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Altair ULTRAFLAT Eyepiece

Discussion in 'Eyepieces, Barlows, and Filters' started by Mak the Night, Apr 3, 2019.

Altair ULTRAFLAT Eyepiece

Started by Mak the Night on Apr 3, 2019 at 4:16 AM

63 Replies 1185 Views 0 Likes

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  1. Mak the Night

    Mak the Night Well-Known Member

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    Those finders sound heavy. I usually just use a reflex, or sometimes a straight-through on my 127mm Mak and 150mm Newtonian. The zenith, or near it, can be a bit of a challenge though. Two inch widefield low power eyepieces can be a solution, or possibly a zoom.

    k7QTqBk.jpg

    This is the ST102 with both finders and the Baader Hyperion zoom. The AZ5 seems to handle it all and I'm getting some dexterity back into my right arm and hand, so when the sky soup finally clears I may get to use it on the zenith.

    Screenshot 2019-05-01 at 19.20.52.png

    I may have to wait about a fortnight, but the BBC Weather app said it's definitely going to get better. I don't believe them ...

    Happy Beltane!
     
  2. Gabby76

    Gabby76 Well-Known Member

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    The Antares and Stellarvue finders weight 0.54kg (19oz) so a bit heavier than a standard Synta finder.
    The difference is they have helical focuser and 1.25"prism diagonal and the ability to turn the diagonal if needed without misaligning it.
    There is also no plastic in them :)
     
  3. Mak the Night

    Mak the Night Well-Known Member

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    HALF A KILO? :eek:
     
  4. Mak the Night

    Mak the Night Well-Known Member

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  5. Leonard

    Leonard Well-Known Member

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    No, mine did not come with a compression ring.
     
  6. Mak the Night

    Mak the Night Well-Known Member

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    I ordered both rings (ED72 & ED80) from FLO on 1st of April but the ED80 ring hasn't arrived yet. FLO reckon I should be getting it soon though. Apparently they're more or less made to order in the UK.
     
  7. Leonard

    Leonard Well-Known Member

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    I bought mine 9 or 10 years ago from Orion of USA. I was looking for a grab and go scope for my Vixon Porta Mount. I bought that mount a few years before the scope because I had a scope I wanted to use as my grab and go. But even though the scope came in under the weight classification and limits if the mount, it wobbled and moved incessantly.

    The Vixon techs assured me the two would match. I even send the the specs of the scope I planned to use. Yet when I asked for some relief they said no.

    So, I saved up and hunted for a scope to match. An 80mm F7.5 was perfect. But I didn’t want an achromatic scope. I went with the APO.
     
  8. Mak the Night

    Mak the Night Well-Known Member

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    The Synta ED80, f7.5 is an achromat (doublet), but it has ED glass. I nearly bought an ES 102mm triplet but the OTA with tube rings weighed over 5 kg. And that's without diagonal, EP and finder. So I went with the Altair ED doublet which was a kilo lighter.

    For visual an ED doublet is probably as good as a triplet, I think it's only with AP that any real differences show. I use an SXG tripod with my Porta II. It will hold 5 kg pretty easily.

    https://www.firstlightoptics.com/vixen-mounts/vixen-sxg-hal-130-tripod-sx-gp.html
     
  9. Leonard

    Leonard Well-Known Member

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    I believe your correct in and ED Doublet performing as well as a Triplet for visual use.

    I don’t think our eyes (or at least my old eyes) can discern s difference. That and the issue of sky conditions will also make any differences minot.

    And since I am wholly a visual observer, I felt putting any more money into a triplet was a waste. A larger aperture might have been a decision. The Orion company sells several larger doublets that receive high reviews. But as s grab and go (even if the economics added up) the larger aperture presents problems in that I would have had to purchase a larger mount.

    Finally, my ED 80mm enables me to consistently reach mags as high as 200x on a good night. I have actually pushed it higher, but beyond 200x the image breaks down. Under normal sky conditions in West Virginia, USA (which is about 300 due west of Washington DC) I can reach mag of 150x to 175x. I do fight light pollution from a near by freeway, US Rt 50, and a close by street light. But when that pollution is somewhat negated when viewing planets.

    In all my 80mm ED Doublet is a fine scope.
     
  10. Mak the Night

    Mak the Night Well-Known Member

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    I can believe the ED80 can reach 200x. I could often get that on my old ST80, although conditions will dictate magnification usually. I've been looking at my notes for this time last year. I was using the ST80 often for Venus and Jupiter but the humidity was hindering any magnifications above about 100 - 130x on Jupiter.

    We had a very cold prolonged winter last year which was often referred to as The Beast from the East as it was mainly blown from the Ural mountains. It's not uncommon where I live to get cold winter blasts from the Russian Steppes as I'm at a very high altitude above mean sea level. I live in the country but there is a town about a kilometre to the north east of me which can produce some LP especially when the transparency is poor due to heavy humidity.

    H7dkbBJ.jpg

    I got turned on to the Synta ED doublets after buying the ED72. Synta are a bit coy about what the doublet actually consists of. The crown is Schott but no one really knows what the flint (Abbe number of 50 to 55 or less) consists of. On the ED80 it is Schott/FPL53 Ohara which also seems to be what is utilised on most of the other Synta-made scopes (Sky-Watcher, Orion et al). My guess is that the flint is some indigenous high refractive index glass, probably manufactured in Taiwan or China. Like I said earlier, FPL53 Ohara has more or less become a marketing term now, and is synonymous with high quality. Either way, the ED72 is every bit as good as the ED80 optically.

    4ZhPo9M.jpg

    The 72ED is a nice scope for rich field but with a focal length of only 420mm is a bit short for any lunar/planetary observing. I can't really point the ED80 at the zenith without adding the pillar to the AZ5. It's not a difficult job to set it up but it does complicate things for me. It is a good all rounder though.

    IMG_20190505_174916.jpg

    I just wish the bloody carrying case was a bit lighter lol.


    https://www.oharacorp.com/index.html
     
  11. Leonard

    Leonard Well-Known Member

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    It’s a very nice looking case, but it looks heavy......lol.

    I have several different scopes: 3 reflectors, an achromatic refractor, 2 SCTs. Most work well in a particular area, but my 80mm gets the most use. I believe it’s due to my age.

    I’m 65, and even though I’m in good health, ease of set up and take down is an important issue for me. Also, and probably more important, I have learned to be satisfied with a nice, crisp view at lower mag. As a younger amateur astronomer, I was enamored with high mag and large aperture. I don’t think I caught aperture fever, as my largest scope’s aperture is 200mm. But I always pushed the limits. Now I am content with a well produced image.
     
  12. Mak the Night

    Mak the Night Well-Known Member

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    Yeah, the case is Jason Statham hard but I'm physically disabled and it can get heavy. I like a challenge though lol.

    85d8U3R.jpg

    So far, this year, these two scopes (ED72 and ST102) have been the most used. Basically as they are the easiest to take out and set up. The ST102 is difficult to beat for rich field although it's not ED.

    uIEypKV.jpg

    In a couple of weeks I'll set the EQ5 up and cover it with a tarpaulin as usual. Once the EQ5 is set-up it's easy enough to take the 150mm OTA out to it. I've only had the ED80 out once this year. I'm still waiting for the visual back compression ring.
     
  13. Mak the Night

    Mak the Night Well-Known Member

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    The ED80 compression ring was finally delivered!

    ring1.jpg
    It has a slightly lower profile so may give slightly more in-focus.

    ring2.jpg

    Seems to work well.

    mirror.jpg

    It certainly makes it easier to rotate the diagonal.
     
  14. Mak the Night

    Mak the Night Well-Known Member

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    1fx.jpg

    And fits in the case better with the Baader adapter!

    2fx.jpg
     
  15. Leonard

    Leonard Well-Known Member

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    So, does that ring enable u to rotate the diagonal? Do u have to loosen the screws to rotate the diagonal?
     
  16. Leonard

    Leonard Well-Known Member

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    My 80mm has a single speed Crawford focuser. But it has been sufficient for my needs. I have a 2” helical micro focuser insert I purchased from Orion a few years ago for my DOB. I can use it in my 80 ED, but never felt the need.

    It did wonders for high mag focus work with the DOB. It’s a 200mm F6 Reflector and was able to provide nice high mag views, but the focuser was a rack and pinion type. I had problems obtaining critical focus at high mag. The most economic fix was the 2” helical focuser. It was a 2” inset and did a very good job. I later updated the focuser to a single speed Crawford and kept the insert. At high mag with that DOB it was still useful.
     
  17. Mak the Night

    Mak the Night Well-Known Member

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    Yes, it's just a compression ring, I have to slacken the screws slightly to rotate. I'm partially paralysed in my right arm and hand so I have limited dexterity. Most of my diagonals have slight nose tapers and won't just pull out when the compression ring is slackened slightly. It does enable me to rotate the diagonal enough for a comfortable viewing position. The ring makes it smoother when it is being rotated and holds it more securely.
     
  18. Mak the Night

    Mak the Night Well-Known Member

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    I have a Baader T-thread helical focuser I usually use on my 150mm Newtonian as it has a single speed Crayford.

    IMG_20170218_143827.jpg

    Although it does alter the focal plane slightly. Talking of Crayfords, as far as I know John Wall never patented the design.

    https://en.wikipedia.org/wiki/John_Wall_(inventor)

    Both of my Evostars (ED72 & ED80) have stock two speed Crayford focusers. They're pretty good which is why I'm reluctant to replace them with rotating focusers like my other refractors.

    pX4sJYh (1).jpg

    I have some diagonals with helical focusers.
     
    Last edited: May 14, 2019 at 4:25 AM
  19. Leonard

    Leonard Well-Known Member

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    Cool.

    I have a now discontinued Meade LXD75 with tubular legs. It supports my Celestron 90mm, F11 Achromat. It’s a really good match. The LXD75s were often paired with the Meade 5” and 6” achromats and comparable reflectors. So, it easily supports my 90mm. However, that 90 has a standard rack and pinion focuser and I can’t move the diagonal without greatly loosening the screws. It’s s 1.25 focuser.

    Sometimes it’s a real pain.

    But, views of planets at approximately 160 to 175x are very clear. There is very little chromatic aberration I believe due to the long focal length. Plus the stability of the mount is such that focusing with the rack and pinion is without noticeable vibrations.

    My only complaint is how at times a GoTo GEM mount will put the eyepiece in a difficult location. I can normally overcome this issue by loosening the focuser screws, but it’s a pain.

    Maybe I’m spoiled. Lol.
     
  20. Leonard

    Leonard Well-Known Member

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