A Galaxy Filter for Light Polluted Skies.
Posted 25 January 2013 - 12:21 PM
For visual astronomy only; regarding the use of filters and other observing techniques for enhancing the views of galaxies in light polluted skies:
1. What have you tried and how successful has it been?
2. Of what (filters/observing techniques) have you heard?
3. What might be tried?
Posted 25 January 2013 - 02:06 PM
Although I have not used one, DGM makes a filter for galaxies that, I think, works like the Sky Glow filter.
Posted 25 January 2013 - 02:09 PM
CN REPORTS: The DGM Optics GCE Filter
As has been mentioned before, the best filter for galaxies is a "gasoline" filter (i.e., drive as far away from city lights as you can). Clear skies to you.
Posted 25 January 2013 - 07:40 PM
What has worked is to observe late on a Sunday night, or any other night when LP is at its lowest. The night after New Year is another good one, when most are tired (hung over) and the stores are closed. A smaller scope that can be left set up by the door and will acclimate relatively quickly is another one I do. If I wake up in the wee hours of the morning I can bring the scope outside and observe for a while, although my dogs think I'm nuts and I feel like a zombie later on at work.
Posted 25 January 2013 - 07:49 PM
I have tried M&SG, UHC, etc., and none have helped me. I live in suburban Miami with bad LP. I hate to sound like a broken record, but the only filter that has worked for me is the 'gas' filter David and many others refer to.
What has worked is to observe late on a Sunday night, or any other night when LP is at its lowest. The night after New Year is another good one, when most are tired (hung over) and the stores are closed.
The dark sky real estate filter works great too . If you have one of those , you don't really need the gas filter .
Posted 26 January 2013 - 01:32 AM
On the other hand, if you have no choice, broad band is about the only way to go.
Under dark skies, I've experimented around with filters on the showpieces. I've used an O-III on the bright galaxies like M-33 and M-32 and have had mixed results finding some of the IC and NGC galaxy knots. The same with the UHC. The H-beta didn't help at all, so far.
I tried an LPR which I guess is the same as broad band (I guess that's what they were called in the 90's?) and it helped a bit on the galaxy knots also.
However, those were very bright galaxies and for faint fuzzies, no filter really does anything because when it comes to taking something away, there just isn't enough light to go around, at least not in my experience.
Posted 01 February 2013 - 12:39 PM
I've got one of those filters for my cam called 'Remove sky background' and it works even with severe LP or moonlight - how else could I survive
...The dark sky real estate filter works great too....
Posted 01 February 2013 - 10:00 PM
Me and a friend once noticed that the Andromeda galaxy showed somewhat improved contrast when using our broadband filters on our 100mm F/4 Orion SkyScanner scopes in a green/blue-zone dark sky.
Posted 02 February 2013 - 10:42 AM
Posted 07 February 2013 - 01:26 PM
As filters go I was reasonably inpressed with this filter. I used it on my Lightbridge 16 with a Meade 24mm UWA eyepiece with and without a 2x Barlow. The sky conditions were on the poor side of fair with moderate seeing and poor transparency (the best we've had in a month). The effect of these filters is always subtle and this was no exception. Overall I noticed a significant drop in sky brightness without a notable drop in the brightness of the object resulting in increased contrast. The improvement was very subtle for bight targets like M42 (a bit more of the fan was visible with the filter and the structure in the core stood out better), but it was immediately apparent for faint targets like M1 and M79. For the first time ever I had absolutely no problems finding M1 from my back yard. It wasn't bright and contrasty by any means, but easy to see as a ghostly puff of smoke rather than a slightly brighter smudge of sky glow. M79 was particularly nice as it is so low above the horizon and buried in schmuck.
Soooo, I give this filter a modest thumbs-up. It's not like turning on the lights, but it is a nice addition to my toolbox.