything clamped down as tight as can be. This shows up without a scope mounted: just gripping the "T" and twisting back and forth with my hands reveals a sudden movement. I've sent videos to the supplier and obtained permission to attempt to tighten it up without risk to the warranty. However, how to do it? I've seen talk of grub screws and lock nuts and the like but it would be handy if anyone has a step by st
  11. Had a brief outing in the garden last night before it clouded over. Seems to be quite a lot of movement in both axes of the Skytee. Even with everything clamped up tight, if I grab the eye piece and wiggle it, the objective end wobbles up and down about an inch! Not smooth movement but simple slop. I know the Skytee has a bit of a reputation of being quirky but is this just an adjustment issue or should I be thinking of returning it for replacement?
  12. Just to stay off topic for a bit longer... A black hole event horizon marks the point where gravity is so fierce, light would have to exceed the speed of light in order to achieve the escape velocity necessary to get away from the black hole. As light can't go faster, it is the cause of not being able to see what it is going on in that particular region. The expansion of the universe at a rate greater than the speed of light is another cause of not being able to see what it is going on in a particular region. In both cases the seeing problem is a limitation produced by the ligh
  13. Thanks. That makes sense in that it explains why I prefer the crispness and "look" of views at 100x compared to 150x with scope. I'll try some double stars to see if the higher mag works better.
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