Eyepiece v Barlow?

[Quacker64]

Ok one of the first recommended purchases with scopes are EP's (unless one or two are included) and especially the purchase of a 2x Barlow. (Oh and a lunar filter). Now assuming I was wanting a range of magnification from say 4mm 8mm 16 mm and 32mm, would the obvious thing be two purchase 32mm and 8mm and a Barlow to cover all four magnifications?

On a similar note and I assume there's a degree of compromise, are 3x zoom EP's of sufficient quality to warrant investigation? Again these questions are coming from someone who hasn't ordered their first kit yet and might be asking silly questions. Apologies for the numbers quoted above as they seem quite obvious but in order to ask the question, they needed to be

[Roy Challen]

There's no straight answer to this question. It depends on your budget and your scope. You are correct in that buying two eyepieces and a barlow will cover four magnifications, but will you be able to use the highest mag in your scope? What is the focal length of the scope - this will determine the magnification an eyepiece delivers. Eg, a 1000mm f/l scope with a 4mm eyepiece will have a mag of x250 which is getting on for the limit for most scopes in this country under most sky conditions. You need to consider what magnifications will be of most benefit to you. My personal view is that most of the time Barlows are unnecessary, and two well chosen, good quality eyepieces will serve you better than four cheapo ones.

Zooms of reasonable quality are certainly useful, I have a Vixen LV zoom, but they aren't a substitute for fixed f/l eyepieces.

[Paul73]

As Roy says, choose the scope then the eyepieces. Start with 2 good quality eyepieces and go from there. A Barlow can be added whilest you build your collection, but, unless you are spending mega bucks, it won't be as good a dedicated eyepiece. I have one, but rarely use it.

Paul

[laudropb]

Good advice above. Planning eye pieces and other accessories depends on the scope in question.

[BillP]

I agree.  First order of business is to determine what are the range of focal lengths appropriate for the scope.  After that can tackle the Barlow integration.  And I often find that I want the lowest power eyepiece to be a 2" one so I can get the most TFOV practical for the scope, so I usually do not include that one in the equation.  As example, for a long time with my XT10 Dob I would use just 4 eyepieces and a Barlow.  I had a 40mm Paragon for widest views, then the 24, 17, and 13 Hyperions with a 2.8x Klee Barlow.  This 3 Hyperions I could use in sequence, then put the Barlow in for the remainder of the sequence.  I found that setup just fine for almost all observing with that scope.  Fun too having so little eyepieces. 

Over the years I have found that I enjoy the stronger Barlow so I do not have to jump around with eyepieces as the focal length progresses.  I prefer it that once the Barlow goes in, then all the eyepieces just rotate on it to get to highest magnifications.  The other thing to be aware of is that Barlowing a long focal length eyepiece wil long eye relief may cause it to be more prone to blackouts or difficult eye positioning as the eye relief will extend some with the Barlow most times.

[timwetherell]

It's worth remembering that almost any short focus eyepiece with a wide field of view and decent eye relief will have a barlow built in anyway  A good one should expand your EP collection without degrading the optical performance of the scope. If you have an SCT or Mak, then the secondary is in effect a barlow!

[YKSE]

  As example, for a long time with my XT10 Dob I would use just 4 eyepieces and a Barlow.  I had a 40mm Paragon for widest views, then the 24, 17, and 13 Hyperions with a 2.8x Klee Barlow.  This 3 Hyperions I could use in sequence, then put the Barlow in for the remainder of the sequence.  I found that setup just fine for almost all observing with that scope.  .

Bill,

I have to ask a couple of questions:

1. Did you see secondary shadow with 40mm Paragon? How washed-out was the background?

2. There are many comments about Hyperions don't work well in fast scopes, How's your impression?

[BillP]

I don't see a secondary shadow with the Paragon in my XT10 Dob.  I don't think I have tried observing the Moon in that configuration so can't comment there, but for all other observing no issue.  And yes, at that wide open exit pupil it is not made for faint fuzzy hunting...heck, even M42 looks unimpressive.  But for star fields, it is spectacular to have all that TFOV from that scope.  FWIW, I don't feel the background sky is too bright with it, so I enjoy it for expansive star fields from the XT10.

The 24mm Hyperion definitely is not all that great in the XT10 given it is f/4.7.  But still I did not overly fault it for that as it wored better in longer focal ratios plus I used it mostly as the low power finder...and Barlowed it was just great.  The 17, 13, 8, and 5 though all handled to fast scope good enough for pleasing views.  17mm as I recall still had a little of the off-axis abberated, as did the LVW 17mm, but the 13mm and shorter were all just fine.  I had a 12T4 while I had the 13 Hyperion and at the same 68 degree point the Nagler was only the slightest tighter star point...had to really look hard to see the difference.  But the Hyperion won hands down for comfort.  Overall, the Hyperions are not perfect to the edge eyepieces in a fast scope, but they are very good!  And they are very comfortable.  And they are fun with those fine tuning rings.  Frankly...I have fonder memories of my time with the Hyperion line than I do with the Nagler line I had, or the Meade 500 UWA line, or the ES82 line.  Hyperions were certainly good enough over most if not all of their AFOV and had a lot of other attributes that made them a fun and memorable line for me.  I find that when something is "perfect" it is typically also very cold and clinical as well...so not something that has character.  Over the long haul, I find that equipment with "character" is usually more enjoyable and memorable.  So I liked them...and have lots of good memories of using them.

[Dave In Vermont]

As I've said in many threads before: Low-cost Barlow's, while servicable, are likely to sit unused or sold. If a Barlow is in the forecast - get the best one made. I rarely mention TeleVue, but in a Barlow, I make an exception. There are other top-drawer Barlows out there, but TV is what I use and know. It would be the last Barlow a person buys. There is no going-up in quality. Some others may well match these, and someone will likely appear to tell us.

The best Barlow will practically disappear in your optical pathway. It won't dim the view or make the view look like a puddle of mud. Save up for one of the best Barlows, or at least look to the 'used' market. People are always selling off their lower-cost ones.

There is another thread that's still alive here, which you may find helpful:

http://stargazerslounge.com/topic/251682-new-eyepeice-or-new-barlow/

The 'Barlow or Eyepiece' question is one just about everyone has. And is certainly an excellent one. And one with no cut & dried resolution. Another type of optical-device to throw into the mix is called a "PowerMate" - made by TeleVue. These work in a different way, but also magnifies the image. And many consider them far better than a conventional Barlow-lens. Very much worth looking into. A search of SGL will yield many references on this. But, as has been said, you can't really answer your question until you decide on a telescope. Many will come outfitted with eyepieces and a Barlow.

Happy hunting,

Dave

[YKSE]

Thanks for the explanations Bill, much appreciated, it's always good to know some more details than simplified terms like good or bad.

[Quacker64]

Thanks everyone for all input. The first scope will most likely be the Skywatcher MAK 127 with GOTO etc. theoretical max magnification 250x (254x) 1500mm. Focal length. The standard kit comes with Skywatcher's own 10mm 25mm and 2x Barlow. That will give me sufficient glass to begin with, to learn with and find out what works for me and specifically my setup.

From the above a 12mm barlowed or 6mm prime would be as much magnification as required. Indeed the supplied 10mm and Barlow would suffice. I'd also be inclined at better/wider views as opposed to raw power - an error I've made in the past with optics. Time will tell if I'm happy with the supplied optic or hell bent on upgrading.

Please excuse the ramblings and simple calculations as its all new to me.:-)

Steve

[John]

The Mak 127's are great scopes for narrow field planetary / lunar / double stars but are never going to be a wide field scope - it's not in their nature. Worth being aware of that

You will start to see why astronomers own more than one scope !

I doubt a barlow is going to be much use in a 5" scope with a focal length of 1,500mm to be honest. a 6mm "native" eyepiece is going to give 250x which is about the top whack for the scope.

[triton1]

I think you should try using what is supplied with the scope,try different combinations on different targets and get a "feel" for the scope.I bought my scope without ep,s and bought a supplied one off eBay for £2.50.I know it,s not a good ep but I saw the Cassini division with it and was totally blown away for silly money,astronomy can be cheap(ish) so I would hold off for abit until you realise the scopes limitations.

[triton1]

I Didn,t mean to quote Dirty Harry

[Quacker64]

The Mak 127's are great scopes for narrow field planetary / lunar / double stars but are never going to be a wide field scope - it's not in their nature. Worth being aware of that

You will start to see why astronomers own more than one scope !

I doubt a barlow is going to be much use in a 5" scope with a focal length of 1,500mm to be honest. a 6mm "native" eyepiece is going to give 250x which is about the top whack for the scope.

From the very start and initial research based on my criteria I was well aware of this. My location, space (or lack of) and LP around the doors meant stRting small and compromise. A portable kit which I can take out and about with me is essential. I travel a lot and have several trips and weekends away each year. This seemed a good first choice.

My second scope will be to attempt to address anything I feel I'm missing out on or need improvement on;-)

[Quacker64]

I think you should try using what is supplied with the scope,try different combinations on different targets and get a "feel" for the scope.I bought my scope without ep,s and bought a supplied one off eBay for £2.50.I know it,s not a good ep but I saw the Cassini division with it and was totally blown away for silly money,astronomy can be cheap(ish) so I would hold off for abit until you realise the scopes limitations.

This is the plan Jonn, but I'm asking questions more for my own curiosity as much as future planning. The supplied glass may well suffice, they may well be upgraded or sold etc. if nothing else having a load of EP's means I can justify a few more scopes. All in good time. As yet I don't even know where my interests lie.

Steve

[bomberbaz]

I will keep my response brief. I recently sold a lot of eyepieces and bought the orion ultrascopic barlow to use in place of lower power barlows. I have not noticed any difference in my views at high power and really enjoy using the barlow.

So if you are going to use a barlow, I agree with dave, dont use a cheapo.

Ps, would love to compare a tv barlow with mine

[bomberbaz]

Note, i meant in place of lower power eyepieces not barlows

[Quacker64]

As never having purchased an EP or Barlow, I've no idea what constitutes cheap, expensive or indeed "mid-range". I understand from previous hobbies cheap or expensive is very subjective of course. I might possibly need to factor in EP's for my particular scope, for example. Part of the learning curve methinks.

Steve

[bomberbaz]

Ok I have had several barlows, I still retain 3 off them but my orion orthoscopic is by far the pick of the bunch. 

[RT65CB-SWL]

I hardly use my Klee 2.8x when using my ETX105 or C6/SCT-xlt as I prefer using prime e/p's. 

I do find a MagniMax is useful with the aforementioned 'scopes. Only 1.6x and screws in the nosepiece of 99.9% 1.25inch e/p's.

With regard to a Lunar/Moon filters... I mainly use a variable one. It too screws in the nosepiece of 99.9% 1.25inch e/p's.

[John]

Of the barlows I've owned, the Tele Vue, Celestron Ultima and Baader Q-Turret 2.25x have been the best of the 1.25" types, in optical terms. In the 2" fitting the Antares 1.6x is optically excellent.

Of the budget ones I've owned I think the Revelation 2.5x 1.25" was one of the better ones.

Powermate, TeleXtenders and Focal Extenders perform better again and don't have the impact on the focal position of the eyepiece thats being used or the eye relief that barlow lenses do. More £'s needed for these devices though.

[bomberbaz]

Sorry, didnt mean that last post to sound erm brusque, but it is a fact though,

regards, steve

[Quacker64]

Not sure if that was aimed at myself, Steve but sounded good to me based on your own experience and not brusque at all. I will need to find what works for me. Any new EP's inc. Barlows or even a Powermate will be with an eye to the future. A 32mm plössl will Barlow tom16mm - seems a good idea for someone with 10mm and 25mm EP's. At least to my inexperienced logic;-)

Syeve

[John]

Barlows are a good way to expand an eyepiece set with a single purchase and also for finding out which eyepiece focal lengths / magnifications work well for you and your scope. If you find a couple of focal lengths become real "bread and butter" ones that are frequently used you could then plan to get dedicated eyepieces of those focal lengths in due course.