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Omegon Flatfield ED Eyepieces 1.25"

Omegon Flatfield ED Eyepieces 1.25''
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Focal Length: 5mmFocal Length: 8mmFocal Length: 12mm
Focal Length: 15mmFocal Length: 18mmFocal Length: 25mm
Price  £108.00
(Inc. 20% VAT)
+

Model:  18815O
Brand:  Omegon

       
2 Year Warranty On All New Items
(Excluding Batteries & Globes)




Product description:

Omegon OD Flat Field Eyepieces - combining flattened image field with high contrast


Most eyepieces suffer from image distortion at the edge of the field of view. If you move the object observed into the outer part of the field of view it becomes distorted. Omegon ED flat field eyepieces counteract this effect. Who does not want a really true to life and undistorted image?
You can get really close to this ideal with flat field eyepieces. These flat field eyepieces have an ED lens element included which gives particularly good colour purity. Their optical construction also means that these eyepieces offer extremely high contrast and sharpness, way above the usual level.

Wide field of view

With a 60° apparent field of view, these eyepieces belong to the wide angle eyepiece category. Classic 'tunnel vision' eyepieces stay more and more in the drawer. Compared to the familiar Ploessl eyepieces, ED flat field eyepieces give a field of view which is around 20% wider.
The body of the eyepiece combines up to six lens elements, producing a really high quality eyepiece. All glass/air surfaces are multi-coated, preventing unwanted reflections and guaranteeing high brilliance and transparency. You can therefore expect extraordinarily good contrast when observing planets and DSOs through these eyepieces.


Between eye and eyepiece

The eye relief with these eyepieces means they are particularly pleasant to use. There is no shadowing, even if you are not looking directly along the optical axis. These eyepieces are available in focal lengths of 25/18/15/12/8 and 5mm. All these focal lengths have large ocular diameter of 21mm, meaning relaxed observing is possible even at high magnifications. Omegon ED flat field eyepieces have a rigid screw-out eyecup to block scattered light. The 16mm of eye relief means these eyepieces are also suitable for spectacle wearers, as a rule allowing them to see the entire field of view. The eyepieces can be used with most telescopes without problem. Even with Newtonian telescopes with a fast aperture ratio of f/5, the edge of the field of view has good edge definition.

 

The advantages in a nutshell:

  • flat field optics, giving a flat field of view
  • ED element for high contrast and image colour purity
  • wide angle eyepiece with 60° field of view
  • good eye relief
  • multi-coating on all lens surfaces
  • 16mm eye relief, suitable for spectacle wearers
  • rigid, screw-out eye cups
  • 1.25“ barrel with 1.25“ filter thread

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Some items that are showing as in stock are in stock at our holding warehouses, not at the shop. To double check the stock levels at the shop, please contact us on 01909774369 or sales@rothervalleyoptics.co.uk.

The delivery times for most items is 1 - 2 days but again, please double check stock levels on important orders before placing an order via the website.

The delivery costs for courier next day are for mainland UK only. If you live in the Scottish Highlands/Islands, Channel Islands or Northern Ireland, then a shipping surchage will apply. please contact us for prices. Smaller items can still go 1st class via Royal Mail.

Please note that if you are wanting to take advantage of our Saturday and Sunday timed services or next day pre 12 or pre 10:30 services, you MUST check that the stock is here at the shop before placing orders. Also, orders using the Saturday and Sunday services must be placed before 1pm the previous working day. Also, please remember to check that the stock is here at the shop before placing orders. If the stock is not at the shop, we won't be able to ship on any of the timed services. 

Please note International customers will need to contact us for a shipping price prior to ordering via the website. We don't ship all items internationally. It is at our discretion what we ship outside of the UK. This all depends on the size and weight of the items. Please get in touch with us for any postage costs. Please note we do NOT ship telescopes or heavy items outside of the UK. This is due to massive postage costs and problems regarding returns.

If you have any questions regarding stock levels or delivery, please get in touch.

Zygo Interferometer Testing For ED Refractor Telescopes!

We are extremely pleased to announce our Zygo Interferometer is now installed and ready for use! Our experienced staff can test refractor lenses up to 120mm aperture and provide a comprehensive 2 page report showing the optical quality and Strehl ratio, plus much more information. We are using the very latest Zygo MX software to provide a more detailed report compared to other standard reports.

 

The interferometer is essentially a measuring instrument. Within the interferometer is a calibrated laser that is pointed through the optical test surface, then onto a high quality reference sphere, then back through the test subject then to an internal camera which gives us the measurement on the screen. From this, we can adjust the position of the test optic and the reference sphere to obtain a perfectly calibrated system. The more central the laser to the test optic and then on return, the better and more accurate reading and measurement we can take. This takes a lot of adjustment to get the best results from the optical surface. Once the measurement has been taken, we are provided with a series of results that show the optical quality of the surface plus other information. Continue reading for an explanation of the individual values and you can also see a test report that was done on one of our RVO Horizon 60 OTAs. 

We are offering certain telescopes with a Zygo test at an extra cost. Mainly ED doublets and triplets. All available telescopes with a Zygo test report are listed here. Just select Zygo Test Report from the drop down box at the top of the listing and we will test the optics in house and provide a full 2 page report with your scope. This will show you the optical quality of your telescope optics. We can also offer this service on your refractor telescope. Please get in touch for more details about this. 

At Rother Valley Optics, one thing we pride ourselves on is customer service and quality of our equipment. When we test your telescope, we will ensure that it is of the highest quality otherwise, we will reject the scope under our strict quality control and test another model for your peace of mind. One of the main values to look at when testing a refractor is the Strehl ratio. The higher this number, the higher quality lens you have. At Rother Valley Optics, we will guarantee the highest possible Strehl ratio for your telescope.  We will aim to provide 0.95 Strehl or higher on Takahashi, RVO Horizon, William Optics and many more! Generally, the higher the Strehl ratio, the lower the Astigmatism and Coma meaning a better image quality from your instrument. 

Other measurements such as the PV and RMS are important too. With these measurements, the lower the number the better as it shows less curvature on the lens. The flatter an optical lens, the better it will perform. The PV rating (Peak To Valley) is a measurement from the highest point (Peak) to the lowest point (Valley). From this we get the RMS (Root, Mean, Square). This is a similar figure to the PV and measured exactly the same way. The RMS is basically an average height difference from the PV so again, the lower the better. As you can see form the example below, we measured an RMS of just 0.027 wave which is a very good value.

We also measure the Power with our systems which is essentially the error from the reference sphere to the test optic. The reference sphere we use on our system is a very high quality sphere so the closer to zero the Power, the less error between the 2 elements thus ensuring a higher quality optical surface. 

You will also see some more values such as Astigmatism and Coma. Again, these are measured by the interferometer when we take measurements of the optical surface after adjustment. These are values which ideally would be at 0 but as our test optics are all curved lenses, there will always be astigmatism and coma present. The lower the number, the less of these aberations you will effectively see but with most refractors, you can buy field flatteners which will compensate for the coma anyway. The astigmatisms value is explaining the error between the symmetrical curvature of the lens. Basically, no lens will be perfectly symmetrical, the lower the astigmatism, the more symmetrical the lens surface is. 

Once the Zygo test report has been completed, the optical alignment is thoroughly tested and tuned to ensure they are spot on before they leave us. 

All available telescopes are on the website at the link below and ones we've tested already that are available straight away are also listed.

https://www.rothervalleyoptics.co.uk/zygo-tested-refractors.html

Here is an example of the test what we provide. This was a test on one of our Horizon 60 ED OTA's.

For any questions about this amazing new service, please either call 01909774369 or email sales@rothervalleyoptics.co.uk.

 


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Rother Valley Optics Ltd
Rother Valley Optics Ltd