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Eyepeices for Orion XT8 Plus DOB

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#1 ShaneinSpace

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Posted 26 June 2019 - 08:22 PM

I just recently purchased a Orion XT8 Plus Telescope after it came highly recommend on here from others. I am looking to invest in Eyepeices for this scope. I am new to Astronomy and it's a little overwhelming trying to choose the right one. Here's what I am looking to do...

*View the Planets. Distant and near
*I like details vs wide range of view
*But also don't want magnification being too high where I must constant readjust the scope.
*a happy median for details and view with crisp images

My XT8 Plus accepts both 2" and 1.25" eyepeices. Should I purchase a high quality 2" for wider feid of view and use the 1.25 for details. Or if I get a 5mm 2" eye peice that will be the best of both worlds? Thanks.

#2 Jond105

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Posted 26 June 2019 - 08:32 PM

A 2” 5mm won’t be the best for both worlds. And only a few makers have the double housing for both 1.25” and 2” eyepieces. You can easily get a 5mm in an 1.25” format still having up to 100 FOV. I think you’ll want a couple high power and low power eyepieces with a respectable FOV for the dob.
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#3 vdog

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Posted 26 June 2019 - 08:55 PM

So, if I understand you correctly, it sounds like you are asking for recommendations for a planetary eyepiece in the 5mm range?  A budget would be helpful; there are many choices ranging from dirt cheap to more than your scope cost.

 

I have experience with these EPs and can recommend them for planets. They are in the 100-150.00 range and have an 82 degree field, which is useful for viewing planets with a manual dob at these magnifications:

 

Meade 5.5mm

Explore Scientific 4.7mm


Edited by vdog, 26 June 2019 - 08:56 PM.


#4 ShaneinSpace

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Posted 26 June 2019 - 09:28 PM

I'd be willing to spend upward of $150 for an eye peice. Yes I would like a recommendation on Name and model of the product. I like the details I get with a 10mm plossl and a 2x Barlow lense of Saturn and Jupiter. Too me it seems so concentrated on the object that I must constantly readjust the Telescope. Where my 2" 28mm plossl I can stay focused much longer. I want the best of both worlds. If that means that I must spend $150 on a single lenses so be it. Or if I should purchase 2 mid range price point lenses to switch out instead.

#5 N3p

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Posted 26 June 2019 - 09:58 PM

Getting the whole range of eyepiece over time. The lowest eyepiece could have an exit pupil of 6~7mm maximum and the the highest eyepiece 1mm exit pupil minimum. I would skip the 4mm, or shorter and buy later if required.

 

For the planets and the moon I think it's nice to have a tight sequence like 9, 8, 7, 6, 5 mm, I have 9, 7, 6, 5, 4.7 and use them all.

 

Also, it's nice to have one low power eyepiece in the 1.25" and one even lower in the 2" to be able to use a 2" nebula filter with the largest exit pupil possible. Then, of course, a couple of eyepieces are required in the midrange too.

 

At then end you could have 8, 9, 10 eyepieces?

 

My situation stabilized at 9 eyepieces, I don't feel more is required now.


Edited by N3p, 26 June 2019 - 09:59 PM.


#6 SeattleScott

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Posted 26 June 2019 - 10:46 PM

Yes, you can have the best of both worlds, to an extent.

What you are seeing is the high magnification of the barlowed 10mm is making the field of view (FOV) small, requiring a lot of manual tracking. Well, the Meade and ES eyepieces suggested have over 60% wider viewing angle, meaning you will have a wider FOV and targets will not drift out as fast. The Meade is a bit cheaper and a bit less aggressive/lower magnification, so Targets will stay in view longer than with the ES. The ES provides a bit more magnification. My guess is the Meade would probably be a better fit as you are more focused on minimizing manual tracking than maximizing magnification.

There are a variety of 2” eyepieces to choose from also, to get a wider FOV at low power. Do you normally observe under light pollution or dark skies?

Scott

#7 ShaneinSpace

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Posted 26 June 2019 - 11:34 PM

I am in an extremely light polluted area. I mostly observer in my neighborhood cause dragging my kids out to go to a park miles away at 10-11pm won't work. I do go to less light polluted areas alone but not frequently. What I really need seems like a larger FOV eyepeice so I don't have to adjust so frequently and manual track the object. If I were to get a 5mm EP which equals the magnification I currently use, 10mm with 2x Barlow, and gives me the details I am satisfied with. Having that wider FOV eyepeice should help reduce manual tracking?

#8 ShaneinSpace

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Posted 26 June 2019 - 11:43 PM

Now the question what brand? Haha. I've read about Televue and Explorer Scientific being great but they are pricey. Seems like ES EP are what I am looking for on my quest lol. They have the magnification and an 82° FOV that sounds perfect. Maybe I can find them used but they seem to hold they're value well according to eBay. What is the standard FOV for a standard plossl eye peice that comes with a Telescope so I have a comparison to others? Thanks for the info I am definitely learning more about the eye peices

#9 Jond105

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Posted 26 June 2019 - 11:51 PM

Now the question what brand? Haha. I've read about Televue and Explorer Scientific being great but they are pricey. Seems like ES EP are what I am looking for on my quest lol. They have the magnification and an 82° FOV that sounds perfect. Maybe I can find them used but they seem to hold they're value well according to eBay. What is the standard FOV for a standard plossl eye peice that comes with a Telescope so I have a comparison to others? Thanks for the info I am definitely learning more about the eye peices

The ES do hold some value, but the classifieds here, people pretty much price them accordingly, between 100-130. The Meade UWA’s aren’t as pricy and just as well made. Just bulkier housing. 

 

Standard plossl FOV is 52 degrees 



#10 Starman1

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Posted 27 June 2019 - 10:21 AM

I just recently purchased a Orion XT8 Plus Telescope after it came highly recommend on here from others. I am looking to invest in Eyepeices for this scope. I am new to Astronomy and it's a little overwhelming trying to choose the right one. Here's what I am looking to do...

*View the Planets. Distant and near
*I like details vs wide range of view
*But also don't want magnification being too high where I must constant readjust the scope.
*a happy median for details and view with crisp images

My XT8 Plus accepts both 2" and 1.25" eyepeices. Should I purchase a high quality 2" for wider feid of view and use the 1.25 for details. Or if I get a 5mm 2" eye peice that will be the best of both worlds? Thanks.

I won't recommend brands, but I will recommend some eyepiece focal lengths and explain why.

First, you want a low power with a wide field for large objects like star clusters and some nebulae.

I think a 24-25mm with a wide angle, in 2" should do just fine. Around 50x.

Second, a general use eyepiece you'll use a LOT on most deep sky objects.

It will be a 1.25".  I recommend a wide field 12-13mm.  Around100x

Third, an eyepiece with a high enough power for small objects, yet not so high that seeing will make the image blurry a lot.

It will be 1.25".  I recommend an 8-9mm, preferably wide angle.  Around 150x.

 

You can go higher, and you may want to do so on nights that are very stable, where high powers don't cause blurring of the objects.

For that, I recommend a good 2X Barlow, yielding 200x with the 100x eyepiece and 300x with the 150x eyepiece.

 

So, an economical set of 3 with a 2X 1.25" barlow.

 

Good 50° field eyepieces can be had for <$50

Good 60° eyepieces for $60-$70 each

Good 68-70° eyepieces for $90-160 each

Good 80° eyepieces for just a little more.

 

You'll spend the most time with your two lowest power eyepieces, but you'll spend time with the 3rd eyepiece and Barlow a lot on the planets, Moon, and double stars.


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#11 ShaneinSpace

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Posted 27 June 2019 - 10:41 AM

I have another question related to EP I think. When veiwing Saturn and Jupiter with a 10mm EP and 2x Barlow the image becomes clear then distorted. Almost like a gassy haze blurred the image but then becomes clear again. What is that called? Is it do to high magnification? Am I seeing heat rising off the blacktop where my Telescope sits near? Or all the above? It happened with my Celestron 100mm Inspire and my new Orion XT8 Plus. 2 different Scopes with same issue

#12 astrophile

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Posted 27 June 2019 - 10:55 AM

That’s atmospheric seeing but probably strongly exacerbated by heat off the asphalt around you, as you suggest.  Try to set scope on grass or slightly helpful on a large carpet.

 

If you need your eps to hold value, buy them used.


Edited by astrophile, 27 June 2019 - 11:06 AM.


#13 Starman1

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Posted 27 June 2019 - 11:26 AM

I have another question related to EP I think. When veiwing Saturn and Jupiter with a 10mm EP and 2x Barlow the image becomes clear then distorted. Almost like a gassy haze blurred the image but then becomes clear again. What is that called? Is it due to high magnification? Am I seeing heat rising off the blacktop where my Telescope sits near? Or all the above? It happened with my Celestron 100mm Inspire and my new Orion XT8 Plus. 2 different Scopes with same issue

When you magnify, you magnify everything--the object, the atmospheric turbulence, the heat in the scope, the smog and dust in the atmosphere, and the light scatter caused by the atmosphere.

It won't take long observing the moon to notice what looks almost like water waves passing over the moon.  This is variable densities in the atmosphere, causing refraction, passing in front of the Moon.

Here are some ways to mitigate "local" seeing problems:

--place the scope on grass or dirt instead of asphalt, or put down a piece of carpet to insulate the scope from the pavement.

or observe later, when the asphalt has lost some of its heat.

--never use high powers in a scope until the scope has sat outside for a couple hours. Heat in the glass of the optics will slowly be released, and until the glass has cooled to the air temperature,

the warmth will have an effect on the image quality.

--never look at high power directly over a roof.  Roofs give off the heat of the day most of the night and cause turbulence in the air.

--never try to use high powers on a planet or Moon when it is lower than 30° from the horizon.  The air at 30° is exactly twice as thick as the air at the zenith, so you are looking through more water vapor, smog, dust, and air movement than you are when it's higher in the sky.  Every object will be at its best,approximately, when it crosses the N-S meridian in the sky.

 

You can evaluate the Seeing conditions (turbulence) by looking at the bright stars.  If they are steady, the air is moving less than if they are twinkling.  You will notice that stars at the zenith are steadier, with less twinkling, than stars near the horizon.  On the best nights, all the stars seem steady with no twinkling.  On the worst nights, they twinkle like crazy all the way to the zenith.

 

Seeing conditions are usually best when the heat of the day has stopped causing the air to move.  At most sites, this is from midnight till dawn, though some sites have a quiet period shortly after sunset.due to environmental factors.

Here is a series of 3 articles written by a weatherman/astronomer to help you figure out when seeing will be good and high powers can be used:

http://www.cloudynig...observing-r1396

http://www.cloudynig...udy-night-r1413
http://www.cloudynig...observing-r1436


Edited by Starman1, 27 June 2019 - 11:28 AM.


#14 SeattleScott

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Posted 27 June 2019 - 03:11 PM

The Meade or ES will work nicely in your scope. Optically they are the same. There are cheaper options but the performance is not as good. Meade has a 5.5mm or ES has a 4.7mm. You can even go wider at 100 degrees instead of 82 but the price roughly doubles.

Scott


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