ฟิลเตอร์ส่องดวงอาทิตย์ Thousand Oaks ID 2.75" (70mm) Solarlite #S-2750

ฟิลเตอร์ส่องดวงอาทิตย์ Thousand Oaks ID 2.75" (70mm) Solarlite  #S-2750

• ใหม่! รุ่น Solarite คงคุณภาพของภาพของรุ่นกระจก + จุดแข็งที่เหนียวและเบาของ polymer เข้าด้วยกัน จึงมีความคงทนมากที่สุดรุ่นนึงในตลาด
• วัสดุฉีกขาดยาก ทนต่อการเป็นรูหรือรอยขูดขีด น้ำหนักเบา ไม่ต้อง rebalance กล้องหลังสวมใส่
• คงสีเหลืองส้มของดวงอาทิตย์ตลอดทั้งพื้นที่
• สวมเข้ากับขอบของหน้ากล้องอย่างแน่นพอดี (เสริมด้วย felt lining ที่รวมอยู่ในชุด) เพื่อป้องกันการหลุดของฟิล์เตอร์ กรองแสงดวงอาทิตย์ที่จะเข้าสู่หน้ากล้องได้ 99.999%
• ขอบนอกทำด้วยอลูมิเนียมที่เบาทนทานและแข็งแรง ขอบในเสริมวัสดุที่ช่วยให้การสวมใส่แน่นกระชับ (friction fit) เพื่อเพิ่มผิวสัมผัสกับขอบกล้องดูดาว ป้องกันอุบัติเหตุที่อาจทำให้ฟิลเตอร์หลุดโดยง่าย
• ส่งผ่านแสงเพียง 1/1000 ของ 1% (Optical Density 5) เหมาะสำหรับใช้สังเกตด้วยตาและการถ่ายภาพ
• ขนาดขอบใน = 2.75" (ใช้ได้กับกล้องที่มีขอบนอกระหว่าง 2.50" ถึง 2.75" โดยใช้ felt lining เสริมขอบในของฟิลเตอร์ 3-6 ตำแหน่ง)
• ถ้าใช้งานอย่างระมัดระวัง ฟิลเตอร์ Thousand Oaks Optical รุ่นนี้สามารถอยู่ได้ไม่ต่ำกว่า 20 ปี และอาจนานชั่วชีวิตคน
• สินค้าแบรนเนมคุณภาพจาก USA; รับประกัน 2 ปี

ข้อควรระวัง:

1. วิธีเลือกฟิลเตอร์ที่พอดีกับหน้ากล้องสามารถทำได้โดยการวัดที่ขอบนอกของหน้ากล้อง (OD)โดยตรงและเทียบกับขนาดขอบใน (ID) ของฟิลเตอร์ (OD ของขอบกล้องดูดาวมักจะใหญ่กว่าหน้าเลนส์หรือกระจกของกล้องดูดาวเป็นปกติ เช่นกล้องดูดาวขนาด 8" อาจมีขอบกล้องที่ 9.25" เป็นต้น) ขนาดฟิลเตอร์ควรมี ID ที่พอดีหรือมากกว่าขอบกล้องดูดาวไม่เกิน 0.25"  ดูวีดีโอหรือรูปประกอบได้จากด้านล่าง

2.ไม่ควรมองดวงอาทิตย์โดยไม่ผ่านฟิลเตอร์ที่ออกแบบสำหรับส่องดวงอาทิตย์แม้เพียงเวลาเสี่ยววินาที เพราะอาจทำให้กระทบการมองเห็นอย่างถาวร! การใช้ฟิลเตอร์ต้องให้สวมให้แน่นและกระชับ ไม่หลุดง่าย และให้ตรวจดูว่าไม่มีรูรั่วในเนื้อฟิลเตอร์ที่แสงจะเล็ดลอดผ่านได้ทุกคีั้งก่อนใช้งาน

Regarding Safety

1. Extended direct and unprotected viewing of the Sun (not just in visible light, but also the in dangerous and invisible UV and Infrared radiation) causes the sunlight to be focused onto the retina of the human eye. Inflammations of the inner eye as well as permanent eye damage may result.
2. It is absolutely necessary to make you aware of the dangers of insufficient eye protection (such are “home made filters” consisting of sooth glass, exposed film negatives, CDs, ineffective foil filters, etc.). After the solar eclipse of 7 March 1970, 145 cases of total or near-total blindness due to solar viewing with insufficient protection were recorded in the USA alone. The number of unreported cases was probably much higher. Even minor retinal damage, though painless (and thus especially dangerous) can cause days of unbearable pain later.

 Use Thousand Oaks filters to avoid pain and problems with your eyes.

CAUTION: Never look at the Sun, either directly or through a telescope, without a professionally made protective solar filter installed that completely covers the front of the instrument, or permanent eye damage could result.

Who said you have to be in the dark to do astronomy? Turning your telescope to the Sun is fun and educational. Watch the march of giant sunspots, the clouds of glowing vapor in the photosphere, and solar "granulation" detail. But be sure to protect your precious vision with a safe Thousand Oaks solar filter! Looking at the Sun without one, even for an instant, can permanently damage your eyes.

Solarlite: NEW (Best Value)
After years of R & D Thousand Oaks Optical have developed a new solar film that has the optical quality of the glass with the advantages of impregnated polymer (Thousand Oaks Optical Black Polymer). Will never develop pin holes or scratches that can let in light and ruin a filter. Other advantages: Light weight and does not require re-balancing tube assembly, will not break, consistent yellow-orange solar image, even density with any aperture, flat surface compared to other thin film filters that have wrinkles and creases. Will not tear or puncture. Stronger than any other solar film on the market. Also available in sheets. Guaranteed 15 years.

Each Thousand Oaks filter is mounted in an aluminum cell that slide-fits over the front of your telescope. Size shown in the chart below is the ideal diameter of front of telescope; filter will fit diameters up to 1/4" smaller with foam tape liner supplied.

CAUTION: Never look at the Sun, even for an instant, without a protective solar filter. Doing so can permanently damage your eyes.

Determining the Correct Thousand Oaks Solar Filter for your Telescope

A full-aperture solar filter is designed to fit over the front of a telescope. It allows safe viewing of the Sun by reducing the light by 99.99% and preventing concentrated heat from entering the telescope, which could cause injury to the user or damage to equipment.

If your telescope is not listed on our solar filter reference chart, you can determine the size of filter needed for your scope by taking the following steps:

1. Measure the maximum outside diameter (OD) of the front end of your telescope.

 

2. The solar filter sizes listed in our catalog and on our website refer to the inner diameter (ID) of the filter's foam-lined metal cell for Thousand Oaks, which slip over the front of the telescope. Choose a filter whose size matches the OD of your telescope's front end, or that is up to 0.25" larger than the front end (for Thousand Oaks Filters only). For a filter that is up to 0.25" larger in diameter than your telescope, apply the supplied adhesive foam tabs as needed to the inside wall of the cell until the cell fits snugly over the front opening. 

Pinholes and Minor Scratches

Pinholes and minor surface scratches are common in solar filters, however, Thousand Oaks Optical's multi-coating technique keeps them to a minimum. A "bright" pinhole may cause "ghosting" due to scattered light. If this is seen during observation, the pinhole(s) should be blocked out. Blocking out any pinholes should be done on inside coated surface. Hold filter 1-2 feet in front of a standard 60-100 watt "soft white" light bulb. Blocking can be done with a fine point felt marker, small drop of paint, typing correction fluid etc. The touch up procedure will not degrade the optical performance. It is not necessary to touch up any small pinholes that do not cause image problems. There is no danger if some small non light scattering pinholes or minor scratches are present. All filters are tested for safety before shipment.

Frequently Asked Questions (FAQs)

WHAT SIZE DO I ORDER? The application guide below lists sizes by clear aperture (filter size) and outer cell wall inside diameter (I.D.) The I.D. of the cell slips over and around the O.D. of the telescope tube or lens holder. Please note that the brands and sizes listed are only a guide. Telescope manufacturers sometimes make changes so we strongly recommend the outside diameter of the tube be measured to be sure the correct part number is chosen. Choose the closest outer cell I.D. size larger than the outside diameter measurement of your instrument. Example: part # 4250 (4 1/4") would fit O.D. measurements from 4" to 4 3/16". Do not choose a size the same as your O.D. since it will be too tight and not allow room for a felt lining. Ample felt is included for custom fitting. If your application requires additional felt; Velcro, felt, and other types of material can be found at most fabric or home improvement stores.

ARE THE FILTERS COMPLETELY SAFE? All of Thousand Oaks Optical Glass 2+, Solarite, RG-Solar Film & Silver-Black Polymer filters are completely safe for unlimited visual use. If handled with care and common sense, all will last a minimum of 20 years to life.

DO THE ALUMINUM CELLS COME WITH THUMB SCREWS? Thumb screws may seem like a good idea, however, our extensive testing found that in most cases it's actually less secure than a felt lining which covers a lot more surface area for a secure friction fit. If the tolerance is within a few thousands of an inch such as with eyepiece holders, it would be fine, but this is rarely the case. Thumb screws can also dent and scratch the tube and put strain on the filter glass. Thumb screws are simply a "one size fits many" manufacturing shortcut and provide a false security.

CAN THE TELESCOPE OPTICS GET HOT OR DAMAGED? No, all the heat and intense light is blocked before it can enter the telescope. Your telescope may get warm from sunlight shining on it, not from the small amount of visible light transmitted through the filter.

WHAT DETAIL IS VISIBLE? Sunspots and surface granulation are the two main features. The only detail that cannot be seen with a standard filter (commonly called white light filter) are prominence and flares which require our highly specialized H-Alpha filter system.

WHY ARE THREADED CAMERA FILTERS ONLY AVAILABLE IN BLACK POLYMER? RG and Glass filters have highly reflective coatings that can cause internal reflections between the filter and camera lens since the filter and lens are in close proximity. This problem is less likely to occur with telescopes, however, mounted telescope filters can be tilted slightly to move any internal reflections off axis and out of view.

SOLAR FILTERS White Light  (580-630nm)

Printable SolarLite Filter Instructions

TECHNICAL DETAILS:

Glass 2+:  High quality hand selected glass with metallic coating on inside surface facing optics.

SolarLite Film:  Metallic coating outside surface & absorptive material within substrate.

Silver-Black Polymer Film:  Metallic coating outside surface absorptive material within substrate.

All filters block 99.999% of the energy from entering the instrument. For visual and photographic use.

IMPORTANT:

• Check the solar filter for damage before each use.
• The filter must be FIRST in-line between sun and instrument. Do not use filter behind any lens.
• Truss design telescopes must NOT be used without covering the open section of tube. Sunlight entering from the side will reflect off mirror and damage the solar filter.
• Secure filter properly. (See mounting instructions)
• Do not leave instrument unattended where a child or inexperienced adult could point it at the sun without the filter properly attached.
• Keep the finder-scope covered if not equipped with a proper solar filter.
• Point the instrument away from sun when attaching and removing solar filter.
• Do not place the filter up against a smaller instrument. The end of the tube will damage the filter.
• When looking through the focusing tube without an eyepiece, there may appear to be small defects in
• the coating that are not seen when observing through the eyepiece. This is normal and is not a coating defect or safety concern.
• “Ghosting” can occur due to internal reflections (glass filters only). If this is a problem, simply tilt the filter slightly.
• Filter may absorb solar energy and get hot during use. Use extra care when removing.

Pinholes and minor surface scratches are common in glass solar filters; however, our multi-coating technique keeps them to a minimum. A “bright” pinhole in the coating may cause “ghosting” due to scattered light. If this is seen during observation, the pinhole(s) should be blocked out. Block out any pinholes on inside surface facing telescope. Hold the filter 1-2 feet in front of a 50-100 soft white light bulb. Blocking can be done using a fine point felt marker. There is no danger if a few pinholes or minor scratches are present. The touch-up(s) will not lessen the optical performance. Small pinholes need not be blocked if not causing an image problem.

MOUNTING:

If your filter is too loose, it can be custom fitted using the extra felt included. If the paper backing is difficult to remove, dampen with water or alcohol using a wet sponge or fine spray mist. Peal backing off slowly. Let dry if necessary before installing on inside of cell. Extra felt can be added over any existing felt. Test fit before removing the backing and permanently installing the felt. We cannot exchange for another size if the felt is installed.

TIPS:

• Allow instrument and filter to equalize to the outside temperature for at least 15 minutes.
• If possible, do not view over pavement or buildings. Viewing over grass or water will help avoid heat currents that will degrade the image.
• Cover dark colored instruments with a light colored cloth.

CLEANING:

Glass: Loose dust can be blown off with up to 15 PSI. Clean with Isopropyl (rubbing) alcohol and a soft tissue. Do not use a cloth. It’s best to mist the filter with a spray versus soaking the tissue. Use a 3 inch or larger circular wad of tissue and lightly rub across surface using long strokes. Lightly wipe dry with a fresh dry tissue.

SolarLite & Silver-Black Polymer Film:  Same as glass, however, polymer is more susceptible to small surface scratches, so extra care should be taken. Surface scratches will not compromise the safety.