Celestron RASA 8" f/2 Rowe-Ackermann Schmidt Astrograph optical Tube (OTA only)-91073

Celestron 8" f/2.0 Rowe-Ackermann Schmidt Astrograph (OTA Only)

The Celestron 8" f/2.0 Rowe-Ackermann Schmidt Astrograph (RASA) is specifically designed for astrophotography and astro-imaging with a large aperture and fast focal ratio. Using four-element rare-earth optical glass lenses ensures accurate color rendition and eliminates aberrations such as coma and field curvatures. The improved StarBright XLT multi-coating system, which includes anti-reflection coatings on the lenses and highly reflective coatings on the mirrors, increases light transmission throughout the entire optical path. An integrated fan reduces cooldown time and provides optimal airflow through the optical tube assembly (OTA) while filtering harmful dust from the interior.

The astrograph design is defined by its fast focal ratio, which reduces exposure times without sacrificing image quality and gives you more time for multiple shots of the same object for layering or with different filters. Its internal Ultra-Stable focusing mechanism enables very precise focusing to clearly resolve topographic details on the Moon or split double stars and reveal details of most other celestial objects in between, while minimizing unwanted lateral movement of the primary mirror when focusing or slewing. Since this OTA is designed as an imaging scope, a 42mm camera T-adapter and C-mount imager adapter are included that are compatible with most camera-specific T-rings that are widely available.

Optical Performance

• 203mm (8") diameter aperture enables near- and deep-sky viewing without being prohibitively large or heavy for easy transport to viewing locations
• 400mm focal length helps to produce a fast focal ratio
• Fast f/2.0 focal ratio requires significantly lower exposure times versus slower ratios to produce the same results
• Rowe-Ackermann Schmidt astrograph (RASA) design is purpose built for astrophotography and imaging performance, and is not recommended for visual use
• Proprietary StarBright XLT fully multi-coated optical system
• Four-element rare-earth glass for true color rendition without aberrations across the entire field of view
• Wide 390-800nm spectral range improves images of deep space objects like galaxies and nebulae
• Image circle: 22mm (0.86")
• Resolution: 0.68 arcsec (Rayleigh), 0.57 arcsec (Dawes)
• Back focus: 25mm (0.98") with included camera adapter, 29mm (1.14") from top of threaded collar
• Optical window can be removed and replaced with optional filters such as a light pollution filter
• Integrated cooling fan brings optical system to ambient air temperature for better performance
• Runs on eight user-supplied AA batteries or optional 12VDC power adapter

StarBright XLT Coating System

• Multi-layer mirror coatings made from layers of aluminum, SiO2 (silicon dioxide), and TiO2 (titanium dioxide)
• Reflectivity is flat across the light spectrum, for both astrophotography/astro-imaging
• Multi-layer anti-reflective coatings made from layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide)
• High-transmission water white glass corrector lens with 97.4% light transmission

Focuser

• Focusing system moves primary mirror forward and back to achieve tack-sharp images
• Ultra-stable design minimizes unwanted lateral movement of the primary mirror when focusing or slewing
• Fine adjustments for precise focusing, approximately 30 turns of the knob runs through the focus range

Mounting

• OTA only, mount and tripod required for proper use
• Includes large CGE/Losmandy-D dovetail plate for use on larger more stable mount heads
• Weight: 17 pounds

Packaging Info

General

Optical Tube Assembly

Included Items

• 8-inch RASA Telescope.
• M42 camera adapter.
• C-thread camera adapter.
• Fan battery pack.

1.1 How can I check the shipping cost for my order?
You can add the items you want to your shopping cart, enter your country/state/city/postal code, and then view the shipping options and costs on the cart page. Before checkout, you can choose your preferred shipping speed/method/carrier.

You can also contact us and send us the item model, quantity, and shipping requirements. We will calculate the accurate shipping cost for you and inform you accordingly.

1.2 How are free shipping items delivered?
Items marked as "Free Shipping" on the product page mean you do not need to pay any shipping fees. This usually applies to buyers from any country (except for certain special countries or regions).

For free shipping items, buyers cannot choose the shipping method. We will select the shipping method based on the destination country.
Typically, we use standard surface shipping methods such as 4PX, EMS, or local postal services.
We may also use UPS, FedEx, DHL, Aramex, etc., depending on the specific order and country. The final choice is at our discretion. Regardless of the shipping method used, we will notify you upon dispatch and provide a tracking number and tracking website.

• Standard tracking website: https://www.17track.net/en
• UPS: https://www.ups.com/
• FedEx: https://www.fedex.com/
• DHL: https://www.dhl.com/

Please note: If you return an item (excluding quality issues or incorrect items), you will be charged for all shipping costs incurred, including delivery, return, and customs fees.

1.3 What if I want to specify a shipping method for a free shipping item?
If you want to specify a particular shipping method (e.g., UPS or DHL) for a free shipping item, please contact us before placing your order. You will need to pay additional shipping fees, and we will ship via your preferred method.

1.4 What if I buy multiple items, some with free shipping and some that require shipping fees?
You can place your order as usual. You only need to pay shipping fees for the non-free shipping items.
If you want to specify a shipping method or have other special requests, please contact us.

1.5 How long does it take to ship my order?
After receiving your order, we need some time to process it.
Orders received before 5:00 PM China time will be shipped within 3 days.
Orders received after 5:00 PM China time will be shipped within 4 days.
Orders placed during Chinese public holidays may be delayed by 1–2 days (due to courier holidays).

1.6 When will I receive my package?
Delivery time varies depending on the shipping method used:

• 4PX, Postal Services, EMS, etc.: about 15–25 days
• UPS: about 7–15 days
• FedEx: about 7–10 days
• DHL: about 5–9 days

These are estimated times. Actual delivery is subject to the carrier's schedule.

If your package tracking has not been updated for a long time, please contact us.
If you haven't received your package after a long period, please contact us.
If there are any other irregularities, please contact us.

Please note:
After we ship your package, it may take 2–3 days for tracking information to become available.
Based on our experience, packages shipped to South America and Central Asia typically take longer.
Shipping around public holidays may result in delays due to carrier workload.

If delays occur, we kindly ask for your patience and understanding. We share the same desire as our customers—we hope every package is delivered quickly and safely.

If you want a faster and more secure delivery, we strongly recommend choosing UPS, FedEx, or DHL.

1.7 What does it mean when tracking shows "Label Created" but the order hasn't shipped yet?
When we provide a tracking number, your package has already left our warehouse.
However, the tracking status may show "Label Created" or "Awaiting Package" because the package is still en route to the courier's sorting facility.
Due to China's vast geography, transit between cities can span over 1,000 km, so it takes time.
It may also be undergoing export customs clearance. Your package should be delivered soon.

If your tracking status doesn’t update for a long time, please contact us.

1.8 What if my package needs special delivery instructions or other requests?
If your shipment requires an invoice to be attached, special packaging, delayed dispatch, or other requests, please contact us.
We will do our best to accommodate your needs and provide the best service possible.

1.9 About receiving the package
Whether you sign for the package personally or through a representative, it is considered as acceptance of the package, the quantity, and the included items.
To protect your rights, we strongly recommend recording a video while opening the package and verifying it against the order and packing list.

1.10 I don’t live in China. Can I have my order shipped to a Chinese address?
Yes, you can. Just place your order and provide a Chinese recipient address.
For orders shipped within China, we do not charge any shipping fees. If your item shows a shipping fee, please contact us to have the fee waived.

You are responsible for all applicable taxes and fees that may be imposed by your country or region, including but not limited to import duties, value-added tax (VAT), customs handling fees, and other similar charges.

These import duties, VAT, and customs fees are not included in our product prices or shipping charges.
We have no control over, and cannot predict, these charges or how they will be collected—whether they will be charged at the time of delivery or through other means.

Customs policies vary greatly by country. Some countries (such as Brazil, India, etc.) strictly enforce high duties and additional taxes.

It is your responsibility to check with your local customs office before purchase to determine what additional costs may apply.

Customs fees are usually charged by your local courier or postal service, often at the time of delivery or pick-up. The shipping carrier (especially UPS) may also charge brokerage or clearance fees for handling customs on your behalf. These are not unpaid shipping charges and must be fully covered by you.

If the package is returned, held, or destroyed due to the buyer’s refusal or failure to pay customs duties, any resulting costs will be borne entirely by the buyer. These costs will be deducted from your refund.

1.1 What is your return policy?
I ordered the wrong item/size, or I changed my mind—can I return it?
I received the item but decided I don’t like it—can I return it?
I received the item but found it’s not suitable for me, or I found a better option—can I return it?

In the above cases, we accept returns within 30 days of receiving the item, provided that the product is in brand new and unused condition.

• Buyers must apply for a return and send the product back to us within 30 days of receipt.
• You are responsible for all return shipping costs.
• We will deduct the original shipping cost incurred to deliver the item to you.
• We will deduct 4% for credit card or PayPal transaction fees.
• If you choose to receive a store credit instead of a refund, we will waive this 4% fee.
• If the returned item shows signs of use, a handling fee may be charged.

If the returned item is damaged, missing parts, or shows excessive wear, we reserve the right to reject the return and no refund will be issued.

1.2 Where should I send the return?
Please contact us for the correct return shipping address. (The return address may not be located in Mainland China.)
Please ensure the item is properly packaged and that the original product packaging is not damaged.

Important: Do NOT return the product to the sender’s address shown on the parcel. You must contact us first to obtain the correct return address. Unauthorized returns may be lost or undeliverable—any such loss will be fully borne by the buyer.

1.3 Can I return or exchange the item after 30 days?
For any reason, we do not accept returns or exchanges after 30 days.
30 days is considered a very reasonable and standard return period for online purchases.

1.4 What if I received a wrong or defective item?
Please contact us within 3 days of receiving the item and provide photo evidence or a clear description of the issue. We will promptly send a replacement item.

If you return the item to us:

• Please use the least expensive shipping method.
• We will reimburse part of the shipping fee from your original order as compensation.

If you’re unable to return the item or don’t know how to ship it, please contact us—we may provide a free return shipping label.

1.5 How will I receive my refund? How long does it take?
We will process the refund within 7 days of receiving your returned item.
Refunds are usually issued via the original payment method.
Processing the refund involves internal verification and approval by management, so we appreciate your understanding and patience.