Dismiss Notice
New Cookie Policy
On May 24, 2018, we published revised versions of our Terms and Rules and Cookie Policy. Your use of AstronomyConnect.com’s services is subject to these revised terms.

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 1974 Views 0 Likes

Reply to Thread Post New Thread
  1. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    Last edited: Apr 20, 2019
  2. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    449
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    At least the green barrel makes it stand out a bit!
    Hopefully you can evaluate it soon.
     
  3. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    449
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    The Meade HD and Celestron X- Cel LX are the exact same eyepiece.
    I have a good laugh when I see people comparing them. :)

    The APM UF have a good reputation so if the Altair is the same it should be a nice eyepiece.
     
  4. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    It's been suspected that the Meade HD and X-Cel are the same eyepiece with different housings for a long time. I'm not absolutely sure though as there seems to be some differences in the series and I don't think they have exactly the same focal lengths. I'm pretty certain the 12mm Meade will be more or less the same thing. I'd bet money the APM and Altair are the same. I'm not the only one to suspect this. The Altair are more convenient to order for me though. I've known their stuff to be delivered to my door the day after ordering.

    ZmOofUT.jpg

    I'm pretty sure this is the same as the Sky-Watcher 8-24 zoom. But this comes with a groovy plastic tube case. lol
     
  5. Leonard

    Leonard Well-Known Member

    Joined:
    Feb 1, 2019
    Posts:
    94
    Trophy Points:
    18
    Location:
    West Virginia USA
    That’s a good one.

    But as far as astronomy equipment company decisions go, most of what seems to me as strange, is simply a marketing decision. What can or will sell under what label. I often have to remind myself, for the companies this is a business. IE, why did company “A” discontinue that eyepiece series? Or redesign a bad product but keep its name. And on an on. To the company it is a decision based on projected profits.

    I often use my plossls. Though my favorites are the 5 lens Meade series 5000 Plossls (not the currant HD) which per our conversation are not true plossls. They have been discontinued for a while, but I love the 60 degree FOV. And they provide me with nice, bright, contrasted views.

    I have the 26, 14, 9, and 5.5 mm. I have been looking for the 20mm for a while, but no go. I often use them with my Orion 80mm ED, F7.5 APO.
     
  6. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    449
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    The Meade and Celestron are the identical eyepiece, no suspecting needed :)
    It is common practice for a retailer to change focal lengths by a slight amount to make it seem different.
    Have you ever noticed that William Optics telescope objectives are 1mm larger than everyone else?
     
  7. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    Celestron kept the X-Cel name (more or less) and produced these.

    lx.jpg

    The originals were a bit dodgy, although I never owned one. The 'LX' makeover EP's are very good. I think marketing is a thing in itself. Its main function is to separate you from your spondoolies.

    fPqfz1n.jpg

    Yes, I think these Bresser are the same. My 5.5mm was a borker but I have a bino pair of the 20mm. I also have the 14mm and 9mm.

    https://www.bresseruk.com/astronomy...ces/bresser/bresser-pl-20mm-60-1-25-inch.html

    I reckon they would be good in the ED80. Speaking of which, I've ordered a visual back with a compression ring for my ED80.

    R755VzW.jpg

    I ordered one for the ED72 as well, you can see it above.

    d8b5T85.jpg
    It makes rotating the diagonal a lot easier. Plus, it's cheaper than buying a Moonlite focuser lol.

    https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-synta-skywatcher.html

    I'm still waiting on the ED80 one. They have a different thread to the ED72 so aren't compatible.
     
  8. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    You're probably right, I just don't know. I'll do a shoot-out comparison of them eventually. I don't know about WO, I just thought they sourced from someone who made odd sized objectives lol. Why does my Altair 102mm refractor have exactly 714mm focal length? Apart from the fact it gives it a perfect f/7 focal ratio.

    kRySNUT.jpg
    I'm fairly convinced these dielectric diagonals are made by the same OEM. Altair have one without carbon fibre side plates that's more or less the clone of the APM.

    Screenshot 2019-04-23 at 17.31.29.png
    I got the Altair a bit cheaper than retail as it wasn't the one I actually ordered. I suppose they just wanted a sale lol.
     
  9. Leonard

    Leonard Well-Known Member

    Joined:
    Feb 1, 2019
    Posts:
    94
    Trophy Points:
    18
    Location:
    West Virginia USA
     
  10. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    Well, it came today.

    alt1fx2.jpg

    Daylight tests in the ED80 seem OK.

    alt2fx.jpg

    The eyeguard rolls down nicely. I'm not so sure of the claimed 16mm eye relief. Seems more like 12-13mm to me. I can believe the 65° AFOV although they may be rounding it up a little.

    alt3fx.jpg
    Similar in overall size and appearance to the 19mm TV Panoptic. I'm still ambivalent about the safety barfs.

    alt4fx.jpg
    Size comparison with 15mm SuperView, TS Planetary HR and Celestron Luminos.
     
  11. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    hd601.jpg

    Yep, could be identical light trains.

    hd60xl.jpg
    The focal plane seems identical between the two. I reckon I could use them as a bino pair!
     
  12. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    449
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    f/7 for ED refractors is considered a cutoff point between using 53 or 51 (and equivalent) glass.
    If shorter use 53, longer use 51.
    I hope Skywatcher has not started a trend with all of this green anodizing going on this year lol. It seems everyone wants to be like Tak and TV with things black and green.
    How are the views with it? At least the lines should not really catch anything unless your compression ring has a bend in it. They look a bit more for show than anything.
    Give the Meade and X-Cel a try in the BV, you should not notice a difference.
     
  13. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    I'll take your word for it. You know I'm going to ask you to elucidate on this, right? lol

    Ordinarily I would have just posted the video of 'Fashion' by David Bowie or something. But admin would remove it as being irrelevant. So you'll just have to sing it to yourself. It's either fashion, marketing strategy or a combination of the two anyway. Or maybe Synta et al got a deal on green anodising. Speaking of anodising, my ED80 visual back/compression ring is being anodised as I write this. I should get it soon.

    The safety barfs (kerfs) are just as effective as the Baader ones. No bloody use at all. I've only daylight tested the 15mm ULTRAFLAT but it seems very good. Ergonomics feel right and the image was bright and crisp.

    I'm bound to try this at some point lol.
     
  14. Leonard

    Leonard Well-Known Member

    Joined:
    Feb 1, 2019
    Posts:
    94
    Trophy Points:
    18
    Location:
    West Virginia USA
    That’s s new one for me. What is 51 glass... etc.
     
  15. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    I think Gabby's referring to the FPL53 ED glass element in my 102mm Starwave.

    nR7YldQ.jpg

    I don't know much about this though. I think Japanese FPL53 ED Ohara made glass is as close as you can get to fluorite glass without it actually being fluorite, which is apparently prohibitively expensive. I'm guessing the O'harry chap in Japan knows he's doing. I suppose for doublets with focal ratios greater than f/7 they can use Tesco glass or something. I mean, who'd buy a doublet slower than f/7 anyway lol?

    MEvOLO9.jpg

    Oh ... that would be me.

    mi5zNoD.jpg
    According to Sky-Watcher the ED80 has Ohara FPL-53 Extra-Low Dispersion glass as well. So I'm none the wiser.
     
  16. Leonard

    Leonard Well-Known Member

    Joined:
    Feb 1, 2019
    Posts:
    94
    Trophy Points:
    18
    Location:
    West Virginia USA
    Lol. Yep, I understand now. Thanks.
     
  17. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    Last edited: Apr 28, 2019
  18. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    449
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    FPL-53 is better for making shorter focal length telescopes, FPL-51 works very well but best at lengths above f/7.
    It is just the way the mating elements/ refractive indexes normally work out.
    That is not to say you will never see a shorter 51 or longer 53 though.

    FPL-53 is not a marketing term but an actual product of known attributes.
    Terms like Semi-apo and ED Apo ARE marketing terms in these under informed times unfortunately.
    How many times have you heard someone call an ED refractor an apo? How many manufacturers do it?
    All the ED means is that the achromat has a extra low dispersion element that IF made and mated properly should give 2x better colour correction than a Fraunhofer doublet of BK7/ F2 glass.
    So a FPL-53 102mm f/7 should have the colour correction of a achromat 102mm f/14 (this is simplifying greatly of course)

    In answer to your short doublet question Mak, that iswhy they use FPL-53 shorter than f/7, to get the same colour correction using FPL-51 it would have to be a triplet.

    Have you tried using the different eyepieces in the BV yet? If there is a difference it MAY be a slight difference in coatings.
     
  19. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,243
    Trophy Points:
    113
    Thanks Gabby. I guessed it was something like that. I know FPL-53 is an actual 'thing' but it's still used in marketing spiel. I meant it was now effectively a marketing term as it is recognised as being glass of a particular quality. A bit like BAK 4 which I also don't really know anything about lol.

    1.jpg

    The 12mm EP's do seem to have different coatings, I'll bino them when I get the chance. Meanwhile here's a pointless jpeg of my X-Cel collection.

    2.jpg

    I was looking at the zenith a while ago with my ED72. I almost dislocated myself trying to use a reflex sight. So I may try this RACI next time. It's only 22mm smaller than the objective lol.
     
  20. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    449
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    This is one of the reasons I use the Antares or Stellarvue RACI finders which have the ability to have the eyepiece changed.
    Sometimes it is easier to use the finder as a telescope and get the widefield view :)
     

Share This Page