Collimation is the proper alignment of the optical elements – lenses and mirrors - in your telescope. Collimation is important for getting the best out of your scope. Poor collimation will result in op]]> Collimation is the proper alignment of the optical elements – lenses and mirrors - in your telescope. Collimation is important for getting the best out of your scope. Poor collimation will result in op]]> Night Time Star Collimation

After successfully completing daytime collimation, night time star collimation can be don]]> Magnification of a telescope is actually a relationship between two independent optical systems – the telescope itself and the eyepiece you are using. ]]> Celestron manufactures telescope series, which each feature several models that differ mainly in aperture. Sometimes that is the only difference and the mounts and assembly are the same.

Yes. Your telescope can be used in several ways to take photographs of celestial and even terrestrial objects.

The most basic way is to use the telescope as a piggyback mount, so-called because th]]> Solar filters are absolutely essential for observing the sun safely with your telescope. Our star is so bright it can permanently damage both your eyes and the scope’s optics unless both are properly p]]> After pressing the ALIGN button on the last alignment star, the message STARPOINTER OFF flashes briefly on the hand control of the NexStar GT, SLT and SE series telescopes.To get a correct view when using the telescope for ground or terrestrial viewing, use an erect-image diagonal (available from Celestron) for your refractor or erect-image ey]]> If the StarPointer no longer shows the red dot when turned on, it probably needs a new battery. It uses the 3-volt CR2032 lithium wafer battery. You can get these cells at most drugstores, hardware stores an]]> The dovetail bars on the NexStar SLT line of telescopes are the same size as those used on our Advanced CG-5 GT German equatorial head and the SE computerized dri]]> You can manually enter in your location via the hand control.  You need your latitude and longitude in the degrees-minutes-seconds format.  Get this information from ]]> Your NexStar SLT’s alignment procedures will prompt you for location and time at the beginning of every observing session. You will need to enter everything the first time you do it. Subsequent alignme]]> You can obtain a replacement hand control for your NexStar SLT scope. 

Simply contact your dealer.  Or go to Celestron.com a]]> Your altitude clutch is slipping, causing the scope to droop in altitude.

Remove the optical tube, unscrew the tube clamp tightening knob as much as needed, and s]]> When you start the SkyAlign procedure, the display should be cycling through three messages. They are ENTER IF OK, UNDO TO EDIT and one of the following: if your GPS is turned ON, you will see GPS LINKING; i]]> The scope relies on your input to get the correct time-site information. If you neglect to change daylight savings time, your scope will be 15 degrees off west or east when the time changes in the spring and]]> Time zones that are fractional ½ hour aren’t in the current firmware. These include most of India, as well as all ]]> Your NexStar telescope is designed to be motor-driven under control of its GOTO firmware. The hand control functions and arrow keys allow it to point anywhere in the sky. The only limits are those imposed by]]> The current NexStar series do not have a real-time clock. When the scope is powered on and an alignment method is chosen, the last-entered time and location a]]> Your NexStar scope has several different SkyAlign procedures to choose from. In general, the number, positive ID and wide spacing of objects improves a SkyAlign and any subsequent GOTOs and tracking. Thus, t]]> If your NexStar SLT scope isn’t performing well, you can try the following three steps yourself.

Due to the design of the mount and tripod and the balance point of the tube, your scope will be unable to point directly to the zenith. The electronics have special filters in the hand control that]]> It appears that your hand control is stuck in programming mode. 

Fortunately, the fix is easy.

First, try cycling the power of your scope. This will often clear the ]]> Your scope is experiencing backlash, play in the drive gears. All telescopes have some backlash, as gears can’t be too tight, preventing the motors from turning. Backlash causes the delay in scope move]]> It’s best to protect your telescope from the elements and bring it inside between observing sessions. 

Allow the scope to w]]> If you are following the instructions in the manual and cordwrap isn’t working, most likely you need to upgrade your motor control firmware.

Make sure no buttons are stuck. If not, then you can try the following three steps yourself.

First, power supply. Fresh batteries in a clea]]> The AUX port can be used with the CN16 GPS accessory to get location and time information for your scope from the GPS satellite system.

MENU – SCOPE SETUP – GOTO APPROACH lets you choose the direction the scope will use when approaching an object during the final part of slewing. The best way to use it is to minimize backlash.&]]> It could be an encoder problem. The encoder is a light-emitting diode (LED) device that measures how much the motor has turned. Try this general test of the encoders:

If you can’t find anything with your telescope, you may need to try aiming the telescope and aligning the StarPointer in daylight. This is best done when the scope is first set up.

You need to review and adjust the button direction logic in your hand control menu.

The directions are made user-adjustable so you can match the direction the star moves in the eyepiece with the ]]> Cordwrap safeguards against your scope slewing more than 360 degrees in azimuth, which can spiral your power and accessory cables around the b]]> Please go to this web page on the ASCOM Initiatives website:

Most likely it’s because the NiMH (nickel metal hydride) or Ni-cad (nickel cadmium) batteries just aren’t providing enough voltage because of their chemistry.

Celestron]]> Once you have your solar filter over the front of your scope, you can safely point it at the sun. However, as a safety feature, the sun does not appear in the hand control unless you enable it.

Go]]> No. The reason the tube on this scope is so short is because its optical design incorporates a Barlow lens built into the focuser. This lens extends the focal length of the primary mirror and therefore the t]]> The drivers and software used with most Celestron products are (as of Fall 2009) not compatible with Mac operating systems.

Though Celestron provides no support for these work]]> If you have NexRemote, HCupdate, MCupdate,PECTool compatibility issues, simply download the latest versions from Celestron’s Manuals/Drivers page. ]]> A computer crash or communications break between your PC and the hand control during an MC update may result in either “Initializing”, blank screen, “No Response 16” or “No Resp]]> Nothing is wrong. These scopes are Newtonian reflectors that normally give inverted views. They are designed for astronomical use. 

The payload weight is defined by Celestron’s engineering/product development department as the load that is carried by the mount’s dovetail clamp.

These are the payloa]]> No. Only stars brighther than or equal to magnitude 2.5 (bright stars) can be used for alignments with Celestron’s NexStar computerized mounts.

Even though there are about 250]]> First, find the AUX  port to plug it in on your mount.

For the Advanced GT using the CN-16,]]> You need to remove the mount from its Celestron tripod.

The mount base has a 1/4x20 threaded hole that can be used with aftermarket tripods that can be aligned equator]]> Interrupt the mount’s GOTO slew by pressing any arrow key. The mount will halt the GOTO in progress.

Since this is a regular h]]> The dovetail bar (sometimes called a rail) is one of the great ideas in small telescope design. With the clamp on the mount and a bar on the tube, telescopes (OTAs) and mounts ca]]> There are several ways to do-it-yourself when it comes to collimating tools.

The easiest way is to just drill a 1/16” to 1/8” hole in the center of your ey]]> The NexStar 130SLT has a parabolic mirror.

Telescope mirrors are described by their figures in terms of the curvature of the optical surface. A spherical figure is one]]> Yes, with the included 2" adapter.