Celestron 4se -- Recommended Eyepieces?

[fallstand]

I've been doing my research -- some things have been becoming more clear and others not so much.

I'm planning on buying my first eyepiece. I've read on this forum about the 8mm TMB Planetary II which seemed to be recommended quite often, but they seem hard to come by. Does anyone have any good recommendations? I guess I'm most interested in viewing planets and the moon currently until I get a bit better with all of this.

And maybe someone could clear something up that's been confusing me regarding barlow lenses. If I buy an eyepiece that maxes out the magnification of my telescope, and attach a barlow, would that be hurting me in the long run? Or would it literally double the magnification with out any quality loss?

Thanks for the help!

[ronin]

At f/13 start out with a 12mm eyepiece, that will give 110x.

An 8mm will give 165x and adding a barlow will give 330x and a complete blur.

Suspect that an 8mm is as short as makes sense with the 4SE, and I would say the 12mm will be used more often.

Which make, the TMB's are reckoned to be good, the Astro -Tech Paradigms generally acknowledged as better.

[fallstand]

Hey thanks for the quick reply -- just so that some I can understand/absorb some information, why would the 12mm be a better choice than maxing the magnification (I'm a photographer by profession, everything seems backwards with telescopes)

[Chris]

a 12mm BST exployer with its 60 degree FOV and great eye relief plus ED glass element would also be a good choice from Skies the Limit -Ebay shop.

[fallstand]

Any opinion on the Celestron X-Cel LX 12mm Eyepiece?

[ronin]

On paper an 8mm gives more magnification however the quality of the image drops off.

In very general terms if the eyepiece focal length = the f number you get what is often called optimum performance. With yours being f/13 that would imply a 12mm eyepiece (13mm if you want to be exact but 12mm is more common).

Below that it starts to be gain in magnification but lose in image quality (sharpness).

There is the "rule" that you can get a magnification of 2x diameter (again in mm) so you would by that be able to use an 8mm, however not many years back the rule was 1.5x diameter. Recemtly I have seen companies advertise 3x diameter. Seems it is becomming more a claim by marketing, As in:

Yours does 2x dia, ours does 3x dia.

The whole lot is really garbage in my view.

The same claims are the same for a cheap achro and an recognised excellent apo, so why do people pay $1000 for an 80mm apo when a $100 achro has the same claims. Simple answer they do not perform the same.

I tend to go with the max mag = 1.5x diameter, it avoids disappointment, and there are many posts of I tried 200x on my 100mm scope and it was garbage.

So that is why I suggest a 12mm to start with, it will work all of the time, the 8mm I would expect to work well but there will be times when the image you see is poor, atmospheric conditions will simply prevent it being much use.

One eyepiece will not do everything is really the situation, the 12mm and the 8mm will cover you however.

The Celestron X-Cels are good, people here have compared with the Astro-Tech's and some claim one better then the other in about equal amouts, some say they are so close to each other they cannot seperate. As they are about 40% more then the Astro-Techs I simply left them out. They do however have a better selection at the short end. The AT's have 5mm and 8mm, the X-Cels have 5mm, 7mm and 9mm. If you definitely wanted magnification then with safety in mind try the 9mm (147x). I am sticking to my 1.5x diameter rule .

Have a look at the CN forum, there is a comparison of the Astro-Tech against the XO, agreed the XO comes out better but just better and it costs 3x the AT. In one or two areas the AT is reckoned to be as good as or better, Another CN posts summed it up very well: The TMB performs like a $60 eyepiece, the AT performs well above a $60 eyepiece. Whoever designed the AT's appears to have got it dead right.

The only other thing to say is get a few of the same set, they tend to be designed to be par-focal so there is less refocussing when you swap eyepieces. Often ignored but very useful.

[bomberbaz]

Good write up ronin and i would agree with that spot on. Although the op mentioned a barlow. Using a 2x barlow simply double the magnification of a given eyepiece. For example a 20mm eyepiece in a 104mm xF13 gives you 67.5 magnification. Add a 2x barlow and you get 135. I had a 4" sct for a short while ( neighbour has it now) and best i got that too was 170 and adter that image started to deterioate. Using your scope that would be an 8 mm as quoted by ronin.

Sent from my iphone

[fallstand]

Hey thanks for taking the time to explain that Ronin, that made things a little less confusing

I had asked about the x-cels simply because B&H Photo carries that line and I know they can deliver to me next day. I'm leaving for vacation where stargazing will be 100 times better than where I live. I plan on shopping around for the Astro-Tech EP, hopefully I can find someone who can deliver in time.

Thanks again