Jump to content

Narrowband

Mr Spock

Moderators
  • Posts

    18,302
  • Joined

  • Last visited

  • Days Won

    63

Everything posted by Mr Spock

  1. I would say a slight shift in focal length and the Svbony 7-21 is one of the sharpest out there - if you can stand the narrow field of view.
  2. Designed by someone who's never seen a telescope before
  3. That's really odd. I've just looked through my observing book and there's nothing. I remember having a long session in CMi and the area around, and remember commenting about the large number of easy 10-11mag doubles in the bottom of CMi. I've got one session in Hydra, then the next is Leo/Gemini, with nothing in-between. Strange...
  4. I remember having an easy split last year, but haven't written it down. It was probably with the 12". I'll give the 4" a go this year and see what happens.
  5. You already have an 8"CC - what would a 125mm bring over that? What is your intended use? If it's a complement to the 8" then 4" would be a good choice. It would fit on a much lighter mount than the 125mm. Sounds like you have the right plan!
  6. Here are my 'twinsies'. The 4" on an EQ5 and the 12" on an EQ platform. I must have tracking! The 12" is heavy and bulky. I move from my shed (off picture to the right) on to the patio only. I have a bad back as well and it's still manageable that short distance. I've since created a better patch to the top patio but haven't been brave enough to lug the 12" up there yet.
  7. I had a C9.25 for close to ten years. It never really performed unless the seeing conditions were perfect. Most of the time it was, put it out to cool, go back hours later, see how mushy the view was, bring it back inside. The 10" Newtonian I had prior to that was superior in every way. It was just too bulky to lift on to my EQ6. I had my best ever views of Mars with that scope. It was just an ordinary blue tube Skywatcher, but it performed well. These days I use my 4" apo most of the time. When the seeing is good I get the StellaLyra 12" Dob out. That spanks everything else I've ever looked through.
  8. What you should do is repeat the test with better seeing to see if the distortion is consistent. If it is, - First thing to check is if it is the primary or secondary. If it is the primary, the oval shape should change direction if you rotate the primary cell. If it is the primary, check to see if the mirror is being distorted by being held too tight. Same if it's the secondary - it's probably miss-mounted or being gripped too tight in the cell. If either of the mirrors is astigmatic themselves and it's not mechanical, then the only cure is refiguring
  9. The oval shape is a sign of astigmatism.
  10. The 42mm LVW has the largest field stop available in 2" eyepieces. Mine is very sharp.
  11. Final solution to the MEF-3 Expensive, but you know its worth it
  12. Once you've seen the Pleiades through the 30mm you'll be convinced As well as framing all the stars you can see the nebulosity too - even in my LP.
  13. You can get top quality now without spending hundreds per eyepiece. If I was starting from scratch on a limited budget, I reckon a 30mm UFF, 13mm Nirvana and the Svbony 3-8 would be a hard combination to beat for value. About £350 for the lot - or £20 more than just one of my TOE eyepieces
  14. Should be fine. I use it in a Baader T2 which is an undersized prism and it's ok in that.
  15. The StellaLyra is a 304/1520 f5 but quite manageable.
  16. No, it suffers from field curvature. It's still sharp in the centre so I use it as a next to low power finder when I'm doing doubles. So I go 42mm LVW, then with the Nirvanas 16mm, 7mm (actually measures 8mm), and 4mm. A nice progression in the FC100 - x19 (3.7°), x46, x93, x185.
  17. A 4mm eyepiece would give you x179 which is a decent magnification but below what the Starfield is capable of. A 3mm would give x238, so the Svbony 3-8 is useful, going from x238 to x89. I've not seen much difference between my orthos and the Nirvanas, other than the latter being twice the fov! I can't recommend the 16mm, but the 13mm is excellent and would give you x55 and 1.5°.
  18. I've not had it on Sirius in good seeing conditions. I have separated 0.5" stars though.
  19. It's much better than the C9.25 in every way possible
  20. I'm a big fan of the SLV. Even though I sold them all because of the other premium eyepieces I have, I've 're-bought' the 6mm as it will be an excellent lunar eyepiece and fills the gap between my 8mm and 5mm LVWs.
  21. I wouldn't swap my StellaLyra (GSO) 12" for anything. The optics are superb. It's well built and the focuser is very smooth. Only negative is the primary springs aren't strong enough but they are easily replaced.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.