- mirror lens
- imaging telescope
- tube assembly
This has been my primary imaging telescope for several years now. I must admit I am still learning how to use it (and when I do I will probably buy up to an 8"). The 1370 mm focal length is good for most small and medium sized objects and with guiding the f 9 focal ratio is fine. Collimation has never been a problem as mine arrived in good collimation and recollimating was simple. The focuser has worked well with my DSLR and I use an old 500 mm mirror lens as a guide scope. I have other telescopes for visual.
Unfortunately, I have not had time to use the scope so I can't comment on it's optical capabilities yet (sorry). What I can say it that this is a very well built optical tube assembly. It is well assembled and well painted. It looks and feels very nice. I am quite happy with this so far!
When I picked up the telescope from the box, the focuser just banged in and out of the tube. There are NOT any gear teeth on the focuser. How is it supposed to work??? I don't think I would have picked this one if I had know how it was made. Maybe after I learn how to make it work I might change my rating. I really thought the focuser would have a rack and pinion to move it. I just looked at it and it looks like it is a polished steel 1/8th inch shaft pressed against the smooth aluminum of the focuser. REALLY, I am not happy right now... And to top it all off, by the time it was delivered the seller was closed for three days. PS I even looked inside the scope for the book, but nothing there either. I added a star since trying it out. I would give it five start if it came with a one page instruction about the focuser. I had never seen a Crayford focuser before this and did not know what to expect.
I got this TPO Ritchey-Chretien telescope from OPT a few months ago, and I could not be happier. I had used, and still have an Explore Scientific ES102 and ES80 APO refractors. I was quite happy with the astrophotography images the refractors gave me. But the TPO RC-6 took the magnification, and resolution up to a great new level. And perhaps what I like the most is the flat field of the images without the need for a field flattener. I know a lot of people are unsure about RC style scopes due to collimation horror stories and complicated tools. But, after a lot of research, I simply got a $30 Celestron collimation eyepiece and used it once. It basically let me set the collimation in the ball park. But the method that works perfectly every time, in 10 minutes or less, is the "star test". In the star test, you simply set the scope to look at a reasonably bright star overhead. Then you back the focus back away from the scope until the out of focus star looks like a big doughnut with a cross hair in the center. Align the three screws on the front of the scope's secondary meter a slight turn at a time until you move the inner dark circular region of the doughnut to be concentric to the outer circle. This is best done with an attached DSLR screen pointing toward the front of the scope so you can see your adjustments' effects ... or to let your astro camera show you the same thing on your computer's screen, while adjusting the screws. While looking at the out of focus "doughnut" image, place your hand slightly over the front edge of the scope until you see your hand's blurred shadow on the screen's image. Move your hand around the front side of the scope until it is over the "fat" portion of the "doughnut". That's the point where the center dark circle close to the center is farther away from the outer circle edge. Then find which one of the three adjustment screws on the front of the secondary mirror is closest to where your hand is. Adjust that screw (in or out) using very slight turns (1/8th of a turn or so at a time) until the dark inner circle is most concentric with the doughnut. (Don't adjust a screw too tight inward ... If you run out of threads while tightening, loosen one of the opposite side screws instead to accomplish the same thing.) As the dark circle shifts, reposition your hand as needed and adjust other screws closest to your hand as needed. WARNING: Don't touch the center screw on the secondary mirror.WARNING: And never use the 4mm hex wrench to adjust the screws without strapping it to your wrist. You don't want to drop it down the tube and onto your mirror. This procedure has given me absolutely beautiful pinpoint stars and collimation every time I've used it. A bit of a hassle ... but absolutely worth it ... at roughly 10 minutes per night. As a side note, make sure the TPO RC 6 you receive has the LRS focuser on the scope as the OPT website page says it will. To my knowledge OPT is the only vendor selling the RC 6 with the much stronger and more stable LRS focuser. Thanks OPT for, yet again, being the best supplier for all my astrophotography needs. (Sorry for the extensive write up ... too much coffee.)
Wife turned the Crawford focus know and was heard a block away exclaiming “WHAT”. That smooth hardware impressed her and examples all the threads and construction of the unit. AND the bloody images for photo work are heavenly (sorry about the pun). Saving for a BIG one now. I have lot to compare it too, this is more resolution and sharpness for the buck.
The scope is attached to my Ioptron CEM25 , used it visual and with a canon 6d. It is hard to get in focus because of the lousy focus mechanism, real jerky even though the scope is new. I am getting a linear bearing focuser from gso to put on it. Hopefully that will cure the problem. if the focuser was upgraded I would give it 5 stars.