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

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.

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.

Update: 02/21/2017The 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: 02/08/2017I 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.

Works exactly as it should, great image quality.