Quote:
Originally Posted by cometcatcher
Hi guys, I'm an old school, film era deep sky astro-photographer getting back into astrophotography now with my very first ever DSLR camera. I still have the old achromatic refractors. With film, purple fringe and bloating wasn't a problem, but of course now with digital my old lenses all look like they are made with 1 dollar plastic lenses lol.
The way I see it I have two choices. One is to try and revive them with some kind of fringe or UV/IR cut filter in the path, or two to bite the bullet, forget the old gear and save for a new APO imaging refractor. This may take a while as my $ to spend on astro gear is limited.
In order to help me decide I've been trying without success to find before and after shots with various UV cut filters on basic refractors. I'm sure there must be a myriad of threads here on the forum, but I suck at finding anything.
If anyone has some before/after image examples or advice I'd be very grateful. 
P.S. This is for 600mm f/L and shorter as when I reach 750mm it's reflectors from there on. |
Kevin, I have tried Baader Fringe-Buster filters with an old achromat in the hope of eliminating the bloating of stars in the images. Unfortunately, it didn't really make a sufficient difference to encourage me to press on with that plan. Also, it gave a jaundiced yellow tinge to everything. I was using a one-shot colour camera at that time.
I figured that the only way I could make use of the achromat was with narrowband filters and a mono CCD where you can focus each filter individually. That would work OK.
Peter