Quote:
Originally Posted by Blue Skies
We really want to know... is whether an 8" is enough aperture to pick up this star using a focal reducer and my gstar camera
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Hi Jacqui,
Short answer... YES!
Slightly longer answer... Yes, an 8" f10 SCT with a f3.3 focal reducer and a Gstar camera is enough for you to detect the mag. 15 target star and mag. 14 Pluto.
Longer answer... Yes, an 8"... blar blar blar... I use my 8" LX90 and WAT-120N to observe asteroid occultations of faint stars. I prefer my 10" newtonian as it's already set up and lives in my skyshed ready to go with the minimum of fuss, but the 8" SCT is good enough. The 10" gives a slightly better Signal to Noise video but not by much. A 12" 14" or 20" will give you even better S/N @ a faster frame rate but in the end, if you use what you have to the best of your ability, you can't go wrong.
Remember, the mag. 14.0 Pluto will merge with the mag. 15.2 target star and the pair will brighten to mag. 13.7 and if/when the star disappears you will see a mag. 0.3 drop in brightness.
Bottom line. In the days before the event, practise observing Pluto appulsing (approaching) the star to determine the fastest frame rate you can achieve to "only just" detect the target star. This is best done at a similar time of the event so that the targets are at a similar altitude and so atmospheric extinction will be the same as that on event night. This, in the trade is called a mocultation... mock-occultation.... get it...
