[. . . ] DSI North America. Active 150 things is Å/°C ground; Double Stacking - This greatly increases contrast by narrowing the bandpass to <0. 5Å and gives a spectacular 3D effect showing increased surface detail. [. . . ] An or a second external etalon & T-Max tuner can be matched and installed. This will greatly increase contrast by narrowing the bandpass to < 0. 5 Å and increase surface detail. Contact Coronado directly for pricing and to schedule your upgrade. Å/°C 70 70 Double Stacking - This greatly increases contrast by narrowing the bandpass to <0. 5Å and gives a spectacular 3D effect showing increased surface detail. The SolarMax 90 is double stacked by installing a matched 60mm etalon inside the OTA or attaching a second matched 90mm external etalon & T-Max. Double stacking filters must be matched to the primary etalon with blocking filter. The SolarMax 90 telescope can be ordered this way or later upgraded by Coronado. [. . . ] Meade/Coronado reserves the right to change product specifications or to discontinue products without notice. PN: C901900 [. . . ]