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

Good range of brightness levels. Came reasonably collimated (adjustable). Works great with the Barlowed laser technique. Really easy and effective! Brightness: quite dim on the lowest setting to quite bright by the 4th or 5th. Collimation/alignment of the laser itself. I setup a fixture using Legos (great suggestion I read online), placed it on a granite countertop (tape the fixture to the countertop so it won’t move), and targeted the wall 6 meters away. The diameter of the circle traced on the wall as I rotated the laser on the fixture was 2 cm. Not bad but not perfect. This alignment (right out of the box) was +- 0.2% (equivalently +- 0.1 degree). For my 1200mm focal length scope, the targeting of the center of the primary would be +- 2mm; as reflected back onto the target on the laser (2x focal length): +- 4mm. (It could be adjusted better than that if I wanted to, but see below.) While googling to see if that alignment would be sufficient, I came across the Barlowed laser method. I tried it, and it works GREAT! I was very happy. Super easy and convenient! (Assuming your telescope collimation is pretty close, secondary ok, and you just need to fine-tune the primary, which is typically the case with a frequently-used and unabused Newtonian....) 1. Put the laser in a 2x Barlow. 2. Put the Barlow in your focuser. 3. Turn on the laser, using a fairly bright setting. 4. Observe the shadow of the primary mirror’s center marker “donut” in the target area of the laser. 5. If the donut is already centered on the target, you’re done. Mine was about 1/4” off. 6. Loosen the lock screws on the primary. 7. Adjust the primary, turning one screw at a time to see where the donut shadow moves on the target. (You can see the target while at the primary end, so you don’t have to move back and forth between the primary end and the focuser like you would with a Cheshire or collimator cap.) 7. When the donut shadow is centered on the target, tighten the lock screws, and you’re done. Quick and easy. Love the Barlowed laser method. Note: unlike with the direct laser method, the Barlowed laser method is insensitive to small laser collimation and positioning errors. So this works even with the laser alignment a little off.

quality item,works great.

Was gifted an old Celestron Comet Catcher from the 80s and the images were super blurry. The "Youtubes" suggested collimation and 15 minutes later, it's like a new telescope! Easy to use with several brightness settings and as a plus, it comes with a 2 inch eyepiece adapter

Update: 02/21/2017 The replacement collimator I received was also not in collimation. However, I was able to adjust this one into perfect collimation, unlike the original. So, still 4 stars, but now I have a collimator that can be used to properly adjust a telescope. Once again I had to use a tiny eyeglass screwdriver to dig out the rubber used to seal the adjustment screws. Would be nice if they simply acknowledged that it is probably impossible to ship these half way around the world and have them remain in collimation. Plastic plugs could be used instead of the rubber glue, for instance,which could be removed easily for access to the adjustment screws. Just a thought. Adjusting the laser is still not straightforward. The screws don't always do what you expect. Not sure if they are pushing the laser or pulling it. One screw on each of my collimators does almost nothing regardless of how much it is turned in or out. But, after a good 30 min I was able to get this one is nearly perfect collimation. Will see if it holds this setting. --------------------------------------------------- Update: 02/08/2017 I received a couple of emails from the seller over the past week asking for further explanation as to the problem I documented below with the collimator iteslf being out of collimation, and the inability to adjust it even after exposing the collimation screws. So I replied to them with details. Out of the blue I received a new collimator in the mail. I've yet to try it to see if it is in collimation, but I'm impressed with the customer service, regardless. I've changed my review to 4 stars based simply on the prompt customer service, desire to make things right, and unexpected replacement of the collimator. If it turns our that the new collimator is in alignment, I'll bump it to 5 stars. --------------------------------------------------- The general construction, price and intent is fine. But the unit arrived out of collimation to a degree that makes it useless. I read here that this is a common problem. There are indeed three adjustment screws for aligning the collimator, but as others have noted they are potted with silicone that you have to dig out to gain access to the screws. Even after doing that and then creating a jig to perform the alignment, I've been unable to get the collimator collimated. It was not a simple job of just turning the screws one way or the other to adjust the laser, as you'd expect. The only way I can get the device even close to being aligned is to leave one alignment screw slightly slack. It makes no sense, but I can't see inside the device to determine what might be preventing the adjustment from working logically. I was able to use the collimator one time to adjust the telescope (after an hour of digging out silicone, making a jig, and trying to align the laser). But it appears that just one day later the collimator is already out of adjustment. I'm sure the fact that I can't tighten all three screws and have the collimator be in alignment is the reason. Anyway, not happy. A waste of $$. I suppose I can't return it since I dug out the silicone plugging the adjustment-screw holes. Orion sells a nearly identical looking collimator here on Amazon for 2.5x the price. Maybe the difference is that theirs comes aligned to begin with.

How to collimate a Newtonian reflector telescope Some 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.

Great product fast shipping

I purchased this collimator for $26 in 2020. Three years later I am still using it and I thought I should share the meaningful characteristics. The collimation error of the laser is less than 0.1%. I am getting less than 1mm deviation at 5 meters (less than 1/16" at 17 feet). Note that the factory collimation wasn't good at all - more on this later. There are 7 levels of brightness. 7 is way too bright to be useful. In some cases, the lowest level is still a bit brighter than I would like, but for most use cases the range of brightness is perfectly adequate. The adjustment knob works very well is ergonomic. The battery (CR2032) is easy to access, but I doubt I will ever need to replace it. The spot is elliptical but reasonably tight: at 5 meters it is 5x3mm (at 17 feet it is about 1/4x1/8"). Construction and overall quality of materials and machining is very good. The main drawback is that the adjustment screws to collimate the laser are covered with rubber so that the screws can't be accessed. The collimation error of the laser was originally in the order of 1% - perhaps a bit more - somewhat usable but annoying when collimating a telescope: it requires remembering in which direction the error is, and pointing the laser to the correct edge of the marker of the center of the mirror. However, it is possible to remove (destroy) the rubber protection on the adjustment screws with toothpicks or hard plastic implements (the third screw is under the laser warning label). Once the screws are exposed (metric 2mm hex wrench), it is possible to adjust the collimation of the laser as easily and as accurately as on laser collimators that are 5 times more expensive.

I've used this to collimate my dobsonian telescope, and it has increased the telescope's image quality. It's a permanent addition to my backpack of telescope parts, and doesn't take much space there either (although, it's easier to fit when outside of its box). Connecting this to the focuser is easy, and when turned on, the laser shows up clearly, and has different levels of intensity. I did notice that the dot that gets reflected back is less of a dot, and more of a wider circle, but it's still easy to tell when it's centred. It functions well for my purposes.