Author Topic: equatorial mounts confusing !  (Read 124 times)

Harry Smull

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equatorial mounts confusing !
« on: December 25, 2017, 10:44:09 AM »
As much as I have tried I do not understand how a equatorial mount works at all I know how to align with polaris but after that im confused I have a xt8i intelliscope that really does the work for me but I would like to use my own celestron 114 astromaster as another set of eyes but dont know how to use it properly...I celebrity hop today and dont even use the mount properly because I dont know how



toughhalrechal

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Re: equatorial mounts confusing !
« Reply #1 on: December 27, 2017, 10:50:16 PM »
Hey Gunny,

I see that you are a member of the Indiana Astro Society.....I would reach out to your local club as much as possible and ask for assistance. There are a few YouTube videos on setting up and using an equatorial mount. Yours is fairly straight forward as there's no goto, or motor, (motor drive is an option), but it should be fairly easy to use.

As for the 8I reflector, worst case is you don't need to use the push to. What is the issue with this scope?

Gary

Logan Budd

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Re: equatorial mounts confusing !
« Reply #2 on: December 29, 2017, 02:14:02 PM »
Perhaps you can share a photo of what your setup looks like / where you got stuck, not clear exactly what you're looking for on this forum based on your post. If you search for Forrest Tanaka on YouTube you'll find some videos where he shows how the mounted scope looks like (you can ignore the astrophotography bits), and then compare it to your setup. There may be other videos on how to set one up from scratch.

Bob Meade

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Re: equatorial mounts confusing !
« Reply #3 on: December 29, 2017, 11:02:25 PM »
Here is a link to the manual for that scope.
https://www.manualsl...4eq.html#manual

Phil Barela

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Re: equatorial mounts confusing !
« Reply #4 on: December 29, 2017, 11:41:00 PM »
I find star hopping easier with an EQ than an Alt-Az. The reason is that the orientation of any object with respect to another is always the same in RA/Dec than Alt-Az.

Take a galaxy that is 30' directly east of a 3rd magnitude star. To find that galaxy in an EQ you center the 3rd magnitude star and then move half a degree due east (that is, toward the east in RA). That is true where ever in the sky the star and galaxy are.

How do you find it in an Alt-Az? The answer requires you to also know where in the sky it is. When the pair are about 20 degrees above the eastern horizon, the galaxy is down and to the left (as you face them). When the pair are at their highest, the movement the mount needs to make depends on how you've set it up. When the pair are 20 degrees above the western horizon, the galaxy is above and to the left of the star. Their orientation constantly changes.

The only truly confusing* thing is that the coordinate system is angled with respect to up/down, left/right and the angle depends on your latitude. What I found easiest in star-hopping with an EQ is to completely ignore terrestial directions. Put your atlas in Equatorial mode (if you're using paper atlases, they already are) and locate your jumping off point. After that, only make moves in RA or Dec. If you have even crude setting circles they can help.* As opposed to the confusion that comes naturally from using an Alt-Az and then moving to Equatorial. Or vice versa. You can't mix how you think: either move in equatorial directions if you are using an EQ mount or move in Alt-Az if using an Alt-Az mount. If you are using an EQ and try to make an Alt-Az move, you will get lost and confused for certain.Note: If you're just wondering how to polar align, then, for visual use, just sight Polaris down the polar axis. It'll be close enough.

Doug Woods

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Re: equatorial mounts confusing !
« Reply #5 on: December 30, 2017, 02:50:11 PM »
Orion Telescopes has a good tutorial video on how to set up an equatorial mount. Also, for visual viewing polar alignment doesn't have to be exact. Just make sure the mount is reasonably level, the latitude is set for your location, and you're pointed north. If you can't see the North Star use a compass or the one on your iPhone. That's it. Set up only takes minutes.

retpoiwerround

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Re: equatorial mounts confusing !
« Reply #6 on: December 31, 2017, 05:41:07 AM »
Quote
Orion Telescopes has a good tutorial video on how to set up an equatorial mount. Also, for visual viewing polar alignment doesn't have to be exact. Just make sure the mount is reasonably level, the latitude is set for your location, and you're pointed north. If you can't see the North Star use a compass or the one on your iPhone. That's it. Set up only takes minutes.

Yep, watch a few videos on German Equatorial Mounts to get a sense of how they move around. Get the scope balanced properly and practice moving it around and aiming it inside.

Loosen the Right Ascension and Declination axis locks and move the scope around. It can be awkward at first but after 15 to 30 minutes with the mount you'll get used to how it moves and swings around.

For visual use polar alignment is easy, and once done you can track objects using just one slow motion control.

rackramasca

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Re: equatorial mounts confusing !
« Reply #7 on: January 03, 2018, 09:00:17 PM »
"as much as i have tried i i do not understand how a equatorial mount works at all i know how to align with polaris but after that im confused i have a xt8i intelliscope that does the work for me but i want to use my celestron 114 astromaster as a second set of eyes but dont know how to use it properly...i star hop now and dont even use the mount properly because i dont know how"

AND THAT IS EXACTLY WHY I tell new people NEVER EVER buy an EQ mount, get an AltAZ and I speak from experience

People rush out and buy what looks good, great when in doors in the warm, then wonder why they are fed up not being able to use it, kneeling in wet grass peering through a polar scope to align it every time they want to use it

I used to have one, £5,000, white Observatory class scope on Sphinx Vixen mount, rarely got used, now I have a Celestron

Find and join an astronomy club.

There will be dozens like you on the forum after Christmas   Attached Thumbnails




Eric Shaffer

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Re: equatorial mounts confusing !
« Reply #8 on: January 04, 2018, 05:09:07 AM »
OK say you want to find an object you you’re right assesion is17hr 30 min And your declination is -23.30 The object is the sun and that’s the readings I have current how would I move my telescope and I started having a Polaris centered that’s the kind of questions I have about a equatorial mount my coordinates or 39° north and 86° west

Todd Topcic

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Re: equatorial mounts confusing !
« Reply #9 on: January 04, 2018, 10:36:20 AM »
Quote
"as much as i have tried i i do not understand how a equatorial mount works at all i know how to align with polaris but after that im confused i have a xt8i intelliscope that does the work for me but i want to use my celestron 114 astromaster as a second set of eyes but dont know how to use it properly...i star hop now and dont even use the mount properly because i dont know how"

AND THAT IS EXACTLY WHY I tell new people NEVER EVER buy an EQ mount, get an AltAZ and I speak from experence

I agree with you hundred % but I’m so **** stubborn I want to learn how to use this thing LOL

Daniel Ferguson

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Re: equatorial mounts confusing !
« Reply #10 on: January 04, 2018, 12:14:27 PM »
Quote
Hey Gunny,

I see that you are a member of the Indiana Astro Society.....I would reach out to your local club as much as possible and ask for assistance. There are a few YouTube videos on setting up and using an equatorial mount. Yours is fairly straight forward as there's no goto, or motor, (motor drive is an option), but it should be fairly easy to use.

As for the 8I reflector, worst case is you don't need to use the push to. What is the issue with this scope?

Gary

Push to works great i’m just trying to learn how to use an equatorial mount I have a celestron 114 am also

Rick Reiter

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Re: equatorial mounts confusing !
« Reply #11 on: January 04, 2018, 09:22:17 PM »
An equatorial mount works *exactly* the same way an altaz does. The only difference is that instead of having the horizontal axis pointing straight up, you tilt it, so that it now points towards Polaris and the vertical rotation is now no longer vertical, but aligned with the Earth's axis.Clear skies!
Thomas, Denmark

halespbourvi

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Re: equatorial mounts confusing !
« Reply #12 on: January 08, 2018, 07:26:08 AM »
Here's some useful videos:

https://www.youtube....h?v=TdkB5NCnFps

https://www.youtube....h?v=_TNrPLHB21k

I think because these are similar to the equatorial mount you have that it may help.

Gary

libulbinis

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Re: equatorial mounts confusing !
« Reply #13 on: January 08, 2018, 09:20:54 PM »
Quote
OK say you want to find an object you you’re right assesion is17hr 30 min And your declination is -23.30 The object is the sun and that’s the readings I have current how would I move my telescope and I started having a Polaris centered that’s the kind of questions I have about a equatorial mount my coordinates or 39° north and 86° west


If you want to find the sun, the easiest thing is to forget coordinates and put a solar finder on the scope and simply find it. Even star hopping, you'll always need to find a jumping off point manually.

How do you know you have Polaris centered in daytime?

I find goto scopes, in general, to be poor for finding the Sun because you can't get them aligned well in the daytime.

pesorramidd

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Re: equatorial mounts confusing !
« Reply #14 on: January 09, 2018, 03:30:25 AM »
So, let's take this apart:

<p class="citation">Quote
my coordinates or 39° north and 86° west
[/quote]

You're south of Indianapolis. Your latitude should be the same as the angle to which the mount is tilted. Since you're at 39 degrees in latitude then you can achieve a rough polar alignment by angling your mount at 39 degrees and pointed to true north. Imagine the two extreme cases. If you were at the equator, zero degrees, then Polaris would be straight north on the horizon: zero degrees up in altitude. If you were at the north pole, Polaris would be directly overhead. In other words: 90 degrees above the horizon. Same if you were at 45 degrees. Same as at 39 degrees.

<p class="citation">Quote
say you want to find an object you you’re right assesion is17hr 30 min And your declination is -23.30 The object is the sun
[/quote]
You want to find the sun? Well, this is a bit of an artificial target to find with coordinates. Let's go for something a little more realistic and step through that. Moreover, not all mounts are equipped the same way. Traditionally, a GEM has mechanical setting circles which help you find objects. More modern mounts have a GoTo computer in addition to, or in place of, the mechanical setting circles. Really simple, or cheap, GEMs have neither. Your mount has setting circles, although they may not be precise enough to pick off small and dim objects.

In this case, we'll use those setting circles. Suppose that you want to find the double star Albireo. You looked the star up in an atlas or with a computer and you know that it is located around RA: 19h 31m and DEC: +28 degrees. Because the stars are moving over head, you'll need to calibrate your setting circles to the night sky at your location and time before you can find anything. After all, your equatorial mount doesn't know where it is or what time it is.

Suppose that you can find the star Vega because you recognize it as the north-west star in the summer triangle. So, you point your telescope to Vega and center it in the eyepiece. Because your mount does not automatically track an object, you'll need to work quickly: Since you are using Vega as the calibration star, you'll adjust your setting circles so that they read Vega's coordinates when the telescope is pointed at Vega. By looking Vega up in your atlas, you know that Vega is located about RA: 18h 37m and DEC: 38 degrees and 48 minutes. Many GEMs have a fixed DEC setting circle because that coordinate doesn't change in relationship to the mount's angle. You will, however, have to rotate the RA setting circle until it shows 18h and 37m. In reality, your setting circle won't be this precise - you'll have to approximate it. Make sure that you're reading the north/south scale correctly or it will be backwards.

Now, the telescope should be pointed at Vega and the setting circles should read the coordinates for Vega. At this point, you're ready to find Albireo. Simply rotate the mount in right ascension (should be clockwise facing north) until the RA setting circle reads 19 hours and 31 minutes and then move the mount south in declination until that scale reads about 28 degrees north. Now, if you look at the sky with a wide angle eyepiece, Albireo should be somewhere in the field of view.

Once you find Alberio, you can swap out eyepieces until you have a pretty high-power eyepiece in use. Unfortunately, that high power eyepiece will also give you a narrow field of view and because your mount doesn't track the night sky with a motor, the star will soon drift out of the eyepiece. Fortunately, you have the slow motion knob and cable attached to the right ascension gear and you can keep the star in the field of view by slowly rotating that single knob in your hand while you look through the eyepiece.

This is a classic astronomy skill, but it takes time to develop. A more modern computerized mount performs, essentially, the same task.It sounds more complicated than it is.

You can also use the GEM to hop around the sky while using your atlas or celestial coordinates. For example, if you wanted to move from Vega to Albireo and you're reasonably good at estimating angles then you would swing the mount in right ascension a little more than an hour (about 16 degrees) towards the east and then south about 11 degrees. This process is very similar to "star hopping" with a manual alt-az mount except that the mount is aligned to the celestial coordinate system rather than one based on the horizon.

One of the things that you will need to wrap your head around is celestial coordinates. The declination is simple enough (degrees above and below the celestial equator - a projection of the earth's equator) but, as indicated by the unit, the RA is really time. Specifically, sidereal time, which represents the actual 23 hour 56 minute rotation of the earth. In other words, no matter where you are on the earth, the current sidereal time for your location corresponds to the RA that is directly over head (but not usually the solar time as shown by most clocks). For example, the Andromeda Galaxy will always be directly overhead at 43 minutes after midnight local SIDEREAL time.

If I have failed to confuse you, let me know and I'll try again. On the other hand, don't over think it. It's just a way of moving a telescope back &amp; forth and up &amp; down - but on an angle that matches the motion of objects in the sky for your location instead of the horizon.