Quote:

---

Quote:
I would read the papers *if* I had access to them




Go to the nearest university library and get it.

---

Quote:

---

Quote:
The Oxygen III line filter experiment I described earlier *does* indicate that the reddish color I was seeing in the nebulosity was due to red light from M42 getting into my eye and not some illusion as you seem to allege.


You have no way to prove this. I show you how a porcess tha is alway active in our mind may literally invent red where there only is black. How can you be sure that the same did not happen?

---

Quote:

---

In addition I have Lumicon UHC which incidentally have a similar red leakage. I measured it with my own hands (so I beleive it is correct) using a research class instrument (the spectra are not from some official datashet).

Here it is: http://photos1.blogger.com/blogger/6869/1731/1600/logaritmico.jpg />

---

http://www.astroamateur.de/filter/oiii.html

In any case, the DGM Optics NPB has a *dedicated* H-alpha secondary passband, so it is in the correct location and at a high level of transmission. In large scopes, that filter does help bring out the faint reddish hues in M42 in a way somewhat like that older OIII filter did.

--------------------
David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info

Post Extras