Learn how to easily align your equatorial mount

Hi and welcome to eyes on the sky my name is David fuller and I try to make it easier to understand the science of astronomy in this video I'll be discussing how to set up and align a telescope on an equatorial mount sometimes known as a German equatorial mount now for the newcomer there can be a myriad of knobs and clutches and angles that don't seem to make a lot of sense but hopefully by the end of this video you'll be able to set up and align your mount with ease so let's begin in this video we'll cover the following latitude leveling and balancing alignment and starting point the celestial pole and polar alignment first take your telescope off of your mount we'll be doing some adjustments to the mount and this will help avoid any accidents that could damage your scope do a quick internet search of where you live or a large city or town within a hundred miles or so and find your approximate latitude find the latitude scale on your mount which may look like this or this and then after unlocking the clutch set the pointer on the latitude scale to the latitude at or near the latitude of where you live relock the latitude adjustment it doesn't have to be perfect for right now within a few degrees is fine next is leveling the tripod and mount a good way to avoid accidental tip overs with your equatorial mount is to make sure that the entire assembly is level on the ground if your mount doesn't have a bubble level on the mount like this you can tape a large coin to a piece of string and hold it directly underneath the center of your telescope if the coin hangs right over the middle of the eyepiece tray then it's level the next step is often misunderstood but it's very important and that is balancing your scope there are two axes to an equatorial mount but let's start with the right ascension axis very often there are setting circles on the right ascension taxes and it's likely the larger of the setting circles like this or this this is the axis that has the telescope on one side and a counterweight on the other begin by setting up your telescope similar to how you'd be using it at night so start by placing your telescope back onto the mount and put a low power eyepiece in the focuser these will often have a 20 25 or 26 printed on them somewhere like these now unlock the right ascension clutch and rotate the mount so that your telescope is off to one side like this holding the telescope with one hand and leaving the clutch unlocked release the set screw on the counterweight and slide the counterweight back and forth on the counterweight shaft until you can feel that the telescope tube neither drops nor rotates back up it should be well balanced you unlock this clutch and turn the telescope most mounts will have the telescope tube in some kind of rings or cradle loosen the cradle or ring locks just enough that the tube can slide back and forth this axis is a bit harder to get balanced well especially with lighter tubes but if you sort of set the scope sideways then push it back and forth you can get an idea of which side may still be heavy like this adjust as necessary when you're satisfied that the telescope tube is well balanced in this axis point the telescope so that it is straight up over the equatorial mount then relock the clutch now your scope is in the starting position I know I know all that just to get to the starting position it helps to understand why an equatorial mount was developed recall that the earth spins on its axis making one rotation in 24 hours well as the Earth spins the objects in the sky appear to move across the sky but in reality they're not moving it's us that are the ones that are spinning look at this video of a sped up representation of the night sky all that is due to the earth spinning not the stars themselves spinning over us so because we're spinning we want to be able to point a telescope at a given object in the sky say the moon or Jupiter or even another galaxy and keep that object centered in the eyepiece without it drifting out of the field of view that's what an equatorial mount does and with a motor drive or slow motion control it keeps the night sky object stationary in the eyepiece so how do we set up our equatorial mount to counteract the spinning of the earth on its axis so that objects don't drift out of the field of view in our eyepiece by aligning our latitude adjusted levelled and counterbalance telescope at the celestial Pole the celestial pole is simply an imaginary spot in the sky around which all the other objects in the sky appear to rotate let's go back to that video of the stars rotating note how there's a bright star very close to the center of the video that we saw for those of us in the northern hemisphere we align our equatorial mounts towards that star which is Polaris or the North Star so the telescope rotates slowly on the right ascension axis opposite the direction from the Earth's rotation since that axis will be parallel to the Earth's axis by being aligned with Polaris thereby counteracting the Earth's rotation so how do we align at Polaris first begin with your telescope tube in the starting position on the equatorial mount as we discussed earlier next make sure that the tube is aligned with the right ascension axis and the declination axis so that everything is parallel and square now whatever tripod leg is closest to pointing to the south set it so that it is sitting due south you may even need to re-level your tripod and if that is necessary after moving do that now your telescope may or may not be pointing north anymore but that's okay unlock the azimuth lock and turn the entire mount and telescope assembly without turning the tripod so that it is facing due north like this crouched down behind your telescope tube and looking up over the top of it you can eyeball how close you are to Polaris and since it's daytime while we're shooting this video we need to stand in for Polaris of course when you move down alongside of the telescope tube Polaris may still be too low or too high so remember how you pointed that one telescope leg to the south unlock it and push the scope tripod mount assembly up or down until you have Polaris more closely aligned now unlock the latitude adjustment and if you have one use the fine adjustment to eyeball the tube closer to Polaris if you don't have a fine adjustment neck and mechanism be careful and have someone help you with this part looking through your finder scope see if you can locate Polaris if so great you're very close to polar alignment continue using the fine equatorial adjustment and azimuth adjustment until Polaris is centered in your finder scope crosshairs when Polaris is centered in your finder scope look through the low power eyepiece in the focuser of your main telescope tube is Polaris there if your finder scope is aligned properly it should at least be visible through the main telescope continue making fine adjustments until Polaris is centered in this eyepiece okay so now you found Polaris and aligned your scope lock the azimuth and latitude locks and drumroll please now your polar aligned so let's quickly review set the latitude adjustment on your telescope mount to the latitude of your location get the mount and tripod close to level balance the mount by adjusting the counterweight and by sliding the tube in the cradle or rings align the tripod assembly and place the scope in a starting position find the celestial Pole find Polaris in the finder scope and adjust until Polaris is centered in the main scope and that's pretty much it now if you are able to take your telescope intact and bring it inside then you're all set because what you can do is actually bring the telescope back outside and put it in the exact same location to be able to observe on subsequent observing sessions however if this is not possible what you can do is at least be able to set up the telescope more quickly when you do a polar alignment and besides you won't have to do certain things a second time such as the latitude adjustment if you have any other astronomy questions please feel free to visit me at eyes on the sky.com we have all kinds of free star charts information on how to find things in the night sky as well as ways to be a more frugal astronomer while enjoying the night sky more I'm David fuller keep your eyes on the sky you never know what you might see

Channel: Eyes on the Sky

Views: 777,046

Keywords: equatorial mount, german equatorial mount, eq mount, telescope mount, aligning telescope, telescope set up, how to set up a telescope, how to align a telescope, beginner astronomy, using a telescope, polar align, polar alignment, polar aligning a telescope, how to align an equatorial mount

Id: plx6XXDgf2E

Length: 11min 47sec (707 seconds)

Published: Mon Nov 29 2010