SVBONY Red Laser Collimator for Newtonian Marca Telescope Alignment 1.25 inches 7 Bright Levels Triple Cemented Lens with 2 inches Adapter

How to collimate a Newtonian reflector telescopeSome telescopes come with a simple collimation aid that amounts to a piece of circular cardboard with a pinhole in its exact center, which you insert into the eyepiece. This gadget (or a DIY version of it) will not allow you to get the collimation as precise as it needs to be. The laser collimation tool is very inexpensive and it will enable you to get the collimation perfect.The telescope that I recently purchased and that I needed to collimate is the Sky-Watcher Virtuoso 150. Some minor details of the procedure that I will describe are specific to this telescope, however the procedure applies broadly to all Newtonian reflector telescopes.Collimation of a Newtonian telescope is done in three steps. In step 1, you position the secondary mirror directly under the focuser, so that when you look straight into the focuser, you see the secondary mirror without needing to look “at an angle”. In step 2, you adjust the tilt of the secondary mirror so that it is precisely aimed at the primary mirror. In step 3, you adjust the tilt of the primary mirror so that it is aimed precisely back at the secondary mirror.Make certain that the tube is tilted slightly down in front so that nothing can drop into the tube and land on the primary mirror. The secondary mirror has a base that is permanently attached to the mirror, presumably made of plastic. The base is held to a support (the “spider”) by one center screw and three smaller screws surrounding the center screw. With the Virtuoso 150, the center screw has a Phillips head; the three small screws require a 2mm hexagonal wrench. Be certain to use the correct size of Phillips screwdriver for the center screw. The screwdriver tip needs to fit fully into the cross-slot, but not be able to rock back and forth.The center screw slides freely through the support and is threaded into the mirror base. In the space between the mirror base and the support, there is a spring that pushes forward on the mirror base. The screw moves forward along with the mirror base, and thus remains in contact with the support. Before you will be able to loosen the center screw, you will need to loosen the three small screws. Turn all three of them counterclockwise. With my telescope, I simply turned all three of these screws until the tip of each screw (the end where the hexagonal wrench meets the screw) was roughly flush with the surface.I will first describe a very low-tech method I used to check whether the secondary mirror is directly under the focuser. With one eye covered, position your head about a foot away from the focuser, and with your eye centered in the focuser (without the pinhole gadget in the focuser). If your eye is off-center, the interior wall of the focuser will not look uniform all the way around. With your eye centered, look at the secondary mirror. Ignore what you see in the mirror, and concentrate on the perimeter of the mirror. Its appearance will be that of a circle, and what you want is for this circle to be centered within the circular opening of the focuser. You will need to move your head closer and further until the mirror circle is ever-so-slightly smaller than the circular opening through the focuser. As you move your head forward and back, continue to pay attention to the interior wall of the focuser, to insure that your eye is centered.If you are using the laser tool, set the power only as high as it needs to be for you to see it. You want to check where the laser is hitting the secondary mirror. If you have a collapsible telescope that permits you to see the secondary mirror, you want to identify the spot where the laser directly hits the secondary mirror. If you stick a sheet of paper into the light path between the two mirrors, this will make it easier to tell which laser dot is the one for the direct light from the tool. If your telescope is not collapsible, the best way for you to see where the laser dot lands on the secondary mirror is by using another small mirror. You carefully insert this mirror into the open end of the telescope and hold it wherever you are able to get a good view of the secondary mirror and the red dot.With either of these methods, you want to mostly ignore the centering on the minor axis of the elliptical secondary mirror (the lateral centering). You are concerned almost exclusively with the centering along the major axis of the elliptical secondary mirror. With the Virtuoso 150, I found that the correct position for the secondary mirror was all the way back against the support. But you don’t want to position the mirror right up against the support, because if you do this, you won’t be able to adjust the tilt. Therefore, if your telescope is like mine in this respect, you will want to gently grasp the mirror by the base so that it is rotationally correct (i.e., faces toward the focuser) and then turn the center screw counterclockwise one-quarter to one-half of a turn.Once you are satisfied with the position of the secondary mirror, you want to begin tightening the three small screws, but doing this in small increments so that one of them does not end up being too far in. You want to turn all three of these screws until they are just barely touching the mirror base. If you are using the pinhole gadget, what you want to see, when you look through the pinhole, is whether the reflection of the primary mirror is centered in the secondary mirror. If you are using the laser tool, look down into the open end of the telescope and look to see whether the laser strikes the primary mirror at its center (which is typically marked with a tiny circle). You will likely need to rotate the secondary mirror slightly, and you will likely need to loosen one or more of the three small screws a few times until you get good at this.When you are satisfied with the tilt of the secondary mirror, you’re ready for the final step: the tilt of the primary mirror. I suggest that you start by visually inspecting the gap you see between the back of the telescope and the black metal ring that holds the primary mirror. This gap should not be very great, and it should be roughly constant all the way around. For a small 6” telescope like the Virtuoso 150, it should be only about 1/4”. (Don’t waste time measuring this. Just eyeball it.)To adjust the tilt of the primary mirror, you first loosen the three locking screws, which are the three long, slender screws. The other three screws, the ones that are shorter and not so skinny, are the adjusting screws. You turn them clockwise to pull the edge of the mirror closer and make the gap more narrow near that screw, and you turn them counterclockwise to make the gap wider.When you look into the pinhole (if you are using the pinhole gadget), you will see, working from the perimeter to the center: (i) the perimeter of the secondary mirror; (ii) the image of the primary mirror, reflected off the secondary mirror; (iii) a dark ring; (iv) the image of the secondary mirror, reflected off the primary mirror; (v) the crumpled back surface of the alignment gizmo; (vi) a small dark circle that marks the center of the primary mirror; (vii) the pinhole that you are looking through. What you want is for the image of the pinhole to be centered in that small dark circle.If you are using the laser tool, you want to look at the target mounted within the tool. You want the laser to strike the target at its exact center.

Wow! This makes collimating easy.

If you are new to Newtonian telescopes as I was, this collimator is a terrible experience. The expectation was that this collimator was calibrated and I would just need to plug it to the new imaging Newtonian and be ready for pictures. After collimation, all my stars looked terrible. After several day of debugging what I thought was a bad telescope, I decided to get one of those OCAL collimation cameras and realized that the problem was not the telescope but rather this collimator being way off where it needed to be. Nowhere in the documentation does it say that this needs to be realigned first. The alignment screws are sealed (easy to unseal though) so it it give a false sense of this thing being calibrated. It was cheap and it can be fixed, but considering the amount of imaging hours I wasted trying to get this working, I think this is a terrible value.Edit (12/26/2024):---SVBONY reached out after the initial review and tried to solve the issue with the collimator. After it was determined that the issue was the factory calibration of the collimator, they offered me either a refund or a replacement. I opted for the replacement and am happy to report that the issue was a one-off. I'm updating my original review from 2 stars to 4. Minus one star because the first unit was just badly calibrated, but I am adding 2 stars for their excellent customer service.

Working out GREAT !!!One word of caution …. Be sure when you put the laser away it is set to “0” and is off ….I made that mistake and the battery was dead when I took it out of the box a week later.

Excelente producto

Easy to mount even easier to collimate; took me 3min and I’m a beginner!! Great for beginners!

Very easy to use

When you spin it inside the optic tube the laser dot moves off center so I think the laser itself is not collimated.