Hmmm, I am pretty new to this stuff but I cant for the life of me find a descriptive word for what Plossl means.....or panoptic.....nagler.....
I even tried Wiki!!! no help!! Is there a definitive glossary for eyepeices so I can get my head around all the jargon?
I am also looking to get a collimater for my Newtonian type telescope. Whats a good way to go...I am not 100% sure of the collimation process.
Basically, they pretty much mean an optic design. Think: Nagler = Rolls Royce, Panoptic/Pentax = BMW, Plossl = Ford/Holden, Kellner = Hyundai etc. if you get what I mean. Of course, you can get pretty impressive Hyundai's and entry level BMWs...but you can still expect the BMW to outperform the Hyundai in certain ways!
A Plossl has been around for ages and used to be regarded as "the bees knees" in optics (1970-80's). There are also Kelners, Orthoscopic etc that have been around for even longer. Generally, these designs give you a view of 50 degrees or less.
Panoptic is a term for TeleVue eyepieces that offer around 70 degrees. My Pentaxs also give 70 degrees, but the layout of the lenses inside the eyepiece will be different, possibly even a different number of elements (number of actual lenses), in different groups, this is basically lenses that are "stuck together" in the assembly. Some groups may have just one element, sort of defeats the definition of the word a bit.
Orion Stratus give 68 degrees and also have another layout of lenses.
Naglers give 82 degrees and have yet another layout of lenses. Generally, the wider the field of view, the higher the price. Compare a Nagler to a Plossl of the same focal length and you will see what I mean.
From my observations, the actual lens that you place your eye against varies in size with the design of the optic. My Plossls have a big piece of glass in the 32mm which is easy to find in the dark while a 4mm has a tiny pinhole of glass you have to find in the dark. A lot of the wide angle designs (Pentax, Stratus, Hyperion, Panoptic, Nagler etc) generally have a big bit of glass regardless of focal length. The eye glass of my 7mm and 30 mm Pentax XWs are the same size and easy to find at night!
If you look at the optical layout of some of the eyepieces on the manufacturer websites, you will see what I mean.
Collimation? I think most here would say you can't go past a decent Cheshire, but then again, this may also open yet another can of terminology worms.
Just learn a few buzz words and a bit about some of them, and you will seem like an expert (to the general public at least)....I do!
Good overview above on the eyepieces. My bit would be not to worry about it at all as the knowledge will grow over time. In the beginning a few plossls will keep you going for quite a while.
As for the collimator, I will second the suggestion for the cheshire eyepiece, get the one from Bintel as its longer and easier to use the Orion Collimating Tool.
Basically, they pretty much mean an optic design. Think: Nagler = Rolls Royce, Panoptic/Pentax = BMW, Plossl = Ford/Holden, Kellner = Hyundai etc. if you get what I mean. Of course, you can get pretty impressive Hyundai's and entry level BMWs...but you can still expect the BMW to outperform the Hyundai in certain ways!
Hey I like that good way of putting it. What sort of car would a Huygens e/p be?
Hi rapidfire!
Just a few words on care for eyepieces...as they will over time be subjected to fingermarks, dust, sneezed on, etc.
Clean them only if you really have to..the anti-reflective coating can easily be scratchced if you're not careful.
A puff or two of canned air available from electronics and camera shops..(make sure you give a test spray to clear any fluid fromm the nozzle!) will remove most dust...or a "Lenspen" which is handy have also.
Fingermarks can be removed by firstly cleaning off any dust with canned air..then use a corner of a clean white kleenex tissue dipped in Isopropyl alcohol..(available from Chemist's)..then wipe the eyepiece side to side using the weight of the tissue only!
If the fingermark is still there..use another tissue dipped in Isopropyl alcohol then finish off using a "lenspen"
Stick with the Plossl's for now as they do provide a good field of view for most objects..A cheshire collimator is a good way to learn about the collimation mechanics of your scope..and yes it will difficult and time consuming at first..patience is the key..plus it helps to stop and have a break every so often.
Cheers!
Thanks guys - many of us have found the information to be of great benefit!
As a newb myself, I have found the best way to learn the lingo is to read read read everything you can get your hands on - books, forums, astro mags, catalogs etc.
The steep learning curve can be fun and interesting.
wow thanks for all the info guys. excellent site Henri. loads of detail there.
I had already looked at the Bintel collimator. I think I 'll go for that.
it is a case of read read and then read some more. I enjoy the challenge on learning something entirely new. It dregs up distant past high school lessons in physics that i never really paid much attention in hehe.
good way of putting it. What sort of car would a Huygens e/p be?
