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low power eyepiece for an 8inch 1200mm dob

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#1 simoncarlisle

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Posted 02 March 2021 - 06:07 AM

Hi there! 

 

I'm most interested in D.S.O and I realise I don't have the best telescope for deep sky viewing but I am not in the financial position to buy a low focal length telescope. 

 

the lowest useful magnification is 29x and I'm pretty sure a wider FOV is important. Is their anything I'm missing? I don't want to make a poorly informed purchase that I may regret.

 

thank you to you all, this forum has been fantastic for getting me into astronomy, giving me tips and not making stupid purchases.


Edited by simoncarlisle, 02 March 2021 - 06:09 AM.

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#2 vkhastro1

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Posted 02 March 2021 - 06:35 AM

First of all, on behalf of my fellow CN members, welcome to CloudyNights.

 

Your scope has an f/ratio of f/5.9.

Maximum exit pupil for an eyepiece is ~ 7mm - depending on your age.

So your maximum eyepiece focal length would ~ 40mm.

 

You could help us out with more advice by providing a little more info.

Age ?

Location ? City, semi rural or rural - ie Bortle # ?

Budget for buying eyepiece(s) ?

etc



#3 Tropobob

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Posted 02 March 2021 - 06:38 AM

Low powers are good for finding things and for casual observing, but 60x will give a much better view of many deep sky objects. 

 

In reality, a range of powers is needed. For example, most planetary nebulas only reveal themselves at high power.  


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#4 simoncarlisle

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Posted 02 March 2021 - 06:44 AM

First of all, on behalf of my fellow CN members, welcome to CloudyNights.

 

Your scope has an f/ratio of f/5.9.

Maximum exit pupil for an eyepiece is ~ 7mm - depending on your age.

So your maximum eyepiece focal length would ~ 40mm.

 

You could help us out with more advice by providing a little more info.

Age ?

Location ? City, semi rural or rural - ie Bortle # ?

Budget for buying eyepiece(s) ?

etc

Thank you! 

 

I'm 17, Edinburgh in Scotland, Bortle 5

 

My budget is under £130

 

If the absolute maximum focal length is 40mm, is it worth getting a 40mm or would it be a decrease in quality compared to a lower power since it is pushing the lowest useful magnification?



#5 simoncarlisle

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Posted 02 March 2021 - 06:49 AM

Low powers are good for finding things and for casual observing, but 60x will give a much better view of many deep sky objects. 

 

In reality, a range of powers is needed. For example, most planetary nebulas only reveal themselves at high power.  

I  see. From my experience so far, high power tends to make the image far less detailed and blurry. Is that a problem with my eyepieces or is that because of the Bortle 5 light pollution?



#6 Supernova74

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Posted 02 March 2021 - 07:11 AM

Your sky conditions sky bortale 5 are actually not that bad not the best not the worse somewhere in the middle and in clear transparent nights the Milky Way should be visible.yes the 40mm would be your lowest really usefull magnification.and on most occasions would be your most used magnification for deep sky observing,however don,t be frightened to rank up the power a little when seeing conditions allow!?.there is no reason I cannot see with your aperture scope going in between the 

100-150x mark as is needed for smaller deep sky targets ie planetary nebula etc.


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#7 dark_night

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Posted 02 March 2021 - 07:11 AM

i am sure others will have much more insights into the eyepieces . but wanted to point out that low power eyepieces might not be the right tool to observe DSO but only to locate them. I personally don't observe through them for long. Use them to locate an object and then shift to something in the 10-20 mm range in my 8" F 5.9 dob. 

Having said that  they are the only option for large objects like Pleiades or Beehive cluster.

 

As for the suggestion for an eyepiece - Skywatcher Panaview SWA 32 or 38 mm and Skywatcher Aero 35 or 40 mm have in general got good reviews. They should be within your budget and many vendors offer similar product under slightly different names.


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#8 Linked-In-The-Stars

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Posted 02 March 2021 - 08:28 AM

Just wanted to chime in quick, I'm very new to actually observing with my first telescope myself. But I will say I'm in bortle class 4, and I can see the pleaides very very well, orion nebulae very well even under a full moon, and a few others along with clusters etc. I've been starting my search for dso's and it takes a little work, I have been using my 2" 40mm, and 2" 33mm by Williams Optics. They have a great field of view for observing and pick these objects up with no problem whatsoever and, with great clarity. I'd imagine you could do the same with an 8" as mine is a 10" so I would definitely think it would be no problem for you as well. These eyepieces are also under your budget, just wanted to throw that out there.! CS!



#9 simoncarlisle

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Posted 02 March 2021 - 08:35 AM

Your sky conditions sky bortale 5 are actually not that bad not the best not the worse somewhere in the middle and in clear transparent nights the Milky Way should be visible.yes the 40mm would be your lowest really usefull magnification.and on most occasions would be your most used magnification for deep sky observing,however don,t be frightened to rank up the power a little when seeing conditions allow!?.there is no reason I cannot see with your aperture scope going in between the 

100-150x mark as is needed for smaller deep sky targets ie planetary nebula etc.

I have an eyepiece that is 42x and another which is 60x. the 60x was a cheep eyepiece that came with my very first 70mm travelscope back in 2017. the 42x however came with my xt8 plus and seems to be a fairly highly rated eyepiece that can be bought separately.

 

would it be better to get an even lower power eyepiece than my current 42x or to get a higher quality higher power eyepiece?



#10 geovermont

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Posted 02 March 2021 - 08:49 AM

Welcome to CloudyNights. I think that you would find a 40 mm Plossl eyepiece very helpful for finding objects and for the wide view. Another very useful and commonly available alternative is a 32 mm Plossl.



#11 Pokemoncrusher1

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Posted 02 March 2021 - 09:21 AM

I have an eyepiece that is 42x and another which is 60x. the 60x was a cheep eyepiece that came with my very first 70mm travelscope back in 2017. the 42x however came with my xt8 plus and seems to be a fairly highly rated eyepiece that can be bought separately.

 

would it be better to get an even lower power eyepiece than my current 42x or to get a higher quality higher power eyepiece?

Idk the fov you have but the gso superview 2” is a 60 dollar decent option at 68 degree fov, other than that agena SWA for 100 at 70 degree, fov. What low power do you have now?



#12 Supernova74

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Posted 02 March 2021 - 09:58 AM

I have an eyepiece that is 42x and another which is 60x. the 60x was a cheep eyepiece that came with my very first 70mm travelscope back in 2017. the 42x however came with my xt8 plus and seems to be a fairly highly rated eyepiece that can be bought separately.

 

would it be better to get an even lower power eyepiece than my current 42x or to get a higher quality higher power eyepiece?

The powers you already own of 42x,60x is marginal even for deep sky observing yes by all means it’s worth upgrading to higher quality eyepieces it all depends in how much you like spend!? An very happy medium in my opinion is around the $100 dollar mark and the general rule I go by is try to go for increments of magnification exsample 50x,100,150,200 you get the drift this gives you steady magnification range.for exsample the baader Hyperion range of eyepieces are very good value for money and you can even change the focal lengths across the entire range with optional spacer rings that can be puchased separately.this makes this very ideal for your observing style exsample one evening you may just want to observe the moon and planets and perhaps on the other deep sky objects.


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#13 simoncarlisle

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Posted 02 March 2021 - 10:13 AM

Idk the fov you have but the gso superview 2” is a 60 dollar decent option at 68 degree fov, other than that agena SWA for 100 at 70 degree, fov. What low power do you have now?

the 42x is the lowest power I have and it's 54 degree fov. 



#14 simoncarlisle

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Posted 02 March 2021 - 10:25 AM

The powers you already own of 42x,60x is marginal even for deep sky observing yes by all means it’s worth upgrading to higher quality eyepieces it all depends in how much you like spend!? An very happy medium in my opinion is around the $100 dollar mark and the general rule I go by is try to go for increments of magnification exsample 50x,100,150,200 you get the drift this gives you steady magnification range.for exsample the baader Hyperion range of eyepieces are very good value for money and you can even change the focal lengths across the entire range with optional spacer rings that can be puchased separately.this makes this very ideal for your observing style exsample one evening you may just want to observe the moon and planets and perhaps on the other deep sky objects.

Wow I didn't know deep sky required high power eyepieces, I do have a 10mm which gives me 120x but in all honesty it's utterly terrible and I can't find it anywhere on the internet. Those Baader Hyperion eyepieces are in my price bracket thank you! In Bortle 5 light pollution with 100x magnification with the quality of eyepiece you mentioned, what kind of detail would be expected on objects such as the Dumbell nebula and Ring nebula?


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#15 pregulla

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Posted 02 March 2021 - 10:30 AM

Imo Aero ED 35mm at FLO for 99GBP is a very good deat atm.

https://www.firstlig...-eyepieces.html

It is pretty closer to maximum FoV (44.5mm fiedl stop out maximum possible 46mm). It is better corrected than PanaView, and being nearly same price at the moment is a better buy IMO. 


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#16 Starman1

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Posted 02 March 2021 - 11:52 AM

Hi there! 

 

I'm most interested in D.S.O and I realise I don't have the best telescope for deep sky viewing but I am not in the financial position to buy a low focal length telescope. 

 

the lowest useful magnification is 29x and I'm pretty sure a wider FOV is important. Is their anything I'm missing? I don't want to make a poorly informed purchase that I may regret.

 

thank you to you all, this forum has been fantastic for getting me into astronomy, giving me tips and not making stupid purchases.

Very few DSOs look better below about 50x magnification.

So a 24mm would make an excellent lowest power, preferably something in the range of 82°.

That might be out of your budget, though.

100x will be used a LOT more, so concentrate on a good 12-13mm eyepiece.


Edited by Starman1, 02 March 2021 - 11:52 AM.

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#17 Linked-In-The-Stars

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Posted 02 March 2021 - 12:01 PM

Williams also makes a nice 1.25" EP in 20mm, and down to 9mm, 5 elements, 72 deg. fov's, and very fair eye relief. Each is only $87 as well, very reasonable. 

 

https://www.highpoin...yepiece-e-swa20



#18 simoncarlisle

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Posted 02 March 2021 - 12:22 PM

Very few DSOs look better below about 50x magnification.

So a 24mm would make an excellent lowest power, preferably something in the range of 82°.

That might be out of your budget, though.

100x will be used a LOT more, so concentrate on a good 12-13mm eyepiece.

I think an £100 eyepiece 13mm would be ideal. I don't think I've had a good enough high power eyepiece to be able to reap the true benefits of D.S.O at high magnification as they have always seemed incredibly blurry and undetailed. I was thinking of getting a Baader Hyperion 13mm that was recommended by one of the replies. Would you have any other suggestions around that price range? Thanks for your help.


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#19 dark_night

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Posted 02 March 2021 - 12:41 PM

I have not used Hyperion but have the OVL Nirvana 16mm. It's good, not the most convenient (I found that eye positioning took me some time to get used to), but optically it's great. Very sharp and high contrast views.

You can also consider baader classic ortho 18mm. Only tradeoff against Nirvana 16mm is that it's has much smaller fov 52 deg against Nirvana's 82 degree.

Edited by dark_night, 02 March 2021 - 01:09 PM.


#20 JamesDuffey

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Posted 02 March 2021 - 01:11 PM

I think an £100 eyepiece 13mm would be ideal. I don't think I've had a good enough high power eyepiece to be able to reap the true benefits of D.S.O at high magnification as they have always seemed incredibly blurry and undetailed. I was thinking of getting a Baader Hyperion 13mm that was recommended by one of the replies. Would you have any other suggestions around that price range? Thanks for your help.

This is a good eyepiece, won’t break the bank, and is available in the UK. 

https://www.firstlig...d-eyepiece.html >


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#21 SeattleScott

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Posted 02 March 2021 - 01:25 PM

Honestly if you find higher powers blurry or terrible, a $600 high power eyepiece won’t do you any good. What you really need is a collimation tool. It’s like you are driving around in a BMW with a flat tire, complaining that it is pulling to the right and the ride is really rough, and asking if upgrading the shock absorbers will fix it. The real problem is you need to fix the flat tire. Until you do that, the ride will be rough no matter what shocks you put on it.

With Bortle 5 skies and F6, I would stick to about 35mm or less for a low power eyepiece. The cheap ones will show a good deal of edge distortion.

Scott

Edited by SeattleScott, 02 March 2021 - 01:33 PM.

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#22 CowTipton

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Posted 02 March 2021 - 01:31 PM

I have basically the same telescope as you do and live in suburban Chicago.  My skies are brighter (worse) than yours, about Bortle 7-8.

 

30mm 70° (40x)

or 24mm 82° (50x)

 

I think either of those will give you great views of DSOs.

The 30mm should give you a slightly wider TFOV  (around 1.7°)

The 24mm should give you higher power and more contrast but a little less fov (around 1.6°)

Most DSOs should fit into either and look great.

 

I use a 30mm 70° eyepiece for now.  It's great for finding the objects and viewing them once they're acquired ( I don't have goto or pushto yet.)

And if I want higher power I swap in a zoom eyepiece or an 11mm eyepiece for closer looks.

Still 75% of my viewing time is with the 30mm.

 

The GSO 30mm 68° is very good for the price.

The Baader 31mm 72° is excellent.

They should both be in your budget.

 

I don't know of any 24mm 82° EPs in your price range unfortunately.  Someone else may have a better idea on those.


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#23 sevenofnine

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Posted 02 March 2021 - 10:38 PM

I have basically the same scope...the Orion XT-8 Plus. This 2 eyepiece combo works really well for me. They are not in your budget now but might be worth considering saving for or buying used. The Explore Scientific 2 inch ES 28/68 is my finder eyepiece and the Baader Mark lV 8-24 zoom with it's dedicated 2.25x barlow are all I use now. These 2 eyepieces give very sharp and clear views of any object. They also cover virtually all focal lengths from 28mm-4mm. That a lot of eyepieces! Good luck with your choices! hmm.gif



#24 aeajr

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Posted 02 March 2021 - 11:32 PM

Hi there! 

 

I'm most interested in D.S.O and I realize I don't have the best telescope for deep sky viewing but I am not in the financial position to buy a low focal length telescope. 

 

the lowest useful magnification is 29x and I'm pretty sure a wider FOV is important. Is their anything I'm missing? I don't want to make a poorly informed purchase that I may regret.

 

thank you to you all, this forum has been fantastic for getting me into astronomy, giving me tips and not making stupid purchases.

An 8" Dob is an excellent scope for deep sky viewing!

 

Understanding Telescope Eyepieces
https://opticsaide.c...-for-telescope/

 

 

Thank you! 

 

I'm 17, Edinburgh in Scotland, Bortle 5

 

My budget is under £130

 

If the absolute maximum focal length is 40mm, is it worth getting a 40mm or would it be a decrease in quality compared to a lower power since it is pushing the lowest useful magnification?

For each of my scopes I have an eyepiece that provides the widest view I can get with that scope.  As you will see when you read the article I posted above, that is based on the AFOV, apparent field of view of that eyepiece.   So low power alone is not enough.  You want a low power eyepiece that has a wide AFOV. 

 

For my XT8, 1200 mm, F5.0 8" Dob I used a 2" 38 mm eyepiece with an AFOV of 70 degrees which provided about a 2.2 degree true field of view. That is about as wide as you can go in this scope.

 

Agena Astron Super Wide 38 mm 70 degree

https://agenaastro.c...epiece-set.html

 

The Orion Q70 38 mm is the same eyepiece

https://www.telescop...uts?keyword=Q70

 

 

 

I  see. From my experience so far, high power tends to make the image far less detailed and blurry. Is that a problem with my eyepieces or is that because of the Bortle 5 light pollution?

We add magnification until the image degrades.  How much we can add depends on the atmospheric conditions and our equipment.   My XT8 often topped out at 180X.  I could go higher but the image would degrade so there was no point.  But on a perfect night I could take it up to 300X with excellent results.

 

Transparency and Seeing are the key factors here.

 

What is SEEING and why it can be bad.  How it will limit how high you can go.

This is not a problem with your telescope or your eyepiece.

http://www.skyandtel...ing-the-seeing/
http://www.damianpeach.com/seeing1.htm
http://www.damianpea...m/pickering.htm

 

 

I have an eyepiece that is 42x and another which is 60x. the 60x was a cheep eyepiece that came with my very first 70mm travelscope back in 2017. the 42x however came with my xt8 plus and seems to be a fairly highly rated eyepiece that can be bought separately.

 

would it be better to get an even lower power eyepiece than my current 42x or to get a higher quality higher power eyepiece?

There are dozens of eyepieces that could produce 42X in your scope.  Any 28 mm eyepiece will provide that magnification.

 

A 28 mm Plossl, 52 degree AFOV, would be 42X but provide 1.2 degree field of view.   

 

A 28 mm 82 degree AFOV eyepiece would also be 42X but would provide a 1.9 degree field of view.

 

Same magnification but a MUCH larger field of view with the second one. 

(see the article on understanding eyepieces)

 

the 42x is the lowest power I have and it's 54 degree fov. 

That is not a wide view eyepiece.  A 2" eyepiece of 65 to 82 degrees would be wide. 

 

I think an £100 eyepiece 13mm would be ideal. I don't think I've had a good enough high power eyepiece to be able to reap the true benefits of D.S.O at high magnification as they have always seemed incredibly blurry and undetailed. I was thinking of getting a Baader Hyperion 13mm that was recommended by one of the replies. Would you have any other suggestions around that price range? Thanks for your help.

13 mm in that scope would be 92X.  That would be low medium range eyepiece.  I used eyepieces from 38 mm to 5.5 mm in my 8" Dob.  My 8.8/82 degree, 136X and 6.7/82 degree, 179X were used much more than my 14 mm / 82 degree.

 

Actually my most used eyepiece is an 8-24 mm Zoom eyepiece.

 

In your price range, that would probably be a Celestron zoom.  I have one and it works well in that Dob.

 

I also have the Baader Hyperion 8-24 zoom which is a better eyepiece and my most used eyepiece, but it is 3X the price. 

 

Lower cost zoom – Celestron 8-24 – This was my first zoom.  Works well at the price and a good way to test your interest in zooms. $85
Higher priced Zoom – Baader Hyperion 8-24 mm – My main eyepiece in the XT8i – $290  There are other choices.
https://agenaastro.c...lanetarium.html


Edited by aeajr, 02 March 2021 - 11:40 PM.

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#25 SeattleScott

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Posted 03 March 2021 - 12:04 AM

Ed, great information, but you are talking about high power as 180x. The OP says 120x is blurry and utterly terrible. I know Plossls aren’t the best but my gosh they shouldn’t be blurry and utterly terrible. Obviously he needs to collimate his mirrors. Until he does that it won’t matter what eyepieces he gets. If he collimates his scope, he might even decide his 10mm eyepiece is pretty good. Probably not, but you never know.

Scott
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