Saturday, 15 February 2014
Where can I download the software driver for my digital eyepiece EE300 for Windows 8?
Please go to this User Guide page for the software download.
Why won’t my erect image eyepiece or diagonal always give right-side-up images with my telescope?
Image erectors won’t work in all circumstances. The orientation of the image produced by your scope depends on its optical design and its orientation. Though optics of many scopes create inverted images, an image may actually be right-side-up, sideways, or at an angle depending on how your tube is oriented, how your head is oriented and looking in the eyepiece, etc.
An erect image eyepiece is a series of prisms combined with eyepiece lenses designed to rotate the image from a telescope’s main optics by 180°. It’s most commonly used with the Newtonian reflector. It simply replaces whatever eyepiece you would normally use. When used with the reflecting scope where the image is presented upside down, it will give a right side up image that’s correct right to left.
An erect image diagonal is a right-angle or 45° star diagonal that replaces a regular prism with an Amici or roof prism. When used with a refractor (where the straight-through image is inverted), it will give a right-side-up image that’s correct right to left. A regular prism star diagonal also gives a right-side-up image, but it’s mirror-reversed.
Image erectors--whether eyepieces or diagonals--are also affected by orientation. They will work properly only in certain scope and viewer orientations.
An erect image eyepiece with a Newtonian will give the erect views only when the tube is in certain positions and you are looking into the tube from a certain position relative to the tube’s axis. The combination works when the main tube is level and the eyepiece drawtube is level on the right-hand side and you are looking directly into the eyepiece. The corresponding position on the left-hand side will also work (tube is rotated 180° in the tube rings). A third position that gives an erect image is with the tube level, the eyepiece drawtube on top, and looking into the eyepiece from behind (standing back towards the mirror end of the tube). Any other position will give a tilted or even upside down orientation, despite the use of the erecting eyepiece.
For Newtonian telescopes with dovetail mounting systems that place the eyepiece at a convenient 45° position for astronomical observations, you can't get an erect image, only a tilted one. So these scopes will show landscape scenes and terrestrial views at an angle.
An erect image diagonal has similar limitations. It will work with a level refractor tube when looking straight down into the diagonal and the eyepiece you’ve inserted. It will also give an erect image when rotated 90° right or left and you are looking in from the right or left side. Other orientations of the diagonal and your viewing angle will give slanted views.
Note: A simple trick will work with a Newtonian reflector without any erecting optics. Point the level scope at what you want to see and rotate the eyepiece drawtube so it is pointing straight up. Now stand in front and to the side of the scope (not blocking light from getting in the tube), looking back towards the mirror end of the tube. Bend over and look into the eyepiece from this position; you will see an erect image.
An erect image eyepiece is a series of prisms combined with eyepiece lenses designed to rotate the image from a telescope’s main optics by 180°. It’s most commonly used with the Newtonian reflector. It simply replaces whatever eyepiece you would normally use. When used with the reflecting scope where the image is presented upside down, it will give a right side up image that’s correct right to left.
An erect image diagonal is a right-angle or 45° star diagonal that replaces a regular prism with an Amici or roof prism. When used with a refractor (where the straight-through image is inverted), it will give a right-side-up image that’s correct right to left. A regular prism star diagonal also gives a right-side-up image, but it’s mirror-reversed.
Image erectors--whether eyepieces or diagonals--are also affected by orientation. They will work properly only in certain scope and viewer orientations.
An erect image eyepiece with a Newtonian will give the erect views only when the tube is in certain positions and you are looking into the tube from a certain position relative to the tube’s axis. The combination works when the main tube is level and the eyepiece drawtube is level on the right-hand side and you are looking directly into the eyepiece. The corresponding position on the left-hand side will also work (tube is rotated 180° in the tube rings). A third position that gives an erect image is with the tube level, the eyepiece drawtube on top, and looking into the eyepiece from behind (standing back towards the mirror end of the tube). Any other position will give a tilted or even upside down orientation, despite the use of the erecting eyepiece.
For Newtonian telescopes with dovetail mounting systems that place the eyepiece at a convenient 45° position for astronomical observations, you can't get an erect image, only a tilted one. So these scopes will show landscape scenes and terrestrial views at an angle.
An erect image diagonal has similar limitations. It will work with a level refractor tube when looking straight down into the diagonal and the eyepiece you’ve inserted. It will also give an erect image when rotated 90° right or left and you are looking in from the right or left side. Other orientations of the diagonal and your viewing angle will give slanted views.
Note: A simple trick will work with a Newtonian reflector without any erecting optics. Point the level scope at what you want to see and rotate the eyepiece drawtube so it is pointing straight up. Now stand in front and to the side of the scope (not blocking light from getting in the tube), looking back towards the mirror end of the tube. Bend over and look into the eyepiece from this position; you will see an erect image.
Why do I see stars only as points of light even when using my highest power eyepiece?
The ability to see details on an object ultimately depends on how far away it is and how big it is. Stars are so very far away that they will never show a real disk or ball shape in a telescope.
Planets, the Moon, and the Sun are much closer and will show discernible disks and details even at low or medium powers in most telescopes. Nebulae and galaxies are also very far away, but are so enormous they will also show details in many telescopes.
What you will see looking at stars at high magnifications (assuming a steady atmosphere that will allow this) is an optical pattern known as the diffraction pattern. It’s a bull’s-eye with a bright central area or disk surrounded by one or more concentric rings. It is not the actual disk of the star you are seeing. The diffraction pattern is due to the way the telescope’s circular lens or mirror acts on light from a pinpoint source like a star.
Planets, the Moon, and the Sun are much closer and will show discernible disks and details even at low or medium powers in most telescopes. Nebulae and galaxies are also very far away, but are so enormous they will also show details in many telescopes.
What you will see looking at stars at high magnifications (assuming a steady atmosphere that will allow this) is an optical pattern known as the diffraction pattern. It’s a bull’s-eye with a bright central area or disk surrounded by one or more concentric rings. It is not the actual disk of the star you are seeing. The diffraction pattern is due to the way the telescope’s circular lens or mirror acts on light from a pinpoint source like a star.
Why does there appear to be a black circle in the middle of my image when I look at a star or planet?
If you can see the shadow of the secondary mirror (black circle) and spider vanes in the eyepiece, the telescope is not focused.
As you move the focuser up, the image should get smaller until you reach a point where the shadow disappears. This image is now in focus. If you continue turning the focus knob and the shadow returns and image grows larger, you have passed focus and need to turn the knob in the opposite direction. If you want to make the focused image larger, you will need to use a higher power eyepiece (or zoom in if you use a zoom eyepiece).
As you move the focuser up, the image should get smaller until you reach a point where the shadow disappears. This image is now in focus. If you continue turning the focus knob and the shadow returns and image grows larger, you have passed focus and need to turn the knob in the opposite direction. If you want to make the focused image larger, you will need to use a higher power eyepiece (or zoom in if you use a zoom eyepiece).
How do I connect a SLR (Single-Lens Reflex) camera to my telescope?
To connect an SLR camera to your telescope, you’ll need two accessories: a camera T-ring and a T-adapter. T-ring is also known as T2 mount, and T-adapter is sometimes known as T-mount. This system is a worldwide standard 42mm thread to connect cameras to other devices.
A T-adapter attaches to the scope and a T-ring attaches to your SLR camera. A T-adapter with a 1.25” eyepiece barrel is very versatile and slips into the eyepiece drawtube of most telescopes. Other types of T-adapters with threads are specific to certain types of scopes. (Specialized accessories like a radial guider or tele-extender have T-threads that take T-rings, so they act like specialized T-adapters). For example, a T-adapter has been purposely designed to connect various SLR cameras to the Nipon 25-125x92 spotting scope.
The threads on the T-adapter fits into all T-rings. Since each brand of camera has its own specific thread size or bayonet type, you need the proper T-ring. Thus Canon has its T-rings (two of them); Nikon has its own T-rings; Minolta has their own specific rings, and so on. Some T-rings are available here for most popular brands, such as Sony, Olympus 4/3, Olympus Micro 4/3, Pentax K, in addition to those mentioned earlier.
To attach SLR cameras to your telescope, first, remove the visual accessories you are using – eyepiece, diagonal, visual back. Then either screw on or insert the correct T-adapter for your scope and the type of photography you want to do.
For example, to use the T-adapter with the 1.25” barrel, remove your SLR's lens and attach the T-ring to your camera, then the T-ring to the T-adapter and slide the 1.25” barrel into your eyepiece holder. Add a shutter release and the camera is now ready for prime-focus photography. Your telescope acts as a platform and can be used to provide tracking if the scope has been polar aligned. Tracking may not be needed for very short exposures of the sun, moon and planets.
Important Note: For some Newtonian telescope models, the focal plane of the telescope may not be far enough from the tube to allow you to focus with the T-adapter/camera setup you are using. Try using a T-adapter with a built-in Barlow lens (with the lens at the forward end), such as this Nikon SLR adapter, to extend the focal plane to reach your camera’s imaging plane. Another way that will achieve infinity focus with almost any Newtonian or other telescope is eyepiece projection directly into your camera with a large 32mm, 40mm, or 10-30mm zoom eyepiece. Some eyepieces have even got T-threads under the rubber eyecup, so simply thread it into your camera T-ring and then attach to your camera and put the assembly into your scope’s eyepiece drawtube.
More information can be found from this link: Digiscoping
A T-adapter attaches to the scope and a T-ring attaches to your SLR camera. A T-adapter with a 1.25” eyepiece barrel is very versatile and slips into the eyepiece drawtube of most telescopes. Other types of T-adapters with threads are specific to certain types of scopes. (Specialized accessories like a radial guider or tele-extender have T-threads that take T-rings, so they act like specialized T-adapters). For example, a T-adapter has been purposely designed to connect various SLR cameras to the Nipon 25-125x92 spotting scope.
The threads on the T-adapter fits into all T-rings. Since each brand of camera has its own specific thread size or bayonet type, you need the proper T-ring. Thus Canon has its T-rings (two of them); Nikon has its own T-rings; Minolta has their own specific rings, and so on. Some T-rings are available here for most popular brands, such as Sony, Olympus 4/3, Olympus Micro 4/3, Pentax K, in addition to those mentioned earlier.
To attach SLR cameras to your telescope, first, remove the visual accessories you are using – eyepiece, diagonal, visual back. Then either screw on or insert the correct T-adapter for your scope and the type of photography you want to do.
For example, to use the T-adapter with the 1.25” barrel, remove your SLR's lens and attach the T-ring to your camera, then the T-ring to the T-adapter and slide the 1.25” barrel into your eyepiece holder. Add a shutter release and the camera is now ready for prime-focus photography. Your telescope acts as a platform and can be used to provide tracking if the scope has been polar aligned. Tracking may not be needed for very short exposures of the sun, moon and planets.
Important Note: For some Newtonian telescope models, the focal plane of the telescope may not be far enough from the tube to allow you to focus with the T-adapter/camera setup you are using. Try using a T-adapter with a built-in Barlow lens (with the lens at the forward end), such as this Nikon SLR adapter, to extend the focal plane to reach your camera’s imaging plane. Another way that will achieve infinity focus with almost any Newtonian or other telescope is eyepiece projection directly into your camera with a large 32mm, 40mm, or 10-30mm zoom eyepiece. Some eyepieces have even got T-threads under the rubber eyecup, so simply thread it into your camera T-ring and then attach to your camera and put the assembly into your scope’s eyepiece drawtube.
More information can be found from this link: Digiscoping
How much magnification can I use, and how much is too much?
Telescope magnification is actually a relationship between two independent optical systems – the telescope itself and the eyepiece you are using. To determine power, divide the focal length of the telescope (in mm) by the focal length of the eyepiece (in mm). By exchanging an eyepiece of one focal length for another, you can increase or decrease the power of the telescope. For example, a 25 mm eyepiece used on a 1250 mm focal-length telescope would yield a power of 50x (1250/25 = 50) and a 10 mm eyepiece used on the same instrument would yield a power of 125x (1250/10 = 125). Since eyepieces are interchangeable, a telescope can be used at a variety of powers.
There are practical limits of magnification for telescopes. These are determined by the laws of optics and the nature of the human eye. As a rule of thumb, the maximum usable power is equal to 50-60 times the aperture of the telescope (in inches) under ideal conditions. Powers higher than this usually shows a dim, lower contrast image. For example, the maximum power on a 127 mm telescope (5” aperture) is in the range 250x - 300x. As power increases, the sharpness and detail seen will be diminished. The higher powers are mainly used for lunar, planetary, and binary star observations.
Most of your observations will be done with lower powers (6 to 25 times the aperture of the telescope in inches). With these powers, the images will be much brighter and crisper, providing more enjoyment and satisfaction with the wider fields of view.
A good way to increase magnification is to use a Barlow lens. A Barlow lens rated at 2x can be used with your existing eyepiece and it will double the magnification of any existing eyepiece.
There are practical limits of magnification for telescopes. These are determined by the laws of optics and the nature of the human eye. As a rule of thumb, the maximum usable power is equal to 50-60 times the aperture of the telescope (in inches) under ideal conditions. Powers higher than this usually shows a dim, lower contrast image. For example, the maximum power on a 127 mm telescope (5” aperture) is in the range 250x - 300x. As power increases, the sharpness and detail seen will be diminished. The higher powers are mainly used for lunar, planetary, and binary star observations.
Most of your observations will be done with lower powers (6 to 25 times the aperture of the telescope in inches). With these powers, the images will be much brighter and crisper, providing more enjoyment and satisfaction with the wider fields of view.
A good way to increase magnification is to use a Barlow lens. A Barlow lens rated at 2x can be used with your existing eyepiece and it will double the magnification of any existing eyepiece.
What are the different types of eyepiece filters: Colored, Neutral Density and Polarizing?
Eyepiece filters are an invaluable aid in lunar and planetary observation. They reduce glare and light scattering, increase contrast through selective filtration, increase definition and resolution, reduce irradiation and lessen eye fatigue.
Most quality eyepieces have threads in the base of the tube to accept filters. Many manufacturers use the same threading.
The effectiveness of the filters depends on several factors, including: the aperture and focal length of the telescope, the magnification being used, and seeing conditions. Here are descriptions of what to expect from each filter: Yellow, Orange, Red, Blue, Green, Violet, ND and Polarizing–in different observing situations. At the same time, you’ll become familiar with the astounding variety of enhancements available through these simple accessories. Also given for each filter is the percentage of light transmitted (T).
Yellow:
#12 Deep Yellow 74% T
#15 Deep Yellow 67% T
Moon – Enhance lunar features.
Jupiter – Penetrate and darken atmospheric currents containing low-hue blue tones. Enhance orange and red features of the belts and zones. Useful for studies of the polar regions.
Mars – Reduce light from the blue and green areas which darken the maria, oases and canal markings, while lightening the orange-hued desert regions. Also sharpen the boundaries of yellow dust clouds.
Neptune – Improve detail in larger telescopes (11" and larger apertures).
Saturn – Penetrate and darken atmospheric currents containing low-hue blue tones. Enhance orange and red features of the belts and zones.
Uranus – Improve detail in larger telescopes (11" and larger apertures).
Venus – Reveal low-contrast surface features.
Comets – Enhance definition in comet tails.
#8 Yellow 83% T
All observing information for this filter is the same as that given for the #12 and #15 Deep Yellow filters, with the exception of the following:
Mars – Improves the Martian maria by reducing scattered light from blue areas, while allowing passage of additional green light for studying yellow dust clouds.
Comets – Brings out highlights in yellowish dust tails and enhances appearance of comet heads.
Orange:
#21 Orange 46% T
Moon – Greatly enhances lunar features.
Jupiter – Improves appearance and detail revealed in structure of Jovian belts. Enhances viewing of festoons and polar regions.
Mars – Reduces light from the blue and green areas which darken the maria, oases and canal markings, while lightening the orange-hued desert regions. Also sharpens the boundaries of yellow dust clouds.
Mercury – Reduces the brightness of blue sky during daylight observing, to reveal surface features.
Saturn – Improves structure of the cloud bands and highlights blue polar regions.
Venus – Use during daylight observing to reduce brightness of blue sky. Comets–Enhances definition of comet dust tails and heads in larger telescopes (11" and greater aperture).
Solar – When using some Mylar Solar Filters, adding this orange filter will give a truer color rendition.
Red:
#25 Red 14% T
Moon – Improves lunar features.
Jupiter – Useful for studying bluer clouds.
Mars – Ideal for observation of the polar ice caps and features on the Martian surface. Sharpens the boundaries of yellow dust clouds.
Mercury – Improves observation at twilight, when the planet is near the horizon. During daylight, it reduces the brightness of the blue sky to enhance surface features.
Saturn – Useful for studying bluer clouds.
Venus – Use during daylight observing to reduce brightness of blue sky. Occasionally deformations of the terminator are visible.
#23A Light Red 25% T
All observing information for this filter is the same as that given for the #25 filter, with the exception of the following:
Mars – Reduces light from blue and green areas which darkens the maria, oases and canal markings, while lightening the orange-hued desert regions. Sharpens the boundaries of yellow dust clouds.
Comets – Improves definition of comet dust tails.
Blue:
Light Blue 30% T
#82A Pale Blue 73% T
#38A Blue 17% T
Moon – Enhance lunar detail.
Jupiter – Enhance the boundaries between the reddish belts and adjacent bright zones. Useful for viewing the Great Red Spot.
Mars – Very useful during the violet clearing. Helpful in studying surface features and polar caps.
Mercury – Improve observation of dusky surface markings at twilight, when the planet is near the horizon.
Saturn – Enhance low-contrast features between the belts and zones
Venus – Useful for increased contrast of dark shadings in upper Venusian clouds.
Comets – Bring out the best definition in comet gas tails.
Green:
#56 Light Green 53% T
Moon– Enhances lunar features.
Jupiter – Increases visibility of the Great Red Spot. Useful for observing the low-contrast hues of blue and red that exist in the Jovian atmosphere.
Mars – Excellent for increased contrast of Martian polar caps, low clouds and yellowish dust storms.
Venus – Useful for Venusian cloud pattern studies. Reduces brightness of blue sky during daylight observing.
#58 Green 24% T
All observing information for this filter is the same as that given for the #56 Green filter, with the exception of the following:
Saturn – Enhances white features in the Saturnian atmosphere.
Comets – Useful for observing brighter comets.
Violet:
#47 Violet 3% T
Mars – Useful for detecting high clouds and haze over the Martian polar caps.
Mercury – Helpful in detecting faint features.
Saturn – Good for ring structure studies.
Venus – Increases contrast of dark shading in upper Venusian clouds.
Comets – Useful for observing brighter comets.
#96ND (Neutral Density)
#96ND 50% T – Density 0.3
#96ND 25% T – Density 0.6
#96ND 13% T – Density 0.9
Moon – Excellent for reducing irradiation, glare and subject brightness. Colors are unaltered, as light is transmitted uniformly over the entire spectrum. Each model performs somewhat differently, depending on the brightness of the Moon.
Planets – Stacking in combination with color filters lowers transmission, but retains true color balance for specific applications. Reduces glare on brighter planets and minimizes irradiation.
Binary (Double) Stars – Helpful in splitting binary stars, because it reduces glare and diffraction effects around the brighter star of the binary pair.
Polarizing:
Reduces reflected polarized light in the Earth’s atmosphere.
Moon & Planets – Invaluable in reducing irradiation and glare.
Binary Stars – Helpful in splitting binary stars, because it reduces glare and diffraction effects around the brighter star of the binary pair.
Most quality eyepieces have threads in the base of the tube to accept filters. Many manufacturers use the same threading.
The effectiveness of the filters depends on several factors, including: the aperture and focal length of the telescope, the magnification being used, and seeing conditions. Here are descriptions of what to expect from each filter: Yellow, Orange, Red, Blue, Green, Violet, ND and Polarizing–in different observing situations. At the same time, you’ll become familiar with the astounding variety of enhancements available through these simple accessories. Also given for each filter is the percentage of light transmitted (T).
Yellow:
#12 Deep Yellow 74% T
#15 Deep Yellow 67% T
Moon – Enhance lunar features.
Jupiter – Penetrate and darken atmospheric currents containing low-hue blue tones. Enhance orange and red features of the belts and zones. Useful for studies of the polar regions.
Mars – Reduce light from the blue and green areas which darken the maria, oases and canal markings, while lightening the orange-hued desert regions. Also sharpen the boundaries of yellow dust clouds.
Neptune – Improve detail in larger telescopes (11" and larger apertures).
Saturn – Penetrate and darken atmospheric currents containing low-hue blue tones. Enhance orange and red features of the belts and zones.
Uranus – Improve detail in larger telescopes (11" and larger apertures).
Venus – Reveal low-contrast surface features.
Comets – Enhance definition in comet tails.
#8 Yellow 83% T
All observing information for this filter is the same as that given for the #12 and #15 Deep Yellow filters, with the exception of the following:
Mars – Improves the Martian maria by reducing scattered light from blue areas, while allowing passage of additional green light for studying yellow dust clouds.
Comets – Brings out highlights in yellowish dust tails and enhances appearance of comet heads.
Orange:
#21 Orange 46% T
Moon – Greatly enhances lunar features.
Jupiter – Improves appearance and detail revealed in structure of Jovian belts. Enhances viewing of festoons and polar regions.
Mars – Reduces light from the blue and green areas which darken the maria, oases and canal markings, while lightening the orange-hued desert regions. Also sharpens the boundaries of yellow dust clouds.
Mercury – Reduces the brightness of blue sky during daylight observing, to reveal surface features.
Saturn – Improves structure of the cloud bands and highlights blue polar regions.
Venus – Use during daylight observing to reduce brightness of blue sky. Comets–Enhances definition of comet dust tails and heads in larger telescopes (11" and greater aperture).
Solar – When using some Mylar Solar Filters, adding this orange filter will give a truer color rendition.
Red:
#25 Red 14% T
Moon – Improves lunar features.
Jupiter – Useful for studying bluer clouds.
Mars – Ideal for observation of the polar ice caps and features on the Martian surface. Sharpens the boundaries of yellow dust clouds.
Mercury – Improves observation at twilight, when the planet is near the horizon. During daylight, it reduces the brightness of the blue sky to enhance surface features.
Saturn – Useful for studying bluer clouds.
Venus – Use during daylight observing to reduce brightness of blue sky. Occasionally deformations of the terminator are visible.
#23A Light Red 25% T
All observing information for this filter is the same as that given for the #25 filter, with the exception of the following:
Mars – Reduces light from blue and green areas which darkens the maria, oases and canal markings, while lightening the orange-hued desert regions. Sharpens the boundaries of yellow dust clouds.
Comets – Improves definition of comet dust tails.
Blue:
Light Blue 30% T
#82A Pale Blue 73% T
#38A Blue 17% T
Moon – Enhance lunar detail.
Jupiter – Enhance the boundaries between the reddish belts and adjacent bright zones. Useful for viewing the Great Red Spot.
Mars – Very useful during the violet clearing. Helpful in studying surface features and polar caps.
Mercury – Improve observation of dusky surface markings at twilight, when the planet is near the horizon.
Saturn – Enhance low-contrast features between the belts and zones
Venus – Useful for increased contrast of dark shadings in upper Venusian clouds.
Comets – Bring out the best definition in comet gas tails.
Green:
#56 Light Green 53% T
Moon– Enhances lunar features.
Jupiter – Increases visibility of the Great Red Spot. Useful for observing the low-contrast hues of blue and red that exist in the Jovian atmosphere.
Mars – Excellent for increased contrast of Martian polar caps, low clouds and yellowish dust storms.
Venus – Useful for Venusian cloud pattern studies. Reduces brightness of blue sky during daylight observing.
#58 Green 24% T
All observing information for this filter is the same as that given for the #56 Green filter, with the exception of the following:
Saturn – Enhances white features in the Saturnian atmosphere.
Comets – Useful for observing brighter comets.
Violet:
#47 Violet 3% T
Mars – Useful for detecting high clouds and haze over the Martian polar caps.
Mercury – Helpful in detecting faint features.
Saturn – Good for ring structure studies.
Venus – Increases contrast of dark shading in upper Venusian clouds.
Comets – Useful for observing brighter comets.
#96ND (Neutral Density)
#96ND 50% T – Density 0.3
#96ND 25% T – Density 0.6
#96ND 13% T – Density 0.9
Moon – Excellent for reducing irradiation, glare and subject brightness. Colors are unaltered, as light is transmitted uniformly over the entire spectrum. Each model performs somewhat differently, depending on the brightness of the Moon.
Planets – Stacking in combination with color filters lowers transmission, but retains true color balance for specific applications. Reduces glare on brighter planets and minimizes irradiation.
Binary (Double) Stars – Helpful in splitting binary stars, because it reduces glare and diffraction effects around the brighter star of the binary pair.
Polarizing:
Reduces reflected polarized light in the Earth’s atmosphere.
Moon & Planets – Invaluable in reducing irradiation and glare.
Binary Stars – Helpful in splitting binary stars, because it reduces glare and diffraction effects around the brighter star of the binary pair.
What are the different eyepiece sizes / diameters?
Astronomical eyepieces are described by the diameter of the base tube or barrel and come in several standard diameters. This is not to be confused with the focal length of individual eyepieces. The eyepiece diameter for your telescope is important to know when purchasing other accessories, such as cameras, adapters and filters.
Eyepiece diameters commonly found in the market are 0.965", 1.25" and 2".
0.965" eyepieces are an older size that is still used on some smaller telescopes. They are inexpensive to make and are well-suited to simpler eyepiece optical designs that have 2 or 3 lenses. For example, Nipon 300x70 refractor is fitted with these eyepieces.
1.25" is widely considered to be the standard size for eyepiece barrels today. There are many different designs and focal lengths available from many manufacturers. Almost all accessories that fit into focusers are available in the 1.25" size. Most Nipon telescopes use 1.25 inch eyepieces.
The largest eyepiece size commonly encountered is the 2 inch barrel diameter eyepiece. The larger optics in these eyepieces provides wide, unobstructed fields of view. They are heavier and more expensive than standard 1.25 inch eyepieces and are best used on larger-aperture telescopes which have larger beams of light from the optical system.
Eyepiece adapters are available, enabling a particular telescope to use different diameter eyepieces. For example, you can use 1.25" eyepieces on telescopes with 0.965" eyepiece holder, with a 0.965" to 1.25" eyepiece adapter.
Eyepiece diameters commonly found in the market are 0.965", 1.25" and 2".
0.965" eyepieces are an older size that is still used on some smaller telescopes. They are inexpensive to make and are well-suited to simpler eyepiece optical designs that have 2 or 3 lenses. For example, Nipon 300x70 refractor is fitted with these eyepieces.
1.25" is widely considered to be the standard size for eyepiece barrels today. There are many different designs and focal lengths available from many manufacturers. Almost all accessories that fit into focusers are available in the 1.25" size. Most Nipon telescopes use 1.25 inch eyepieces.
The largest eyepiece size commonly encountered is the 2 inch barrel diameter eyepiece. The larger optics in these eyepieces provides wide, unobstructed fields of view. They are heavier and more expensive than standard 1.25 inch eyepieces and are best used on larger-aperture telescopes which have larger beams of light from the optical system.
Eyepiece adapters are available, enabling a particular telescope to use different diameter eyepieces. For example, you can use 1.25" eyepieces on telescopes with 0.965" eyepiece holder, with a 0.965" to 1.25" eyepiece adapter.
How do I use eyepieces with my telescope?
Your eyepieces are the first accessories you should have and use with your telescope. Since they are interchangeable, a telescope can be used at a variety of powers.
Look through the eyepiece by placing your eye just behind it to take advantage of its eye relief, the spacing between the lens and your eye. This should be at least 15 mm for the best comfort, maybe more if you wear eyeglasses. You’ll lose field of view if you place your eye farther away and may even move your eye out of the beam of light from the eyepiece. Viewing too close to the eyepiece will prevent you from blinking and may also cause a black ring to appear around the field of view.
Now turn the focus knob of the telescope, first one way then the other until the object is in focus.
Always start with the lowest power eyepiece (i.e., the one with the highest number in millimeters printed on it). It is much easier to focus and has a wider field of view, making it easier to aim the telescope at a distant target.
As power increases, the sharpness and detail seen will be diminished. The higher powers are mainly used for lunar, planetary, and binary star observations.
Most of your observations will be done with lower powers. With these lower powers, the images will be much brighter and crisper, providing more enjoyment and satisfaction with the wider fields of view.
A good way to increase magnification is to use a Barlow lens. A Barlow lens rated at 2x can be used with your existing eyepiece and it will double the magnification of any existing eyepiece. Since longer-focal-length eyepieces generally have longer eye relief, using a Barlow to increase magnification will allow more comfortable high-power viewing.
A basic set of eyepieces would be 32 mm, 20mm (or 26mm), and 10mm (or 16mm), plus a Barlow (2x or 3x power).
Look through the eyepiece by placing your eye just behind it to take advantage of its eye relief, the spacing between the lens and your eye. This should be at least 15 mm for the best comfort, maybe more if you wear eyeglasses. You’ll lose field of view if you place your eye farther away and may even move your eye out of the beam of light from the eyepiece. Viewing too close to the eyepiece will prevent you from blinking and may also cause a black ring to appear around the field of view.
Now turn the focus knob of the telescope, first one way then the other until the object is in focus.
Always start with the lowest power eyepiece (i.e., the one with the highest number in millimeters printed on it). It is much easier to focus and has a wider field of view, making it easier to aim the telescope at a distant target.
As power increases, the sharpness and detail seen will be diminished. The higher powers are mainly used for lunar, planetary, and binary star observations.
Most of your observations will be done with lower powers. With these lower powers, the images will be much brighter and crisper, providing more enjoyment and satisfaction with the wider fields of view.
A good way to increase magnification is to use a Barlow lens. A Barlow lens rated at 2x can be used with your existing eyepiece and it will double the magnification of any existing eyepiece. Since longer-focal-length eyepieces generally have longer eye relief, using a Barlow to increase magnification will allow more comfortable high-power viewing.
A basic set of eyepieces would be 32 mm, 20mm (or 26mm), and 10mm (or 16mm), plus a Barlow (2x or 3x power).
Why don't the images I see through my telescope look the same as photos taken with the same telescope?
The reason photos sometimes look better than what you see with the unaided eye is due to the camera’s ability to store light continuously as long as the shutter is open. The human eye doesn’t do that. Instead, it captures a scene moment to moment.
Many pictures you see in magazines and catalogs are time exposures. The camera shutter is kept open for several minutes or even hours while the telescope tracks the object across the sky. This allows the camera to record fainter detail and colors that cannot be seen with the naked eye.
Many pictures you see in magazines and catalogs are time exposures. The camera shutter is kept open for several minutes or even hours while the telescope tracks the object across the sky. This allows the camera to record fainter detail and colors that cannot be seen with the naked eye.
I have a refractor telescope with 900mm focal length and 60mm objective lens. Why can't I get a clear image when I try to use a 2x Barlow lens with a 6mm eyepiece?
This is because you’ve exceeded the practical limits of magnification for your telescope. The practical limits of magnification of a telescope are determined by the laws of optics and the nature of the human eye.
As a rule of thumb, the maximum usable power is equal to 50x-60x the aperture of the telescope (in inches) under ideal conditions. Powers higher than this usually give you a dim, lower contrast image. For example, the maximum power on a 60 mm telescope (2.4 in aperture) is in the range 120x-142x. The higher powers are mainly used for lunar, planetary, and binary star observations. As power increases, the sharpness and detail seen will be diminished.
The combination of the 6 mm eyepiece, 2x Barlow, and 900 mm focal length gives 300x. This is well beyond the maximum usable power of the scope.
The Earth's atmosphere also plays an important part in limiting the maximum magnification you can use. Instabilities in the atmosphere such as heat radiating from the ground and surrounding buildings, high altitude winds, and other weather conditions can cause the image to blur. This "bad seeing" can drastically distort your image. This also explains why bright stars appear to twinkle. The best time to use high magnification is on nights when the stars do not appear to twinkle very much.
As a rule of thumb, the maximum usable power is equal to 50x-60x the aperture of the telescope (in inches) under ideal conditions. Powers higher than this usually give you a dim, lower contrast image. For example, the maximum power on a 60 mm telescope (2.4 in aperture) is in the range 120x-142x. The higher powers are mainly used for lunar, planetary, and binary star observations. As power increases, the sharpness and detail seen will be diminished.
The combination of the 6 mm eyepiece, 2x Barlow, and 900 mm focal length gives 300x. This is well beyond the maximum usable power of the scope.
The Earth's atmosphere also plays an important part in limiting the maximum magnification you can use. Instabilities in the atmosphere such as heat radiating from the ground and surrounding buildings, high altitude winds, and other weather conditions can cause the image to blur. This "bad seeing" can drastically distort your image. This also explains why bright stars appear to twinkle. The best time to use high magnification is on nights when the stars do not appear to twinkle very much.
Everything I see through my refractor telescope is an inverted upside down image. How can I correct this?
To correct an inverted image, you will need a 90° diagonal lens. When a 90° diagonal is used, the mirror flips the image over, giving a right side up but reversed left to right image. You can achieve a fully corrected image using an erect image prism diagonal.
These image converters are available from Nipon Scope online store.
These image converters are available from Nipon Scope online store.
How to determine a telescope's magnification?
The magnification of a telescope changes as the eyepiece is changed. Magnification can be calculated by dividing the focal length of your telescope by the focal length of the eyepiece.
Calculating magnification = Telescope's focal length / Eyepiece focal length
Always start with your lowest magnification eyepiece (longest focal length) and work upwards from there.
A 2x Barlow lens will double the magnification of whatever eyepiece you use with it while preserving its eye relief. For example: using a telescope with a 800 mm focal length with a 16 mm eyepiece will give you 50x magnification. Using the same telescope and eyepiece with a 2x Barlow lens will give 100x magnification. This would be the same magnification as a 800 mm telescope with a 8 mm eyepiece.
Calculating magnification = Telescope's focal length / Eyepiece focal length
Always start with your lowest magnification eyepiece (longest focal length) and work upwards from there.
A 2x Barlow lens will double the magnification of whatever eyepiece you use with it while preserving its eye relief. For example: using a telescope with a 800 mm focal length with a 16 mm eyepiece will give you 50x magnification. Using the same telescope and eyepiece with a 2x Barlow lens will give 100x magnification. This would be the same magnification as a 800 mm telescope with a 8 mm eyepiece.
How far can I see with a telescope?
The farthest you can see in the sky with your telescope will depend on its ability to gather light and where you observe.
The most distant objects visible with amateur-sized telescopes are faint galaxies and the brightest quasars. They will be brighter and easier to see in a telescope that gathers more light and has a greater magnitude limit. Here bigger is better and a larger aperture scope will see more remote objects.
Location is also important. Even with a big telescope, you’ll see fainter, deeper and farther out into the universe from an isolated dark-sky site than from the heart of a megalopolis. For example: quasars are all very faint as seen from the earth. The brightest one is 3C 273 in Virgo. It is magnitude 12.9. A good 4-inch scope is capable of seeing it in dark-sky conditions. You’ll need a larger scope to be able to see it at all from a city.
The most distant objects visible with amateur-sized telescopes are faint galaxies and the brightest quasars. They will be brighter and easier to see in a telescope that gathers more light and has a greater magnitude limit. Here bigger is better and a larger aperture scope will see more remote objects.
Location is also important. Even with a big telescope, you’ll see fainter, deeper and farther out into the universe from an isolated dark-sky site than from the heart of a megalopolis. For example: quasars are all very faint as seen from the earth. The brightest one is 3C 273 in Virgo. It is magnitude 12.9. A good 4-inch scope is capable of seeing it in dark-sky conditions. You’ll need a larger scope to be able to see it at all from a city.
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