From: Brian Skiff
Newsgroups: sci.astro.amateur
Subject: Messier 81 naked-eye
Date: 10 Jan 1997 18:40:31 -0800

     As mentioned briefly in the binocular-observing post, I was able to see
M81 naked-eye last night from Lowell's Anderson Mesa dark-sky site.  In case
others would like to try this, here are some details.  For reference, have a
look at Uranometria chart 23.
     The two galaxies lie in a string of faint stars that starts with 24 UMa
(also the variable DK UMa) at the west end, and arcs eastward and a bit south
past M81 and NGC 3077 to a mag. 6 star appearing on chart 24 (brightest of a
triangle).  M81 in fact is one element of the string.  To have a hope seeing
M81, you need first to identify several of these stars.  The brighter star
about 1.5 degrees west of M81 is HD 83489, at V mag. 5.7.  Next identify the
fainter star at the east end of the string (the one on U2000 chart 24), which
is HD 89343 = EN UMa, a very small-amplitude delta-Scuti star, at V mag. 6.0.
     Now, between HD 83489 and 89343 I consistently saw (glimpsed is a better
term, however) at least three star-like objects.  First, about 1.5 degrees east
of M81 (and just west of HD 89343), is HD 87703, which is V mag. 7.1.  If this
star isn't pretty readily visible (at say the 20-30 percent detection level),
then you probably won't be able get the galaxy.  Much more difficult (at the
5-10 percent detection threshold) is the group of stars shown on the U2000
chart near NGC 3077.  These are HD 86458 (V=8.0), HD 86574 (no photometry, but
roughly mv=8.0), and HD 86677 (V=7.9).  I saw these three (or perhaps just the
closer pair 86458/86677) as a single object.  Assuming V=8.0 for 86574, the
combined brightness of the three stars is V=6.8, but the extended nature of the
trio means the surface brightness will be lower to the naked eye than a single
star of that magnitude, making it more difficult to spot.
     The third object, repeatedly spotted in the same (correct) place, is M81!
Again, this is a threshold object, which I detected only 5-10 percent of the
time with optimally-averted vision together with the other faint stars just
mentioned.  On occasion I also seemed to pick up another star, HD 85828, which
is about 40' south of the galaxy.  This star has no published photometry either,
but has a rough magnitude of 8.0.
     My observation is neither all that remarkable nor unprecedented.  Appended
below is a response to this observation from Brent Archinal.  The SAO star he
mentions seeing is HD 87703 from the foregoing.  I think the three previous
visual sightings are not the only ones published.  I vaguely recall a brief
Sky & Telescope letter or note (late-60s or early-70s?) discussing the
visibility of M81 and other bright galaxies, such as NGC 253 and NGC 5128.
Perhaps someone with a collection of old S&T's can dig that one out for us.
     Both NGC 253 and NGC 5128 are somewhat closer than M81, which is
probably the most distant discrete object visible to the unaided eye, at
something like 3.6 megaparsecs (11.8 million light-years)!
     Having tried this observation seriously (and unsuccessfuly) twice before,
I found the key this time was getting all the field stars sorted out.  Because
there are several stars of similar brightness nearby, you really must be able
to identify each of these in order to securely locate the galaxy.  As mentioned
in the binoculars post, I was using the 6x30s as a guide, which I don't have a
problem with, although it could probably be done using only unaided eyes and a
chart such as the relevant field from the Tirion "Sky Atlas 2000", which shows
all the necessary stars.

\Brian Skiff  (bas at lowell.edu)

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From: Brent A. Archinal
Subject: Re: Minor observing milestone
To: bas at lowell.edu
Date: Fri, 10 Jan 1997 13:34:39 EST

>      A fine photometric night tonight (10th Jan UT) with typical very-low
> wintertime extinction.  While doing some binocular observing with my
> marvelous Fujinon 6x30s, I spotted M81 quite convincingly naked-eye.
> This by the way, from the catwalk of the Lowell 1.1-m on Anderson Mesa.
> Yipee!
> \Brian


Brian -

Sounds like a wonderful night!  Congratulations on the naked-eye
observation of M 81.  By my count, this brings to four the number of
people who been able to do so, including Stephen O'Meara, myself, and
Aristides Tzarellas (Webb Society "Deep-Sky Observer", Oct., 1996, p. 1). 
Could you also see SAO 15100 (V=7.2) to the east?  This was the faintest star
visible in the area (10 degrees above the horizon!) when I managed my
observation from Colorado.


Regards,
- Brent
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