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azrabella

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Posts posted by azrabella

  1. This from the Long Perng website: So I guess they are the same.

    E12.5L-A Long Eyerelief Eyepiece(celestial)
    Long eye-relief eyepieces 
     
    Model # E12.5L-A
    Focal length (mm) 12.5
    Eye relief (mm) 20
    Barrel size 1.25”
    Field of view (degrees) 55°
    lens constrution  7 elements in 4 groups 
    construction  Aluminum
    coating  Fully multi-coated 
  2. Canvassing opinion on the best way to clean eyepiece optics - especially the eyelens element as I am forever laying down eyelash grease and detritis on mine - tight eye relief issue, I guess! Anyway, I am sure many visual observers have this issue and I would like to gather others thoughts here. Currently I  use the classic LensPen and am reluctant to try fluid as I have had past experience of over applying which is then a mini nightmare to remove. Always the worry of fluid getting between the optical components.

    So, if anyone wants to volunteer advice, I would be very interested to hear.

    Thanks in advance

  3. I would like to canvas opinions regarding the relative merits of these two classes of ocular. I am fully aware of the fashion for ever widening field of view of modern multi element eyepieces, but ultimately most widefields seem to fall over when combined with relatively fast scopes (f/5 or so). The only major gain that I can see is that with manual tracking they hold the object being viewed in the field for longer. Given that the narrower field orthos generally are sharper and more contrasty than all but the most expensive wide fields, would any ortho user consider it a worthwhile trade-off? It would be interesting to hear any views. Are there any dedicated ortho users who can persuade me to ditch my 80 + degree eyepieces and opt for a "better" view albeit with a smaller field of view.

  4. For an 82 degree field, some distortion in the outer 10% of the fov is to be expected unless you are willing to pay BIG BUCKS. I did find when I used the same scope that you are using it was probably more coma than astigmatism, depending on your choice of eyepiece. I doubt it's your eyes. It was also one of the reasons I chose the 6" f/8 Dobsonian.  I did find the eyepieces performed much better in a slightly slower scope. You could always cut out an aperture mask or alternatively use a barlow with the Nirvana to see if that clears up the edge of field issue. I have compared the Nirvana with a much more expensive Explore Scientific 82 degree equivalent. Nirvana was better on eye relief and no difference detected optically. I sent the ES back and kept the Nirvana.

    • Like 1
  5. Although I have been a visual astronomer for some time, I find myself wondering if I can improve my choice of eyepieces. I have been a lone observer and have arrived at my choice of oculars "organically" through trial and error. I now only use a 6-inch Dobsonian with Hilux coated mirrors and my subject matter tends to be open clusters, variables and double stars. I live in a quite heavily light polluted area on the outskirts of a city, and find that most deep sky subjects are quite impossible to view from my location, hence my choice of subjects. The eyepieces I have currently quite suit the scope, and more importantly - my eyes. I have a quite limited budget so please don't suggest Ethos or Nagler or other high end oculars because I simply cannot afford these. Image supplied.

     

    510414421_Eps.thumb.jpg.7f061c2e1b075ed46cbbd085af26acbb.jpg

  6. I have just disassembled an Explore Scientific x2 focal extender for cleaning (dust internally) and while the larger of the two optical elements is now clean, I cannot remember the correct configuration. Does the highly curved lens surface face the eyepiece end or the other way about? It's raining cats and dogs outside so cannot test with the scope. Can anyone help. Thanks in advance.

  7. The final rinse after cleaning a primary mirror was done with "distilled" water from a condenser tumble dryer. It seemed to work as there appeared to be no noticeable residue or water marks left after the mirror had been allowed to air dry. Has anyone else tried this? Only reason for asking is that it is quite difficult to obtain commercial distilled water readily and I regularly produce about 5 litres costing nothing, which normally gets thrown away.

  8. A Happy New Year to you.

    I can recommend the BST's. I think they are very good value and with your particular scope the 25mm BST would give you 26x - great low power, wide vista views. Followed by a 12mm @ 55x and an 8mm yielding approximately 82x - all with excellent eye relief and all with a 60 degree field of view. If you want to go wider field of view then the Skywatcher/OVL Nirvana eyepiece range, while not as extensive as the BST's (16, 7 and 4mm), are very good indeed. Couple them with a good quality Barlow  and you have a nice range of focal lengths at reasonable cost. All these are better than standard plossls by some margin.

    • Like 1
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  9. Practical visual astronomy is virtually off the agenda here in the south west of the UK - no clear night skies for several months. A fortune wasted in equipment and nothing to show. I have ben a visual astronomer since 1960 and have now given up on this pastime - 60 years of observations yet prctically nothing for most of this year. I'm too old now to move to sunnier climes so the only other option is to take up ASTROLOGY - at least that is not weather dependent.

    • Sad 8
  10. Hi - anyone know what's occurring with Stellarium? I've been running it for a year or so with no issues, but as of today it won't run on any of my laptops. I've tried reinstalling (several versions) but to no avail. Splash screen loads then it opens normally, but within a few seconds it crashes.

  11. Hi folks,

    Has anyone had any experience with the BC&F AC555 Magnimax barlow/multiplier??? I believe they offer something like a x1.6 amplification. Useful for getting those "in between" powers with my eyepieces. I  am also of the belief that they are fairly rare nowadays. Any info would be appreciated. I've just managed to grab one for a tenner on AstroBoot UK - I thought at that price it must be at least worth a punt.

  12. Hi folks,

    Has anyone had any experience with the BC&F AC555 Magnimax barlow/multiplier??? I believe they offer something like a x1.6 amplification. Useful for getting those "in between" powers with my eyepieces. I  am also of the belief that they are fairly rare nowadays. Any info would be appreciated. I've just managed to grab one for a tenner on AstroBoot UK - I thought at that price it must be at least worth a punt.

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