Documents Tagged with "Eyepiece"

Q: Can I use PENTAX eyepieces for telescopes / astronomy?A: Yes.PENTAX eyepieces are ideally suited for astronomical use.PENTAX eyepieces feature premium quality materials, workmanship, and optical performance, and are highly regarded by astronomical telescope users; as well as those who use PENTAX PF Series spotting scopes.

Q: What should I look for in an eyepiece?A: Magnification, field of view (FOV), exit pupil, eye relief, optical coatings, materials, and build-quality are all important factors in determining which eyepiece(s) are suitable for your needs.Many users prefer to use a selection of eyepieces for different magnifications and FOV to address specific viewing applications.

Q: What is the Field Stop?A: Built in to an eyepiece is a circular metal ring or “mask” that defines the visible field of view in the eyepiece.The angular diameter of this (visible) circle is the called the apparent field of view (AFOV), which is a set property of the eyepiece, by design.The field stop diameter is measured in (mm).

Q: How do I Calculate Magnification?A: Magnification is determined by the focal length of the scope's objective lens and the focal length of the eyepiece (in combination).Please note the formula for calculating the magnification of your scope: focal length of scope objective ÷ focal length of eyepiece = magnification For Example: 500mm (scope’s objective lens focal length) ÷ 10mm (eyepiece focal length) = 50X magnification.

Q: What is True Field of View?A: True FOV is the actual area of the sky (in degrees) that you see through the eyepiece, and is strictly determined by the eyepiece being used.To calculate True Field of View (TFOV), use the following formula: Apparent FOV ÷ Magnification = TFOV This formula is helpful when selecting an eyepiece for astronomy applications.

Q: What is the eyecup and how do I use it?A: The eyecup is the extendable rubber or plastic tube (or shield) that surrounds the eyepiece at the viewing end.It may be extended outward and is used to set eye relief.For those who do not wear eyeglasses, simply back out (extend) the eyecup until the full field of view is visible in the eyepiece.

Q: How do I clean my eyepieces?A: We may recommend using any suitable camera lens cleaning materials (available at most photo shops).Some sport optics dealers may offer lens cleaning materials with anti-fogging properties, which may also be suggested.For the best results, follow packaged recommendations, and carefully clean lenses as soon as possible when required.

Q: How should I care for my eyepieces when not in use?A: Your eyepieces should be stored, dry, and in as clean a condition as possible, optically and mechanically.This will make them ready for use on demand.Keeping your eyepieces as clean as possible during use upholds their condition and performance, and will make preparation for storage quite easy.

Q: What type of glass is used in PENTAX eyepieces?A: PENTAX eyepieces feature rare-earth lanthanum crown glass for premium quality and outstanding optical performance .This glass type features a high refractive index and extra-low dispersion for maximum light transmission and superb optical clarity.

Q: Can I attach an SLR camera lens to an eyepiece?A: Yes, some SLR lenses can be attached with an appropriate step-up ring (adapter).The eyepiece ring (top of the eyecup) on XW Series eyepieces (and on the XF Series Zoom eyepiece) is removable in order to expose a 43mm - (0.75mm pitch) thread on the eyepiece barrel.

Q: Is it normal for eyecup drive tension to vary from one eyepiece to the next?A: Yes.Because a very coarse thread is used for eyecup drive, there may normally be some variation in the amount of “drag” on the eyecup drive; (which is set as the result of manufacture).Never attempt to lubricate this assembly, as penetration of lubricants may damage optical components.

Q: Why are there notches in the mount tube of my PENTAX zoom eyepiece?A: Small notches are machined into the mount tube of the zoom eyepiece in order to key the eyepiece in place within in the focuser.This is to keep the eyepiece from rotating within the focuser tube whenever the zoom collar of the eyepiece is turned.

Q: Can filters be used on PENTAX eyepieces?A: Yes.Although PENTAX does not produce filters for our eyepieces, some astronomical product manufacturers may offer a number of suitable filters for specialized applications in astronomy.The most commonly available filters are for 1.25” eyepieces.Simply screw an appropriate filter into the mount tube of an eyepiece.

Q: Does PENTAX produce a guiding eyepiece or an eyepiece with a reticle?A: No.PENTAX has not announced plans to produce such a product.

Q: Can I use the PENTAX XW30 or XW40 eyepiece on a PENTAX spotting scope?A: No.These eyepieces feature 2” mounting tubes which will not fit onto a PENTAX spotting scope.(PENTAX spotting scopes feature a 1.25” focuser).The XW30 and XW40 eyepieces are designed for telescopes with a 2” focuser, and provide breathtaking wide views of the night sky.

Q: Does PENTAX produce a Barlow lens?A: No.PENTAX has not announced plans to produce such a product.

Q: Does PENTAX produce planetary eyepieces?A: Yes.PENTAX XO series eyepieces feature outstanding performance and quality and are ideally suited for planetary observing at high magnifications.