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By stevebty
Good evening everyone
I am looking at a SkyProdigy 6 telescope for a friend. the mount had a rattle/lose part. I partially unscrewed the casing and the plastic cylinder pictured below fell out. Anyone got any idea what it is or where is comes from. Looks plastic but can feel metal in the centre.
Does anyone have a service manual or disassembly guide?
Many thanks in advance
Steve
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By Quetzalcoatl72
I'm after a cassegrain reflector but I don't know which one to buy,
I have a celestron c5 and it worked wonders for all fields, I now want the same but twice as powerful as my final upgrade
I am looking at a c9.5 for £1350 or a c11 for £2000, My question is an extra 2.75" focal worth it for £750 more?
I will likely purchase one this week
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By Welsh Dave
Hello Ladies & Gentleman,
I would in need of require your assistance for my current tube that I have got.
I currently have a Celestron Starlight XLT tube and I am looking for a new Finderscope (This one did not come with as I bought it of one of my Uni friends). I am not fussed into the red dot sites and I would like someone similar to the EXPLORE SCIENTIFIC ES 8x50.
Any questions by all means ask :)
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By Abhishek Pawse
Hi guys. Please tell me if collimation is required for the celestron 9.25 edge HD after using the hyper star system( after putting back the secondary mirror in its place ). Or it holds its collimation.?
Thanks In advance for help :)
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By andyrawlins
Here is a review and then a couple of questions to the forum
The experience I gained assessing my new Nikon Action EX 10x50s https://stargazerslounge.com/topic/369052-comparison-of-pentax-sp-50-wp-10x50-and-nikon-action-ex-10x50-cf/?tab=comments#comment-4009551 led me to dig out my old Vivitar Series 1 8x25. I bought these in 1995 for £99, so not an insignificant amount then. Series 1 was Vivitar's premium range at a time when (I believe) they were well regarded for their optics (now they seem to sell basically children's toy binoculars). Anyway, despite their price/apparent pedigree and excellent build (made in Japan) I never got on with them, finding them very difficult to focus and to keep in focus. They rarely got used and indeed got superseded for general use by the Inpro 10x50 mentioned in the thread above.
Using what I learned when assessing the Nikon's I decided that the focus problems were down to four things: 1. a small exit pupil, quoted as 3.12mm, so you need to have the eyepieces correctly positioned over each eye; 2. a short eye relief that I estimated to be about 11mm. I found the view (without glasses) to be best with the short (4.5mm) rubber eye cups folded down. Wearing glasses, it was like looking down a drain pipe with a severely vignetted view; 3. difficulties getting the interpupillary distance right: for some reason the image is significantly brighter when the binoculars are set wider than the correct distance. However, at this, what would appear to be the correct separation, they will not come completely to focus. When they are brought down to the correct distance (60mm for me) the image suddenly gets darker but actually focusses well; 4. a very 'low geared' focus wheel and seemingly very short depth of field which necessitates a lot of focus twiddling every time you change view (not for objects at infinity, obviously). Because of these things, its crucial to get the binoculars correctly positioned over the eyes and to keep them in that position. Once they are correct the image is actually not bad. To be specific, the image is almost exactly like it looks with the naked eye: the same colour balance, the same detail and resolution, the same clarity, the same brightness - just a bit bigger. Its quite uncanny really. In contrast, the Nikons give an almost hyper-real clarity, detail and brightness and as serious wow factor.
Compared to the 10x50s they really didn't seem to magnify that much (I found the objectives to actually be 23mm so 7.4x not 😎 but maybe this is something to do with AFoV. FoV is quoted as 'Wide Field 8.2°'.
So basically they magnify the image but not the brightness which is fine for daylight use but fairly useless as night. The big advantage, however, is that whereas the Nikon's are over a kilogram and will only just fit inside my zipped up coat when round my neck, these weigh a third as much (350g) and are a fraction of the size (105x120mm). They easily fit in my coat pocket.
So I think I should give them more of a chance by keeping them in my coat pocket so they are there when I need them (the best binocular is the one you have with you!).
On to my question then: does anyone know anything more about these older Vivitars: whether they are actually any good and when and why the company seemed to give up with proper optics? I can find nothing on the internet. All I have is the Vivitar brochure from the time (attached) in which the certainly seem to regard themselves as makers of 'proper optics'.
I'd also welcome comments on the issues I found and whether my conclusions are correct.
IMG_20210113_0002.pdf
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