ZWO 1.25" LRGB Filter Set
This filter set from ZWO includes four 1.25" mounted filters: Red, Green, Blue, and Luminance. They are a great match for the ZWO five-position color filter wheel. The filters have high transmission (over 90%), are anti-reflection coated on both sides and have IR-Cut built in.
- Additional Information
SKU ZWO-LRGBSET1 Manufacturer ZWO Type of Filter LRGB Filter Usage Imaging Single or Set? Filter Set Filter Size 1.25" Filter Shape Round Filter Mounted? Mounted Warranty 2 Year Warranty Filter Kit Contents Blue (B), Green (G), Luminance (L), Red (R)
- Included Items
- Red 1.25" Filter
- Green 1.25" Filter
- Blue 1.25" Filter
- UV/IR Red 1.25" Filter (for Luminance)
- Questions & Answers
Product QuestionsQuestion by: falcoleprof on Mar 1, 2014 7:20:58 AMThe ZWO filters' substrates are made to be of the same thickness. So at the most broad level, yes, they are meant to be parfocal. However, much like APO in the world of refractors, that term could use a little further explanation...
Filters introduce additional refraction in the optical path. With this being a function of the thickness and refractive-index of their substrate, two filters using the same substrate (at the same thickness) will equally effect refraction, and be considered parfocal.
However, the filters are only one part of the optical-system. If the telescope itself or accessory optics (flatteners, reducers, tele-extenders) use refractive elements (lenses), it will be helpful if not necessary to refocus between parfocal filters. This will be especially true if the combination of telescope focal-length and camera pixel-size lead to very high sampling-resolution.
So to offer the best answer to your question: yes, these filters are supposed to be parfocal, but depending upon the telescope and optical accessories in use, you may still need to refocus between filters to obtain the sharpest images for every channel.Answer by: Eric_B (Admin) on Mar 3, 2014 5:38:00 AM
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