B33 CanonEOSII Rebel T7i using a 'TPO 80A light-blue 2in. filter' thru a TeleVue 2XPowerMate for 2400mmF/L . I saw in 'cloudynights.com' about 30sec images with filters with an 85mm f2 lens will do the Antares area . So, I'm thinking that using a 2400mm setup that what would be if a 100mm f2 lens was being used and that 100 into 2400 would be ' 24 ' and 24 times 30sec is 720sec or 12minutes . This image is 9minISO6400 and maybe it should be at least 12minute images no matter what filter I use , so I will try to do that when an 'object' has real low light content like the HorseHead Nebula .x
