Quote:
Originally Posted by swannies1983
I was just wondering is there some sort of 'rule of thumb' or 'crude' way of roughly estimating the ZHR under different sky limiting magnitudes?? i understand that many factors will impact this number. However, I'm just trying to get some idea. For example, with the current Orionids....the predicted ZHR is about 25 under perfect conditions. What could I expect under suburban Adelaide skies?
What about the Geminids? The predicted ZHR is 120.
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yes there is swannie, but considering ZHR is an imaginary/theoretical figure anyway, as the radiant is rarely/never at the zenith of course (unless your at the equator for this one when it crosses meridian) first you have to deduct the degrees away from zenith in the equation to give you the actual possible, and remember that is also under 6.5? mag pristine 'nearly as good as it gets' skies/conditions, rate.
I can't remember the simple equation for it offhand tho, and anyway thats changing rapidly every degree the radiant rises anyway, so its not really important once you know that, but take it into account.
then you have to know the known averaged overall median brightness of the shower members, its usually about +3 +4 area overall, thats what the leonids usually are for instance, in 'normal' years, some showers brighter, some dimmer averages.
i guess you could take that in to account with your local LM to get a rough idea anyway. but i find in the suburbs trees and buildings/houses get in the way just as much as LP with showers, and particle pollution is heaps worse in town, and imo, adds to the problems of visibilty.
i like wide open treeless areas for showers if possible
If the shower is a bit mild, you know in binocs your LM goes up, so you can see the dimmer previously invisible meteors zip thru fov, i have entertained myself that way in a dim shower once - was great to do now and then in lulls
i remember a storm (leonids?) but all the meteors were about mag +7 thru to mag 10 or something LOL radio obs catches it all tho - invisible meteor storm - cool!