Baader CMOS-Optimized 5.5nm H-Beta Narrowband Filter - 1.25" Mounted # 2961080

Baader CMOS-Optimized 5.5nm H-Beta Narrowband Filter

- 1.25" Mounted # 2961080

Product Details

Baader H-Beta-Filter– the H-Alpha-Filter for visual observations!

The Baader H-Beta-Filter with 5.5nm halfband width is especially useful at telescopes with 8" or larger apertures or if you are working with large exit pupils. This narrowband-filter delivers a much higher contrast, compared to common visual H-beta-filters. H-Beta-nebule-filters with a wider half-width deliver a brighter image and will also show you e.g. the California nebula,but it won't be so clear, and you will miss many of its inner structures. Without any filter, this nebula (to name just one of many) will be completely invisible under brighter skies.

About Baader H-alpha Filters and why they aren't suited for visual observations

The development of narrow-band H-Alpha-filters soon proved to be a "Game-Changer" for Amateur-Astrophotographers. No other spectral line of emission nebulae will give you so much information for the creation of "pretty pictures" as this Hydrogen-line. This is supported by the better coatings, sensitive CCD-cameras, motorized focusers and last but not least the the incredible tracking precision of modern mounts, which allow for very long exposure times with very narrow-band filters. Modern images are often based on exposure times of 30 hours through the three common, very narrow-band nebula filters. But to make use of this, the mount must provide "subpixel"-tracking, the focuser must not flex even for a micron, and its motor must compensated for temperature changes by keeping the focus up to a fraction of a millimeter... All this is possible – but you need high-end equipment.

This is not necessary for visual observations. But unfortunately, we do not profit from those photographically wonderful filters when we are looking through the eyepiece – at low intensities at night, the human eye is almost blind for this part of the spectrum. During daylight, when there is plenty of light, we can easily see H-Alpha. But at night and low-light, we can't perceive these wavelengths. In contrast to a camera, our eyes also can't add upp the light.

Because of this, most visual observers use the well-known O III-filter. The human eye has got its highest sensitivity between 500nm and 520nm, where we can observe many structures in supernova-remnants, planetary nebulae and so on. But they are pretty useless for deep sky objects which shine mainly in H-alpha.

The alternative – Baader H-Beta filter for visual applications

For the H-alpha-objects mentioned above, the H-beta-line is a good option: At 486nm, it still quite close to the region of highest sensitivity of our eye. Because of quantum-mechanical coupling with H-Alpha, we can usually see the same structures. H-Beta-filters are much more efficient than O-III, because most nebulae emit hydrogen-light – although H-Beta is not as popular as H-Beta.

A H-beta filter can be regarded as a visual H-Alpha-filter.

The H-Beta-spectrum is indeed very interesting. Quantum-mechanics define a fixed ratio between H-Alpha and H-Beta, but because of the shorter wavelengths, H-Beta has got a higher energy. That's why H-Beta suffers from a higher extinction rate in interstellar dust regions, which can easily be detected. The ratio between H-Beta and H-Alpha gives you information about the amount of dust between us and the source, which is especially interesting for scientific work. For astrophotography, you can scale down the intensity of H-Alpha to simulate an H-Beta-filter – and if you are observing with your eyepiece, you will see structures which were almost invisible before.

Visual observers profit from the fact that a H-Beta-filter can show the dust regions in hydrogen-emitting nebulae quite clearly, similar to a photographical H-Alpha-filter. Larger telescope apertures can even show the split-up into two lines – and the soft phase-out towards the edge.

The filter is almost as impressive when you are looking at the dust tails of comets. Especially light with shorter wavelengths will be scattered more in the dust tail, so that the contrast to its surroundings increases. Light with even shorter wave-lengths will be scattered even more, but our eye is not so sensitive for these parts of the spectrum. The true dimensions of the sometimes very long dust tail may only be recognizable in the eyepiece with the help of a H-Beta-filter. The H-Beta line is also outside of the prominent lines of the gas tail, so the dust tail can be better deiscerned from the gas tail – and the contrast is increased even more.

Conclusion:

A dielectric H-Beta-filter is no allround-filter like e.g. a Neodymium-Skyglow-filter. But it is the best available tool to see faint details, because you can visually see the dominating hydrogen emission lines in the sky – something which an O-III-filter can't show you. Together with an O-III-filter, it covers the most important spectral lines of emission nebulae and is an important tool for visual deep-sky-observers.

Features

• 1¼" x 2 mm Baader CMOS H-Beta Narrowband Filter – Precision Grade – with 1¼" (28,5 mm) filter thread
• 5.5 nm FWHM, recommended for optical systems from f/15 to f/1.8
• Reflex-Blocker™ hard coated and planeoptically polished – with sealed coating edges (Life-Coat™)
• Blackened edges all around, with filter-lead-side-indicator in the form of a telescope-sided black outer rim
• Optimized for modern CMOS cameras, but likewise excellent for CCD camera technologies
• Mounted in Baader Low Profile Filter Cell (LPFC) – 6 mm height

Specification

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.