HA filter on a C14 telescope

[icytailmark (Mark)]

anyone ever used a HA filter on a c14 telescope? Can you produce images as good as solar scopes? "solarmax etc"

Would i need to use a focal reducer?

[Paul Haese]

I think you will find you need to have a full aperture mask with a ha filter (possibly a 90mm filter) then blocking filter at the rear. I would have thought though heat would be a significant factor. That being the tube would heat up and cause tube currents.

[icytailmark (Mark)]

thanks for that paul maybe ill save up for a solarmax

[Peter Ward]

Jean Dragesco had some great (film based) examples of H-alpha photography
using DayStar filters with C14's from the mid 1990's.

Daystar's however needed very long F-ratios to work well.

Tube currents would have been problematic with the C14, plus newer front Etalon based systems allow you to vary the focal length with no penalty.

Even though I have a Coronado system, the test bang for buck IMHO are the pressure tuned 80mm Lunts which should deliver similar results to what I get... eg:

http://www.atscope.com.au/BRO/gallery121.html

[frolinmod]

I've not seen any good Ha images taken with a C14, but I have seen some spectacular white light images showing incredible detail taken through a C14 with a FULL aperture Baader AstroSolar safety film filter mounted up front and a Baader solar continuum filter with an IR blocking filter in front of the camera.

Large (39-inch x 20-inch) sheets of Baader AstroSolar safety film are available here: http://www.baader-planetarium.com/sofifolie/sofi_start_e.htm

From what I've seen, the best Ha images taken by amateurs seem to be taken with either double stacked Lunt LS100Ha or single stacked Lunt LS152Ha scopes. I haven't seen any images taken with their new LS230Ha (9-inch !!!) scopes yet.

Many of the best images are here: http://solarchat.natca.net/index.php/en/

[Poita (Peter)]

In short it isn't a viable option. The tube currents during the day would wash away any detail and you wouldn't get as good an image as you would through an 80mm refractor. The cost of a front ERF would be prohibitive as well. I think even of you could do it, an 80mm solar scope would be cheaper and give better results.