locating stars etc...

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ste_06

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just afew quick questions. to locate a star do i just put in the coordinates so they line up with the r.a. indicator? and which part of the r.a. setting circle means hours and minutes? hope that made sense. thank you.
 
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ste_06

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one more thing do i need to keep changing the altitude depending on what i wanna look at? its getting me confused
 
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doubletruncation

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I personally think that for most objects the easiest way to find them is to first learn the constellations that you can see with your naked eye. Then get a good star chart for the night you'll be observing and when you want to find something faint see what stars it is near. First find the brightest stars that you can see with your naked eye (and manually point the telescope at that star), then move your telescope to the fainter stars until you reach the object you want. <br /><br />If you want to use coordinates to find an object, then how you do it depends on what kind of telescope you have. If it has an RA/Dec indicator, then presumably it's an equitorial mount. In that case, you would need to align your scope with the celestial pole before you can use the RA/DEC to find objects. To do this, you need to align the axis about which the RA moves with the celestial pole, if you live in the northern hemisphere you would want to get it so it's pointing basically at polaris (the north star). For the RA indicator to mean anything you also need to set the time in some fashion. If you have an electronic goto telescope, then you'll probably find a one-star or two-star align routine in the menu. The routine may ask you to set the time, then choose stars from a list and manually point to the telescope at them (you'll need to know how to find bright stars like Vega, Sirius etc by eye - so if you haven't done so already, get yourself a star-chart and start learning the constellations). If you don't have an electronic goto telescope, then after you do the polar alignment manually point the telescope at a star whose RA/DEC coordinates you know. Adjust the RA indicator so that the correct RA value is indicated when you're at the star. If you have a motor, you'll want to start it when the star is in your field of view. Once you're aligned you can move the telescope following the RA/DEC indicators to pre-set positions. (If you aligned on polaris rather than the actual celestial <div class="Discussion_UserSignature"> </div>
 
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doubletruncation

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<font color="yellow">which part of the r.a. setting circle means hours and minutes?</font><br /><br />Sorry, I don't quite understand. Usually the big numbers/ticks are for hours and the small ticks are for minutes (or 6 minutes if there are only 10 ticks between the big ones). Sometimes the RA setting circle is in degrees. If it goes to 24 then it's in hours, if it goes to 360 it's in degrees. To convert from HMS to degrees take degrees = 15.0*(hours + (minutes/60.0) + (seconds/3600.0)).<br /><br /><font color="yellow">do i need to keep changing the altitude depending on what i wanna look at?</font><br /><br />If you have an equitorial mount telescope, then no, once you've aligned on the celestial pole by adjusting the altitude control then you should not touch it again. You'd use the RA/DEC controls to find different objects on the sky. <div class="Discussion_UserSignature"> </div>
 
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ste_06

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i figured out how to do the DEC and i know how to put the hours in but im not understanding the minutes? for example- <br /><br />RA 14h 29m DEC -13degrees <br /><br />so i put the dec in as -13. then i rotate the RA setting circle to 14h, then i rotate the telescope to the minute but when this is done the scope is at a very steap angle and its touching the mount. what am i doing wrong? the scope has 15 ticks between each number. for example- <br /><br />l''''l''''l''''l and so on until it reachs 12. <br /> 1
 
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doubletruncation

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If you're trying to look at something that hasn't risen yet, or has already set, then the scope will be at a very steap angle and touching the mount. I'm a little confused by why the RA setting circle goes only to 12 instead of 24. (Do the numbers go all the way around the full circle)? If they do, then you'd need to mulitply everything by 2. Note that minutes are a finer gradation of hours. There are 60 minutes in an hour, so 14h 29m is very close to 14 and a half hours. The 15 ticks between the numbers would correspond to intervals of 4 minutes. If you've already set the RA for a star whose position you know, then to go to 14 h and 29 m you would want to rotate the telescope about the RA axis until the indicator is at a mark that is 29/4 = 7.25 small ticks beyond the 14 h mark. If you haven't set the RA for a star whose position you know, then you would want to manually point the telescope at that star and then move the RA indicator so that it lines up on the RA value for the star. <div class="Discussion_UserSignature"> </div>
 
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ste_06

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sorry, i made a mistake the setting circle does go to 24 and yes the numbers do go all the way round. i think i got it now, i'll go practice on the scope. thank you for your help!
 
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doubletruncation

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Good luck! Remember to start your motor once you set the RA indicator for a star whose position you know. If you don't have a motor, then to use RA/DEC you'll have to first align on a star whose position you know every time you want to move to another object. <div class="Discussion_UserSignature"> </div>
 
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