I have been using this OTA for over a year now. It has served me well. I've paired it with a TV Paracorr and have been using it for astrophotography. I can recommend it. Here are a few observations. 1. The price is right. It gives a lot of telescope for the money. No complaints here. 2. The edge of the mirror is imperfect (not unusual). I 3D printed a mask to cover up the rough outer edge of the primary. This also hides the mirror clips from the light path and gives a smoother halo of scattered light around my stars. 3. The focuser works well. It's solid enough to hold my QHY168C camera and Paracorr without issues. I've been able to pair it with an autofocuser from ZWO to focus remotely and precisely. 4. The cooling fan needs to be used carefully, if at all. I've noticed a change in focus when the fan is being used. If I happen to use it, I have to give it a few minutes for the focal point to stabilize. 5. The collimation process is straightforward and not too difficult. 6. The spider vanes that hold the secondary were not all pointing directly away from center. Some of the diffraction spikes in my images were doubled up as a result. I loosened the nut holding the vane closest to the focuser then shaved and tightened the nut farthest away from it. This gave me a perfect + shape and fixed the problem with the diffraction spikes. 7. The images through the scope tell the final story. The large aperture can capture amazing detail.
Over half a century of telescopic viewing provided experience from a child's 60mm draw-tube to Palomar's cage. Like all serious sky scanners, I struggled with aperture fever. Hunting for the instrument yielding hoped-for, breath pausing resolution is a seriously formidable process when absent wealth. Fortunately, such quality instruments today are readily available through better market sources such as OPT. I must commend them for this product offering. You receive what you see: an OTA complete with the now-standard primary fan; a nice Crayford focus system (the 10:1 micro-focus ultra-defines beautifully); deep inset secondary locus for contrast enhancement equivalent to flocking; and nicely portable for either storage or travels [This IS a mirror set you will want to realize in dark sky, low LP setting]. For those who have been working with 200 mm and below, the additional 50 mm's with this FL4 primary provides exciting resolution that literally yields definition to most here-to-fore gray smudge images to details yet seen. For example, M13, the great Hercules closed-cluster, is seen in its glory with separation and definition of the stars themselves. Same for the Swan and Trifid nebulae with a relieving definition of the actual shapes and separations, even defined gas cloud subtleties. That extra 2" of diameter is the doorway to such observations. This particular F4 mirror is top-notch in design and coating, provides very sharp detail discerning ability. Pair this instrument with good objectives and filters, please. I recommend an LPR and lunar filter set (polarizers are really nice for lunar work); standard colors for planetary views are always very nice. You'll find that other than lunar viewing, most will work within the 14 to 40 mm objective range. The Orion Nebula system was (for me) so perfectly portrayed using a 2" 20 mm erfle. You'll lose time when trapped by the sublte definition. Pardon the verbosity but this is an instrument requiring real experiences provided as well as allowing those newer to the study to know the system that will answer their viewing desires. Besides, it is an exciting scope and felt the need to share a little of that. Daryl
Haven't actually been able to use it yet, too cloudy. I did get the telescope collimated, happy with that. I like the focuser it seems solid.