- For Use on Refractor and Maksutov OTAs
- Reduces Heat Load on Filter Assembly
- Absorbs or Reflects UV and/or IR Light
- For H-alpha, Sodium, Helium D3 Filters
- Inside Diameter of Cap: 12 cm (4.724")
Daystar Filters' 100mm-Aperture Energy Rejection Filter is designed for on-axis use with Refractor and Maksutov-style OTAs to reduce the heat load on your filter assembly by absorbing or reflecting UV and/or IR light while transmitting light in the desired spectrum. This ERF can be used with H-alpha, Sodium, and Helium D3 solar filters, but is incompatible with calcium wavelengths.
Choose the ERF aperture size to approximately match your refractor's objective aperture or Maksutov corrector plate. Select the correct filter cap size by measuring the outside diameter of the OTA's dew shield and choose the ERF with the smallest inside diameter that will fit over the dew shield. A set of screws is included to secure the ERF into place. This ERF's cap has an inside diameter of 12 cm (4.724").
SAFETY FIRST: Observing the Sun without the proper protection may result in serious personal injury, including permanent eye damage and blindness, and/or damage to equipment. Never point an optic at the sun without an approved solar filter on the front of the optic. For direct solar viewing, viewing the sun through an optic, or when using cameras with an optical viewfinder, ensure your filter is ISO 12312-2 (also written as ISO 12312-2:2015) certified. Never use photographic neutral density filters for direct solar viewing, viewing the sun through an optic, or when using cameras with an optical viewfinder.
You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Easy 30 Day Return Policy
If you are dissatisfied with your purchase for any reason, you may return it to Kellards within 30 days of the purchase date, subject to the conditions and exclusions below.
You may initiate a return or exchange by requesting an RMA at firstname.lastname@example.org.
Securely affix your return label to the outside of the shipping package. Return shipping fees are the responsibility of the customer. We recommend you ship via insured ground service with a tracking number. We cannot be responsible for lost packages.
Return AddressKellards Return
3237 Greenpoint Ave.
Long Island City NY 11101
Please read conditions below. If all conditions are not met, Kellards reserves the right to refuse the return or to charge a minimum 15% restocking fee. All returned items must be in new condition, in their original unaltered box (including an intact UPC code) and must include all packing material, blank warranty cards, manuals and accessories. Kellards can only refund the original purchase price. Shipping and handling fees are nonrefundable.
- Electronic software downloads
- Opened consumable items (e.g., film, tapes, paper, bulbs, CD, DVDs, ink cartridges, etc.)
- Underwater equipment that has been submerged
Defective or Damaged Items
Defective items may be repaired, exchanged or refunded at our discretion for the same model or manufacturer's equivalent model.
Please allow 3-5 business days for mail-in exchanges to be processed.
Refunds & Credits
Once we receive and inspect your item(s), we will credit your account. Please allow 5-7 days for a credit to appear on your account. In most cases, we will issue your refund in the same way you made the original purchase.
We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.