[AZ-Observing] Re: Tonight (Friday)
- From: Frank Kraljic <fjkraljic@xxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Sat, 24 Feb 2007 01:25:00 -0700
Jeff,
I haven't been following this thread too closely, but to my knowledge
seeing and photometry are not related to each other. Transparency
and photometry, yes, but not seeing. For example, I've experienced
great seeing (in excess of 500x on Mars and Jupiter with sharp
results) under cirrus conditions, which should invalidate any
photometry data. Although many on this list would quantify seeing
based on observable double star separations (i.e. sub-arcsecond,
arcsecond seeing), I personally value the seeing based on how high a
magnification I can put on a stellar or planetary object and attain a
fine airy disk or observe extreme fine detail on the planets (based
from experience). In my opinion, the seeing is decent if one maxes
at 250x. Once you get past 400x with sharp images (assuming one's
scope is also in proper collimation), then I would classify seeing as
good. I'll admit this is a subjective approach to the topic.
Hope this may clarify any semantic differences when classifying the
night as great in terms of seeing, transparency, or both. Perhaps
Brian can fill us in on the professional definitions and differences
of photometric, spectroscopic, etc. nights.
-FRANK
On Feb 23, 2007, at 7:52 PM, Jeff Hopkins wrote:
> Hello Janis,
>
> I just came in from doing JH band photometry with the 12" LX200. It
> looks like another great night. Just to be sure when I fished my
> photometry I swung the telescope down to Orion and M42. M42 is
> spectacular. The stars of the Trapezium were very distinct. At 7:40 I
> was treated to a slow moving UFO just below the Trapezium. I followed
> it for awhile, but it was too small to resolve any detail.
>
> I won't know the photometry data spread until I reduce the data, but
> can tell it will be another good night.
>
> Jeff
>
>
> At 07:30 -0700 02/23/2007, Janis Schoenfeld wrote:
>> Jeff.....This really is most interesting. As I live practically down
>> the street from you to the west, at an almost identical latitude, the
>> seeing was pretty dismal here (8 p.m.-ish). With M42 and environs
>> in an
>> absolutely primo position in early evening sky right now, I had hoped
>> for a good session with it and was able to resolve very little detail
>> using a 12" SCT (even the large dust lane failed to show), so I
>> packed
>> up about 9 p.m..
>>
>> If you truly have some kind of a bubble over you, I guess the
>> solution
>> is to drag the scope down the street and leave it in your backyard
>> and
>> come visit you and those wonderful critters of yours a lot. Do
>> you cook?
>>
>> Best, Janis
>
> --
> Jeff Hopkins
> HPO SOFT
> Counting Photons
> http://www.hposoft.com/Astro/astro.html
> Hopkins Phoenix Observatory
> 7812 West Clayton Drive
> Phoenix, Arizona 85033-2439 U.S.A.
> (623)849-5889
> www.hposoft.com
> --
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