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Eyepiece range

DRT

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DRT

DRT

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I have more or less decided to purchase a 10" or 12" Dob as my first step-up, probably from the Skywatcher Skyliner range.

I currently have 7mm and 18mm Celestron C-Cel LX eyepieces and would like to complete the set. I have read many articles here about the limits of magnification that are effective in the UK but I'm sorry to say I do not yet understand the maths behind all of that stuff so would appreciate some advice on what to buy next.

The options available are 2.3mm, 5mm, 9mm, 12mm, 25mm plus 2x and 3x Barlows. At £70-£80 a pop these are not inexpensive items so I don't want to buy anything that will be redundant due tomy choice of scope or location. So which of these should I aim to buy to improve my viewing experience?

All advice greatfully recieved.

Thanks

Derek

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John

John

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With my 12" F/5.3 dob I use regularly eyepieces with focal lengths from 31mm (51x) down to 5mm (318x). I occasionally go a bit higher than this when seeing conditions are excellent and the object being viewed will benefit from it, but mostly the range described are my work horses.

The focal lengths I have in my set for this scope are:

31mm, 20mm (2 inch fitting)

13mm, 8mm, 6mm and 5mm (1.25" fitting)

I prefer not to use a barlow so I have eyepieces in those focal lengths.

From the Celestron X-Cel LX range I'd say the 5mm through 25mm would be useful plus the 2x barlow to get the very useful 6mm focal length but a 2" 32mm of some sort would be a good addition too.

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John

John

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The 2" format allows a wider field of view than the 1.25" one. A 32mm eyepiece in the 2" format can show about 40% more sky than the same focal length in the 1.25" size. For extended deep sky objects a nice wide field of view can be very nice to have. It's not essential though.

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RikM

RikM

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I use a similar set with my 10".

28mm (2" fitting)

20mm

14mm

10mm

7mm

5mm (under the tree for Christmas :) )

Very occasionally I will use 4mm but to achieve this I use the 10mm with a 2.5x Barlow. I couldn't justify the cost of a nice 4mm for just a couple of times each year. The Barlow was only £50 but is really good quality by Televue. Up until now I have been using the Barlow with the 14mm EP to give me 5.6mm equivalent for my normal 'high-power' focal length.

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RikM

RikM

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I don't like that they extend the eyepiece way out away from the focuser, and you have to tighten a little grubscrew to hold the EP in place. That is not always easy when you are cold and tired, wearing gloves holding possibly a few hundred pounds worth of glass EP. I normally use a twist lock self-centring adaptor rather than grubscrews to hold my EP's securely.

I have noticed that some barlows can introduce a yellow cast to the view. I really don't like this at all. There is also a feeling by some that adding the extra glass elements, also dim the view more than expected from simply increasing the magnification. (Spreading the light out to make the image bigger does make it dimmer anyway). 

I would like to have an 'eyepiece only' set, eventually. With my new 5mm, I will be eyepiece only for 99% of observing with my Dobsonian. 

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bomberbaz

bomberbaz

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Good choice for mid range ep with the x cels. Had them myself for a while and fond them superb . I think you need to decide on your scope choice before you start th7nking about choosing additional eyepieces as the differing focal lengths are vdry important. Also agree with .john that in the lower end magnification 2" ep, s are better for the better tfov.

Wait to hear on scope choice but sounds like youhabeagood idea of what youwant

steve

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Tinker1947

Tinker1947

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My 5mm EP with the 10" reflector didn't get a lot of use, the seeing would not allow it, when it did work viewing Saturn you could drive a bus through the rings, but this was a rare event, were as the 7mm got used nearly every time...i would forget barlows and build up a set of EP it might take a bit of time, but the stars aren't going any place with in your life time....

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DRT

DRT

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My 5mm EP with the 10" reflector didn't get a lot of use, the seeing would not allow it, when it did work viewing Saturn you could drive a bus through the rings

Were those few experiences worth the £70 you paid for it?

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brantuk

brantuk

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"I don't like that they extend the eyepiece way out away from the focuser, and you have to tighten a little grubscrew to hold the EP in place"

Good point Rik - especially on a newtonian where it sticks out the side. I must admit I do use it more on my Sct and frac :)

"Were those few experiences worth the £70 you paid for it?"

A bit of a subjective question Derek. It's really down to personal feelings about it. I have a 5mm that rarely get's used and cost £186 as well as a 3.7mm costing £350. I'm totally happy with the way they both work in my scopes on those rare occasions when they get used. The experiences with them could have come a spot cheaper - I wouldn't have complained lol. But I did spoil myself a bit and the views are deffo worth viewing. :)

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DRT

DRT

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Good points. I do realise that value for money is a very personal thing so to put it in perspective, if like me you are willing to buy four or five eyepieces at £70 each would you buy one that was only likely to be used very occassionally for an exceptional viewing experience? Having never knowingly seen "an exceptional viewing experience" myself it is difficult for me to judge the answer to that question.

I have read and re-read the above five times and still can't decide whether or not it is a fair question, so it seems like there is only one solution. I'll come back to this thread in 12 months and let you know whether or not the 5mm was worth the money :rolleyes:

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Nigele2

Nigele2

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Very interesting and the above type of thinking is certainly swaying my buying thoughts.  I rapidly am persuading myself that to buy as expensive as possible but buy less is the way to go.   

The danger I can see for me however is becoming a collector as opposed to a user.  From what I can see if I buy quality and look after it very well then I can sell secondhand and recycle some of the money.  I know no one likes losing money but an unused EP in my box isn't worth much. 

For example yesterday there was on Ebay a Tele Vue Ethos 13mm which cost £475 list and sold for £300 incl. P&P.  Had I bought it, cherished it, and then put i back on EBay in say a year would I have lost out much?  And then I could put in next years budget and get say a 9mm and a 25mm of equal quality.

Sorry bit muddled but in reply to "Were those few experiences worth the £70 you paid for it?" it is not only the experiences.  The EP still exists and is an assett that can be traded in at any time.  Although looking at the photos of some peoples EP collections I can see parting with friends is easy said then done - and as an owner of 4 flamenco guitars only one of which I play I can see that being me  :grin: 

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brantuk

brantuk

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From another point of view - I have several different scopes and each single eyepiece I own works differently in each scope. So I do tend to pick eyepieces that give at least a good experience in all and exceptional experience in maybe one or two of them.

If chosen carefully then a budget of £70 per each of 4 eyepieces is a healthy sum that will get you very acceptable quality views in most scopes. The ultimate test has to be "try before you buy" which you can do at most observing groups and definitely at a star party. I've not met a stargazer yet who won't loan you an eyepiece for an hour or so to try in your scope.

My eyepiece choices are mostly based on this cos I cba with the maths lol. The things to bear in mind are that the difference between a poor quality eyepiece and a medium quality one are huge and amazing. But as you slip over the £100-£150 bracket eyepieces and head into the top quality ones costing £200+, the differences and improvements become less and less and are really only obvious to the more experienced eye.

Also - the faster a scope is - the more demanding it is on higher quality eyepieces. Pop an Ethos in a f-4.5 newt and the views will be really sweet across the entire lens. Swop it for an average eyepiece circa £50 and you'll notice all manner of CA, edge distortions, bent stars, and much reduced sweet spot. In an f-10 scope however - the average eyepiece can seem perfectly fine - even pleasing.

Hth :)

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John

John

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For example yesterday there was on Ebay a Tele Vue Ethos 13mm which cost £475 list and sold for £300 incl. P&P.  Had I bought it, cherished it, and then put i back on EBay in say a year would I have lost out much?  And then I could put in next years budget and get say a 9mm and a 25mm of equal quality.

You would get at least 90% or that back (maybe more) and you would have had the pleasure of using what is, arguably, the finest 13mm eyepiece made, for a while :smiley:

In a nutshell, thats why I've bought used eyepieces over the years. 

Trying eyepieces personally through buying secondhand or by going to star parties is really the best way to answer the questions "is it for me ?" and "will I notice the difference ?". 

I see that Tinker1947 is a fan of Pentax XW's - again expensive but they really do deliver the goods, time and time again  :smiley:

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brantuk

brantuk

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"Although looking at the photos of some peoples EP collections I can see parting with friends is easy said then done - and as an owner of 4 flamenco guitars only one of which I play I can see that being me  :grin: "

Hahaha - I was like this at one time. In the end I kept the best guitar and sold the others to get eyepieces rofl :grin:

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Naemeth

Naemeth

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Best advice is to buy second hand. Only a few eyepieces in my case were bought new (25mm TV plossl and 3-6mm Nagler zoom, 18mm LV) as I wasn't willing to wait for them to turn up second hand (3-6mm Nagler Zoom is fairly rare on ABS, any of the LVs are incredibly rare on ABS), the rest were all bought second hand and all in very good condition, saving me about 40% of the new price each time (sometimes around 70%!)

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