Classic mount with modern refractor
Posted 12 September 2013 - 03:00 PM
I can now mount my Sky Watcher 100mm ED to Zeiss T-Mount which originally came with Telementor (click on image to get large version):
Need to check it under the stars yet. But it should work, 100ED has the focus only 6cm longer. And the weight of the tube is just a little bit over the Telementor's tube. It can still be balanced with one conterweight. I do not know why, but ED100 seems to be much bigger than Telementor although the measures are almost the same.
Should be a sweet combo, I can still easily lift the setup and navigate through the doors to my backyard. And ED100 reaches just one magnitude deeper than Telementor. It counts from light polluted site as is my backyard.
BTW, do you know why Zeiss picked up a diameter of 63mm for their Telementor lens? The only thing that came to my mind is that it reaches exactly one magnitude less than 100mm telescope. The ratio of lens areas is 2.52, and the difference in light intensity for two stars one magnitude apart is 2.51. Could this be a reason for 63mm diameter? Or is it just 2.5in size (63.5mm)?
Posted 12 September 2013 - 03:31 PM
Having recently acquired a TM-Mount, I now have a spare T-Mount. As the Zeiss GEM also works great in alt/az mode, I would like to use it for our Intes Micro 127mm mak, and also a 60mm Carton refractor we have.
It's difficult to find the right size dovetail to use with the T-Mount here in the UK. I understand Astro Physics used one of a similar size for their Traveler Scope, which is no longer made. Did you have a special dovetail made to use with the Skywatcher rings ?
Posted 12 September 2013 - 04:04 PM
yes, this is a special dovetail plate. My brother made it for me. Normally, I'm using ED100 on AZ5 alt-az mount but I started to like Telementor with its equatorial mount more and more, so I wanted to have an option to use it with my larger scope. What I like on Telementor is that with simple 1 minute mount alignment I can effectively use the declination setting circle to find the targets (first, I use water-level to level the mount, then I just set the declination of Arcturus, +19deg, and I move the mount in RA and around the main pole in such a way that Antares is in the middle of the FOV).
When I'm looking for an object, I just set its declination and then I just roughly point the telescope to it. I can usually very quickly identify the star field using Uranometria 2000.0. This works very well for me in light polluted sky even without finder.
Posted 12 September 2013 - 10:17 PM
Posted 13 September 2013 - 01:15 AM
Posted 13 September 2013 - 04:36 AM
Since last summer I was left at home with only alt-az option for my larger refractors. Now I can run ED100 on equatorial mount again. I think it will be a great help for the upcoming Jupiter season. It really helps when you need to touch the mount just in one direction during making a sketch.
Posted 13 September 2013 - 08:30 AM
Posted 13 September 2013 - 09:09 AM
Posted 16 September 2013 - 01:19 PM
Posted 16 September 2013 - 02:22 PM
BTW, I just had quick look on Moon yesterday. The weather was bad, haze around Moon, clouds, and it was clear that it will be just worse with time.
Still the view through ED100 with TMB16+TV2.5x (141x) was very nice. The combo is usable but little bit shaky. Luckily, the OTA is equipped with dual speed Crayford and I can focus with just light touch. Otherwise I would not be probably able to focus properly at all. Although the scope is just a little bit longer and heavier than Telementor's OTA, the difference is unfortunately quite large.
Posted 16 September 2013 - 02:38 PM
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Posted 22 September 2013 - 03:46 PM
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Posted 23 September 2013 - 05:22 PM