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Yet another 'please vindicate my choice of eyepiece' thread


Jimtheslim
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Just want to chime in on the praise for the Vixen SLV series. I only have the 20mm, but the eyepiece is very well built and a pleasure to use with the good eye relief and the rotate-to-extends eye cups. They are made with a high friction, rubber-like material, so you won't drop them by accident.  I also have  NLVs for higher magnifications. Good performers, but no the same "feel good" build quality about them.

Edited by glennbech
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In my area, I can rarely get above 120x, 100x most typical on Jupiter.

I am using f/12 achro's and even those clearly distinguish cheaper from better ep's. I had ES82's and Hyperions in the past, but have now settled on TV Delite. I also have a 10" f/5 Dob, and I regret that I didn't get the 8" f/6 which is more forgiving. I would definitely go for this over the faster dob's. But generally, my 4" f/12 achro just seems better to cut through lousy seeing and gives overall more enjoyable views.

Secondly, save up to get better EP's and/or buy second hand.

BR

Anders

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Also... After viewing Jupiter almost every session for the last two months; as a novice, the eyepiece doesn't make a difference. The seeing will always be the limiting factor. I doubt that the the views will be dramatically better in super expensive EPS, even on the rare, very good slseeing nights. At least compared to 'okey' EPS. 

My limited experience so far is that is impossible to throw money at Jupiter. Patience works :) my best views so far of the red planet is with a Polarex 60mm vintage refractor and the stock (Polarex 7mm) EP. 

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1 hour ago, glennbech said:

Also... After viewing Jupiter almost every session for the last two months; as a novice, the eyepiece doesn't make a difference. The seeing will always be the limiting factor. I doubt that the the views will be dramatically better in super expensive EPS, even on the rare, very good slseeing nights. At least compared to 'okey' EPS. 

My limited experience so far is that is impossible to throw money at Jupiter. Patience works :) my best views so far of the red planet is with a Polarex 60mm vintage refractor and the stock (Polarex 7mm) EP. 

It was that sort of experience that led me to start this thread:

Seeing conditions are really, really important in this game. Perhaps more than any other single factor ?

Suiter's "wobbly stack" of observing factors is worth considering:

1)     Seeing (not transparency, but the level of atmospheric disturbance which distorts the image moment to moment).

 

2)      Quality of the primary optics.

 

3)      Central obstruction size.

 

4)      Alignment of the optics.

 

5)      The diagonal being used.

 

6)      The ability of the focuser to deliver critical fine focus.

 

7)      The eyepiece.

 

8)      The skill and fatigue level of the observer and their eyes.

 

Perhaps we need more threads on interpreting and reacting to the seeing conditions than on eyepiece choices ? :rolleyes2:

 

 

Edited by John
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I agree with you that seeing is maybe 60-90% responsible of what we see.

What the more expensive Eyepieces seem to offer is Eye Relief in combination with decent AOV. I loved the ES82´s for the sharpness and contrast, but ER was simply not good for me as I need to wear glasses.

The Hyp´s were good in the center, but had more comet-like stars in the edge that I liked, even in my slow fracs´s.

The TV Delite are a delight for me to use; Sharp, contrasty to the edge and very, very comfortable to use with almost no Black outs. I.e. less fatigue than with other eyepieces I have used thus far.

 

BR,

Anders 

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5 hours ago, Anderscn said:

In my area, I can rarely get above 120x, 100x most typical on Jupiter.

I am using f/12 achro's and even those clearly distinguish cheaper from better ep's. I had ES82's and Hyperions in the past, but have now settled on TV Delite. I also have a 10" f/5 Dob, and I regret that I didn't get the 8" f/6 which is more forgiving. I would definitely go for this over the faster dob's. But generally, my 4" f/12 achro just seems better to cut through lousy seeing and gives overall more enjoyable views.

Secondly, save up to get better EP's and/or buy second hand.

BR

Anders

I was fearing that someone might say this. Just as I had my mind set on the 10" f/4.7, knowing it would be less forgiving, I had always wondered if it was worth it over the 8", so hearing that someone regretted not buying smaller it a bit unsettling

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If your primary interest is deep sky observing then the 10" makes all the sense in the world over an 8". If you want to study solar system targets primarily then the 8" F/6, maybe, makes a better case for itself ?

 

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2 hours ago, Jimtheslim said:

I was fearing that someone might say this. Just as I had my mind set on the 10" f/4.7, knowing it would be less forgiving, I had always wondered if it was worth it over the 8", so hearing that someone regretted not buying smaller it a bit unsettling

Well if it helps you I regret not buying bigger, I got an 18 inch and could have easily afforded the 20 inch mirror and scope build but wrongly though it may be a bit on the heavy side. Granted I am in a different country but seeing is rarely so bad that that I can't use the Dobsonian over my other scopes, buy you 10 inch you will love it t bits! You can always make a mask to stop bigger scopes down to say in my case a 7.6 inch without obsruction in the path.

Sound advice from John above too!

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On 3/24/2016 at 06:53, Jimtheslim said:

Watching the GRS transit last night, some fleeting decent conditions meant that for the first time I could definitely pick it out with my 6.4mm (154x mag), however the image was far from sharp. The view through my 12.4mm was, however the GRS was just about impossible to make out, ergo I was looking to buy a decent plossl that would sit in the middle of these.

I was thinking something around 8mm. I currently have a 90mm f/10 frac, but looking to buy a 10" dob in the near future. I know these bigger, faster scopes are less forgiving on eyepieces so you have to pick them well. So far I have looked at and considered an 8mm vixen or possibly a Baader Hyperion 8mm or possibly a Celestron E-xcel LX. Anyone else want to chuck some suggestions in? [insert standard response about used televues here]. Budget wise it depends on my capricious mood swings, but looking to go second hand if I can.

Talk to me people.

Hi Jim,

Your diagonal may be the problem if its a run of the mill mirror. Your scope is probably working at optimum at around 158x, so I'd be inclined to try someone else's eyepieces before buying a new eyepiece. Diagonals are often the weakest link in the optical train leading to mediocre images. Buying a good diagonal is an investment that can remain with you even if you change your scope in the future. Televue's 1.25" dielectric or Takahashi's 1.25" prism diagonals won't cost the earth but will almost certainly enhance the view through any eyepiece.

Mike

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3 hours ago, mikeDnight said:

Hi Jim,

Your diagonal may be the problem if its a run of the mill mirror. Your scope is probably working at optimum at around 158x, so I'd be inclined to try someone else's eyepieces before buying a new eyepiece. Diagonals are often the weakest link in the optical train leading to mediocre images. Buying a good diagonal is an investment that can remain with you even if you change your scope in the future. Televue's 1.25" dielectric or Takahashi's 1.25" prism diagonals won't cost the earth but will almost certainly enhance the view through any eyepiece.

Mike

I have already upgraded to a 99% dialetric which made a lot of difference which I noticed straight away when viewing Venus which for the first time appeared as a Gibbous disc, rather than just a bright light, fairly sure it's not the diagonal. I think I am just being too greedy and trying to see things bigger (aperture fever). My Meade plossls are all used and a closer look at the 12.4 shows a few marks on the coatings, maybe that's causing a bit of the light to bounce around. 

8 hours ago, John said:

If your primary interest is deep sky observing then the 10" makes all the sense in the world over an 8". If you want to study solar system targets primarily then the 8" F/6, maybe, makes a better case for itself ?

 

I think I would like both. My garden doesn't suffer from a lot of LP, but I am right on the edge of rural Northumberland so dark sky is just a short drive away. I would love to continue viewing planets, especially during twilight and if the moon is bright when DSO's would be a struggle, but I also want to start looking for DSO's properly, with a scope that's going to give me a good chance and not one that zig-zags around on an eq mount and that I can look at the sky directly above.

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6 hours ago, alan potts said:

Well if it helps you I regret not buying bigger, I got an 18 inch and could have easily afforded the 20 inch mirror and scope build but wrongly though it may be a bit on the heavy side. Granted I am in a different country but seeing is rarely so bad that that I can't use the Dobsonian over my other scopes, buy you 10 inch you will love it t bits! You can always make a mask to stop bigger scopes down to say in my case a 7.6 inch without obsruction in the path.

Sound advice from John above too!

when I try the field of view calculator here http://www.12dstring.me.uk/fovcalc.php there is no difference on solar system targets between the 8" and 10". Would there be little or no difference as suggested?

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1 hour ago, Jimtheslim said:

when I try the field of view calculator here http://www.12dstring.me.uk/fovcalc.php there is no difference on solar system targets between the 8" and 10". Would there be little or no difference as suggested?

It's not a very accurate simulator in terms of what you actually see. It simulates the width of the field of view and the apparent size of the object within it but the levels of detail, contrast, resoloution that you will see are dependant on many issues other than the scope so no simulator can copy that.

 

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43 minutes ago, John said:

It's not a very accurate simulator in terms of what you actually see. It simulates the width of the field of view and the apparent size of the object within it but the levels of detail, contrast, resoloution that you will see are dependant on many issues other than the scope so no simulator can copy that.

 

so if the apparent sizes of the object are the same in the 10" and 8" on this simulator, is that what you would expect in real life?

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12 minutes ago, Jimtheslim said:

so if the apparent sizes of the object are the same in the 10" and 8" on this simulator, is that what you would expect in real life?

Well the scopes are the same focal length (assuming we are talking about the Skywatcher dobsonians) so the apparent size of an object in a given eyepiece will be the same. In principle the 10" scope should show more contrast and resolve more detail. That will almost certainly be the case with deep sky objects but on the moon and planets a whole bunch of other factors come into play which determine the amount of detail you can see - you can't simulate this and it will vary from session to session, hour to hour and sometimes minute to minute.

 

Edited by John
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Quote

I think I am just being too greedy and trying to see things bigger (aperture fever). 

Beware that this is a bit like upgrading your TV to a 50" from a 24" without switching from the antenna on the roof to HD cable. You will get a 50" image on your TV, but it will be magnified noise.

If I am going to throw a lot of money at Eyepieces, it will be large FOV ones. I have a "cost efficient" William Optics SWAN 33mm / 70 degrees FOV. I thought It were pretty good until my first night at a decent sky. Looking at the double cluster only half of the FOV were pinpoint stars, the rest of the large FOV looked like c*p. I wanted to cry and bury the EP in the snow then and there. I use it to "Star hop" in visual astronomy, so I'll keep using it for that. I think  more expensive EPs do a far better job in the wide field area than budget ones. For planets.. meh.

Huge disclaimer: I've done visual astronomy only this year, and the last six imaging. Don't take anything I say for anything other than my personal opinions and experiences. Listen to the experts :-) 

   

 

Edited by glennbech
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15 hours ago, John said:

It was that sort of experience that led me to start this thread:

Seeing conditions are really, really important in this game. Perhaps more than any other single factor ?

Suiter's "wobbly stack" of observing factors is worth considering:

1)     Seeing (not transparency, but the level of atmospheric disturbance which distorts the image moment to moment).

 

2)      Quality of the primary optics.

 

3)      Central obstruction size.

 

4)      Alignment of the optics.

 

5)      The diagonal being used.

 

6)      The ability of the focuser to deliver critical fine focus.

 

7)      The eyepiece.

 

8)      The skill and fatigue level of the observer and their eyes.

 

Perhaps we need more threads on interpreting and reacting to the seeing conditions than on eyepiece choices ? :rolleyes2:

 

 

The "wobbly stack" concept is probably the most enlightening I've read for visual. I'm sure glad Mod Stu encouraged me to buy Suiters great book. I do find that eyepiece selection makes a difference when seeing is good and the scope is well cooled etc. I personally use a zoom to "catch" the seeing, but a good ortho is very competitive optically. Rumor has it the SLV's are an excellent choice as well.

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10 hours ago, John said:

Well the scopes are the same focal length (assuming we are talking about the Skywatcher dobsonians) so the apparent size of an object in a given eyepiece will be the same. In principle the 10" scope should show more contrast and resolve more detail. That will almost certainly be the case with deep sky objects but on the moon and planets a whole bunch of other factors come into play which determine the amount of detail you can see - you can't simulate this and it will vary from session to session, hour to hour and sometimes minute to minute.

 

Got you, wasn't aware that same focal lengths produce the same size image, I thought it was the primary diameter that determined this.. I'll stick to the 10" then if it's going to be better for DSO's and, conditions allowing, a bit more detail on closer targets

10 hours ago, glennbech said:

Beware that this is a bit like upgrading your TV to a 50" from a 24" without switching from the antenna on the roof to HD cable. You will get a 50" image on your TV, but it will be magnified noise.

 

 

Yes, I'd read that it's the same as enlarging something on a photocopier, like I say, just being greedy and trying to have it all!

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43 minutes ago, iPeace said:

So I guess there's no need for me to mention how much I'm loving my 8mm Ethos. And my Baader / Zeiss prism diagonal. No? Thought not. Disregard please. Thanks.

Thats great to hear :icon_biggrin:

The past two sessions I've had with Jupiter have found the 8mm and 6mm Ethos providing the best views of the night both times.

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46 minutes ago, John said:

Thats great to hear :icon_biggrin:

The past two sessions I've had with Jupiter have found the 8mm and 6mm Ethos providing the best views of the night both times.

Yes the 6mm is a stunner as well... And with my scope, for Jupiter, the 4.7mm keeps me out all night:icon_biggrin::icon_biggrin:!

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