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- From: chaloux@accordion.mitre.org (Dave Chaloux)
- Subject: Re: Evaluation of Filters for Urban Areas?
- Message-ID: <1992Aug18.115337.4440@linus.mitre.org>
- Sender: news@linus.mitre.org (News Service)
- Nntp-Posting-Host: accordion.mitre.org
- Reply-To: chaloux@accordion.mitre.org (Dave Chaloux)
- Organization: The MITRE Corporation, McLean, Va
- References: <1992Aug17.131116.1@novax.llnl.gov> <1992Aug17.204325.10277@pony.Ingres.COM>
- Date: Tue, 18 Aug 1992 11:53:37 GMT
- Lines: 40
-
- George F. McQuary asks:
-
- >I keep seeing these ads proclaiming "Suddenly, there it was --The Veil
- >Nebula!" So of course now I want to ask those who actually know.
-
- >Are the results from filters really that dramatic in urban areas? What if I'm
- >not doing photography but only my own direct visual observations?
-
- etc.
-
- Speaking from my experience the results of using a filter can be dramatic. The
- operative words are "can be". I live under relatively good skies that get
- down to about 6.1 or 6.2 on the best nights at the Zenith. Poorer skies to the
- NW-NE.
-
- I have a Orion Deep Sky Filter. When used with my Celestron 8" SCT the results
- were frankly disappointing. Not quite bad enough for me to want to sell it but
- disappointing. The only objects that showed any improvement were nebula. They
- showed only small gains. The biggest help was with faint Planetary nebula for
- identification purposes. Even there the help was marginal.
-
- I now have a large Dobsonian working at F5. I decided to try the same filter on
- some objects. BIG HELP. I couldn't believe the difference. The veil was there
- with or without the filter but was much prettier and more detailed with the
- filter. Same with the Lagoon, Swan, Trifid, and Eagle.
-
- In terms of which ones to get, "The Backyard Astronomer" says that the Orion
- Deepsky and UltraBlock filters are basically equivalent to the Lumicon
- Broadband and Narrowband filters. The same is NOT true about the Meade and
- Celestron filters which basically take the middle ground. I have heard very
- good things about the OIII filter but have not used one. It will probably be
- my next purchase for a filter.
-
- My thinking is that once I get the OIII I will probably use it the most. However
- I will still want the Deepsky filter for use on Nebula involved with star clusters
- such as the Planetary in M46, the Eagle, etc.
-
- I guess my real advice would be this. Don't buy unless you can return them.
- From my experience the results can be very different on different scopes.
- On some they really pay off and on others the benefit is pretty marginal.
-