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Re: (meteorobs) Questions from Costa Rica [II]

>Two questions here for you and the list:
>1. What does THZ stands for?

Our Spanish-speaking friends can confirm this, but I'd guess this is the
Spanish acronym for "Zenithal Hourly Rate", or "ZHR" to us anglophones!
This is the *THEORETICAL* (doubly emphasized) rate of meteors a perfectly
attentive observer would see from an unobstructed sky with Limiting
Magnitude 6.5, *if* the shower's radiant point were at the Zenith, and the
observer happened to be watching at the exact peak time of the shower... A
useful number for comparison, but not necessarily anywhere near what YOU
will see!

>2. Is it possible to watch these minor showers from a medium light 
>   polluted place like my city?

It may be possible! I watch meteors from my backyard, just five miles from
downtown Boston, Massachusetts sometimes. But keep in mind that you'll see
far FEWER meteors! If your "Visual Limiting Magnitude" (a very important
number to know and measure when meteor observing) is 5.5 instead of 6.5,
you'll see only one HALF to one THIRD as many meteors!

Also, under most circumstances the IMO (International Meteor Organization)
does not suggest reporting meteor observations unless your "LM" is at least
5.0... From my Medford backyard, I can generally JUST get an LM of 5.0 to
5.5 on the clearest nights. For MINOR showers (like the ones you mention),
they also suggest you only COUNT that shower if you will see more than 1-2
per hour: for really minor showers, this often means you need to see the
whole ZHR! So to record data for IMO on the Delta Leonids for example,
you'd need to watch quite close to their max night, and you'd need to do it
from a dark site!

Still, even if your data for a given shower may not be reported to IMO for
whatever reason, it can still be VERY useful and enjoyable for YOU! Still,
at first you may want to pick nights - OR sites - where you'll get at least
5-10 meteors per hour. (Otherwise, you may get bored, and certainly won't
learn as quickly.) This means either watching a major shower max (Lyrids
are coming soon), or watching any night, but from a DARK site...

Also, to maximize the meteors you see when you're starting out, I STRONGLY
suggest watching when there's no moon up, when it's quite clear, and also
AFTER MIDNIGHT: this is when by far the most meteors are seen!

OK... Confused and overwhelmed yet? ;>

>Until next time, clear skies to all.
>Carlos Hernandez

Clear skies to you, and keep those questions coming!
Lew