The MN190 functions as a Newtonian telescope with a corrected field, many thanks to the hefty meniscus lens mounted on the front of that big, beautiful, bendy tube. The field is actually quite flat, and has an advantage of not requiring an additional coma corrector.
This allows the user to enjoy a wide variety of cameras without having to worry about back focus, as well as no diffraction spikes.
At 190mm working aperture, 1000mm focal length, and f/5.3 focal ratio, it's a great all-rounder which has been my workhorse scope for a while now. It satisfies lunar and planetary imaging, Galaxy imaging, nebulae imaging, even planetary nebulae. At 29lb/13kg, it requires quite the mount to keep your stars steady. The EQ6r-pro can struggle at times of a light breeze.
...it becomes apparent that modifying standard off the shelf equipment is necessary.
The primary is a Synta mirror, although I suspect it is one of their more premium mirrors. It came stock with their 2" dual-speed Crayford focuser which in all honesty worked very well at the eyepiece. The focuser did occasionally slip as the surrounding environment changed, which necessitated a more robust focuser. I settled with the Moonlite CR-2 dual speed.
Collimation is done by adjustment of grub screws and other sub-flush screws. No one wants to carry Allen wrenches to the field. No one wants to test 50 wrenches on each bolt to see what size it is. The engineers who decided that forgoing the use of thumbscrews at the expense of a few cents have not collimated a telescope before. Luckily there exist third-party solutions, such as Bob's Knobs screws which work great.
The MN190 is a beast, but suffers from the typical weak points associated with any mass produced reflecting telescope. The tube is rolled aluminium which is detrimental to long exposure astrophotography. The coefficient of thermal expansion for aluminium is quite high, meaning the tube can expand/contract easily throughout the night. I opted for the ZWO OAG, along with the ZWO helical focuser to overcome the differential flexure, and they've worked splendidly so far.
In the relentless pursuit for perfectly round stars, maximizing imaging time, and producing high signal-to-noise images, it becomes apparent that modifying standard off the shelf equipment is necessary.
I used BLK 3.0 paint to touch up shiny surfaces such as screws, as any exposed reflective surface in the tube can cause brighter backgrounds, as well as optical aberrations. I also employed the use of a mirror clip mask to cover the mirrors clips, as this helps produce even cleaner stars.
Conclusions
Retailing at just over $2000, it's a hefty price to pay over a standard imaging Newtonian.
To justify the purchase for the quirkiness of a Maksutov-Newtonian and the ease of use, it's not worth $2000, but it's damn close. I however still pulled the trigger, as there really isn't anything else like it in this category.
Pros:
Great image quality
Holds collimations relatively well
Corrector plate performs great
Cons:
Heavy
Cheaper materials
Poor mirror cell design
Any questions about the telescope? Shoot me a message on Instragram! @Photons_End
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