Question: Has anyone here done a comparison of available O-III filters, such as Lumicon, Thousand Oaks, Orion, etc? I'm wondering if they are all fairly comparable, or if some one has noticed a significant difference between brands. I had a chance to compare Orion's and Lumicon's some years ago, but would like to know if anyone sees anything significantly different between the major offerings. Thanks!
Filter comparo
Started by Larry Seguin, 12/14/2009 11:21PM
Posted 12/14/2009 11:21PM
Opening Post
Posted 12/15/2009 02:42AM
#1
Larry,
I know its been done. I think even one of the magazines did comparison testing a while back. I've searched around, and for the life of me I can't find any one spot with complete information. I found some limted comparisons by typing in "Nebula filter comparison" to my search engine. From what I've read over the years, everyone uses Lumicon as the filter to compare against and its the name most often heard at starparties. I think most reports say the differencs are subtle and can only be noticed in side by side comparisons. I've been happy with the Orion Skyglow and Ultrablock filters although I use the Ultrabock much more than the Skyglow. I also own an Omega OIII which works well too. Take my opinion with a grain of salt though because I'm a "casual" filter user. I'm sure others will offer more info.
I know its been done. I think even one of the magazines did comparison testing a while back. I've searched around, and for the life of me I can't find any one spot with complete information. I found some limted comparisons by typing in "Nebula filter comparison" to my search engine. From what I've read over the years, everyone uses Lumicon as the filter to compare against and its the name most often heard at starparties. I think most reports say the differencs are subtle and can only be noticed in side by side comparisons. I've been happy with the Orion Skyglow and Ultrablock filters although I use the Ultrabock much more than the Skyglow. I also own an Omega OIII which works well too. Take my opinion with a grain of salt though because I'm a "casual" filter user. I'm sure others will offer more info.
Clear, sunny skies.
Tom Masterson
Coronado-Lunt-Daystar Solar Filters forum Moderator
Posted 12/15/2009 10:38AM
#3
Larry Seguin said:
Question: Has anyone here done a comparison of available O-III filters, such as Lumicon, Thousand Oaks, Orion, etc? I'm wondering if they are all fairly comparable, or if some one has noticed a significant difference between brands. I had a chance to compare Orion's and Lumicon's some years ago, but would like to know if anyone sees anything significantly different between the major offerings. Thanks!
Larry:
Of all the filter comparisons I have seen, the one's I most trust are David Knisely's. David is one of the original S.A.A. guru's he has been researching filters for lots of years. He does careful,well documented comparisons as you will see:
http://www.cloudynights.com/item.php?item_id=1520
Myself, I have two O-III filters, a 1.25 inch Orion and a 2 inch Celestron. I have compared to the two a time or two on a few nebulae but I base my preference on the Veil. I am able to compare them using the same 1.25 inch eyepieces by threading the 2 inch to a Paracorr. I prefer the 1.25 inch Orion, the Celestron seems overly aggressive and I seem to see more detail with the Orion.
Jon
Posted 12/15/2009 04:01PM
| Edited 12/15/2009 04:04PM
#4
One difference I've noticed is that some have much
better blocking of red wavelengths than others.
For example, my old Lumicon OIII works great visually,
but if you hold it up to a light bulb you can see it
looks red in color, not green as you would
expect for an OIII filter. Apparently it lets a lot
of red light through -- much more red than OIII.
This doesn't matter so much for visual, since the
dark-adapted eye is not sensitive in the far red, but could
become a problem if you were doing multi-color imaging.
On the other hand my Astronomik OIII filter is
well-blocked and looks green if you hold it in
front of a light bulb.
You can see these differences, for example, in the
spectral tracings in the review by Cristian Buil.
http://astrosurf.com/buil/filters/curves.htm
So it is probably relevant to ask what your application
is -- for visual you mainly want high transmission
at OIII and good rejection of surrounding sky background
wavelengths, but do not care so much what happens in
far red. For imaging you have more strict requirements,
and would like good transmission of OIII and nothing else.
better blocking of red wavelengths than others.
For example, my old Lumicon OIII works great visually,
but if you hold it up to a light bulb you can see it
looks red in color, not green as you would
expect for an OIII filter. Apparently it lets a lot
of red light through -- much more red than OIII.
This doesn't matter so much for visual, since the
dark-adapted eye is not sensitive in the far red, but could
become a problem if you were doing multi-color imaging.
On the other hand my Astronomik OIII filter is
well-blocked and looks green if you hold it in
front of a light bulb.
You can see these differences, for example, in the
spectral tracings in the review by Cristian Buil.
http://astrosurf.com/buil/filters/curves.htm
So it is probably relevant to ask what your application
is -- for visual you mainly want high transmission
at OIII and good rejection of surrounding sky background
wavelengths, but do not care so much what happens in
far red. For imaging you have more strict requirements,
and would like good transmission of OIII and nothing else.
Funding Member
