Best eye pieces i should buy

[Mark-keller]

Hi all ok so I have settled on a celestron cpc 9.25 gps xlt which arrives tomorrow

now I have decided to buy a revelation 2.5 x 3 element Barlow due to a few ppl I know recommending them to me,now then I get a 40mm eye piece with my scope but would expect this to be pretty standard can anyone recommend a eye piece or a set which would help me get better visuals please.

[ronin]

Why do you want a barlow?

The focal length of the cpc is long enough without the need to make it 2.5x longer.

Eyepieces ?

Try the almost standard BST Starguiders at 25mm, 18mm, 15mm and 12mm.

If you get a 2.5x barlow then the 12mm and 15mm are too much and the 18mm questionable.

As asked why a barlow therefore?

I think the only (worthwhile) time a barlow is used on a cpc 9.25 is for increasing the image size when imaging planets.

A 40mm plossl will produce the same view as a 32mm plossl and the same as a 25mm BST Starguider.

[Mark-keller]

Ah ok mate I see I'm new to this so I didn't realise that I would not need a Barlow I was led to believe that everyone had barlows for Veiwing,so I don't really need any for this scope then ?

[Mark-keller]

I'm pretty confused about eyepieces I think I'm gonna have a look on YouTube to see if I can understand them more because unfortunately I don't live near any telescope shops where I can have someone explain them to me properly.

[John]

If you have not already seen it, this piece by one of our members is well worth a read :

http://stargazerslounge.com/topic/43171-eyepieces-the-very-least-you-need/

Ander here is another beginners guide to eyepieces by another of our members :

http://www.swindonstargazers.com/beginners/eyepieces.htm

[Mr Spock]

I can tell you what I use most with my C9.25.

I have a 42mm (x56) which I use for low power.

A 22mm (x107) for deep sky objects.

A 10mm (x235) for planets.

Those would be the ones I'd stick with if I had only 3 eyepieces.

Others I use from time to time are 12mm (x196) and 8mm (x294) for planets/moon - the 8mm only when seeing allows. I also use a 6mm (x392) for double stars.

[BVietje]

Here's a 2nd opinion:  Don't buy the Barlow, or perhaps any other eyepiece for now.  Maybe a good quality 24mm wide field eyepiece for starters.

I suggest that all beginners join a local astronomy club ASAP, if they can find one, and try out as many different telescope & eyepiece combinations you can before spending your hard-earned money.  There are a bewildering array of choices, and some begin to get into some serious money.

factors to consider (among others, I'm sure!):

• What do you intend to observe?  Many beginners either aren't quite sure yet, or find out that their plans to search for comets with an f/10 scope from an urban area are not realistic...  Most develop favorite areas of observing only with experience, and like food or music, our tastes do evolve over time (or with advancing age).
• What sort of observing sites are available to you?  Dark ?  Light polluted?  In-between?
• How much are you prepared to invest in your observing tools?  Its easy to get into a buying frenzy and invest quite a bit, only to find out that some of those aren't used much, or maybe you decide you'd rather have a nice little camera setup instead of a full set of Naglers.
• Not all innovations are required for a great experience observing.  The real requirements are great optics, excellent coatings, and a clean, well-baffled design.
• Caveat emptor -- there are a number of uber-cool sounding gizmos and supercalifragalistic ultra wide field eyepieces that claim you can even see the back of you head while sketching Saturn's spokes (just kidding, of course), but in reality, you may not need this!
• Used equipment:  due to all of the above, there are often used eyepieces on the market (at least here in the USA).  If someone is selling a few Meade Ultra-wides because they decided on a set of Radian or Ethos eyepieces, you can get nice equipment for a good price.  A club may be a way to find out about swap meets, etc...
• When Al Nagler invents a 12-pound eyepiece that actually does make coffee for me, I'm in!

Joining a local or regional astronomy club will help you address all your doubts and confusion.  You can make friends and possibly find a few experienced astro-mentors from whom you can really learn a lot.  You will become a better observer -- and a more discriminating one -- with a lot of experience.  I'd look through everyone else's eyepieces to help you decide what's right for you.

Oh, and a perfectly good reason to use a Barlow is to achieve a given magnification with a much greater eye relief than a short-focus (high-power) eyepiece will provide.  I greatly prefer looking through a 16mm eyepiece with a 2.4x Dakin Barlow to squinting into a 6mm eyepiece, and I usually like using a 24mm with a 2.4X Barlow instead of a 10mm -- a much more comfortable view, IMHO, and with some eyepiece designs, many fewer pieces of glass between me and the stars.

Clear skies,

[russ.will]

Admittedly, my LX200 is slightly shorter in focal length, but my list goes much along the line of Michael's:

40mm - 50x. Lower power for very large DSOs and open clusters

20mm -100x. Largish DSOs and full lunar/solar disk

14mm - 142x. Smaller DSOs and eye wateringly large lunar/solar disk

9mm - 222x. Globs, planets and sunspots/craters.

I think I'd probably give up the 40mm before the 14mm absent from Micheals list, but the higher the mag, the smaller I like the jumps between EPs and personal preference for subjects, does have a bearing as you get more into it.

What I would also consider is the precise reverse of a Barlow - A focal reducer. The Meade & Celestron items are identical and can be picked up second hand for about £50. You put it between the visual back and your diagonal and it multiplies your focal lengths by 0.63x. It also helps correct the natural coma of the scope - As your effectively reducing the focal length of the scope, this will become more apparent in the longer focal length EPs.

With one of those in the chain, my list now reads 31.5x, 63x, 90x & 140x. For nights when planets aren't so prevalent, it gives the SCT a bit more of a DSO biased/friendly spread of magnifications.

Russell

[russ.will]

I'm pretty confused about eyepieces I think I'm gonna have a look on YouTube to see if I can understand them more because unfortunately I don't live near any telescope shops where I can have someone explain them to me properly.

North Essex Astronomy Society.

Russell

[YKSE]

I agree with Michal and Russell about focal lengths of eyepieces useful for a f10 SCT, also John's and Brad's good comments about reading more before jumping into buying frenzy, take your time, use the eyepieces you have to start with. Here's another link I'd highly recommend for everyone:

http://starizona.com/acb/basics/observing_theory.aspx

[russ.will]

You put it between the visual back and your diagonal......

I'm surprized the pedants haven't picked me up on this one! 

You screw it onto the SCT thread of the scope and then screw the visual back onto it. Must have been tired!

Some leave it in place as it effectively seals the scope from dust and because frankly, most SCTs aren't short of focal length even when reduced by 0.63x.

Russell

[Mr Spock]

I do have a 17mm T4 Nagler giving x138 but's rarely used - same for my 13mm LVW at x181. A lot of the eyepices I have weren't bought for the SCT

[Crell]

Thanks for the links in the posts above they're helpful but I'm still scratching my head a little. 

I have a Celestron 9.25 AVX SCT 

I bought a Baader Hyperion 21mm EP, plus the 14mm and 28mm "fine tuning rings" which in theory give me a range of 17.5mm, 15.5mm and 14mm when used in conjunction with the 21mm EP.

Looking at the minimum recommended mm for an F10 OTA, would getting the 17 and 8mm eyepieces give me a good selection or do I need further eyepieces ?

I was working off this chart on the RVO website. Stop me before I push the button on the eyepiece box set  

Thanks

[russ.will]

This is the issue with Baader FTRs - You wouldn't buy EPs at steps of 17.6mm, 15.5mm and 14mm, so why would you faff with unscrewing nose-pieces, screwing/unscrewing multiple combinations of FTRs and re-screwing nose-pieces to achieve a narrow range of slightly different focal lengths? Trust me; in the dark, that's going to get old really quick and you won't do it.

You have a 21mm, which is good. Buy the 13mm & 10mm Hyperion and then, when budget allows, a Maxvison 40mm SWA. Honestly, you'll use that little lot, far more than the FTRs that you, at some point,  will loose in the grass!

Russell

[ronin]

The problem with a 9.25 is not going to be getting magnification, they will produce too much and that is the problem. A fairly common and popular EP focal length is 8mm in a 9.25 it may get used once a year, maybe once every 2 years. At 293x the only object I can think it will be useful on is Mars when (if) conditions allow.

"Good" eyepieces are almost anything, SCT's are very forgiving of eyepieces so from a reasonable plossl up they should work well.

A 25mm BST/X-Cel will give the same field of view as a 32mm plossl and that gives the same as a 40mm plossl, so for width they are the same. So using a 25mm 60 degree as an example:

Mag = 2350/25 = 94x, FoV = 60/94 = 0.64 degree.

That is just over the size on the moon. So at the lowest easy mag the moon just fits in, therefore M42, M45 and some others cannot be seen in their entirity. That is the problem if it is one that bothers you. But seeing all of M45 is nicer then just a bit of it, it becomes apparent what it actually is.

HAve a look at: http://astropixels.com/messier/messiercat.html

Anything in the column Size (arcmin) that is 30 or above is going to be a tight fit or impossible.

(I must save that site just seen it has best viewing season attached :grin: )

Playing with FTR's in the dark and cold is asking for trouble.

The question is what are you intending to look at, and what is the budget.

Do you want a collection of Vixen Plossls, BST's, X-Cel's or more in the Delos, ES82 line?

[YKSE]

Thanks for the links in the posts above they're helpful but I'm still scratching my head a little. 

I have a Celestron 9.25 AVX SCT 

I bought a Baader Hyperion 21mm EP, plus the 14mm and 28mm "fine tuning rings" which in theory give me a range of 17.5mm, 15.5mm and 14mm when used in conjunction with the 21mm EP.

Looking at the minimum recommended mm for an F10 OTA, would getting the 17 and 8mm eyepieces give me a good selection or do I need further eyepieces ?

I was working off this chart on the RVO website. Stop me before I push the button on the eyepiece box set

Thanks

Do you use a f/6.3 reducer or planning for using in native f10 mode? It has big imact on your eyepiece choice,  

What other eyepieces do you have? It'll be much better than you have tried yours first before getting the buying feeble.

Since you already have a 21mm hyperion, buying a 25mm BST is just waste of money, no matter using f6.3 reducer or native f10 mode. And in f10, a 40mm plossl is a much better choice than 25mm BST, since it will give you 4mm exit pupil, which means seeing some DSO insivisble in 2.5mm exit pupil, EVEN though the field of view of both eyepieces are essentially the same.

[Crell]

Russ & Ronin thanks for the advice & pointers. That Messier Catalogue link is really useful as you say Ronin with the viewing season on there as well. 

I wasn't thinking that I'd want or ever use every possible combination and permutation on the chart

Re the FTRs themselves, I wasn't that impressed with the machining of the threads. They don't screw on easily to the EP and I was worried I might thread the EP. Overall I was underwhelmed by the rings, though once fitted they did make a difference when both were used together. I tried to do the changeover in the dark and cold, and as you point out it was a complete faff. I had to go indoors to do it.  

I like the Hyperion 21mm. To my untrained eye it's very clear, with good eye relief and I could even wear glasses, so will probably stick to the Hyperions for now. I did like the fact they convert to 2" as well if I want to in the future. There's so much stuff up there to look at I'm being a bit random at the moment, but Jupiter is a favourite.

That 40mm Maxvision SWA is immense! I think I'd need another counterweight. 

[Crell]

Do you use a f/6.3 reducer or planning for using in native f10 mode? It has big imact on your eyepiece choice,  

What other eyepieces do you have? It'll be much better than you have tried yours first before getting the buying feeble.

Since you already have a 21mm hyperion, buying a 25mm BST is just waste of money, no matter using f6.3 reducer or native f10 mode. And in f10, a 40mm plossl is a much better choice than 25mm BST, since it will give you 4mm exit pupil, which means seeing some DSO insivisble in 2.5mm exit pupil, EVEN though the field of view of both eyepieces are essentially the same.

Hi YKSE, 

I got the F6.3 reducer bundled with the scope, but I thought it would be useful for AP - when I eventually get in to it.

My wife would completely agree I should hold off on the shopping spree . I only have the Celestron EP that ships with the scope (I think it's a 25)  and the 21mm Hyperion (plus the FTRs, which while a nice idea don't prove to be practical unless you've set them up in advance - and I'm not that organised). 

What would you recommend for visual work - Using or removing the reducer? 

For F6.3 what mix of EPs would you recommend for someone starting out vs using it at native F10). 

[YKSE]

I could have used f6.3 reducer for my C8, thus limit my eyepieces to 1.25" only. But I liked to have 2" for other scopes, therefore my compromise is get both the 2" SW 40mm Aero and Baader 31mm, while 31mm is my most used finder scope because of its light-weight and excellent transmission, 40mm Aero get its scope time for some.

C9.25" is a more capable scope than C8 with its better edge correction and full 2" visual back, f6.3 is a cheaper solution for a SCT scope, but if you feel the need to buy a second scope for a wider field of view, it may be better off to get one or two 2" eyepieces.

[bingevader]

What about the moon, that takes bucket loads of magnification?!

If the moon were your thing (be daft if it wasn't as we see so much of it), then that in itself would justify at least one EP delivering some juicy magnification.

Failing that, a Barlow.

[Mr Spock]

I would never use a reducer for visual. It adds more glass in the light path and has a restricted aperture. If you want to go as wide as possible with a C9.25 then you need to have a 2" back and eyepieces.

The only other thing to consider when going wide is the cost. I have a 2" back, 42mm LVW, 22mm T4 Nagler and 17mm T4 Nagler 2" eyepieces. For the price of one of those eyepieces you could get a Dob...

For planets a 10mm is right on the sweet spot of magnification, detail and contrast at x235.

Don't let people kid you into believing you can't use more than x200 (you hear it so often). The moon will take a 6mm eyepiece on good nights. It is a memorable experience scanning craters at a crisp x392

[Crell]

Thanks again, Just totting up the cost of a 2 inch diagonal plus one of the maxvisions (I can't justify spending more). 

When you go to 2" on the SCT 9.25 do you need the diagonal or can you direct mount?