Product Overview
This document provides instructions for the National Geographic RF360MM 50mm Portable Refractor Telescope with Panhandle Mount. It covers setup, usage, safety information, troubleshooting, and technical details.
Important Safety Instructions
READ AND FOLLOW THE INSTRUCTIONS BEFORE USE. KEEP THESE INSTRUCTIONS FOR LATER USE.
- ☀️⚠️ SUN WARNING: NEVER ATTEMPT TO OBSERVE THE SUN WITH THIS DEVICE! OBSERVING THE SUN, EVEN FOR A MOMENT, WILL CAUSE INSTANT AND IRREVERSIBLE DAMAGE TO YOUR EYE OR EVEN BLINDNESS. EYE DAMAGE IS OFTEN PAINLESS, SO THERE IS NO WARNING TO THE OBSERVER THAT THE DAMAGE HAS OCCURRED UNTIL IT IS TOO LATE. DO NOT POINT THE DEVICE AT OR NEAR THE SUN. DO NOT LOOK THROUGH THE DEVICE AS IT IS MOVING. CHILDREN SHOULD ALWAYS HAVE ADULT SUPERVISION WHILE OBSERVING.
- ?️ RISK OF BLINDNESS: NEVER USE THIS DEVICE TO LOOK DIRECTLY AT THE SUN OR IN THE DIRECT PROXIMITY OF THE SUN. DOING SO MAY RESULT IN A PERMANENT LOSS OF VISION.
- ? RISK OF FIRE: DO NOT PLACE DEVICE, PARTICULARLY THE LENSES, IN DIRECT SUNLIGHT. THE CONCENTRATION OF LIGHT RAYS COULD CAUSE A FIRE.
- ?⚠️ CHOKING HAZARD: CHILDREN SHOULD ONLY USE DEVICE UNDER ADULT SUPERVISION. KEEP PACKAGING MATERIALS LIKE PLASTIC BAGS AND RUBBER BANDS OUT OF THE REACH OF CHILDREN AS THESE MATERIALS POSE A CHOKING HAZARD.
- ? DO NOT DISASSEMBLE THIS DEVICE: IN THE EVENT OF A DEFECT, PLEASE CONTACT YOUR DEALER. THE DEALER WILL CONTACT THE CUSTOMER SERVICE DEPARTMENT AND CAN SEND THE DEVICE IN TO BE REPAIRED IF NECESSARY.
- ?️ TEMPERATURE LIMIT: DO NOT SUBJECT THE DEVICE TO TEMPERATURES EXCEEDING 60 °C (140 °F).
- ⚖️ DISPOSAL: KEEP PACKAGING MATERIALS, LIKE PLASTIC BAGS AND RUBBER BANDS, AWAY FROM CHILDREN AS THEY POSE A RISK OF SUFFOCATION. DISPOSE OF PACKAGING MATERIALS AS LEGALLY REQUIRED. CONSULT THE LOCAL AUTHORITY ON THE MATTER IF NECESSARY AND RECYCLE MATERIALS WHEN POSSIBLE.
- ♻️ WEEE Symbol: The WEEE symbol (if present) indicates that this item contains electrical or electronic components which must be collected and disposed of separately. Never dispose of electrical or electronic waste in general municipal waste. Make use of return and collection systems or local recycling programs. Electrical and electronic equipment contains hazardous substances that can contribute to soil and water pollution and endanger wildlife if disposed of incorrectly. It is essential for consumers to reuse or recycle such waste.
California Proposition 65 Warning: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.
Customer Service: Call 1-866-252-3811
Parts Overview
The National Geographic RF360MM telescope consists of the following main components:
Diagram Description: A photograph of the assembled National Geographic RF360MM telescope mounted on a tripod, with key components numbered for identification.
- 1. 50mm Objective Lens: The primary light-gathering lens at the front of the telescope tube.
- 2. Panhandle Mount: A mount designed for smooth, controlled movement of the telescope, allowing for easy aiming.
- 3. Tripod: A sturdy three-legged base that supports the telescope and mount, providing stability.
- 4. Optical Tube Assembly with Dew Shield: The main tube of the telescope, which houses the optical components and includes a dew shield to reduce condensation and stray light.
- 5. Focus Wheel: Used to adjust the telescope's focus to achieve a sharp image.
- 6. Diagonal: An accessory that attaches between the telescope tube and the eyepiece, redirecting the light path by 90 degrees for more comfortable viewing.
- 7. 0.965" Eyepieces (H12.5 mm & H20 mm): Interchangeable lenses that magnify the image. This set includes a 12.5mm and a 20mm eyepiece.
For available downloads, visit: www.esmanuals.com
How To Set Up
Note: We recommend assembling your telescope for the first time in the daylight or in a lit room so that you can familiarize yourself with assembly steps and all components.
- Open the tripod until the tripod spreaders are fully extended. To set the tripod height, unlatch the hinged locking mechanisms on each leg and extend or retract the leg to the desired setting. When the tripod is the proper height, relatch any open locking mechanisms on each leg before attaching the telescope tube.
- Thread the panhandle clockwise onto the mount head.
- Set the telescope tube on the mount head so that the thread is aligned with the locking screw in the center of the mounting plate. Secure the tube to the mount by tightening the locking screw until it is secure. Be careful not to over-tighten the locking screw.
- Insert the diagonal into the focuser and secure it by tightening the thumbscrews.
- Place your chosen eyepiece into the diagonal. We recommend starting with the 20mm because it will provide the widest field of view. Note: Using the telescope without the diagonal could result in not being able to focus on the object. Most rich-field telescopes are designed to include the diagonal in their focal point. So the length of the diagonal is necessary for the light to get to the proper focal point.
Diagram Description: Two images are shown. The first, labeled "Eye view," is a close-up of an eyepiece. The second, labeled "View with regular eyepiece & diagonal," shows the telescope assembly with the diagonal and eyepiece attached.
Using Your Telescope
After you have assembled your telescope, you are ready to start observing. Put the 20mm eyepiece into the diagonal to get the widest field of view. This wider field of view will make it easier to locate and track objects at a magnification of 18x.
| Focal Length | Eyepiece | Magnification |
|---|---|---|
| 360 mm | 20 mm | 18x |
| 360 mm | 12.5 mm | 28.8x |
To move the telescope from side to side, loosen the locking screw on the side of the mount and use the panhandle to slowly turn the telescope until your target comes into view in the eyepiece. When you have the telescope in your desired position, tighten the locking screw to hold the position. To move the telescope up and down, slightly loosen the panhandle by turning it counter-clockwise. Slowly angle the telescope up or down until your target comes into view in the eyepiece. Secure the telescope in position by tightening the panhandle.
It is important to remember that the rotation of the Earth means objects move out of your eyepiece fairly quickly so you will probably have to change the orientation of your telescope frequently during an observing session.
To get a closer look at an object, take out the 20mm eyepiece and replace it with the 12.5mm eyepiece. This will increase the magnification to 28.8x.
Observing Tips
Star Hopping
Star hopping is a technique used by amateur astronomers to navigate the night sky. By using easily recognizable constellations and asterisms as a guide, an observer can locate stars and other objects.
For example, Polaris, which is commonly referred to as The North Star, can be located quickly using star hopping. First, find the Big Dipper asterism in the Ursa Major constellation. The popular pattern is defined by seven stars, and the two stars on the front edge of the Big Dipper's "bowl” are Merak and Dubhe. Next, draw an imaginary line from the bottom star (Merak) on this front edge through the top star (Dubhe) on the front edge. Follow the line to the first bright star you see. That should be Polaris. Finally, to verify your finding, locate the Little Dipper asterism. Polaris is the anchor star at the end of the Little Dipper's "handle."
Diagram Description: A star chart illustrating the "Star Hopping" technique. It shows the Big Dipper constellation, the Little Dipper constellation, and Polaris (the North Star). Lines indicate how to use the Big Dipper's "bowl" stars (Merak and Dubhe) to find Polaris, which is located at the end of the Little Dipper's handle. Other constellations like Ursa Major are also indicated.
Possible Objects For Observation
Terrestrial Objects
To view terrestrial objects, install the diagonal into the focuser, insert the H20mm eyepiece into the diagonal and turn the focuser until the image is clear. After mastering the H20mm eyepiece, switch to the H12.5mm eyepiece and practice scanning and focusing. Choose several terrestrial objects to practice focusing on. As you are exploring, NEVER point your telescope at or near the Sun due to serious risk of blindness.
Diagram Description: Simulated images show how terrestrial objects might appear through the telescope using the H20mm and H12.5mm eyepieces.
The Moon
Diameter: 3,476 km
Distance: Approximately 384,401 km
The Moon is the Earth's only natural satellite, and it is the second brightest object in the sky (after the Sun). Although it is our closest neighbor, a lot of people have never really taken a good long look at the Moon. With your telescope, you should be able to see several interesting lunar features. These include lunar maria, which appear as vast plains, and some of the larger craters. The best views will be found along the terminator, which is the edge where the visible and shadowed portions of the Moon meet.
Diagram Description: Simulated images show how the Moon might appear through the telescope using the H20mm and H12.5mm eyepieces, highlighting features like craters and plains.
Cleaning and Maintenance
Your telescope is a precision optical device and keeping the optics free of dust and dirt is crucial for optimal performance. To clean the lenses (objective and eyepiece) use only a photo-grade soft brush or a lint-free cloth, like a microfiber cloth. Do not press down too hard while cleaning, as this might scratch the lens. Ask your parents to help if your telescope is really dirty. If necessary, the cleaning cloth can be moistened with an optical glass cleaning fluid and the lens wiped clean using very little pressure. The eyepiece is NOT waterproof so do not spray fluids directly onto the glass or dip it in water. Never use harsh detergents! After you have finished cleaning an eyepiece, allow it to fully dry before storing.
Make sure your telescope is always protected against dust and dirt. After use, leave it in a warm room to dry off before storing.
Troubleshooting Guide
| Problem | Solution |
|---|---|
| No picture | Remove dust protection cap. |
| Blurred picture | Adjust focus using focus wheel. |
| No focus possible | Wait for temperature to balance out. |
| Bad quality | Never observe through a glass surface such as a window. |
| Despite using star diagonal prism the picture is "crooked" | The star diagonal prism should be vertical in the eyepiece connection. |
Telescope Terms to Know
Aperture
This figure, which is usually expressed in millimeters, is the diameter of a telescope's light-gathering surface (objective lens in a refractor or primary mirror in a reflector). Aperture is the key factor in determining the brightness and sharpness of the image.
Diagram Description: A diagram illustrating telescope optics. It shows an Objective Lens, Focuser, Eyepiece, and Diagonal, with labels for Aperture (mm) and Focal Length (mm) for both the telescope and the eyepiece. The Focal Point is also indicated.
Objective Lens
The objective lens is the main light-gathering component of a refractor telescope. It is actually composed of several lens elements.
Diagonal
This accessory houses a mirror that deflects the ray of light 90 degrees. With a horizontal telescope tube, this device deflects the light upwards so that you can comfortably observe by looking downwards into the eyepiece. The image in a standard diagonal mirror appears upright, but rotated around its vertical axis (mirror image). To get an image without this rotation, you will need to use a special diagonal with an erect image prism.
Eyepiece
An eyepiece is an optical accessory comprised of several lens elements. It determines the magnification of a particular observing setup.
Diagram Description: Three diagrams illustrate different types of eyepieces: Huygenian Eyepiece (2 Lens Elements), Kellner Eyepiece (3 Lens Elements), and Plössl Eyepiece (4 Lens Elements). Each diagram shows the path of light through the lenses (Eye Lens, Field Lens).
Barlow Lens
A Barlow lens effectively increases the focal length of a telescope. It is inserted between the eyepiece and the focuser/diagonal (depending on the optical setup) and multiplies the magnification power of the eyepiece. For example, a 2x Barlow will double the magnification of a particular eyepiece.
Focal Length (Telescope)
The focal length is the distance in millimeters between the objective lens or primary mirror and the point at which entering light rays converge – otherwise known as the focal point. The focal lengths of the telescope tube and the eyepiece are used to determine magnification.
Focal Length (Eyepiece)
The focal length is the distance in millimeters between the center of the first lens element in an eyepiece and the focal point. The focal lengths of the telescope tube and the eyepiece are used to determine magnification. Short eyepiece focal lengths produce higher magnifications than long eyepiece focal lengths.
Types Of Telescopes
Reflector
A reflector telescope uses mirrors to gather and focus light. Light enters the telescope through its open front end and travels to the concave primary mirror at the back. From there the light is reflected back up the tube to a flat secondary mirror, which sits at a 45° angle in relation to the eyepiece. Light bounces off of this secondary mirror and out through the eyepiece. A reflector's views will be upside down; therefore, it should only be used for astronomical observing because "up" and "down" are irrelevant in space.
Diagram Description: A diagram illustrating a Reflector telescope. Light enters from the front, reflects off a Primary Mirror (Objective) at the back, then off a Secondary Mirror, and finally out through the Focuser to the eyepiece.
Refractor
A refracting telescope uses a collection of lenses to gather and focus light. A refractor's views will be upside down if a diagonal is not in use. A standard diagonal will generate a "right side up" image; however, it will rotate the image on the vertical axis (mirror image). To get the "right side up" image without the rotation, you will need to use a special diagonal with an erect image prism.
Diagram Description: A diagram illustrating a Refractor telescope. Light passes through an Objective Lens, then through a Focuser, and out to the eyepiece. The diagram shows the light path and labels the Objective Lens.
Catadioptric
A catadioptric telescope uses a combination of mirrors and lenses to gather and focus light. Popular catadioptric designs include the Maksutov-Cassegrain and Schmidt-Cassegrain.
Diagram Description: A diagram illustrating a Catadioptric telescope. It shows light entering, passing through a Correcting Lens, reflecting off a Secondary Mirror, and then reflecting off a Primary Mirror (Objective) before exiting through the Focuser.
Key Formulas and Concepts
Magnification
The magnification corresponds to the difference between observation with the naked eye and observation through a magnifying device like a telescope. If a telescope configuration has a magnification of 30x, then an object viewed through the telescope will appear 30 times larger than it would with the naked eye. To calculate the magnification of your telescope setup, divide the focal length of the telescope tube by the focal length of the eyepiece. For example, a 20mm eyepiece in a telescope with a 1000mm focal length will result in 50x power, which will make the object appear 50 times larger. If you change the eyepiece, the power goes up or down accordingly.
Magnification = Telescope Focal Length / Eyepiece Focal Length
Diagram Description: A diagram showing light rays entering a telescope tube of 1000mm focal length and passing through an eyepiece of 20mm focal length, illustrating the concept of magnification.
Focal Ratio
The focal ratio of a telescope is determined by dividing the telescope's focal length by its aperture (usually expressed in millimeters). It plays a key role in determining a telescope's field of view and significantly impacts imaging time in astrophotography. For example, a telescope with a focal length of 1000mm and a 100mm clear aperture has a focal ratio of f/10.
Focal Ratio = Telescope Focal Length / Telescope Aperture
Exit Pupil
The exit pupil is the diameter of the beam of light coming out of the eyepiece. To calculate exit pupil, divide the focal length of your eyepiece by your telescope's focal ratio. For example, if you use a 20mm eyepiece with an f/5 telescope, the exit pupil would be 4mm.
Exit Pupil = Eyepiece Focal Length / Telescope Focal Ratio
Diagram Description: A diagram illustrating the exit pupil. It shows light exiting the eyepiece lens and forming a small beam of light (the exit pupil) before reaching the observer's eye.
Eye Relief
Eye relief is all about a comfortable viewing experience because it is the distance at which you need to position your eye from the eyepiece's outermost surface to enjoy the full field of view. This characteristic is of special concern to observers who wear glasses to correct an astigmatism, because a long enough eye relief is necessary to allow room for glasses.
Diagram Description: Two diagrams illustrate eye relief. One shows a "Short Eye Relief Distance" where the eye must be very close to the eyepiece lens. The other shows a "Long Eye Relief Distance" where the eye can be further away, suitable for eyeglass wearers.
Notes
This section is for user notes.
