I read on another site that: 1/2 the cylinder measurement + the sphere measurement = diopter strength. Because I have a lot of astigmatism this changes the measurements quite a bit (-3.25 cylinder, -3 sphere). Has anybody else used this equation to...
40139
That's the method we used when buying my daughter's goggles. She ended up with -3.625 (R) and -4.25 (L) so we split the difference with a -4 prescription. She says they work well enough for her, and she has to be read a white board to get her workout during swim practice.
77652
Yes, somebody here said +.2 or something like that.It is minor but present; makes screen seem just a little bit bigger.You can get them as prescription lenses if you need more.
998685
It says"Magnifier 2 5x ...". I believe the 2 is just part of the product name, there is no decimal point. A 4" lens diameter can't be 5x, they just can't make them. I even asked my eye doctor about ordering one from him. So I think the lens is a 1.5x with a 3x inset as the lower information on the page description says,. I sent mine back as the one I bought at a fabric store was better. I think you could find a 2x or 2.5x in a large lens with a 6x inset somewhere else. The around the neck batteries wear out very fast so you need rechargeable batteries for cost reasons.
1238980
The equation for the volume of a sphere is: V=4/3 &#960;r^3 (that weird n should be "pie" as in 3.14159) Thus, the volume of a 60-inch in diameter (30-inch radius) sphere is as follows: V=4/3 &#960;&#12310;(30 in)&#12311;^3((&#12310;2.54 cm)&#12311;^3)/&#12310;(1 inch)&#12311;^3 (1 mL)/&#12310;(1 cm)&#12311;^3 (1 L)/(1000 mL)=1853 Liters But, the volume of the balloon will depend on the pressure required to fill the balloon because the recoil force of the balloon will increase as the diameter increases. Basically, the pressure inside the balloon will be much higher than the surrounding air pressure. And the balloon pressure will increase significantly as the balloon diameter increases and approaches its burst pressure. So, the equation will be: (P1 (at sea level))/(P2 (needed to fill the balloon) )=V2/(V1(at sea level)) I work with angioplasty balloons (those used to treat blood vessel narrowings) daily and the burst pressure in those balloons is between 8 and 25 atmospheres for compliant and non-compliant balloons. This balloon is a compliant balloon (meaning that it changes shape with various pressures), so I would guess that the burst pressure is less than 8 atmospheres - probably more like 4 atmospheres. Thus: Volume =(4 atm)/(1 atm) x 1853 L=7,400 Liters (at atmospheric pressure) But, no fear, you don't have to fill the balloons to full capacity. By filling the balloons to only 40 inches in diameter, the volume and pressure will be substantially less. By my calculations, only 1100 Liters. As far as this information, you know what they say about experts: They know more and more about less and less until they know everything about nothing.
1640292
I guess you didn't have the link http://www.amazon.com/Vortex-Solo-10x36-mm-Monocular/dp/B00161ZI4A/ref=cm_cd_al_qh_dp_t Specs: Eye relief: 15 mm; Exit pupil: 3.6 mm; Linear F.O.V: 325 feet @ 1,000 yards; Angular F.O.V.: 6.2 degrees; Close focus: 16.4'; Length: 4.9"; Weight: 9.7 ozs.
727222
The CPC is listed as using 1.25" star diagonal. You should be able to use the 2" star diagonal in this kit to use the eyepieces in this kit. You will need to remove the 2" diagonal and reattach your 1.25" diagonal to use your 1.25" eyepieces.
1193218
The 1.25 dimension is the standard telescope eye size for most scopes. I to have a C90 and purchase a "hybred-diagonal" (.965 to 1.25). This allows me to use all of my 1.25 eye pieces on my C90. Hope this helps.
625014
Don't use it much anymore. When I did, I tested it and found it doesn't make much diff. The thing is, it's field of view widens as it gets further away. So if you measure something that is very small from a longer distance, you'll get a bad reading. When I used it, I was measuring small packages 5x8 inches from a very close distance like 1-2 ft. Sorry I can't be more help.
1469254
I use the 3 and higher for imaging Planets, thet 2X can be used for doubling the power at the eyepiece. The 127 eq is a great scope you should have lots of fun. I had a C5 at one time loved it.
1213132
Measure your lens. My lens was in the 38mm range +/- 2mm (kinda hard to measure with it installed in the lamp). FYI, between my son and I, we have 4 of these. I prefer the wide angle lens for single LED lamps. I ended up taking if off my three led lamp because it made the beam very oddly shaped. But it works beautifully on the single LED lamps completely eliminates the hot spot in the middle of the beam.
1632329
Hi, The focusing distance is always measured from the sensor. Therefore, subtract the distance from the sensor to the front of the lens barrel (approximately 3 inches), and you are left with actual "working distance" of about an inch. Hope that helps.
1679461
Its infinitely variable as far as I can tell. Its like twisting a knob. I don't use this very often, only on one particular lens. I almost forgot about it. Thanks for reminding. No issues with this at all. Just guesstimate only for aperatures.
1213448
+3.5. And, besides: I tried them in a store and found that they they work superbly for adjusting on the fly between -6 and +3.5 correction (more or less). The optics seem excellent. As a fashion statement a bit awkward but hard to make the double lens system look better. The dial adjusters are discretely positioned and effective. I have no idea about durability.
2042953
A 6mm eyepiece will give you about 75x magnification. I get better views of Jupiter in my scope with 4mm and 3.8mm eyepieces at about 115x. I don't like using a Barlow.
290031
If I measured correctly it's 1.5 inches. Like I said I'm still trying to learn how to use it. I haven't had much experience with optics
336773
Hi, I said I would check the use of the MaxTV glasses with my 4.25 Diopter contact lenses removed.I did, the focus adjustment did NOT go quite far enough to give a sharp focus. It was very close,but not quite there. If you used a two diopter, I don't think you would have a problem, even a 3 diopter would probably work. So for what it's worth. Ang, again, they work as I wanted them to.
1052099
According to vortex, it is lower 1/3, not true co-witness. http://www.vortexoptics.com/product/vortex-swing-mount-for-30mm-magnifier