Istar 150mm h-alpha project
Posted: Mon Aug 25, 2014 10:41 am
Hi,
I start making my solar scope
I have:
- Istar h-alpha optimized 150mm F10 lens,
- carbon fibre 160mm diameter tube (painted white)
- Lunt LS100 DS II PT etalon
- BelOptic 105mm sub-ERF
I already gave instructions to machine shop to make all the aluminium parts - objective adapter, baffles, etalon/focuser adapter.
Original Istar 150F10 refractors have ca.20cm of back focus. Isn't it too much? Usually refractors have ca.15cm of back focus.
However, Lunt DS II etalon has 40mm ERF and 36mm front collimating lens on etalon. With 20cm back focus, may cause loosing some lightcone baffled by original 40mm ERF. Extending the tube and cutting back focus a little would help but can it cause other problems?
Thanks in advance for your opinions
I start making my solar scope
I have:
- Istar h-alpha optimized 150mm F10 lens,
- carbon fibre 160mm diameter tube (painted white)
- Lunt LS100 DS II PT etalon
- BelOptic 105mm sub-ERF
I already gave instructions to machine shop to make all the aluminium parts - objective adapter, baffles, etalon/focuser adapter.
Original Istar 150F10 refractors have ca.20cm of back focus. Isn't it too much? Usually refractors have ca.15cm of back focus.
However, Lunt DS II etalon has 40mm ERF and 36mm front collimating lens on etalon. With 20cm back focus, may cause loosing some lightcone baffled by original 40mm ERF. Extending the tube and cutting back focus a little would help but can it cause other problems?
Thanks in advance for your opinions