I've been doing a lot of measuring of fields of view lately in preparation for a new binocular article. This is an excerpt of some of the data used to check Max FOV. You may find it useful. Clear skies, and if not, Cloudy Nights. edz True Field of View TFOV is how much an area of sky you can see at once. FOV is measured in degrees. From horizon to horizon is 180 degrees. Human eyes can take in about 50° to 60° degrees of sky without any optical aid. The distance across Orion's Belt stars is a little less than 3 degrees, considered a small field of view for binoculars. When panning the sky looking for objects it is much better to have a 4° to 6° Tfov at a minimum. Oberwerk 15x70 have a 4.4° Tfov. Orion Ultraview 10x50 have a 6° Tfov. Minolta Activa 7x35 have a 9°+ Tfov Even a 3.5° Tfov begins to make it difficult to orient yourself to the night sky. I have used two different binoculars with fields of view of 3.3° and 3.2°. They were more difficult to use than even 4.2° (Pentax 12x50) and 4.4° (Oberwerk 15x70). For a while I used a pair of 25x70 binoculars that had a 2.6° fov. The 25x70s were mounted for all viewing and although magnification was outstanding, the fov was restrictive and made it difficult for finding objects. Binoculars with a field of view 2 degrees or smaller would be similar to looking thru a telescope eyepiece. You would need a finder scope mounted on top of the binoculars to find anything. Star Fields You Can Use for Measuring Max FOV of Your Binoculars True measure of the FOV can be obtained by noting the limits of star fields and referring to SkyAtlas 2000.0 or Uranometria 2000 for a measure of the field limits. (Refer to the Accessories - Books and Charts section to see my review of SkyAtlas 2000.0 and other Books for Astronomy). I was doing this so often in various areas of the sky that I decided it best to list the measures I was using. I have numerous measures I have taken to obscure stars, getting more exact, but that would lead to confusion. These are the easy to see, easy to remember fields that anybody can use. The data columns listed for SkyAtlas and Uranometria are the measurements in mm determined from SkyAtlas 2000.0 or Uranometria 2000 of the actual measurement in the charts between the two points. The baseline is 82mm per 10° in Sky Atlas 2000.0 and 184mm per 10° in Uranometria. That never changes, the scale remains the same, unlike Right Assencion. RA of 15min at the equator covers a lot more distance than RA of 15min at Dec70°N. A degree is a degree, no matter where you are in your chart. When the measurements varied between the two charts by 0.1°, in general that is only a variance of 2% to 3%. The resultant FOV listed is a rounded off average of the two chart books. There is no need to take the time for a star to drift across the fov of your binoculars. Simply sight stars at the very edge of the field of your binoculars. There is no better indicator of Max fov for your binocular than to look thru it and measure what you see. Much better measurement can be recorded with mounted binoculars. Mounting the binocular adapter on top of an Orion slow motion adapter helps tremendously. Use several readings on different fields to verify your results. Fields for Measuring Max FOV SkyAtlas 2000.0 Uranometria 2000.0 FOV ° point A point B 82mm = 10° 184mm=10° 82 184 mm fov° mm fov° UMi 1 3.2 B 7 UMi y 13 UMi front of the cup of Little Dipper 25.5 3.11 59 3.21 UMi 2 2.7 z 16 UMi n 21 UMi back of the cup of Little Dipper 22 2.68 51.5 2.80 UMi 3 4.8 z 16 UMi B 7 Umi top of the cup of Little Dipper 38.75 4.73 89 4.84 UMi 4 5.4 n 21 UMi y 13 UMi bottom of the cup of Little Dipper 44.25 5.40 101 5.49 UMi 5 3.9 z 16 UMi 15 Umi top of Little Dipper but only to #15 32 3.90 UMa 1 5.4 a 50 UMa B 48 UMa front of the cup of BIG Dipper 44 5.37 98.5 5.35 UMa 2 4.5 d 69 UMa y 64 UMa back of the cup of BIG Dipper 36.5 4.45 83 4.51 UMa 3 10.0 a 50 UMa d 69 UMa top of the cup of BIG Dipper 82 10.00 UMa 4 7.9 y 64 UMa B 48 UMa bottom of the cup of BIG Dipper 64.5 7.87 Dra 1 2.9 B 23 Dra v 24 Dra west side of Draco head shortest 23.75 2.90 53.5 2.91 Dra 2 3.4 v 24 Dra z 32 Dra north side of Draco head 27.75 3.38 63 3.42 Dra 3 5.4 z 32 Dra y 33 Dra east side of Draco head longest 44.25 5.40 99 5.38 Dra 4 4.1 B 23 Dra y 33 Dra south side of Draco head 33.5 4.09 76 4.13 Cas 1 4.9 B 11 Cas a 18 Cas brightest two west side W 39.5 4.82 90 4.89 Cas 2 3.6 y 27 Cas d 37 Cas two closest stars in the W 28.9 3.52 66.5 3.61 Cas 3 3.0 y 27 Cas n 24 Cas center of W south to eta 25 3.05 56 3.04 Per 1 3.7 a 33 Per d 39 Per Mirphak to brightest east 30.25 3.69 68.5 3.72 Per 2 4.8 a 33 Per y 23 Per Mirphak to brightest northwest 39 4.76 87.75 4.77 Per 3 2.1 z 44 Per o 38 Per Perseus foot just N of Pleaides 17 2.07 38.8 2.11 Tri 1 2.0 B 4 Tri y 9 Tri the short base of Triangulum 16 1.95 36 1.96 Tau 1 3.2 a 87 Tau e 74 Tau Aldeberan across the open V, the Hyades) 26.25 3.20 59 3.21 Tau 2 4.0 a 87 Tau y 54 Tau Aldeberan to the point of the V the Hyades) 32.75 3.99 73 3.97 Tau 3 2.4 a 87 Tau 71 Tau part way along bottom of V 20 2.44 45.25 2.46 Tau 4 2.7 74 Tau 63 Tau part way along top of V 22 2.68 50 2.72 Aur 1 2.8 e 7 Aur n10, z8 Aur The Kids triangle (7, 10, 8 Aur) in one view 23 2.80 51 2.77 Ori 1 2.8 z 50 Ori d 34 Ori Orion's Belt stars 22.5 2.74 50.75 2.76 Gem 1 4.5 a Gem B Gem Castor to Pollux 36.5 4.45 83 4.51 Gem 2 3.5 a Gem 75 Gem 75 is just north of Pollux 29 3.54 65 3.53 Gem 3 2.6 1 Gem n eta Gem M35 is between these in Gemini's foot 21 2.56 48 2.61 Gem 4 4.4 1 Gem 13 Gem the whole foot 36 4.39 81 4.40 CMi 1 3.3 a 10 CMi B 3 CMi Procyon to companion 27 3.29 61 3.32 CMi 2 4.3 a 10 CMi B 3 CMi Procyon to companion 35.25 4.30 79.5 4.32 CMi 3 4.6 a 10 CMi B 3 CMi Procyon to companion 37.75 4.60 85 4.62 CMi 4 5.3 a 10 CMi B 3 CMi Procyon to companion 43 5.24 98 5.33 Ser 1 3.3 triangular head of Serpens Caput 61 3.32 Her 1 6.6 pi 67 Her n 44 Her top of the Keystone of Hercules 54 6.59 Her 2 6.6 pi 67 Her e 58 Her east side of the Keystone of Hercules 54 6.59 122 6.63 Her 3 7.3 n 44 Her z 40 Her west side of the Keystone of Hercules 60 7.32 135 7.34 Her 4 4.1 e 58 Her z 40 Her bottom of the Keystone of Hercules 33.25 4.05 75.5 4.10 Lyr 1 3.4 d1d2 11,12 e1e2 4,5 NE stars in Lyra 28 3.41 63 3.42 Lyr 2 2.0 B Lyr y Lyr across bottom of Lyre 16 1.95 37.5 2.04 Cyg 1 6.1 a Cyg y Cyg Deneb to Sadr top to center of cross 50.125 6.11 113 6.14 Del 1 2.7 y 12 Del B 6 Del body of Dolphin 22 2.68 49.25 2.68 Del 2 3.1 y 12 Del z 4 Del body of Dolphin + #4 25.25 3.08 57 3.10 Del 3 4.4 y 12 Del n 3 Del body of Dolphin + #3 in the tail 35.6 4.34 80.25 4.36 Del 4 5.8 y 12 Del 2 Del extending further down the tail 47.75 5.82 106 5.76 Del 5 1.7 y 12 Del 9 Del smaller parts of the diamond 14 1.71 31.25 1.70 Del 6 1.3 y 12 Del 11 Del smaller parts of the diamond 10.5 1.28 24 1.30