Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

  • Announcements

    sgl_imaging_challenge_banner_solar.jpg

     

timwetherell

Advanced Members
  • Content count

    331
  • Joined

  • Last visited

Community Reputation

522 Excellent

6 Followers

About timwetherell

  • Rank
    Star Forming

Profile Information

  • Gender
    Male
  • Location
    Somerset

Recent Profile Visitors

1,249 profile views
  1. Solar Max Coronado 70mm Scope

    Interesting! sounds like my 60 may indeed be an oddly corrected doublet then
  2. Solar Max Coronado 70mm Scope

    Actually it's a coronado solarmax 60mm single stacked scope. I've looked through quite a few PSTs and single and double solarmax 90s, but for me the 60 is about the sweet spot in terms of performance vs expense and hassle setting up
  3. Solar Max Coronado 70mm Scope

    Mine's quite old (not sure how old cos I bought it second hand) but definitely pre Meade. I'm not game to dismantle it, but it's easy to unscrew the etalon and remove the energy rejection diagonal at the back. This is the view through it as a "regular" unfiltered telescope. There's lots of CA. It's possible that it's a doublet with odd correction for H-alpha - Perhaps the two elements are used to eliminate spherical aberration? But definitely not a classic achromat If anyone tries this, please be sure to put the filters back on the moment you've done experimenting - a solar scope with the filters off is a very dangerous thing to leave lying around!!
  4. Solar Max Coronado 70mm Scope

    I had the impression that many of these were actually just crown glass singlets. I think my old 60mm Coronado might be. From what I recall reading the destructions years ago, the rationale is that less glass is less scatter and since they only pass about half a nanometre of spectrum anyway, chromatic aberration isn't an issue. This is all based on my dim and foggy recollections though, so it may be somewhat apocryphal The Coronado eyepieces are definitely achromatic though - quite good GP plossls actually!
  5. Immortalizing Old Observation notes

    Yep me too! I found my old notes from the 70s at my mother's house and digitised them to have a backup copy. Fascinating for a number of reasons - (1) double stars like castor that have changed over the past 40 years and perhaps most interesting, (2) how much more I can see now with a 60mm refractor and my older eyes than I saw as a young man with perfect vision. Just goes to show how observing is a learned skill.
  6. M11 - what have I seen?

    I once saw an equilateral triangle of three satellites moving across the sky about 2° wide along each side. It was kinda weird but I assumed some sort of satellite constellation. I could see stars in the "triangle" bit as they went over so it was obviously three separate small objects rather than a big thing with lights at the points. Just as well really or I might have had to wrap my head in tin foil and join a rather different internet forum
  7. chinese ep's

    I had one of these for a few years - the 30mm 80°. The central 80% of the field was pretty well corrected but there was some softness in the outer 20% in my f7 scope. Set against this, it costs literally 10% of what a 31mm Nagler costs and delivers perhaps 80% of the performance. If you're using a Newtonian with no coma corrector, the outer field will be a bit soft anyway so it's not such an issue. All in all, I'd recommend them if you are budget conscious or have something better to spend the 400 pounds difference on! They also have a big weight advantage over the Nagler! If the cat sitting on your scope will affect the balance, so will the nagler - it's a monster. The Chinese 30mm on the other hand is fairly light. Like any eyepiece issue, it's horses for courses
  8. Astrotech 66mm ED apo refractor

    SOLD
  9. Mayak, Brightest star in the sky.

    On it's own it's probably not a big issue because it won't be visible for the vast majority of the time. My fear is that this will lead to a competition to see who's clown-funded cube sat can be the brightest, and before we know it there'll be thousands of these idiotic things littering the night sky. But I'm probably just a grumpy old man
  10. Circle T 12.5mm orthoscopic boxed

    SOLD
  11. You know it's summer when...

    While you're out looking south, have a try for M7, the most southerly of the Messiers. It's about 4° above the horizon from Exmoor and maybe 2° in co wicklow, so definitely a challenge! If it were a "fuzzy" there'd be no chance, but an open cluster with individual stars shows up surprisingly well considering the ridiculously low elevation
  12. I'm looking at getting a 4" portable refractor myself soon and to me a shorter focal ratio is important because I wan't the widest possible field of view. If I'm traveling to a super dark site, it will be to look at things like the North America Nebula and Andromeda galaxy which are very big indeed! A 4" f5.5 will give me 4.6° with a 31 Nagler vs 3.6° from an f7. So for me the Skywatcher Esprit 100 ED is looking like a good option, though it's not particularly cheap. I guess the fact that it would be faster if I did want to dabble with photography is an additional bonus. Though there'd definitely much more choice in the f7s
  13. Astrotech 66mm ED apo refractor

    PENDING
  14. TMB 16mm Supermonocentric

    SOLD
  15. Circle T 12.5mm orthoscopic boxed

    Price drop, now £39
×