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Date: 19 Nov 2006 22:29:03
From: canopus56
Subject: 7 Iris - an easy asteriod - is visible
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Bright mag 6.8 asteriod 7 Iris, which is covered in the Dec. issue of
S&T, is currently visible and easily located by small aperature
telescopes and, with more difficulty, 10x50 binos. This asteriod is
about 2 deg 45' north east of eps Ari - about 7 degrees south southwest
of M45, about midway between the three main stars of Ari and M45.
Two Cartes du Ciel generated finder charts, that supplement the S&T
chart, are provided:
http://members.csolutions.net/fisherka/astronote/finder/7IrisNames.jpg
http://members.csolutions.net/fisherka/astronote/finder/7IrisMags.jpg
The easiest star hop to 7 Iris is to dead reckon to 4.3 magnitude del
Ari - a brighter star midway between M45 and the main stars of Ari, but
south southwest of M45. Dead reckoning is easier than trying to star
hop from M45. Do not confuse del Ari with the brightest star between
alf Ari and M45 - magnitude 3.6 41 Ari. If you mentally draw a line
between alf Ari and M45, 41 Ari is about 2 degs above this line; the
fainter gam Ari is about 2 degrees below that line, but closer to M45.
To the naked eye, gam - zet - eps Ari appears as a faint patch.
Look for the right-angle asterism created by del Ari, zet Ari and eps
Ari. Confirm your sighting by finding tau1, tau2 and 61 Ari. They form
a smaller triangular asterism about 1 1/2 degrees to the east of del -
zet Ari.
del and zet Ari point away to the east side of 7 Iris; nearby tau 2 and
tau 1 Aries point towards 7 Iris. Divide the zet Ari - eps Ari line in
half. 7 Iris is about 2 deg above this line proceeding towards eps Ari
through 11/29/2006. When sweeping north along the eps - 47 Ari line or
northwest along the tau1 - tau2 line, you wil have gone to far if you
cross 6.8 52 Ari.
There is only one other mag 6.8 star in the vicinity - TYC1784-00214.1.
7 Iris can be distinguished by its yellowish color.
>From a light polluted urban setting with 50mm binoculars, I was able to
find the appropriate asterisms but not the target. From a
suburban-rural light pollution transition zone using a small 60
refractor, I was able to distinguish the object from surrounding stars.
For lightcurve imagers, Henden field RT Ari, which is a no red field,
is 1 1/2 degrees south southwest of gam Ari.
- Canopus56
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Date: 20 Nov 2006 09:45:07
From: Michael Sisson
Subject: Re: 7 Iris - an easy asteriod - is visible
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In article <1164004143.546935.102060@j44g2000cwa.googlegroups.com >,
canopus56@yahoo.com says...
>
> Two Cartes du Ciel generated finder charts, that supplement the S&T
> chart, are provided:
>
> http://members.csolutions.net/fisherka/astronote/finder/7IrisNames.jpg
> http://members.csolutions.net/fisherka/astronote/finder/7IrisMags.jpg
>
Just as an aside, hopefully one that will help you out (not piss you
off!), using the correct image format on your screenshots (.png in this
case) works wonders.
Have a little read at :
http://www.r1ch.net/img-formats/
Not my webpage, but it does an excellent job of explaining the hows and
whys.
MRSisson
--
LOAD "GPL",8
SEARCHING FOR GPL
LOADING
READY.
RUN
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Date: 20 Nov 2006 07:42:35
From: Paul Schlyter
Subject: Re: 7 Iris - an easy asteriod - is visible
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In article <1164004143.546935.102060@j44g2000cwa.googlegroups.com >,
canopus56 <canopus56@yahoo.com > wrote:
> Bright mag 6.8 asteriod 7 Iris, which is covered in the Dec. issue of
> S&T, is currently visible and easily located by small aperature
> telescopes and, with more difficulty, 10x50 binos.
Why with more difficulty with the binos? A 6.8 mag object is easily
visible in such binos, and since Iris currently is near some bright
stars, it would be a matter of a few seconds to locate it with the
binos. It would probably take somewhat longer to locate it with the
small aperture telescope.
--
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Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/
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Date: 20 Nov 2006 17:10:44
From: canopus56
Subject: Re: 7 Iris - an easy asteriod - is visible
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Michael Sisson wrote:
> Just as an aside, hopefully one that will help you out (not piss you
> off!), using the correct image format on your screenshots (.png in this
> case) works wonders. Have a little read at :
> http://www.r1ch.net/img-formats/
Thanks, Michael. I have been sticking with jpg assuming that it was
more cross browser compatiable. But as your page notes, png is now
broadly supported by all browsers and is the better format for this
type of graphic. - C
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Date: 21 Nov 2006 07:42:43
From: Paul Schlyter
Subject: Re: 7 Iris - an easy asteriod - is visible
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In article <1164071443.989542.278980@b28g2000cwb.googlegroups.com >,
canopus56 <canopus56@yahoo.com > wrote:
> Michael Sisson wrote:
>> Just as an aside, hopefully one that will help you out (not piss you
>> off!), using the correct image format on your screenshots (.png in this
>> case) works wonders. Have a little read at :
>> http://www.r1ch.net/img-formats/
>
> Thanks, Michael. I have been sticking with jpg assuming that it was
> more cross browser compatiable. But as your page notes, png is now
> broadly supported by all browsers and is the better format for this
> type of graphic. - C
Png may be supported by *most* browsers or by *all popular* browsers,
but it's not supported by ALL browsers. Here's a browser that doesn't
support png:
http://lynx.browser.org/
Btw, that browser is still being developed....
--
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Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/
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Date: 20 Nov 2006 17:08:46
From: canopus56
Subject: Re: 7 Iris - an easy asteriod - is visible
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Paul Schlyter wrote:
> Why with more difficulty with the binos? A 6.8 mag object is easily
> visible in such binos, and since Iris currently is near some bright
> stars, it would be a matter of a few seconds to locate it with the
> binos.
Just the shakiness inherent in using binos. I just found 7 Iris easier
to appreciate with a fixed mount. - C
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Date: 21 Nov 2006 07:42:43
From: Paul Schlyter
Subject: Re: 7 Iris - an easy asteriod - is visible
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In article <1164071326.182294.327160@m73g2000cwd.googlegroups.com >,
canopus56 <canopus56@yahoo.com > wrote:
> Paul Schlyter wrote:
>> Why with more difficulty with the binos? A 6.8 mag object is easily
>> visible in such binos, and since Iris currently is near some bright
>> stars, it would be a matter of a few seconds to locate it with the
>> binos.
>
> Just the shakiness inherent in using binos. I just found 7 Iris easier
> to appreciate with a fixed mount. - C
I fully agree with the mount issue of course. However, binoculars too
can be put on some fixed mount, e.g. a camera tripod. Good binoculars
come with an adapter for mounting on a standard tripod; for other
binoculars that adapter is an extra accessory which is quite cheap.
And even if you hand-hold your binoculars, you can put your elbows on
some support, and get a much steadier view that way. But if handheld,
7x binos are somewhat preferable to 10x binos. And if you're
middle-aged or older, don't bother using 7x50 binos (your eye pupils
cannot expand to 7 mm anyway) - use 7x35 binos instead: they're
cheaper, smaller, lighter, easier to hold steady -- and they'll show
you an image no fainter than the 7x50 binos.
Anyway, I could use a pair of handheld 7x35 binos to find Iris at its
current magnitude in a matter of seconds, assuming a sky that's clear
and dark enough. To set up a small telescope to view it would take
minutes. And even if you have an observatory with your telescope
permanently mounted, walking there and opening it up would probably
take at least a minute or two, which is longer than the seconds it
takes to find Iris with binoculars.
Mounting the binoculars on a camera tripod would take perhaps some
30 seconds, and finding Iris with the binos mounted perhaps another
15 seconds - a total of less than one minute.
--
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Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/
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