Click here if you are having trouble logging into the forums Cloudy Nights - Official Forums of the 2009 International Year of Astronomy Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User   You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Equipment Discussions >> Binoculars Previous   Index   Next   Threaded   Pages: 1 geoffrey sage Reged: 01/05/04 Posts: 358 Loc: North West England Binoculars - Star Magnitude -Small 'Scopes       #37418 - 01/07/04 04:45 AM Edit   Reply   Quote Quick Reply   1.Does anybody have a list of Binocular magnification v Star magnitude for say 8x, 10x 15x 18x & 20x 2. Does anyone who uses say 18x or 20x prefer them to their small scope. say 4.5 Reflector or 80mm refractor Thanks Geoffrey -------------------- Celestron Nextstar 8SE 6.25" F7.6 Dob Skywatcher ST80 Opticron imagic BGA PC ASF T 8x42 Edited by geoffrey (01/07/04 08:12 AM) Post Extras:       EdZ Professor EdZ Reged: 02/15/02 Posts: 12601 Loc: Cumberland, R I , USA42N71.4W Re: Binoculars - Star Magnification -Small 'Scopes [Re: geoffrey]       #37427 - 01/07/04 06:38 AM Edit   Reply   Quote Quick Reply   Geoffrey, I'm at a complete loss to understand your question about "star magnification". Could you please explain what you mean. edz -------------------- Teach a kid something today. The feeling you'll get is one of life's greatest rewards. member#21 Post Extras:       geoffrey sage Reged: 01/05/04 Posts: 358 Loc: North West England Re: Binoculars - Star Magnitude -Small 'Scopes [Re: EdZ]       #37451 - 01/07/04 08:19 AM Edit   Reply   Quote Quick Reply   Sorry Edz, I did not check my typing. Post now amended to "Star Magnitude" Assume this clarifies? In other words do you really see all that many more stars with 20x against say 10x. Geoff -------------------- Celestron Nextstar 8SE 6.25" F7.6 Dob Skywatcher ST80 Opticron imagic BGA PC ASF T 8x42 Post Extras:       geoffrey sage Reged: 01/05/04 Posts: 358 Loc: North West England Re: Binoculars - Star Magnitude -Small 'Scopes [Re: geoffrey]       #37454 - 01/07/04 08:33 AM Edit   Reply   Quote Quick Reply   I have just answered my own question by this article on Cloudynights:- http://www.cloudynights.com/articles/star_counts.htm However, I would still like to hear from you all which Binos. you prefer for Astronomy, and if anyone prefers the larger Binos. to using a small scope. Geoff -------------------- Celestron Nextstar 8SE 6.25" F7.6 Dob Skywatcher ST80 Opticron imagic BGA PC ASF T 8x42 Post Extras:       EdZ Professor EdZ Reged: 02/15/02 Posts: 12601 Loc: Cumberland, R I , USA42N71.4W Re: Binoculars - Star Magnitude -Small 'Scopes [Re: geoffrey]       #37583 - 01/07/04 01:14 PM Edit   Reply   Quote Quick Reply   Considerably more stars are seen with larger binoculars. Mostly, as magnification increases star counts and limiting magnitude will increase, even if aperture does not increase. These are some examples of recent observations. I've been working on studying the Pleiades with various binoculars. So far I've made about 20 observations in various Naked Eye Lim Mag skies, but these should give you a pretty good idea. All of these observations are on the exact same field of stars. You can observe the same field by using one of the charts in the Call for Participation thread. 69 stars/mag9.7 - 8x42 Swift Ultralites skies mag 5.0 85 stars/mag10.1 - 10x50 Orion Ultraviews skies mag 5.0 92 stars/mag10.25 - 12x50 Pentax PCF III skies mag 5.0 103 stars/mag10.4 - 10x70 Fujinon FMT-SX skies mag 5.0 128 stars/mag10.85 - 10x70 Fujinon FMT-SX skies mag 5.6/5.8 97 stars/mag10.2 - 16x60 Pentax PCF V WP skies mag 4.7 141 stars/mag10.74 - 16x60 Pentax PCF V WP skies mag 5.4 106 stars/mag10.3 - 15x70 Oberwerk skies mag 4.7 139 stars/mag10.80 - 15x70 Oberwerk skies mag 5.4 113 stars/mag10.7 - 16x70 Fujinon FMT-SX skies mag 4.7 156 stars/mag10.94 - 16x70 Fujinon FMT-SX skies mag 5.4 Some scopes used for comparison. We can assume a 20% gain from single aperture to binocular (two aperture) viewing, (based on previous tests, refer to the old post one eyed vs two eyed viewing), therefore an 85mm scope is equivalent to 78mm binoculars. A 5"SCT (minus the central obsrtuction has equivalent to 115mm aperture) is equivalent to 105mm binoculars. 118 stars/mag10.7 - TV85 w/27Panoptic (22x85mono) 22x78 mag 4.6 skies 246 stars/mag11.68 - TV85 w/14Radian (43x85mono) 43x78 mag 5.2 skies 262 stars/mag11.46 - G5 (5"SCT)w/30Ultima (45x115mono) 45x105 skies mag 5.2 ??? stars/mag12.0 - G5 (5"SCT)w/14Radian (96x115mono) 96x105 skies mag 5.2 It's pretty obvious that magnification increases the number of stars seen and the limit of magnitude of stars reached. Although I may not show you enough to see the trend here, magnification has a much greater impact than aperture on how many stars are seen and what magnitude is reached. edz -------------------- Teach a kid something today. The feeling you'll get is one of life's greatest rewards. member#21 Edited by EdZ (01/08/04 11:40 AM) Post Extras:       geoffrey sage Reged: 01/05/04 Posts: 358 Loc: North West England Re: Binoculars - Star Magnitude -Small 'Scopes [Re: EdZ]       #37604 - 01/07/04 02:07 PM Edit   Reply   Quote Quick Reply   Thanks Edz, very kind of you. I am new to all this, but joined a local Ast.Soc. last Sept. I am interested in the Pleiades, so will try my Opticron 10x50 and old Swift 8x40 whenever we get a clear sky. Kenny, do you have any info on the old Swift Belmont 8x40's? I look forward to learning from you all Regards Geoffrey -------------------- Celestron Nextstar 8SE 6.25" F7.6 Dob Skywatcher ST80 Opticron imagic BGA PC ASF T 8x42 Post Extras:       KennyJ Reged: 04/27/03 Posts: 10163 Loc: Lancashire UK Re: Binoculars - Star Magnitude -Small 'Scopes [Re: geoffrey]       #37632 - 01/07/04 03:27 PM Edit   Reply   Quote Quick Reply   Thanks ED for that priceless and most interesting list. Sorry Geoffrey , until recently I must confess to never having heard of the Swift Belmont model. Like many other binoculars with "well -known manufacturers' names" on their data plate , not ALL Swift binoculars are or were of a particularly good standard , and I have looked through quite a few that were little better than terrible. The original "Audubon" Porro in 8.5 x 44 and the subsequent "big brother" model 826 10 x 50 "Audubon Kestrel" really were for a long time the "jewel in the crown" of Swift binoculars. In fact can only speak from other reports about the various "newer" Swift Audubons , some of which are Porros and some of which are Roofs --and some of which have E.D glass and some of which have not. It gets VERY confusing even for ME -- and I really do try to keep on top of these things. I doubt if any of them are much , if any , better than the best of the Opticrons to be perfectly honest. Regards --Kenny. -------------------- If everyone is thinking the same thing , no-one is thinking - General George S.Patton Zeiss 7 x 42 BGAT Captain's Helmsman 7 x 50 Nikon 10 x 42 Superior E Swift Audubon Kestrel 10 x 50 Helios 15 x 70 Observation Strathspey 20 x 90 Televue 76 APO Zeiss 85 Diascope Helios 102 f5 refractor Various eyepieces barlows tripods mounts etc. Panasonic Lumix DMC - TZ5 digital camera Post Extras:       Pages: 1 Previous   Index   Next   Threaded   Extra information 14 registered and 32 anonymous users are browsing this forum. 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