Askar 80PHQ 80mm f/7.5 Quadruplet ED APO Astrograph OTA

Askar introduces the brand-new 80PHQ refractive astrograph. And it’s the second long-focal-ratio astrograph from the PHQ- family.

The overall finish of 80PHQ is evenly painted. The ivory and flawless coating of the main tube feels comfortably pimply, which can not only increase your grip, preventing the telescope from slipping off from your sweaty hands, but also improve its texture, avoiding the tedious monotony.
A pair of clamshell-style CNC-manufactured black tube rings tightly hold the OTA. So you can just turn two locking screws to loosen or tighten the tube rings simplifying the setup by avoiding the frequent use of small tools like Allen wrenches or socket head screws.
The bright green dust cap, handle, locking screws, focusing knob and decorative rings add more energy and vitality to the otherwise deep and profound astrograph. White and green is the classic combination for PHQ series.
There is a 3" rack-and-pinion rigorous focuser on the rear end of the telescope. It’s a smooth focusing unit with dual-speed adjustment. 80PHQ’s rotator is marked with precise graduation which makes your previous subjective adjustment more accurate.

The 80PHQ inherits the optical design of the PHQ- family, adopting a 3+1 quadruplet lens structure which contains two pieces of ED glass that can effectively reduce chromatic aberration and enhance clarity and sharpness. It’s worth mentioning that all astrographs from PHQ- family come with an integrated lens combination rather than simply placing three major lenses and a corrector together in a line. In another word, the whole optical system cannot solely perform without any piece of these lenses. This structure design leads to a more rational lens arrangement, better vignette control and superior image quality. The focal ratio of 80PHQ is f/7.5. It’s a “long” focal-ratio astrograph compared with other counterparts from Askar. It’s a little bit longer even compared with 107PHQ which is f/7 in focal ratio.

Some users may be frustrated that it’s hard to make a trade-off between 107PHQ and 80PHQ, since there seems to be so much in common. And especially for those who are new to astrophotography, the complicated designations and confusing numbers are really a major obstacle when they hopefully try to pick out just the proper one from oceans of dazzling products.

Indeed, 170PHQ and 80PHQ are similar in many aspects partially because they are both the newly-developed refractive astrographs from the same family. However even if they all have excellent mechanical design and sophisticated optical system, there are noticeable differences between these two.

At the first glance, Askar 80PHQ is much more compact. 107PHQ is 603mm in length and weighs 5.7kg whereas 80PHQ is 448mm in length and weighs 3.9kg. So if your equatorial mount is not capable of holding heavy telescopes, or if you are quite tired of carrying a bulky long focal-ratio telescope around, then 80PHQ may be a great option.

Like the 107PHQ, you don't need to calculate the back focus distance within the connection limit. Besides, users don't need to add an extra 1× flattener due to its powerful flatfield optical design, which simplifies the operation.

ASKAR 80PHQ ED APO quadruplet telescope features:
Aperture size：80mm
Focal length：600mm
Focal ratio：f/7.5
Objective lens：Quadruplet air-spaced APO (including two ED glass)
Image circle：44mm
Maximum accessory connection (with the focuser fully retreated)：
1. Imaging mode:
115mm（from the base of M48×0.75 male thread）
135mm（from the base of M54×0.75 male thread）
155mm（from the base of M68×1male thread）
168.5mm（from the base of M76×1 male thread）
2. Observing mode:
148mm（from the end of 2" eyepiece holder）
Total length：450mm（including 1.25" eyepiece holder as dew shield contracted）
540mm（including 1.25" eyepiece holder as dew shield fully stretched）
480mm（including the 4-piece adapter as dew shield contracted）
570mm（including the 4-piece adapter as dew shield fully stretched）
Net weight：3.9kg
Gross weight：4.7kg
Rear-end thread type：M76×1-M68×1
M68×1-M54×0.75
M54×0.75-M54×0.75
M54×0.75-M48×0.75（M48×0.75 filter thread inside）
Standard package items：an 80PHQ OTA，a pair of tube rings, a handle, an Askar 300mm Vixen dovetail plate, a set of 4-piece photographic adapters, a manual

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.

Are you interested in this product but would like to speak to someone with some more information? Simply fill in the form below and we will get back to you as soon as we can!

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