Solar Filters -SCT

[JGM1971]

I have had my Nexstar 6SE for several months now and when the weather up here in Newcastle allows it, I've been more than impressed with it.

I'm now looking to start Solar observering, but need some advise on filtering an SCT.

Firstly, is there a generic Solar Filter for the 6SE?

Next, as a Baader filter is in white light and I can't hit the shops for a Coronado or Lunt just yet (the wife would kill me!) can I add a Hydrogen Alpha filter to the mix to give similar results?

[Cornelius Varley]

1. The Astrozap solar filter http://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html should fit.

2. No. A Ha filter (eyepiece screw-in type) won't give the same results as a dedicated Ha solar telescope.

Peter

[DirkSteele]

I purchased a glass solar filter for my 11" SCT from Thousand Oaks Optical in the US for use with the 2004 Venus transit. They are very high quality, though you will be faced with import duty and tax if you import it from the USA. They do manufacture cells for the 6SE.

http://thousandoaksoptical.com/solar.html

[JGM1971]

1. The Astrozap solar filter http://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html should fit.

2. No. A Ha filter (eyepiece screw-in type) won't give the same results as a dedicated Ha solar telescope.

Peter

[JGM1971]

Thanks Peter.

[michael.h.f.wilkinson]

I use a Thousand Oaks glass filter (expensive, but solar film was not known to be as durable when I bought 14 years ago) on my C8, and Celestron produce their own solar-film like filters. Nice for white light. The short focal length of the primary of an SCT means you really have to prevent the full blast of the sun's rays to enter the scope. The secondary might shatter under thermal stresses otherwise. Herschel wedges are out of the question. In theory you could put an H-alpha etalon in front of the corrector plate, and a blocking filter at the rear, but a full-aperture etalon would cost the earth (a 60mm costs more than EUR 2000). I have found it is actually cheaper to get an entire 60mm set-up from Lunt, than to buy the etalon and blocking filter and attach them to my 80mm F/6. Weird.

Still have not got that 60mm.