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Topic: Apochromatic

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Chromatic aberration

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	Apochromatic lens triplets with aspherical lens elements - Patent 4915483
		This invention relates generally to apochromatic lens triplets of the type in which a fluidal liquid lens element is contained between two identical rigid lens elements, and more particularly to a technique for optimizing performance of such a lens triplet by providing aspherical lens surfaces.
		2 for the apochromatic lens triplet of FIG.
		7 for the apochromatic lens triplet of FIG.
	www.freepatentsonline.com /4915483.html (4470 words)

	Apochromat - Wikipedia, the free encyclopedia
		Apochromatic lenses are designed to bring three wavelengths (typically red, green, and blue) into focus in the same plane.
		Apochromats are also corrected for spherical aberration at two wavelengths, rather than one as in an achromat.
		Apochromatic lenses for astrophotography in the 60-150 mm aperture range have been developed and marketed by several different firms, with focal ratios ranging from f/5 to f/7.
	en.wikipedia.org /wiki/Apochromatic (459 words)

	* Apochromatic - (Photography): Definition (Site not responding. Last check: 2007-10-21)
		Apochromatic lenses are sometimes recommended due to their improved focusing across the spectrum.
		Apochromatic; a type of lens which focuses different wavelengths of light on the filmplane for improved image sharpness.
		Apochromatic lenses must be used for critical work in color copying and duplication.
	www.en.mimi.hu /photography/apochromatic.html (360 words)

	Defining Apochromatism
		With the proliferation of apochromatic refractors that are available to the amateur astronomer, it is time to define the parameters of a true apochromatic objective lens.
		Apochromat: an objective corrected parfocally for three widely spaced wavelengths and corrected for spherical aberration and coma for two widely separated wavelengths.
		Abbe's definition, to put it in clearer terms (I hope) is that a true apochromat is an objective that has three color crossings that are spaced far apart in the visual spectrum (~4000A, deep violet to ~7000A, deep red).
	geogdata.csun.edu /~voltaire/tmb/definition.html (849 words)

	Optical Assembly
		Chromatic aberration is the result of light focusing at different places resulting in an image that appears blurry and surrounded by a halo of color.
		The ED Apochromatic refractor, shown below, uses modern optical design to correct for chromatic aberration by using a precisely computed combination of lens surface radii and air spacing distance between the elements of the objective.
		Apochromatic refractor (or Apos for short) are not light buckets like a Newtonian or Schmidt-Cassegrain.
	www.mnastro.org /learning/optical_assembly.htm (1016 words)

	apochromatic
		A lens or optical system virtually free of chromatic aberration, which for practical purposes means that light of at least three different wavelengths is brought to focus at the same point.
		However, because fluorite is expensive to manufacture, and, because of its brittleness, difficult to grind, polish, and mount, high quality apochromatic refracting telescopes are costly.
		Reflecting telescopes, on the other hand, are apochromatic in performance without the extra expense.
	www.daviddarling.info /encyclopedia/A/apochromatic.html (157 words)

	OPT - Astronomy Telescopes, Accessories, CCD and Digital Cameras (Site not responding. Last check: 2007-10-21)
		Instead of basic two-element designs like the achromatic, the apochromatic refractor uses either three or four lenses, each made of a different material; a two-element lens, one of which is fluorite; or a newer two-element design of ED, or "extra-low dispersion" glass.
		Faster focal length refractors, while sought after because of their portability, also have the most stubborn color fringing, so the invention of the apochromatic design is a boon to those of us who want to take our refractor everywhere.
		Of course, apochromatic refractors are more expensive, but the views through them are exquisite, providing a velvety background and pinpoint star images.
	www.optcorp.com /info_refractor.asp (1029 words)

	Are Nikkor-W lenses apochromatic? - Large Format Photography Forum
		Apochromatic correction is really only an issue with long lenses for smaller formats and lenses used at the extremes of their image circle.
		Is the Apo Rodagon or Apo componon an apochromat?
		I am afraid that the word Apochromat has become somewhat of a marketing tool, open to wide interpretation, and which appears to now mean reduced secondary spectra by those who market their lenses.
	www.largeformatphotography.info /forum/showthread.php?t=1937 (1561 words)

	Epinions.com - Rich's Telescope Primer Part 1
		The achromatic and apochromatic telescopes are variants which use multiple lenses on the front end made from different materials with different indexes of refraction to try to correct for this effect.
		Since there isn't a very clearly defined cutoff between the optical performance of achromatic and apochromatic telescopes, these designs have been referred to as "semi-apochromatic." However, in practice they are mostly recognizable since they cost about half of what an APO telescope does.
		Apochromatic telescopes have three to four objective lens elements and at least one of them will be made from calcium flourite.
	www.epinions.com /elec-review-C0D-504D19B-39CA3E80-prod5 (4534 words)

	Meade Instruments Corporation - ED Apochromatic Refractors
		It was not until the early-1980's, however, with the advent of ED (Extra-low Dispersion) glass, that truly first-rate apochromatic objective lens designs became physically realizable in moderate apertures and at reasonable pricing levels.
		Meade ED Apochromatic Objective Lenses: The objective lenses included with Meade ED apochromatic refractors are made at the Meade Irvine facility and utilize the highest-grade optical glasses available; they are free of striae and other imperfections that can degrade optical performance.
		Observing with the Meade 6" Model 152ED: Fortunate indeed is the observer with a Meade 6" ED apochromatic refractor at his or her disposal.
	www.meade.com /catalog/apo/index.html (2093 words)

	TMB Website
		Incorporating the largest aperture range of true apochromatic lenses in the world, our air spaced fully multicoated triplet lenses are totally free from secondary color, providing the highest contrast possible.
		The German made matching CNC tube assemblies are built to the same high standards, making the TMB Apochromatic refractors edge of the art telescopes.
		These are the eyepieces for the observer that wants to see the maximum detail and contrast that their telescope is capable of.
	www.tmboptical.com (178 words)

	Meade Instruments Corporation - ED Apochromatic Refractor Accessories
		Manual, coarse focusing of the image is not affected by the addition of the #1207 unit.
		Motor Drive Systems: Factory pre-installed on all Meade apochromatic models as standard-equipment are two DC servo motors, one each inside the polar and declination axes.
		Installing either of the optional drive systems requires no more than a few minutes and entails simple plug-in connection of the declination motor to the power panel and attachment of the power panel to the declination casting.
	www.meade.com /catalog/apo/apoac.html (1024 words)

	How to Use an Apochromatic Refractor Telescope - eHow.com
		Apochromatic telescopes are more expensive than reflecting telescopes, but they require less maintenance and are extremely portable.
		STEP 3: Know that apochromatic telescopes use three or four lenses to eliminate chromatic aberration.
		STEP 4: Enjoy the advantage of an apochromatic refractor, which is never having to say the word "collimate." This type of telescope comes pre-assembled from the factory with all of its optics aligned.
	www.ehow.com /how_10333_apochromatic-refractor-telescope.html (273 words)

	There are a few drawbacks to the reflector
		It is the diffraction of a secondary mirror in reflectors which keeps these telescopes from matching the image quality of the apochromatic refractor.
		I mentioned earlier that apochromatic refractors excel in showing details on the planets of our solar system and on other objects which are relatively close to Earth.
		The smaller apochromatic telescope will usually cost three to four times the price of the reflector and give you razor sharp views of the planets.
	www.singularsci.com /ScopeTypes5.htm (525 words)

	A CIRCA 1941 SPENCER MICROSCOPE.
		The microscope at one time belonged to another amateur diatomist, John L. Stone, who outfitted it with two apochromatic objectives in addition to the normal ones and two extra sets of oculars, with a measuring reticle in one ocular of each set.
		The apochromats are 44X (NA 0.96, dry, with collar) and 95X (NA 1.30) and the normal objectives are 10X (NA 0.2), 44X (NA 0.66) and 95X (NA 1.25).
		I had the microscope cleaned by a professional (it had not been used since Stone died) and was told that the stand was solid steel (I can believe that—it is very heavy) and other than steel the only other component of the microscope is glass.
	www.microscopy-uk.org.uk /mag/artmay05/drspencer.html (502 words)

	TMB Website
		These lenses proceeded Roland's article in Sky and Telescope, October 1981, page 376, "An Apochromatic Triplet Objective." This was a groundbreaking article, and was the beginning of the new age of Apochromatic refractors.
		Seven apochromatic refractors were listed, and the most impressive was the 6" f/12 Super Planetary for $1540.
		A few 9-inch and 10-inch apochromats were sold to Universities and rich individuals, the design details being kept secret.
	www.tmboptical.com /itemsGrid.asp?cat_id=28 (2045 words)

	Refractor (Site not responding. Last check: 2007-10-21)
		Most -or all- these problems are avoided by using reflecting telescopes, that can be made in far larger apertures.
		However, modern designs using apochromatic optics built with special, extra low-dispersion materials essentially eliminate these problems.
		Such telescopes contain elements of fluorite or special, extra low-dispersion (ED) glass in the objective and produce a very crisp image which is virtually free of chromatic aberration.
	www.theamazingsky.com /Refractor.htm (796 words)

	Optical Design of Telescopes
		This term is a bit misleading of course since apochromatic means "no color" and three colors in focus is certainly not all colors.
		Such a design may not be quite as perfect in focusing three colors as a fluorite apochromatic lens but it can be so close that only optical bench tests will show the difference.
		There are many other new glasses that can be used in combinations to make achromatic (three colors), super achromatic (four colors) or hyper achromatic (five colors) lenses to focus more colors and even those outside the visible spectrum to one point.
	www.mailbag.com /users/ragreiner/opticsmisc.html (1778 words)

	TMB 8” F/9 Apochromatic Refractor - Review
		The attributes of the apochromatic refractor include sharp, contrasty, color free images and superb definition.
		My conclusion therefore is that, given an apochromatic refractor, 5-6” of aperture is enough, and, 7”or greater is preferable up to the limit imposed by seeing conditions, which I suspect is in the 8-10” range.
		Putting everything together I concluded that seeing conditions would limit the useful aperture, an apochromatic refractor is as good as it gets inch for inch, and, 8” aperture would certainly be “enough”.
	www.cloudynights.com /item.php?item_id=956&pr=2x6x17 (5180 words)

	Surgical Microscopes - Neurological Product Matrix - Medcompare
		Optics: The apochromatic design delivers extraordinary image quality, improved resolution and incredible...
		Features: Apochromatic Carl Zeiss optics ensure outstanding color fidelity, razor-sharp, crisp imagery and an...
		Optics: Apochromatic optics deliver brilliant images, a new Varioskop objective lens provides large working...
	www.medcompare.com /matrix.asp?catid=744 (721 words)

	TMB telescope, an apochromatic refractor
		This is the story of my TMB refractor 115/805, an "ultra high performance apochromatic telescope".
		Apochromatic refractors, especially apochromatic triplets, are supposed to be the upper class of telescopes and TMB refractors are supposed to be among the best refracting telescopes.
		Update: stranger things do happen in apochromatic refractor land - see this thread for example...
	www.datarescue.com /life/kepler/tmb/index.htm (881 words)

	Company Seven \| Orion 80mm ED Apochromat Refractor Telescope
		And finally on 6 August 2004 this new telescope was introduced to the world at Company Seven as the 100mm ED telescope.
		The Orion 80 mm ED Apochromatic refractor telescope is in that class of telescope, and it has earned its space in Company Seven's showroom.
		The downside of this arrangement is that it requires a bit of getting used to for someone used to conventional focusers, the proper adjustment of the friction control is critical.
	www.company7.com /orion/telescopes/orion80EDf7.5.html (4325 words)

	Andy's Shot Glass - Webstore Catalogue - amateur astronomy, astrophotography equipment, Orion telescopes, SkyView Pro, ...
		The term "apochromatic" comes from an old word that means: "All comparable scopes suck".
		Apochromatic lenses are simply a combination of lenses that focus the colors to roughly the same spot, eliminating (or nearly so, depending on the quality of the lenses) the chromatic aberration common in achromats.
		I am tempted to say it's not rocket science, but actually it is. These scopes are not easy to make and usually cost many thousands of dollars.
	www.andysshotglass.com /links2.html (2872 words)

	Astromart Reviews - Orion 80mm f/7.5 ED Apochromatic Refractor Versus Masked 80mm Televue 102 Apochromatic Refractor
		The Orion 80mm ED was outfitted with a 6mm Orion Expanse eyepiece(yielding 100X), while the masked Televue 102 was equipped with a 9mm Orion Expanse eyepiece(yielding 98X): The ED scope was secured to a Televue Upswing mount, while the Televue 102 was positioned on a Gibraltar mount.
		This one was very easy to split at 30X, when using the Highlight 20mm plossl eyepiece, as the Orion ED 80 showed a “clean” separation between the yellow primary and the blue companion of this picturesque double star.
		Conclusions: The Orion 80mm ED Apochmatic Refractor is a true “bargain” in the world of apochromatic telescopes and, in my opinion, may not be easily equaled, both optically and mechanically, when considering the open-market of quality refractors.
	www.astromart.com /articles/article.asp?article_id=25 (1520 words)

	Company Seven \| Vixen 102-FL Fluorite Apochromat Refractor Telescope (Site not responding. Last check: 2007-10-21)
		Right: 102FL - 4 Inch f9 Apochromatic Refractor Telescope shown as most recently imported by Orion on optional Vixen GP German Equatorial Mount and Tripod (13,789 bytes).
		These apochromatic telescopes were introduced in the early 1980's in order to provide the finest optical imaging performance for the serious amateur astronomer.
		The automated manufacturing of the optical tube mechanical components and of the optional Vixen Great Polaris mount by Vixen Development and Manufacturing Co., Ltd. allow this telescope and suitable mounts to be priced most attractively.
	www.company7.com /vixen/telescopes/vixen102fl.html (2646 words)

	WarboysAstro - Images Of The Universe - Equipment
		The Pentax SDHF is a triplet apochromatic design 75mm aperture f6.7 refractor (503mm focal length) with the third lens element of the triplet being the field flattener.
		The Takahashi FS60C is a wonderful short focus wide-field apochromatic (Fluorite) refractor.
		Sadly, the fully illuminated field circle is neither large nor flat enough to fully illuminate the STL-11000XM sensor, but I have used this OTA in the past with smaller cameras and achieved fantastic results.
	members.aol.com /warboysastro/equipment/equipment.htm (845 words)

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