All, Do any of you own 2-inch color planetary filters? The reason I'm asking is, I have the perfect telescope for doing image comparisons if you do. I own a 16-inch f/6.25 Astrosystems Telekit, with their filter slide that is built-in under the focuser; I can mount up to 3 two-inch filters and, without removing my eye from the eyepiece, the filters can slide into and out of the field of view. I'm therefore free to use any 1.25 or 2-inch eyepiece, and make immediate comparison to the view with/without a filter. So far my only 2-inch filter is a Lumicon O-III, but eventually plan to acquire some 2-inch color filters; I'm particularly interested in observing Mars in the coming months. I had a number of people from ALPO last summer tell me #25 red is one often used for Mars. Anyway, I'd like to try several colors, but so far all the people I know only have them in the 1.25" format. Alas, I've been a victim of the bad economy for nearly the past year, and am in a rather big financial hole, so buying these won't happen right away (despite the fact that they are not very expensive). But if any of you own some, or could easily afford to purchase a few for this occasion (Orion sells a set of 4 for about $89, and both Astrosystems and Hands-On optics sell them between $12 and about $20 each), please let me know and I'd be happy to haul out the 16-inch for such an event. FWIW, Rich --- Brent Watson <brentjwatson@yahoo.com> wrote:
Rich and Jim,
Rich, you have the right idea. A small group of amateurs that all have the same interests are what is needed. What is required is folks who are willing to observe the differences.
Jim, the filter must be compared in the same telescope. Since all telescopes are not created equal, having a filter in one and comparing it to the image in another is not a good comparison. You need to take the uncertainty of the telescope out of the experiment. Comparisons of filter vs. no filter or filter against filter can only be done in the same telescope. Certainly, filters can be passed from one telescope to another to see how they perform in that telescope. This is the reason I don't feel comfortable sharing a telescope. These observations need to be made uninterrupted to be of value.
Brent
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