Celestron H-Alpha, H-Beta & OIII Imaging Filter for RASA 8 Astrograph #

Celestron H-Alpha, H-Beta & OIII Imaging Filter for RASA 8 Astrograph # 93619

Description Ordering Info USA Shipping International Orders Returns Our eBay Store 1. PRODUCT DESCRIPTION

• Enhance imaging of nebulae with your 8” Rowe-Ackermann Schmidt Astrograph (RASA) by blocking light pollution, improving image contrast, and darkening the sky background.
• This filter transmits only the key Hα-Hβ-OIII wavelengths from emission nebulae, providing high contrast that makes them “pop.”
• This filter selectively blocks wavelengths of light from sources of light polluted skies and natural sky glow.
• Unlike similar filters with narrower bandpasses, this filter was engineered specifically to work with RASA’s fast F/2 optics.
• Fits into the 8” RASA’s integrated filter mount, maintaining peak optical performance.
• Optically flat surfaces free of defects, constructed of Schott glass with anti-reflection coatings.

Bring out the best in your nebulae astroimages with the H-alpha H-beta OIII (Hα-Hβ-OIII) Imaging Filter for the 8” RASA # 93619. This specialized filter allows high transmission of light from emission nebulae while blocking light pollution, helping to make your images pop with detail off the black sky background with superior contrast.

Fortunately, many sources of light pollution have relatively discreet emission spectra; they emit primarily at specific wavelengths of light. By strategically blocking these “bad” wavelengths, the filter essentially eliminates the effect of light pollution while letting the “good” wavelengths of light associated with the emission nebula pass through to the camera. You’ll notice much higher contrast in your images immediately, even if imaging from your light polluted backyard! And since the transmission at the key wavelengths is so high, the nebula will not be dimmed—only the background will be blacker.

Nebula Hunting

The Hα-Hβ-OIII Imaging Filter for the 8” RASA is perfect for imaging emission nebulae like the North America Nebula (NGC 7000), Lagoon Nebula (M8), Orion Nebula (M42), and the Carina Nebula (NGC 3372). The imaging filter transmits key Hα-Hβ-OIII wavelengths that produce high contrast for emission nebulae.

The transmission spectrum for the Hα-Hβ-OIII Imaging Filter is 85% or greater at key wavelengths (486nm, 496nm/501nm, 656nm) and less than 0.5% transmission elsewhere. The Hα-Hβ-OIII Imaging Filter for the 8” RASA is a narrowband filter that blocks much of the visible spectrum and only lets specific wavelengths through. Because of this, it will not work well on broadband emission objects, such as galaxies and star clusters.

Other similar imaging filters on the market have much narrower bandpasses at the critical Hα-Hβ-OIII wavelengths, but these filters will actually block much of the incoming Hα-Hβ-OIII light for an F/2 optical system. This is because the light is coming into the filter at a steeper angle, which causes a spectral shift. Using filters not designed specifically for use at F/2 will cause some of the light from the nebula to be blocked, resulting in a dimmer image. The Celestron Hα-Hβ-OIII Imaging Filter for the RASA 8 was custom engineered to work at F/2, so none of the “good” light from the nebula is inadvertently blocked by the filter.

Body and Storage

The filter is machined aluminum black anodized cell with knurled rim for easy grip during installation. An anti-reflection coating has been added to the filter to help suppress reflections on the glass. The filter fits directly into the internal filter mount in the RASA 8’s front lens cell, where the optical window normally mounts. By removing the clear window and replacing it with the filter, optical performance for the entire system is maintained. No other adapter is needed.

Each filter comes with a foam-lined plastic storage case and retaining ring to safely store the filter or the placeholder optical window glass that came with your RASA when not in use. You will also receive a spectral transmission graph unique to your specific unit, verifying its performance.

Specifications:

• Glass type: Schott B270
• Glass thickness: 2mm (0.078")
• Filter diameter: 46mm (1.81")
• Clear aperture: 43mm (1.69")
• Coatings: Dichroic multi-bandpass and multi-layer anti-reflection coatings
• Filter cell: Aluminum, black anodized, knurled rim

China

Note: Occasionally, the product you receive might have a slightly different cosmetic appearance or labeling than what is shown. This can often change from batch to batch according to the whims of the manufacturer. However, you will always receive a brand new, original product as described above.

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2. ORDERING INFORMATION

A. Payment: You can pay via any payment method that eBay accepts.

B. Shipping Method: United States Postal Service (USPS) or United Parcel Service (UPS) at your choice and expense (our choice if the item has free shipping option). eBay orders for items over $1,500 can only ship via UPS.

C. Order Processing Time: Orders received by 12 noon Mon – Fri US Pacific Time generally ship on the same business day. Orders received after 12 noon PT or on weekends/holidays will ship by the next business day.

D. Checkout: Please pay for the item(s) within 3 days from your account on eBay or by using the link in the email you receive from eBay.

E. Shipping Discount: We offer combined shipping if you order multiple quantities/items and if items can be combined. eBay will automatically show you the correct combined/discounted shipping costs when you check-out.

F. Combining Purchases: You can combine shipping for items purchased from us on eBay within 3 days. Buy the items individually and check out together for all items. eBay will combine the shipping weights and show you the discounted shipping cost. You must check out for all items together via eBay for this. We cannot combine shipping costs if you check out individually for your purchases.

G. Sales Tax/VAT: Sales tax or VAT may be charged and collected by eBay as required by law based on your ship-to address and local tax/VAT rates. Please check with eBay.

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3. US SHIPPING

A. Delivery Time:

• USPS First Class shipments will generally take 3-5 business days to arrive after we ship it. Priority Mail shipments will generally take 2-3 business days. However, these delivery times are NOT guaranteed by the USPS. Delays of up to 2 (or sometimes even 3) weeks can occur in about 5% of the shipments due to Covid, operational, or other issues.
• UPS shipments will generally take between 1 and 6 business days to be delivered depending on the method you select.

USPS and UPS do NOT offer any refunds for shipping/delivery delays for ANY reason (except for UPS Next Day Air service). Delays are out of our control once your order ships.

B. Tracking/Delivery Confirmation:eBay will update you once your order ships. You can see the order status or tracking information/link from your eBay account at any time.

C. USPS Tracking Limitations: Please note that is common for USPS tracking to show “Shipping Label Created, USPS Awaiting Item” or “Shipment Received, Package Acceptance Pending” even several days after your order ships. This does not mean that there is a problem with your order or that we have not handed over your package to USPS yet. This simply means that your package is en route without an outbound scan and tracking will not be updated until the package reaches a distribution center at your end several days later.

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4. INTERNATIONAL ORDERING / SHIPPING

A. Shipping Cost: Click on the "Shipping and Payments" tab above and select your country to see your shipping choices and cost. If you need a shipping cost estimate for multiple items, please contact us.

B. Delivery Time:

Please note that eBay’s delivery estimates shown are generally too optimistic!

1. UPS (All Shipping Methods):

• • We strongly recommend the use of UPS for international orders due to issues related to the ongoing Covid situation. Delivery time usually varies between 3-7 business days depending on your country and the exact shipping method you select.

2. USPS First Class International:

• • First class packages will usually be carried by GlobalPost (a USPS international delivery partner) for most of the way. Delivery at your end will be handled by your local postal service.
  • Delivery generally takes about 3-4 weeks after we ship your package. This can frequently take 4-6 weeks or more for several countries (8 weeks for Italy, Argentina, and South Africa; 8-12 weeks for Brazil).
  • There is very limited tracking available for 1st class shipments and there is no inquiry/tracing service. Once your package ships, we can do nothing but wait until your package arrives. Please do not become impatient and contact us in 2-3 weeks if your package has not arrived. If you don't receive the package in 6-8 weeks, contact us and we will work with you to resolve the issue.
  • If you don't want to take the risk of this delay or lack of tracking, DO NOT USE First Class mail - use Priority or Express shipping, or better still, UPS instead.
  • Packages are not considered lost unless 60 days have elapsed from the date of shipment.

3. USPS Priority Mail International: Delivery takes about 2 weeks to most countries after we ship your package. This can sometimes take 3-4 weeks to several countries. The USPS provides some basic tracking information for Priority shipping. Packages are not considered lost unless 60 days have elapsed from the date of shipment.

4. USPS Express Mail International: Delivery usually takes 5-10 business days after we ship your package. Packages are not considered lost unless 30 days have elapsed from the date of shipment.

Again, these delivery times are NOT guaranteed by the US Postal Service. The most common reason for delays is slow customs inspection and clearance in your country, and can be very long, even for Express mail packages. Upon shipping your order, delivery delays are beyond our control, so do not leave us negative feedback or file a claim if your package is delayed. Delays are quite common but losses are very rare, so your patience and understanding will be greatly appreciated.

C. Brokerage Fees, Customs and Duties:

• You are responsible for any carrier brokerage fees and duties/taxes that may be levied in your country. These are not included in our item price or shipping cost. UPS brokerage fees can be quite hefty.
• We have no control over these charges and cannot predict what they may be or if they will be levied upon delivery.
• Customs policies vary widely from country to country (Some countries such as UK are strict about imposing hefty customs duties). It is your responsibility to check with your country's customs office to determine what these additional costs will be prior to buying.
• Customs fees are normally charged by the delivery company or your country's postal service or collected when you pick the item up. These fees are NOT additional shipping charges.

Back to Top 5. RETURN/EXCHANGE POLICY

A. US Orders: Returns must be shipped back within 30 days. All returned items must be in brand new, resalable condition with original manufacturer’s packaging. A minimum restocking fee of 10% will be deducted if there is any evidence of use or wear, dirt, scratches, missing packaging/parts, etc. We may levy a larger restocking fee if the condition warrants it, or even refuse returns entirely if returned in heavily used/abused condition. Shipping fees are non-refundable (for items with free or discounted fixed shipping, the actual outbound S&H cost we incurred will be deducted) and you are responsible for all return shipping costs. Please contact us first before returning an item.

B. International Orders: No returns/exchanges accepted unless the item we shipped is defective. Please research the product and ask us any questions BEFORE you purchase to make sure you are buying the correct item for your needs.

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