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Filter advice
Hi guys, another question for you.
Right now I'm looking at getting a filter for use on brighter deep sky objects. I've searched the forum and I've seen a lot of different opinions on what filters are worthwhile. After trying to figure it out for myself, I've decided it'd be better to ask instead of spending money on something which may not do the job (since they're not particularly cheap...).
Anyway, my primary interest is in observing the brighter deep sky objects to try to coax some more detail out of them. I have an ETX-70 as my current scope. My skies aren't terribly light polluted, but they're not dark either. The brighter parts of the Milky Way are easily visible, but I cannot detect the Coal Sack without binoculars. I'm not in Brisbane itself, I'm in Redlands Shire which is just outside of Brisbane. On most nights I can detect the brigter parts of the Lagoon nebula easily. I have streetlights in the east which are white in colour, however not too far away are roads where all the street lights are orange.
After reading around, I've read that the broadband light pollution filters are actually relatively useless, due to the fact that they don't block the light emitted by one of the types of streetlight (the organe ones if I remember correctly, memory is hazy). I've also read that UHC filters are the best ones to go for.
Questions:
1) Is it even worth putting a filter on the ETX-70, or is it too small to even warrant it?
2) Are the light pollution filters really useless for light pollution filtering? I notice that some of them say they block sodium and mercury vapor lights, would they be of any use or are they still a waste of money?
3) Is UHC the way to go?
4) Given the information about my sky that I've provided (more available on request), do you think that a filter would provide an improvement?
5) I haven't really thought too much about a budget yet, but what do you guys think is good value?
6) What's the best place to buy it from? I don't mind paying for freight provided it isn't too much. I don't know of any telescope shops in Brisbane, let alone Redlands Shire. Any Brisbane residents know of any?
And completely off topic but something that just occured to me, what happened to the monthly observing challenge? Is anyone bringing it back?
Okay that's all. Thanks guys.
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