SVBONY Reticle Eyepiece 1.25 inches Illuminated Eyepiece 12.5mm Double-line Crosshair LED Illuminator 40 Degree FOV 4 Elements Design Telescope Accessory Guide Star

Better quality than I expected for the price. Worked well in my finder scope.

I use this for star alignment on my SyncScan system. It is easy to use and make alignment a breeze. I do have some slight issues on losing sight of the star as I'm slewing, but that might be because I move my head or something.

If you use a 2000 mm telephoto lens it doesn't seem to work well for Polar Alignment. Have to use the guide scope. I use this to center the north star on the 2000 mm lens then use the preview on the guide scope and manually center it . That way both scopes are aligned to each other.

This is a terrific product once you figure out how to assemble and operate it without instructions.You will get it with 3 small watch/hearing-aid style batteries. Screw apart the illuminator in the middle. The batteries go into the half with the clear plastic tube that has a small round battery contact inside. The batteries go button side down, flat side up, into the tube. Stack all 3 batteries the same way, then screw the other half of the illuminator back on. You should be able to see the red light come on at the end of the illuminator when you click the switch knob on and turn it all the way bright.Screw the illuminator into the hole in the side of the eyepiece. Turn off the illuminator light and look through the eyepiece in normal room or day light and see the four black crosshairs. Most likely they will be very blurred. The ring on top of the eyepiece is for focusing the cross-hairs, so turn it as many turns as needed to get the two double cross hairs into sharp focus, and you're done. When using it at night through your scope, adjust the illuminator brightness as needed, depending on how bright your target is.On "first light" with this eyepiece, I achieved the best alignment that I've ever experienced with my Alt-Az mount.

The product that I received had a little problem. The illuminator did not fit the lens body properly.The seller took proactive action and reached out to me first and worked very hard resolve the issue.The replacement I received did not have any problem and it works very nicely.However, after not using a few month when I tried to use it agina, the light came on and off. I thought it was the battery, but replacing the batteries did not solve the problem. I took it apart to find out what is causing the problem. The problem was faulty wiring as in the attached picture. The wire was soldered very poorly and it worked only when it was touching the soldering point. It is still covered under warranty. I hope they can would honor the warranty.When it worked, it worked really nicely. I use this eyepiece to align my telescope with stars. The double line cross-hair works very nicely.It increase accuracy of goto functionality of the telescope and alignment accuracy of the finder scope very much.== update =======The seller (Retevis direct) replaced the unit at a small fee honoring the warranty. It is great customer service experience.Thank you again.

There's no instructions, but the cross-hairs are first focused with the dial on top of the eyepiece followed by focusing on the object (e.g., a star) using the main focuser. The barrel portion that inserts into the telescope is polished instead of brushed - and there is no compression ring groove - so extra care is needed to prevent the eyepiece from slipping out when you first start out. The LED illuminator is turned on-and-off as needed since sometimes there's enough starlight and it is best to keep it off. Other times, it is too dark and illumination is needed to see the cross-hairs. If the illuminator floods out a star, then you will find yourself turning it on-and-off while locating the star (explaining the versatile design of the illuminator).When used in this way, it will be very accurate for such tasks as polar alignment or star alignment.(Additional note: If you need a compression ring groove, this might be available under another brand. I think it is called 'Gazechimp').

works fine

The product came very slowly by mail from China. I needed this in addition to my Meade Plossil which has adjustable illuminated cross hairs to use with a finder scope. I did not need the cross hairs to be adjustable, so this fit the bill. However the focus for the cross hairs is implemented by unscrewing the front objective, and the threads are very, very sloppy. More like tapered pipe threads. It caused the objective to wiggle from side to side as if it were about to fall off. I "fixed" this by wrapping several turns of teflon tape around the threads to fix this shortcoming. The illuminator is adjustable, which is very helpful and works well, though here too the threads for the battery compartment are anything but smooth. No comparison whatsoever to the Meade product.