CESDewar
GorillAstronomer
Reged: 01/16/05
Posts: 1679
Loc: Morganton, GA, USA
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M51 is a fine target for binoculars under dark skies, but when Light pollution encroaches, it can become a very difficult target. Neverthless, it is one of the finest galaxies in the sky, so it's definitely worth trying to locate it.
When searching for it in binoculars, it helps a lot to know precisely where M51 is located. If you know that M51 is around 3-4 degrees away from Alkaid in the general direction of Cor Caroli, you may not notice it under borderline viewing conditions.
I find it best to locate Alkaid, and then move towards Cor Coroli and back a bit towards Mizar to locate two relatively bright stars (HIP66385 and 24 Cvn) which should be in the same FOV as Alkaid in most binoculars. These two stars then form a nice pointer to one corner of a trapezoid of 7th mag stars which includes m51. The two pointer stars and the trapezoid that includes M51 is also shown in the overview, so you can be sure to look in the right direction for that pair of pointer stars.
It also helps to know the precise TFOV (True Field of View) of your binoculars so you can accurately gauge the scale of these maps. A typical pair of 10x50 binoculars will have a TFOV of a bit over 5°.
If you have poor skies, it will take some tricks to eke M51 out of the background. Use averted vision to look at any one of the three other stars of the trapezoid and then gently sway the binoculars back and forth. With this star chart, you will now know exactly where M51 is and that should help coax it out of the background.
Under darker skies and at higher magnification, you should be able to see the two separate parts of M51 and also see the orientation. I can just barely make that call with my 18x50 binoculars under SQM 21+ skies. As for smallest binoculars to see M51, I have seen M51 in my 5x32 binoculars under really good dark skies. Cor Coroli is a nice double but too tight for anything but larger binoculars as the separation is only 21".
And if you still find it hopeless from your location with these charts, take it as encouragement to make a sojurn to some really dark skies - you will be amazed at how easy it is to find M51 under those conditions and even if it's a long drive, I'm sure you'll agree it was worth the effort!
Good luck hunting.
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Edited by CESDewar (05/24/08 01:40 AM)
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camvan
Carpal Tunnel
Reged: 05/02/05
Posts: 2079
Loc: British Columbia
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M51 is one of my most favored object to look at with bino's! in fact, it's one of the key objects I hunt for...if I see it easily in my 7x50's, I know it's going to be a good night! 
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Cameron
President of the Kamloops Astronomical Society
"Aperture can only be replaced by even more aperture. Dark transparent skies cannot be replaced by anything else." - Stathis Kafalis
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SkyG
member
Reged: 09/04/07
Posts: 34
Loc: London
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Thanks for the great instructions and top pics. I look forward to training myself and my bins to find the it!
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WO ZD66, Miyauchi Exceeds, besser 10x50, WW2 RAL 7x50s, ZEISS 10X50W Jenoptem
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2295
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Thanks yet again for another one of your fine drawings!
Wes
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mttafire
Pooh-Bah
Reged: 02/02/06
Posts: 1114
Loc: midwest
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Almost any moonless night that is clear M51 can been seen with binos; on my DECK! Its nice to not have to leave your backyard for astronomy.
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God Bless America
Binocular astronomy
for me ONLY.
8x45 Garretts
15x70 Skymasters
2 eyes!
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Nick Lloyd
Carpal Tunnel
Reged: 10/24/06
Posts: 1536
Loc: cincinnati
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I was skeptical that I could see M51 in binoculars. Found it last night! Thanks for the inspiration and guidance.
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"The best scope is the one you use." -rcg
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edwincjones
Post Laureate
Reged: 04/10/04
Posts: 4104
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your sketches (this one and others) make it so easy to find
keep them coming
edj
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n w arkansas
Binocular, Solar, General Amateur Astronomy
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BobinKy
scholastic sledgehammer
Reged: 04/27/07
Posts: 875
Loc: Country road
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CESDewar--
Your reports are amazing--truly amazing! I really enjoy both your finder charts and your narrative. As always, you set a high standard for the rest of us to follow. 
Thank you for sharing your work.
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Bob
38° Kentucky, USA
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5176
Loc: San Francisco Bay Area, Calif...
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M51 is esay to see in binoculars, however if you are looking through high, thin clouds, M51 may get lost in the sky glow. It helps to have relatively transparent skies so that you have good contrast between the background sky and M51.
If you are using binoculars with a field of view roughly like the detailed star chart above, you will see M51 much like it is in the drawing but the cores are less clear. If you took that drawing and simply reduced the brightnes of the two cores you would have a pretty accurate picture of M51 through a hand held binocular.
Through a telescope, using a bit more power and more aperture, the cores of the two galaxies stand out much more than in the low power view through a binocular.
In the Summer, in the SF Bay Area we often have nice tranparency once we get above the low marine layer. This means getting up into the hills that ring the bay.
Good luck,
Rich
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5176
Loc: San Francisco Bay Area, Calif...
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I see the pair of stars (24Cvn and HIP66385) that form a line away from Alkaid as a brighter and easier to find pair than the wider and less bright pair near M51. That less bright pair make a line roughly perpendicular to the brighter pair. To me the difference in brightness is greater than the detailed chart above shows. But, it is still a very nice chart.
When looking for M51 I think of a line between Mizar and Alkaid, then I make a right angle turn at Alkaid and go away from Alkaid little more than half the distance separating Mizar and Alkaid.
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starramus
Pooh-Bah
Reged: 09/01/04
Posts: 1124
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If your skies are dark enough you will notice NGC5195 as a slight nub towards the north off the body of M51. Thanks to Amalia and her Happy New Binos thread and of course darker skies I was able to see this additional detail.
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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5176
Loc: San Francisco Bay Area, Calif...
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In modest power binoculars the combination of M51 and NGC5195 look like an elongated smudg. With more aperture and magnification it is easy to see the cores of M51 and NGC5195 like a pair of glowing eyes. With darker and more transparent skies the rest of the two galaxies come into view.
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Mr Q
sage
Reged: 02/25/08
Posts: 280
Loc: N Central New Mexico
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After years of observing M51 with a scope, the other night I gave it a shot with 10x70s and, knowing its location, it was nice to see the elongated shape of its companion, though small and fairly faint. I too was under the impression that this object was not a likely candidate for binos but was wrong all these years. Now I'm on a quest to observe other previous "scope only" objects. Mr Q
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What goes around, comes around, eventually.
Meade DS-10(10" newt)
10x50, 10x70 binos
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Greg K.
Reged: 12/11/03
Posts: 9494
Loc: Clifton Park, NY
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In dark skies M51 is easy to see in my Orion 9x50mm finderscope, and I've seen it in my 15x70s as well. Definitely a nice target.
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NexStar 11 GPS
Orion SkyView Pro 8EQ w/ Autostar
15x70 Celestron SkyMasters
Orion 90mm Mak
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