Quote:
Originally Posted by dan_iana
Hey all,
Took some narrowband subs of M42 last night on our new ASI1600mm-pro.
What's the easiest way to tell which filter created each subs? I have labelled our filters in the filter wheel as H/S/O based on their packaging but the images that came out were quite surprising and made me think that possibly the filters where in incorrectly labelled packages (we bought them off a iceinspace user).
I'll post them tonight BUT at the following parameters (-10 sensor temp, 300 gain/50 brightness, mono8, 180sec subs):
Halpha - showed the least detail
Sii - showed a huge amount of detail but the core was massive and white
Oiii - similar to Sii
I've tried to find M42 narrowband subs to compare ours against but would have thought that (generally) Halpha would show the most detail when compared with Si/Oiii (but guess it depends on what you are imaging).
So ultimately, I just want to make sure that my filters are labelled correctly 
Will post photos tonight, unless there is an easy way (e.g. look at some histogram in sharpcap or Adobe) to identify the filters based on the wavelength of light registered. |
As a guide to which is which:
(unless you have a spectrophotometer) to test them, then, despite the various coatings, if you handhold the filter and look through the filter at a white object illuminated by daylight, then :
1. The Halpha filter will show a deep red tinge
2. The OIII filter a green tinge
3. The SII filter a darker image than that observed in the Halpha filter as this is getting close to the edge of our visual range
all subject of course to the filter bandwidth.
Look on the bright side there are only 6 possibilities.
It might also help to observe a red/green object or image such as the attached. The Halpha filter will show the
RED as
RED , but will show the
GREEN as
Dark/mid GREYish and conversely the OIII filter will show
GREEN as
GREEN and
RED as
Dark/mid GREYish , excepting any colour perception/blindness issues
Best
JA