D131f700 Refractive Lens For Astronomical Telescope
Thursday, January 7th, 2010 at
2:52 am
Here are some items you might buy on Ebay auctions:
D310F3000 refractive lens for astronomical telescope
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US $4,499.00 End Date: Thursday Jan-07-2010 4:01:19 PST Buy It Now for only: US $4,499.00 Buy it now | Add to watch list |
D131F700 refractive lens for astronomical telescope
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US $129.00 End Date: Thursday Jan-07-2010 4:03:49 PST Buy It Now for only: US $129.00 Buy it now | Add to watch list |
US $12.96
Yes: If two events occur far apart, two observers can agree that both events occurred simultaneously, provided the two observers have the same velocity.
However, that does not mean that the events "really" occurred simultaneously. Simultaneity is itself relative; so the best you can say is that events "A" and "B" were simultaneous with respect to reference frame 1; and also with respect to reference frame 2. However, If there's a reference frame 3 which is moving relative to the other two, then events "A" and "B" are NOT simultaneous with respect to THAT reference frame. In that sense, there is no such thing as a "universal now". Galaxies 1 and 2 (moving at a common velocity) may both agree on what "now" is: but Galaxy 3 (moving at a different velocity) will disagree with them.
I agree but people are different and have different values. Problems on earth feels so insignificant indeed when you look at the vastness of space but when it comes down to it you cannot enjoy the benefits of space exploration in your lifetime. Nor can you spread your values for longer periods than a lifetime. Until mankind can cure/slow ageing we will never succeed in this endeavour and that will one day make us a doomed race.
Refractive index is a medium of measurement. Shop for quality ATAGO brand refractrometer including refractive …
Denver, Aurora, Englewood, Colorado Refractive Surgery – Blog
Denver, Aurora, Englewood, Colorado Refractive Surgery – Blog
Science,isn’t it fascanating!
omg i had to do a physics video thingy and this video saved my butt
thanks a lott
I imagine some type of land unit, like a kilometer or mile.
What kind of telescope was that? and what does it cost? I ask because I think I have the same one. (I think I got a good deal)
One of the most common uses of the refractive index is to compare the value you obtain with values listed in the literature. This comparison is used to help confirm the identity of the compound and/or assess its purity. This is really the only way to try to ID the material if you don't have a reference. The Merck Index contains a great deal of RI tables – check it out in your school library.
Since the refractive index of a substance depends on the wavelength it is important that the refractive index you are comparing to was obtained at the same wavelength as the one you determined. This is usually not an issue since the vast majority of refractive indexes are obtained using the sodium D line at 589.3 nm. (Even refractometers that use white light are normally constructed so that the refractive index obtained corresponds to that for light at 589.3 nm.)
The refractive index also depends on the temperature. Thus, it is best to obtain the refractive index of your sample at the same temperature as the value you plan to compare with; in most cases this will be 20 °C. However, if your refractometer is not equipped with a temperature regulating system, you may simply be stuck with room temperature, whatever that happens to be. For most organic liquids the index of refraction decreases by approximately 0.00045 ± 0.0001 for every 1 °C increase in temperature.
RT Turn an eHow Article into a Squidoo Lens
OK, I'm not going to answer, but the sources will!
However, It's much easier to just get a kick ass macro-lense!
Like this , with a ring flash and focusing rails!
Imaging is probably the most expensive aspect of the hobby of astronomy, so what you're looking for probably doesn't exist.
For taking pictures of the Moon and Planets, you could get by with something like a Celestron Neximage camera with a laptop and a dobsonian telescope. Orion sells Dobsonians that are reasonably well made, at reasonable prices. The Starblast sells for about $200. You'd be better off with a somewhat larger one that includes a 2" focuser.
You could add a white light solar filter to the front of a dobsonian and take pictures of sun spots.
If you want to take photos showing solar prominences, and the granularity of the Sun, the "cheap way" to go is to buy something like a Coronado PST for about $500. You'll need a tripod for it. That scope is only useful for observing the Sun.
If you want to take photos of deep sky objects, you'll need a telescope that uses an equatorial mount. Inexpensive equatorial mounts are not stable enough for imaging.
Avoid any telescope that comes in a box that tells you how much power it has. If it says 300 POWER! and you can lift it, it's a toy that will be frustrating to use.
You'll probably need to spend at least $1,000 to get a suitable mount with a newtonian reflector designed for imaging. Then you'll need a different camera than you need for planets.
Most people I know who take astronomical images have spent at least $5,000 on their equipment. People who are serious about it often spend several times that.
My advice is find an astronomical society or club, and attend some meetings, and see what their members have. You might also try attending some "star parties" – these are gatherings of people who are very serious about the hobby, and it's not uncommon to find at least one person at a star party who is imaging.
Here is a link to some of my images: < >
This is a link to a photo of Saturn a friend and I took with my equipment: < >
If you happen to be within a reasonable distance of south western CT you could visit my astronomical society. < >
Good luck.
i’d like to see how the 50mm 1.8 is made
My professor won't stop saying astronomical black hole. Make him stop.
Kotov and his colleagues had set out in this study to create “superchiral” particles—spirals of nano-scale mixed metals that could theoretically focus visible light to specks smaller than its wavelength. Materials with this unique “negative refractive index” could be capable of producing Klingon-like invisibility cloaks, said Sharon Glotzer, a professor in the departments of Chemical Engineering and Materials Science and Engineering who was also involved in the experiments. The twisted nanoparticle ribbons are likely to lead to the superchiral materials, the professors say.
در یکی از بزرگترین مطالعاتی که تاکنون با استفاده از تلسکوپ هابل انجام شده است، ستاره شناسان، 446000 کهکشان را مورد بررسی قرار دادند. هدف ستاره شناسان مشاهده این بود که چگونه ماده درسرتاسر کائنات توزیع شده است و همچنین جهان با چه سرعتی در حال انبساط است. نتایج نشان داد که با پیشروی زمان، جهان با سرعت بیشتری در حال انبساط و بزرگ شدن است. این یافته تاییدی بر پیش بینی های نظریه نسبیت انیشتن می باشد. دانشمدان می گویند، جهان از سه جزء کاملا متفاوت تشکیل شده است:ماده طبیعی که همان اجرام فیزیکی در جهان مانند سیاره هاست، ماده سیاه که ماده نامرئی است که با ایجاد کشش جاذبه، کهکشان ها را تشکیل می دهد و انرژی ناشناخته موسوم به انرژی تاریک که با نیروی خود موجب انبساط جهان می شود. تایید افزایش سرعت انبساط جهان نشان می دهد که اجزای تشکیل دهنده جهان مانند انرژی تاریک، موجب انبساط و تحت تاثیر قرار دادن ساختار جهان می شوند.
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tags: birds, mystery bird, bird ID quiz
[Mystery bird] photographed near the Serengeti National Park, Tanzania, Africa. [I will identify this bird for you in 48 hours]
Image: Dan Logen, 18 January 2010 [larger view].
Nikon D300, 600 mm VR lens with 1.4 extender. ISO 400, 1/1600 sec, f/6.3. Exposure compensation -1.3.
Please name at least one field mark that supports your identification.
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– they're more sensitive.
– they give instantaneous results.
– they don't require darkroom processing.
– they allow the operators to sit inside, where it's warm. (big plus.)
– image stabilization software can be used to correct for movement.
If poss, could you also get bottle of gin from duty Free – I will reimburse you. Price of alcohol here astronomical.
Cameras with wide angle lens (28mm) are increasingly popular, now there are even ultra wide angle (25mm) cameras available.
Pansonic has lead the way with wide angle lens on so many of their models.
I have a 28mm lens and it allows me to take pictures that I couldn't otherwise.
Here is a good description.
http://panasonic.net/avc/lumix/popup/wide_angle/index.html
The lens is fine, Canon have a balancing act to perform, though – they want to supply a lens to a 'beginner/hobbyist' camera to get people to buy them – but they have to do it economically. The same goes for all manufacturers.
At the same time, they can't give you a lens that is no good. Anyway, that doesn't answer your question.
Photojournalists have a habit of carrying two bodies with a lens on each(and a couple of flashes etc). An increasing number of modern day journo's have a wide/normal zoom and a telephoto zoom. Your kit lens and a 70-200mm are good ranges. The difference between your lens(es) and photojournalists is the speed of them.
They run larger maximum apertures. And there's the rub. Cost.
You'd be paying $1300 for a Canon 24-70 f/2.8 and $1300-$1800 for a Canon 70-200 f/2.8 without or with Image Stabilization to get the speed they require. Sigma and Tamron will offer cheaper alternatives, of course.
You could ramp up the ISO on your camera to keep your shutter speeds high enough with your kit lens and the other lens you choose (and get away with it) but I doubt you can get away with only one body – things happen too fast for you to be able to change lenses at a moment's notice. The flashguns are pretty much essential, too.
If, by beginning photojournalist, you mean 'bit of a hobby because I see a load of celebs' then you're good to go. If, however, you're being paid to get results then you should consider ways of raising the capital to get a higher grade pair of bodies and faster lenses.
How come in this video you talk about large magnifications, but in the other vids, with the same scope your advice for magnification is smaller. Did I miss a link? Or a trick?
National Microscope Exchange is now selling the newly released ATAGO RX-5000 digital benchtop refractometer for testing fruit juices, soft drinks and other products requiring brix or refractive index readings.
Permeability and permittivity are magnetic and electrical properties of a material (they are also properties of free space). There is no way to calculate them from any more fundamental properties.
Call Permeability mu, permittivity epsilon.
The speed of light is 1/sqrt(epsilon*mu) as derived from Maxwell's equations
InquisitionNews: said: Mystery Object Defies Astronomical Classification | Wired Science | Wired.com
OK, I’m curious. How is a non-stabilised version better?