Used acronyms: NEML=Naked Eye Magnitude Limit, SQM=Sky Quality Meter, TML=Telescope Magnitude Limit, CO=Central Obstruction, delta_m=difference in magnitudes between double star components, RoT=Rule of Thumb, pD_mm=proposed D_mm for resolving a binary (ident with earlier used pA=proposed Aperture), D_mm=Diameter (of scope) in mm, UCAC4=USNO CCD Astrograph Catalog 4th edition
150mm MCT f/13, 31% CO
"People say I'm in denial. I disagree."
Meade 305 ƒ/10.4 LX200 • Royce 250 ƒ/19 Dall Kirkham • AstroTech 250 ƒ/8 RC • AstroTech 250 ƒ/4 "RFT" Newtonian • Meade 80 ƒ/6 ED APO • TEC 140 ƒ/7 APO • Orion 180 ƒ/15 Mak Cass ... Denkmeier II binoviewer - Nikon 8x60 binocular
Astronomical Files from Black Oak Observatory
Quote:...but night to night i just examine the visible nimbus around a 3rd-6th mag. star: the "diffusion scale" is just the magnitude at which a noticeable nimbus first appears. (if you don't see a nimbus around Sirius then your diffusion is zero!) the point of the standard eyepiece is that there is scatter in your optical system, too. don't blame the sky for that.
Quote:...One question, though, I've asked before, is how does light below the visible threshold affect a faint companion that /should/ be well above that threshold? ...
Quote:So far I found Deneb of good use for this task: The +11.74 mag companion is in a distance of ~75" giving a good reference for the size of the halo and there are several faint stars ~12mag nearby.
Quote:Aerosol blurring is more sever on brighter stars and falls off on dimmer stars. But, does that mean we can see closer unequal pairs on dimmer stars?
I ache, therefore I am
Quote:The concept I am trying to get my head around is the decrease in blur visibility (falling off below the visible threshold) still affects a dimmer companion that would otherwise be visible...bright enough to peek above a dark sky background but not a background that 'appears' dark.
Quote:...The jury is still out for me as to how much light pollution reduces limiting magnitude...