Filters and band pass scanning

[FaintFuzzies]

I took my ten filters to Lumicon in the Sacramento area and had them scanned by Cary. Some results are as expected with a few surprises. Read on and please comment away.

Narrowband Filters

Interesting results. No degradation, but the transmission results of the Orion Ultrablock are a bit lower than I expected. I bought this filter way back in the early to mid 1990s. Showed no degradation of the coatings and it still looks nearly pristine. I liked it as it kills everything after the last O-III lines. No red stuff.
Orion Ultrablock.jpg

The Omega NPB has a quite a bit of red pass through and gives this annoying "double star" appearance in the eyepiece. The scan confirms this. About 10 years old.
Omega NPB.jpg

Lumicon UHC filter - very good filter. After seeing this result, I will start using this more often than the Orion. I had the Orion since 1995. Great filter and loved it. I picked up this Lumicon about 3 years ago.
Lumicon UHC.jpg

Now after seeing these three results, I think I'm going to switch my main narrow band from Ultrablock to UHC. The NPB will remain my second choice.



Now on to my broadband filters

My very old Celestron Nebular Filter I got since I was in high school in 1984. Wow, pretty broad bandpass and okay transmission. Everything past about 530nm is cut off, which was pretty good considering that this was made almost 35 years ago. I used it with my old RV-6 and original AC powered Celestron C8. Yeah those made in the late 70's.
Celestron Nebular Broad Band.jpg

The very first time I saw Hanny's Voorwerp through my friend's 48" telescope was with the CLS filter. Since that thing is almost 700 million light years away and the O-III lines were red shifted away to about 525-530nm, which is still within the CLS bandwidth. Nothing else worked at the time. Jimi ended up getting the Sloan G filter which helped too.
Astronomik CLS.jpg

Lastly, the Lumicon Deep Sky - a rock solid broadband filter. About 3 years old.
Lumicon Deep Sky.jpg

After seeing the scans, my preference remains the same starting with the CLS, then the Deep Sky.


Line Filters

Lumicon O-III (about 10 years old) Replaced my old blue box O-III
Lumicon O-III.jpg

Lumicon H-Beta (about 10 years old) Also replaced my old blue box H-Beta
Lumicon H-Beta.jpg

Lumicon Comet (about 3 years old)
Lumicon Comet.jpg


Enjoy the scans. If you are interested in getting your filters scanned. Contact Cary at Lumicon.