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Eyepiece Position 10" Scope GEM Visual

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#1 HotRod217

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Posted 18 April 2021 - 12:48 PM

During research about my next telescope I figured out that a 10" Newtonian Telescope on a GEM mount like the Eq-6/ Atlas moves the eyepiece into unreachable positions. Some people said they had no problems at all trying to reach the eyepiece. I am 6'2" tall but that won't help me either if the eyepiece points towards the ground. Would a Dobsonian be a better choice?


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#2 PNW

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Posted 18 April 2021 - 01:07 PM

I call it Astronomy Yoga. It can be avoided by going full Electronically Assisted Astronomy or Astro Photography.


Edited by PNW, 18 April 2021 - 01:08 PM.


#3 sevenofnine

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Posted 18 April 2021 - 01:11 PM

Definitely a better choice IMO. Large Newtonian's on GEM mounts are pretty much things of the past. John Dobson revolutionized the telescope industry with his inexpensive yet highly functional mount. It's much easier to use a scope when the eyepiece is in the same relative position just a little higher or lower. Most Dob users get an astronomy chair which makes it even easier. Star Bound and Vestil are two common perch style chairs. I highly recommend getting a good astronomy guide book like Terence Dickinson's "NightWatch." He explains all the pros and cons of various pieces of astro gear. Plus the guide has seasonal star charts so it's very handy to have next to your new telescope. Good luck with your choices! waytogo.gif


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#4 havasman

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Posted 18 April 2021 - 01:28 PM

There is a reason Dobsonian mounts completely dominate the market of visual Newtonian telescopes: they're the best choice.


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#5 David I

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Posted 18 April 2021 - 01:28 PM

I am also 6'2" tall, still waiting on my first telescope, a refractor and Orion Atlas II EQ-G, to be in stock.

Although I already bought the Starbound Astronomy Chair and I love it.

https://www.amazon.c...18770017&sr=8-1

 

https://www.amazon.c...e/dp/B009P3WL2I

 

https://www.youtube....h?v=Hkia2WeNk3c

 

Good luck


Edited by David I, 18 April 2021 - 01:31 PM.


#6 aeajr

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Posted 18 April 2021 - 01:30 PM

During research about my next telescope I figured out that a 10" Newtonian Telescope on a GEM mount like the Eq-6/ Atlas moves the eyepiece into unreachable positions. Some people said they had no problems at all trying to reach the eyepiece. I am 6'2" tall but that won't help me either if the eyepiece points towards the ground. Would a Dobsonian be a better choice?

You should be able to rotate the optical tube in the rings to help you position the scope.  

 

Is a Dob better?   It is certainly a lot less expensive.  I love mine.

 

I would ask why you originally wanted to put it on an EQ mount?  

 

What mount are you looking at.  I don't find an Atlas EQ6 mount.   Is this the mount you had in mind?

https://www.highpoin...gMaAl_xEALw_wcB

 

Or this?

https://www.telescop....uts?keyword=eq

 

Or this?

https://www.telescop...s?keyword=Atlas

 

 

Certainly by putting the tube on a tripod you immediately lift it high above the ground to start.

 

If you want a 10" Newtonian on a GoTo mount and are concerned about eyepiece height then get a 10", 12" or 14" GoTo Dobsonian.  Eyepiece height can be reached standing on the ground and no need to rotate the tube.

 

https://www.telescop...s?keyword=XT10G

https://www.telescop...S&keyword=XT12G

https://www.telescop...=US&keyword=XXG


Edited by aeajr, 18 April 2021 - 01:33 PM.

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#7 gene 4181

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Posted 18 April 2021 - 01:46 PM

 I still use my GEM with a newt, eastern half of the sky  and once i pass south, flip it in the rings.  Nice thing is when sketching or doing a lot off  reading / charts, extended study in constellations  having tracking, sharing the view especially with in-experienced people .  Planetary and double stars  having the GEM is "handy" changing powers.  IF your tall you might not like the crouching tiger stance  some of the dobs have with eyepiece heights at 47 inches at zenith or less , now your carrying out a "booster " seat for the dob  smile.gif  , JMO    Everything has its good and bad..    In the winter i don't want to sit  so having the GEM -AltAz on a tripod is nice  not having to sit with  the dob into the ice/snow / slush. Get a dob base made from astrogoods , you'll have the best of both worlds


Edited by gene 4181, 18 April 2021 - 01:48 PM.

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#8 aeajr

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Posted 18 April 2021 - 02:13 PM

Gene is right.  With a Dob you tend to benefit from having an adjustable height chair.  I always use min.

 

However I also use the chair with my other scopes too.  I find sitting is more comfortable than standing and it allows me to be more steady when I am observing.

 

I have tracking on one of the refractors and I do find it convenient.  However my 12" Dob and the 8" before it did not have tracking and tracking manually was easy enough that when I went to the 12 I did not get a GoTo version.    The new refractor I have on order will also be on a manual tracking mount. 



#9 rob1986

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Posted 18 April 2021 - 02:29 PM

During research about my next telescope I figured out that a 10" Newtonian Telescope on a GEM mount like the Eq-6/ Atlas moves the eyepiece into unreachable positions. Some people said they had no problems at all trying to reach the eyepiece. I am 6'2" tall but that won't help me either if the eyepiece points towards the ground. Would a Dobsonian be a better choice?


most of those saying it is manageable use manual eq mounts and/or use rotating rings that can be centered.

Thing is, rotating the newt in the tube often voids goto alignment by cone error, and that alignment is best performed with stars on opposite sides of the sky,

so you can use a big newt gem, but you will be buying into a certain style of astronomy. and be warned, a ten inch starts at 120lbs. most people who use gems today use 8inch, because its just more manageable.

but my advice is get a dob. an 8inch f6 should get you started nicely. (if your a heavy lifter you can consider more, but dont go less than approx f5.)
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#10 EricSi

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Posted 18 April 2021 - 03:24 PM

It depends on how much you care about tracking. Years ago I had a Celestron with an equatorial mount, and I found it to be awkward and unintuitive to move it into position.

 

For the last several years I've had a 10" Dob and now I have a 14" Dob, and I've been much happier with them, and moving the scope as an object drifts out of position isn't a problem for me. Dob mounts are a lot easier to work with and lighter and more portable than an equatorial mount for the same size scope (and a lot less expensive).

 

As noted by earlier posts, an adjustable height chair makes a huge difference....


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#11 Dave Mitsky

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Posted 18 April 2021 - 03:32 PM

I started observing with an equatorial mount and have used them throughout the years but I definitely prefer a Dobsonian mount, especially one with smooth motions.


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#12 desertstars  Happy Birthday!

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Posted 18 April 2021 - 05:42 PM

I've been using an 8" Newtonian on an EQ mount since 2004. (The original mount has since been replaced with a Celestron AVX.) I keep the rings loose enough to allow the tube to rotate, and use a third ring - unconnected to the mount and tight to the tube - to keep the OTA from slipping back through the rings. I've gotten pretty good at looking at the part of the sky I'm headed for next, considering where the focuser will end up from where it will start, and making a proactive turn of the tube. Set up this way, I can't remember the last time the position of the focuser is so inconvenient that I can't get to the eyepiece.


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#13 Deep13

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Posted 18 April 2021 - 06:18 PM

I agree with those who say a Dob is so much better than a big EQ mount.

 

Another observation. I believe a 10" on an EQ6 or Atlas is under-mounted. If you are determined to go EQ, I'd go with an 8".



#14 Dave Mitsky

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Posted 18 April 2021 - 06:22 PM

The Naylor Observatory's 12.5" f/6 Cave Astrola Newtonian definitely requires a ladder in some positions and can also involve a lot of tube rotation at times.

Attached Thumbnails

  • ASH Cave Astrola.jpg


#15 Dave Mitsky

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Posted 18 April 2021 - 06:25 PM

The same applies to a lesser degree to our 10" f/7 Cave Astrola.

 

https://www.astrohbg.org/


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#16 maroubra_boy

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Posted 18 April 2021 - 07:04 PM

A few things about dobs:

 

1, Mass produced units can be difficult to move at high magnification.  They are poorly designed, optimised for packing purposes rather than for use.  As a result they have a lot of backlash especially when the altitude friction mechanism is wound up tight.

 

2, A well designed dob can be magic to use, needing only a finger to move a big scope around and following a target at high magnification very smooth and easy.  No friction mechanism is needed with these scopes to compensate for lack of balance, so the quality of action does not change.

 

But this is what you get when you pay for inexpensive - there are compromises somewhere along the line.

 

3, Tracking is possible with a dob by using an equatorial platform.  There are pros and cons with these, but it does allow for tracking for up to 90 minutes.

 

4, Goto and push-to is also possible with dobs.  Some mass production dobs have after market goto kits available for them (you need to check before you buy your dob to see if there is a kit for it).  And of course you can buy tracking-goto dobs.  There are also after market computerised pointing systems for dob, oft called digital setting circles.  These come with varying degrees of accuracy and catalogue sizes  These are also often push-to not goto, where you are doing the moving of the scope by following a count-down indicator on a screen.  Some of these units can also be connected to your smartphone so you can use an astro app to find stuff in the sky.

 

Newts on a GEM:

a,  Can be used with visual, but can leave the eyepiece in some awkward positions.

 

b,  Current GEMs come with goto, so easy to find things and track.

 

c,  The rotating of a scope in its rings is not a trivial thing.  You can get rings made specifically for this purpose, but normal rings can be problematic and can spoil the pointing accuracy if you are not careful.  But can be very useful for both visual and photo.

 

I have both dobs and GEM mounted Newts.  By far my preference for visual is a dob.  I carefully planned and built my own dobs so using them is a breeze.  I also have a digital setting circles for them to help find really difficult objects, though for me this is a item of last resort lol.gif  .  I also have an equatorial platform, but I've used it maybe three times since I got it 5 years ago...  My GEM mounted Newts I pretty much only use for photo.

 

I also don't mind novices handling my dobs.  People really won't damage my dob and if they grab it too firmly and it does move the object out of the FOV there is no harm done.  Most people also get a buzz out of handling a scope themselves.  Now a motorised scope, this can be more problematic if people grab and lever on it.

 

Pros and cons everywhere, and only you can make the final decision.  Going to an astro club meet can be a very good way of familiarising yourself with each type, dob and GEM, before laying your money down.  The current Covid situation though has put a dampener on this opportunity for most of the world at the moment frown.gif .

 

Alex.


Edited by maroubra_boy, 18 April 2021 - 09:12 PM.

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