Rosetta Nebula H-alpha version Main optics: TS ED-APO 90/500 mm with QHY9M @-30°C Filter: Astrodon H-alfa 6 nm, Filterwheel StarlightXpress Guiding: Celestron 102/660 mm with Atik16ic, filter UHC Mount: EQ-6 Pro with EQMOD Stacking : DSS, white and black point correction, small noise reduction. exposures. 36x900 seconds