Ex Demo Altair 72 EDF Refractor Dual Speed R&P Focuser Optical Test Report

Please note this telescope is ex demo but it's brand new. It's only been on display in our showroom, never been used. A bargain price for such a great telescope.

NEW 2022 Version with improved CNC Focuser and X Rings

• ED optics with FPL53 ED Glass
• Optical test report in green light 
• Geared CNC focuser with front and rear rotator.
• Better balancing with long dovetails / cameras.
• New CNC X-Rings with top handle / dovetail (available separately for your pre-2022 AA72EDX)

A great travel scope, suitable for wide field imaging or visual use, day or night-time.

The Altair 72EDFX is a more refined version of the well-known and loved Lightwave 72 ED-R, circa 2013. Since then, this telescope has evolved into a state-of the art imaging or visual refractor, with improved optics in the form of an FPL53 based doublet objective lens providing superior colour correction, a lighter more compact tube, improved CNC Rack n Pinion focuser, a rear camera rotator and tube rings.

Colour correction. When it comes to astro imaging, the optical design has all the performance you need in a dual imaging and visual telescope, offering better colour correction thanks to the "synthetic fluorite" S-FPL53 ED lens element.

Optical quality and test reports. The lenses are guaranteed to arrive in perfect collimation worldwide and are fully tested and adjusted. This Deluxe CNC version comes with an optical test report at full 72mm aperture in green 532nm light (more accurate than red light tests), and which is the optimized wavelength of the lens. Additionally 532nm is very close to the human eye peak sensitivity, and the most sensitive peak wavelength of mono and colour CMOS cameras. Minimum Strehl is 0.95 (a more stringent test than red light, all things being equal). Deluxe lenses are selected from the production batch for their optical smoothness, figuring, and overall performance. Quality is very consistent, and every lens has a unique serial number linked to the glass batch and test report. Altair Astro pioneered this approach to QC in the industry, setting the standard, and ensuring our customers always get the best quality. This ensures the star-images are better than multi-element camera lenses costing many times the price, which usually need to be stopped down give better star-images. Additionally, being a telescope designed to work at infinity, and lacking an iris, results in improved image quality compared to a camera lens, even at the same effective aperture, and in most cases, of larger aperture.

Rear Camera Angle Adjuster (CAA). The Altair 72EDF focuser has a rotating rear end-cap with locking screws, allowing you to frame the object perfectly, without rotating the whole focuser, or the optical tube. This is a distinct advantage, especially when mounting the telescope with other scopes, and motor focusers, to avoid the extra equipment fouling the mounting bars. Furthermore, the entire focuser can also be rotated, useful not only for framing, but also if one wishes to invert it for imaging with a motor focuser.

Imaging friendly CNC focuser (Deluxe CNC version with improved bearings). The CNC machined Rack 'n Pinion focuser has full tension-adjustment to handle heavy loads, like a large eyepiece, CCD or DSLR camera. The drawtube has 75mm travel and a graduated scale in mm. This is a straightforward focuser to use for imaging and automation. Just remove the course focus knob, and attach a motor focuser coupler, mount the motor unit, and you are ready to go. The CNC focuser is the smoothest option for visual use too, with the higher tolerances computer-controlled lathes allow. 2022 version focuser has improved bearings.

Astrophotography and flatteners / reducers. The ED Doublet design offers very good colour correction, while keeping the optical tube extremely compact. At F6, this telescope can be used with the optional 1.0x field flattener or 0.8x reducer for wide field imaging. Optimum spacing is 55mm from the rear flange of the flattener to the image sensor (excluding threads), and spot size is particularly well matched to the Altair Hypercam 183 series, 269C and also 26 series CMOS Astronomy Imaging cameras. Here's a guide to setting up your camera to get the right spacing from flange to sensor.

Visual Observation: For visual use, you will need a mount, eyepieces and a star-diagonal to use this high quality telescope. For a manual "no power" option, we suggest the Starwave Mini-AZ mount (SW-MINIAZ) in matching red. The Altair Astro range of eyepieces such as the ULTRAFLAT range, and Altair 2" or 1.25" diagonals are all the best quality options for visual use. Talk to us about eyepiece and diagonals.

Attaching a finder scope. A finder scope or RDF (Red Dot Finder) is a very good addition, making finding objects quick and easy. Choose the Starwave RDF Finder Kit (Code: SW-RDF-B1-UNIFBR) which includes a base for easy attachment to the focuser. If you want an optical finder, we recommend the Altair 60mm RACI or Starwave 50mm Straight-through finder scopes. For auto-guiding you can also attach the Altair 50mm MG50 or 60mm MG60 guide-scopes, which attach to the focuser by means of the universal dovetail bracket. The Altair MG32 Mini Guider is another super-portable option, all of which are compatible with the Altair GPCAM mono dedicated guide camera.

Hinged mounting ring and tube. The tube rings allows the whole tube to rotate, and can be locked with the stainless screws at the correct position for balancing. The "mounting foot" connects to the dovetail plate with a flat base for a completely rigid connection. A standard Vixen-format dovetail bar is included as well as a top handle with inverted Vixen-format and Arca-format dovetail profile.

Dew control. The aluminium tube achieves thermal equilibrium very quickly, and the metal conducts heat easily to and away from the front optics (essential for imaging and dew control). Choose the DewZapper 3-4" OD Dew Heater (DEWH-34).

Altair 72EDFX Specifications:

• Optical tube with air-spaced 72mm F6 Dual ED lens (432mm focal length), containing an Ohara FPL53 ED glass in a precision CNC machined lens cell.
• Optical test report in green 532nm laser light, which is the optimized wavelength of the lens. Minimum Strehl 0.95
• Super-high transmission coating on all air to glass surfaces.
• Geared dual speed focuser with 1:10 micro-focuser and 360 degree rotation.
• 2" to 1.25" reducer with brass compression rings included.
• Resolving Power (Dawes Limit) 1.61 arc seconds
• Visual Limiting Magnitude 11.8 maximum
• Glare-reducing baffles inside focuser and optical tube.
• Weight approx. 2.5kg, OTA length with dew-shield retracted, 32.5cm.
• Precision CNC machined tube made from light, tough aluminium alloy with matte powder coat.
• Retractable lens shade / dew shield. Adjustable tension by means of grub screws.
• Dovetail bar fits most telescope mounts.
• Top handle with inverted Vixen/Arca-Format profile for maximum compatibility.,

Suggested accessories:

• Altair DewZapper 3/4" Dew Heater.
• Altair 1.25" Dielectric Diagonal for night-time observation. For daytime use, get the 1.25" Image Erecting Prism.
• Altair Ultraflat Eyepieces.
• Altair "RDF" Red Dot Finder, or Altair RACI 60mm or 50mm straight through optical finder scopes.
• Altair Astro Hypercam CMOS Astronomy Camera (ideally Hypercam 183C or 183M series).
• Altair Mini-AZ mount

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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