View Full Version here: : Hydrogen Alpha filters for dummies
DavidNg
15-05-2013, 01:48 PM
Hi,
I bought a secondhand CCD awhile ago which came with a set of LRGB, S, O and 2 HA filters, one is darker than the other when viewed with naked eyes. What are the difference between the two and when to use one or other?
Help appreciated.
David
They are probably different bandpass filters - do they give any indication to their specs on the rim of the filters?? I have an Astronomik 12nm HA filter, I know Astrodon make one at 3nm.... the lower the bandpass, the less light is let through, and you get a higher contrast image, with longer exposures needed....
DavidNg
16-05-2013, 10:14 AM
Thank you Lee for your explanation. I will have a closer look for specs when the filter wheel opened.
pluto
16-05-2013, 11:07 AM
Even knowing the brand might help, my Baader Ha filter is 7nm.
DavidNg
17-05-2013, 12:26 PM
Thanks Pluto, I will find out if there is any logo or mark on the filter rim when it is open.
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