Visual Magnitude
Recently, despite everything, I have felt optimistic enough to do some shopping. That’s right. I decided I may require a cheap yet big binocular. To find out about cheap yet big binoculars, I visited Cloudy Nights which site features Binocular Articles. One of the articles, General Binocular Recommendations for Astronomy, caught my eyeballs. Anon, however, the article sidetracked me from my mission. Here’s how that happened.
How many stars can you see in the Little Dipper? That’s a question posed in that article. Whoa! The Little Dipper!!!! On a good night I can make out Polaris, that Druids often reference as Polar Bear, or, Our Friendly Guide Star. Then, when the Little Dipper is pointed south, I may on a good night espy two more, the twain at the far end of the dipper. Extrapolating, this means that the sky over the Cow Barn off toward the north horizon is Visual Magnitude 3 and a little bit. Uh! Visual Magnitude 3 may not be very good.
Because most of the Little Dipper was not available yesterday evening, I checked out the approximately 3.5 or so Visual Magnitude hypothesis on Eta, and Zeta the kids, Auriga. Eta at 3.17 is fairly easy. Zeta, at 3.75 is barely visible sometimes. This holds true when Capella is at about 45 degrees and emerging from the Highway 290 murk. Some night I may need to check and see if I can espy any Magnitude 4 stars, straight overhead. In any event, the skies over these parts are not generally much better than Visual Magnitude 3.5, fer me, fer me, fer meeeeeee! Dang it!
So what magnitude of star might I espy, theoretically, with a hand held binocular. First I need to subtract two full magnitudes to account for my miserable 3.5 sky. Then I need to subtract another full magnitude for hand holding. That means, to espy a mere Mag 10 star I would require a 30x120 binocular with Atlas mount and tripod.
Yes. I was sidetracked from finding out which binoculars met my requirements, big and cheap, by the unrelated topic, visual magnitude. If I had let myself, I could have been further sidetracked by the topic, What is my inter-pupilary (sic) distance (IPD)?, and/or What is the diameter of my pupil in the dark? Not pupils, pupil. Seems like if you took the trouble to measure the diameter of your pupil in the dark, you should probably do both of them.
Is a narrow IPD, like eyebrows that grow together, indicative of retardation? Certainly, if one’s pupils are too close together, so close that no known binocular can be squeezed down to so narrow a gap, one might conclude, retardation. See, hopelessly sidetracked. And these issues raised by that cruel article are merely a trifle of the total. Mercy!
Yes. Mercy! I might have been sidetracked into never purchasing, much less spying through, a big yet cheap binocular due to all the questions raised in that article. OK. So I have a question of my own. What is the biggest, cheapest binocular there is? Well, on EBAY a 15x80 binocular is advertised for 60 bucks. That’s plenty big and cheap. The price also includes a sturdy tripod adapter. Almost, almost, almost, I would pay 60 bucks just to spy through the advertised, once.
Chances are, that particular EBAY binocular is too big and too cheap. OK. I have arbitraily decided to purchase an 11x70 binocular for 140 bucks. Yes. I shall help out the miserable, starving, communist Chinese by purchasing a big and cheap communist Chinese binocular.
Here’s what I plan to do with my big, cheap commie binocular. Once it arrives I shall check it out. If we can espy the ring around Uranus, we are good to go. Then once we are good to go, we are fixing to head on out in a great gas-guzzling vehicle. Off we shall go. During the daytime, we shall drive, drive, drive. Yet at night we shall search for that mythical dark sky. Yes. That mythical dark sky that may boast M33. Once we have espied M33, and maybe another naked object or two, we shall return to the Cow Barn by the shortest route, stopping only at night.
When and if I am safely home at the Cow Barn, I may decide to sell my Mensheviki binocular. The ad shall read, This is a great binocular. I have espied M33 in this binocular and the ring around Uranus.
How many stars can you see in the Little Dipper? That’s a question posed in that article. Whoa! The Little Dipper!!!! On a good night I can make out Polaris, that Druids often reference as Polar Bear, or, Our Friendly Guide Star. Then, when the Little Dipper is pointed south, I may on a good night espy two more, the twain at the far end of the dipper. Extrapolating, this means that the sky over the Cow Barn off toward the north horizon is Visual Magnitude 3 and a little bit. Uh! Visual Magnitude 3 may not be very good.
Because most of the Little Dipper was not available yesterday evening, I checked out the approximately 3.5 or so Visual Magnitude hypothesis on Eta, and Zeta the kids, Auriga. Eta at 3.17 is fairly easy. Zeta, at 3.75 is barely visible sometimes. This holds true when Capella is at about 45 degrees and emerging from the Highway 290 murk. Some night I may need to check and see if I can espy any Magnitude 4 stars, straight overhead. In any event, the skies over these parts are not generally much better than Visual Magnitude 3.5, fer me, fer me, fer meeeeeee! Dang it!
So what magnitude of star might I espy, theoretically, with a hand held binocular. First I need to subtract two full magnitudes to account for my miserable 3.5 sky. Then I need to subtract another full magnitude for hand holding. That means, to espy a mere Mag 10 star I would require a 30x120 binocular with Atlas mount and tripod.
Yes. I was sidetracked from finding out which binoculars met my requirements, big and cheap, by the unrelated topic, visual magnitude. If I had let myself, I could have been further sidetracked by the topic, What is my inter-pupilary (sic) distance (IPD)?, and/or What is the diameter of my pupil in the dark? Not pupils, pupil. Seems like if you took the trouble to measure the diameter of your pupil in the dark, you should probably do both of them.
Is a narrow IPD, like eyebrows that grow together, indicative of retardation? Certainly, if one’s pupils are too close together, so close that no known binocular can be squeezed down to so narrow a gap, one might conclude, retardation. See, hopelessly sidetracked. And these issues raised by that cruel article are merely a trifle of the total. Mercy!
Yes. Mercy! I might have been sidetracked into never purchasing, much less spying through, a big yet cheap binocular due to all the questions raised in that article. OK. So I have a question of my own. What is the biggest, cheapest binocular there is? Well, on EBAY a 15x80 binocular is advertised for 60 bucks. That’s plenty big and cheap. The price also includes a sturdy tripod adapter. Almost, almost, almost, I would pay 60 bucks just to spy through the advertised, once.
Chances are, that particular EBAY binocular is too big and too cheap. OK. I have arbitraily decided to purchase an 11x70 binocular for 140 bucks. Yes. I shall help out the miserable, starving, communist Chinese by purchasing a big and cheap communist Chinese binocular.
Here’s what I plan to do with my big, cheap commie binocular. Once it arrives I shall check it out. If we can espy the ring around Uranus, we are good to go. Then once we are good to go, we are fixing to head on out in a great gas-guzzling vehicle. Off we shall go. During the daytime, we shall drive, drive, drive. Yet at night we shall search for that mythical dark sky. Yes. That mythical dark sky that may boast M33. Once we have espied M33, and maybe another naked object or two, we shall return to the Cow Barn by the shortest route, stopping only at night.
When and if I am safely home at the Cow Barn, I may decide to sell my Mensheviki binocular. The ad shall read, This is a great binocular. I have espied M33 in this binocular and the ring around Uranus.
posted by ray pistrum at Sunday, January 04, 2009
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