Quote:
Originally Posted by mental4astro
Filter wise, an OIII filter will be more useful for viewing from the big smoke than an UHC type. A UHC is just too narrow in bandwidth transmission for the best results in urban areas. It will work, but an OIII is brighter image wise and with the number of stars it will show. What you can do with 1.25" OIII filter is also make yourself a "blinking paddle" that you use to blink out tiny planetary nebulae so they reveal themselves from their surrounds. While DSO viewing in the city is always second best, blinking for PN's is actually something that's very effective. I've been successful in chasing some of the tiny PN's in the cluster M7 from my home in Sydney. I've attached a pic of my blinking paddle. It's just a piece of MDF that I can screw into a 1.25" OIII filter. I then flick the filter between my eye and the EP. It is very effective and I'd say pretty much the only way to find small planetary nebulae that quite literally are invisible without a filter. With a blinking paddle, these invisible planetary nebulae quite literally "POP" out. Oh, and an OIII filter is better for PN's than an UHC filter.
Mental.
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Alex are you sure you have that the right way round? My UHC -S filter has a broader band then my OIII. In the UHC nebulosity pops out more than no filter but still lets in enough light for most stars to shine through. My filter of choice for the LMC and SMC. My OIII filter on the other hand hits star light like an anvil. But nebulosity in the 10nm range aka OIII is turned up to 11. But, I agree an OIII filter is better for heavy light polluted skies.
I tried that blinking paddle technique on the week end. Just held a filter up to the eyepiece quickly while looking for the Veil and other faint nebula and it worked like a charm. A very clever observing technique.