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Setting circle

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#1 Orion2221

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Posted 18 June 2019 - 07:01 AM

Hi pretty new to it all i can now balance my telescope and polar align.

 

How do you use the setting dials to gind a plannet one if my dials turns buy hand as shown in the pic the rest i need to move the telescope to change the dials reading im not sure if the dails ment to move buy hand.

 

It would be great if some can give me a idiots guide.

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#2 vio

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Posted 18 June 2019 - 07:24 AM

Just did a Google search on “setting up telescope setting circles” and there are a few results, a combination of articles (first from Sky and telescope) and YouTube videos on it.

I never used them on my scope, but mostly have them set when I setup my mount, to the home position of the mount.
Here is a blog entry that you may find useful in all aspects of the setup and polar alignment: http://uncle-rods.bl...alignment party

Clear skies!


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#3 oshimitsu

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Posted 18 June 2019 - 08:58 AM

Those are your RA and DEC setting circles. You will need to know the coordinates of a few stars in the sky to make use of them. In order to use the setting circles you would slew to one of the stars you know the coordinates to and set your setting circles to those coordinates. Once your circles are set you now have a reference point and can slew to the coordinates of an object you want to find. I have never used setting circles but instead learned to star hop when I only had a manual mount. 


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#4 treadmarks

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Posted 18 June 2019 - 09:10 AM

Hi pretty new to it all i can now balance my telescope and polar align.

 

How do you use the setting dials to gind a plannet one if my dials turns buy hand as shown in the pic the rest i need to move the telescope to change the dials reading im not sure if the dails ment to move buy hand.

 

It would be great if some can give me a idiots guide.

Ok, idiot's guide to setting circles: if you're an idiot, don't use setting circles, being smart is a requirement.

 

Quick guide for non-idiots:

1. Polar align the mount as precisely as possible.

2. Point telescope at star with known right ascension and declination.

3. Turn dials until right ascension and declination under pointers matches those coordinates. Make sure you are using the right set of coordinates for your hemisphere. Lock dials.

4. Get coordinates for object you want to observe. Move/turn telescope until coordinates pointed to by setting circles agree with coordinates for desired object.

 

Also setting circles are a poor choice for planets most of the time, unless you're trying for an invisible one like Neptune. If you're looking for Jupiter it's kind of hard to miss right now, look towards the south after 9PM and it's the brightest thing in the sky.


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#5 JGass

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Posted 18 June 2019 - 09:48 AM

Looks like you'll first need to set the polar axis to your terrestrial latitude. It appears in the photo to be set for az-el use, rather than equatorial. 


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#6 oshimitsu

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Posted 18 June 2019 - 10:16 AM

Looks like you'll first need to set the polar axis to your terrestrial latitude. It appears in the photo to be set for az-el use, rather than equatorial. 

2nd this, I didn't even notice that at first. 



#7 JamesMStephens

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Posted 18 June 2019 - 10:20 AM

Orion,

 

You point out that one of the circles turns by hand, this is the Right Ascension (RA) circle.  The Declination circle should be aligned if you polar align the scope.  (This isn't always the case in some scopes.)  If you polar align the scope and rotate it towards the north celestial pole the Dec circle pointer will point to 90 degrees North.  If you now point the scope at a known star, say Vega, the Dec circle will read +38° 47′.  Vega's RA is 18h 37m (to the nearest minute) so you need to rotate the RA circle so that the pointer reads 18h 37m.  You can now rotate the scope to the RA and Dec of your desired target.  Make sure you understand celestial coordinates.  Declination is specified as degrees north (+) or south (-) of the celestial equator, whereas RA is specified in hours (subdivided into minutes and seconds, which are not the same as minutes or seconds of arc).  

 

If your scope had a clock drive (and depending on the design!) the RA circle would move at the sidereal rate with the scope, so you'd only have to adjust it once and engage the drive.  It looks like your mount is manual, so you'd have to realign the RA circle every time you used the circles to acquire a new target.  

 

Here is a brief guide http://calgary.rasc.ca/scircles.htm

 

In my judgement the best explanation of all of this (celestial coordinates, time in astonomy, and setting circles) is here

https://www.amazon.c...n/dp/B001LOJNNO

 

Enjoy,

Jim

 

PS: I'll repeat what the others have said in their responses, the scope in your picture is not polar aligned (unless you're at the North Pole!)  


Edited by JamesMStephens, 18 June 2019 - 11:26 AM.


#8 Orion2221

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Posted 18 June 2019 - 02:33 PM

Hi thanks for your comments i know in the picture its not polar aligned as ive been messing about with it but i have learnt how to do it finally :).

Ill get out and keep practacing soon as the visabilty comes good as its heavily raining.

#9 JamesMStephens

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Posted 18 June 2019 - 04:24 PM

Hi thanks for your comments i know in the picture its not polar aligned as ive been messing about with it but i have learnt how to do it finally smile.gif.

 

Figured that was the case!

 

Just for clarity, let's go from top to bottom in your picture.  The circle at the top is declination circle.  The next one down (the one with the arrow) is Right Ascension.  These are the two setting circles.

 

Immediately below the RA circle there's a circle on the mount support, this is for polar alignment.  Set this to your latitude.  The bottom (horizontal) circle is an azimuth scale and I presume this is intended for adjusting the mount's azimuth when you do your polar alignment using a compass.  It could be useful in daylight or if Polaris wasn't visible.

 

Jim



#10 oshimitsu

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Posted 18 June 2019 - 11:02 PM

Bare in mind that setting circles are very inaccurate due to their size and you have to set the circles very fast because as soon as you set them your target has moved. I recommend picking up a book called "Turn Left at Orion" to learn how to star hop. The reason I say circles are inaccurate is because if you need to set your DEC to something like 42 hrs 30 minutes; you're going to have to figure out where 42 deg and 30 minutes is in between one of those marks. Depending on how large the circle is that can be a difficult task.  Here's a good video explaining what I mean after a quick google search https://www.youtube....?v=geQszAVWMok 


Edited by oshimitsu, 18 June 2019 - 11:05 PM.


#11 Orion2221

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Posted 19 June 2019 - 11:21 AM

Thanks

#12 REC

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Posted 19 June 2019 - 01:10 PM

As said, Jupiter and Saturn are easy to find by finder scope. Where the setting circles are helpful is for deep sky objects, DSO's like nebula star clusters, galaxies.

 

For me, after the scope is set for north, I use my phone App or Stellarium on my laptop. Say I want to see M13, the globular cluster. I'll find it on the phone App and take the RA and the Dec numbers and transfer them to my scope settings. Some like M13 should be visible in your finder scope and in a low power eyepiece. If you don't have Stellaruim yet, go download it and practice with it.


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#13 Orion2221

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Posted 19 June 2019 - 02:28 PM

Hi thanks i have stellarium its very usefull and i also use sharpcap seems great when i use my webcam.

Not sure what other good programes but ill fo a google search.

#14 skfboiler1

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Posted 19 June 2019 - 05:12 PM

Ok, idiot's guide to setting circles: if you're an idiot, don't use setting circles, being smart is a requirement.

 

Quick guide for non-idiots:

1. Polar align the mount as precisely as possible.

2. Point telescope at star with known right ascension and declination.

3. Turn dials until right ascension and declination under pointers matches those coordinates. Make sure you are using the right set of coordinates for your hemisphere. Lock dials.

4. Get coordinates for object you want to observe. Move/turn telescope until coordinates pointed to by setting circles agree with coordinates for desired object.

 

Also setting circles are a poor choice for planets most of the time, unless you're trying for an invisible one like Neptune. If you're looking for Jupiter it's kind of hard to miss right now, look towards the south after 9PM and it's the brightest thing in the sky.

I've had some success finding stuff with the setting circles on my Orion Astroview 6 mount.  I pretty much use these steps to find stuff.  When I first got the scope I was trying to learn how to find stuff by star hopping.  Due to my light pollution, thanks Chicago, and being a newbie, I was only able to star hop to the easy stuff.  After frustration trying to find other stuff I decided to try using the setting circles.  The key for me was first getting the best polar alignment I can get. Second, with the steps treadmarks described, I used a star as close to my object as I can find.  That should increase the accuracy of using the setting circles. For example, to find the globular cluster M3, I used the star Arcturus. The DA was already very close.  I moved the RA dial to the RA of Arcturus..  Then moved the mount to the DA and RA of M3.  M3 was in the field of view of my finders scope.and just out of the field of view of my 25mm EP.  I then turned the RA knob to center it.  I would not expect the setting circles to be accurate enough if using the star something like Vega to go across the sky to find M3.



#15 Steve Cox

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Posted 19 June 2019 - 06:52 PM

Once you get the hang of using RA & DEC manually to find objects, you'll probably find it's quicker than using go-to; and adding nothing more than an RA drive is really all that's needed for visual observing.  Good luck.


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#16 gnowellsct

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Posted 22 June 2019 - 03:15 PM

That mount is set up for alt-azimuth use.  That would be terrestrial, birding, that sort of thing.  

 

You can use it in alt-az if you have a computer to give you alt-az coordinates.   Otherwise you need to loosen the mount and get the angle set for your latitude.  

 

Greg N




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