barlows: TV powermate vs other barlows?

elton · Post by **elton** » Mon Oct 06, 2003 10:58 am

Eu wen,
In case you are thinking of the type 6 nagler, would like to say that they are not great. I just sold off my 9mm T6. While the eye relief at 12 mm seems ok, to get the 82 AFOV view you have to squash your eyeball so close there is practically no eye relief.

Grievous · Post by **Grievous** » Mon Oct 06, 2003 1:30 pm

As always, i prefer the Type 1 Naglers. But they are so hard to find them cheap now!

Charlie

dew · Post by **dew** » Mon Oct 06, 2003 2:12 pm

Or why not come over this weekend and experience them yourself ? Since they are available here for viewing, there's hardly anything that can beat your own personal judgement and evaluation of it since you'll be the one using it in the end. Come try and see if you're comfortable with it.

hi sam,

yeah i would really like to come over to try but im really busy right now.. and will be for the next 2 months.. A levels.. sigh.. but i got lots and lots of time after that and i'm sure bordom will stimulate in me a need to but stuff.. haha.. so i definately wanna try them, and a whole range of other eyepieces if possibe, after my A's..

In case you are thinking of the type 6 nagler, would like to say that they are not great. I just sold off my 9mm T6. While the eye relief at 12 mm seems ok, to get the 82 AFOV view you have to squash your eyeball so close there is practically no eye relief.

hi elton,
havent met you before, actually havent met many ppl here before, read somewhere that you got the 10" teleport right? wow.. thats a really cool scope.. anyway, about the T6 naglers, if their really not that great, any suggestions for a better alternative for high power, wide FOV planetary ep?
thanks!

eu-wen

elton · Post by **elton** » Mon Oct 06, 2003 3:59 pm

Actually the words high power, wide fov and planetary require quite a demanding mix of attributes from an eyepiece ... if any exists which fulfill all the criteria. The best planetary eyepieces are sharp and contrasty --- orthos are good here. However, wide fov eyepieces usually have many many elements which reduce their contrast. High power just makes things more difficult because the shorter the focal length, the eye relief is usually shorter. The keyword here is compromise. For me, I'm now a photon purist and will not tolerate anything more than 5 (or at worst 6) elements in a planetary eyepiece. The trade off is that eye relief suffers (no naglers etc) and so does FOV. For planets, the reduction in fov is ok if you have a driven mount. The trade off in eye relief is more serious because the more time you spend at the eyepiece (waiting for periods of good seeing) usually means the more you see (especially on a good scope).

All the above applies to low contrast planets. For the moon, any sharp eyepiece will do since there is so much light and the features are all high contrast in nature.

Depending on what you are trading off, the following will make good eps:
good quality orthos (UO, tak, pentax, zeiss), tak LE, good quality plossls (ultima, televue etc). If you have money to splash and want more comfort in eye relief, radians and pentax xl / xw are imho better than naglers for planets. Others to consider : Pentax XO, Siebert (very tempting)

harlequin2902 · Post by **harlequin2902** » Mon Oct 06, 2003 6:59 pm

If you're thinking now about the XL (NLA new, replaced by the XW) or Radian, you can hang around Astromart. It seems like there is an endless supply of those going on sale over there almost every other week ! 8)

dew · Post by **dew** » Tue Oct 07, 2003 12:55 am

Actually the words high power, wide fov and planetary require quite a demanding mix of attributes from an eyepiece ... if any exists which fulfill all the criteria. The best planetary eyepieces are sharp and contrasty --- orthos are good here. However, wide fov eyepieces usually have many many elements which reduce their contrast. High power just makes things more difficult because the shorter the focal length, the eye relief is usually shorter. The keyword here is compromise. For me, I'm now a photon purist and will not tolerate anything more than 5 (or at worst 6) elements in a planetary eyepiece. The trade off is that eye relief suffers (no naglers etc) and so does FOV. For planets, the reduction in fov is ok if you have a driven mount. The trade off in eye relief is more serious because the more time you spend at the eyepiece (waiting for periods of good seeing) usually means the more you see (especially on a good scope).

hmm.. yes quite abit to absorb.. i think right now i'm just too inexperienced to be able to make the best choice for my needs..

hey heres an idea, anyone wanna set up an eyepiece comparison test out on the field? i'm sure it would be very useful for all the beginners like me.. people who are willing could volunteer their eyepiecs.. then we can see the difference between different type of eps like orthos, plossels, kellners, naglers and different brands within the same type of ep.. maybe a nagler vs pentax vs meade SWA or something like that?
what you people think?

eu-wen

dew · Post by **dew** » Tue Oct 07, 2003 1:07 am

If you're thinking now about the XL (NLA new, replaced by the XW) or Radian, you can hang around Astromart. It seems like there is an endless supply of those going on sale over there almost every other week !

hmm... is it safe to buy? like what if you buy an eyepiece from some guy in the US, and when it arrives find a huge scratch on the lense or something? i mean.. you never know.. oh and whats the shipping costs like?
thanks

eu-wen

elton · Post by **elton** » Tue Oct 07, 2003 10:24 am

There is a rating system which discourages cheating. Anyway, no harm asking questions on the condition of the item but if anything goes wrong there is little you can do except :
1) go to usa/send a hitman and look for him
2) complain to Herb, he might do something
3) eat the loss and destroy that guy's 5* rating

harlequin2902 · Post by **harlequin2902** » Tue Oct 07, 2003 10:49 am

hmm.. yes quite abit to absorb.. i think right now i'm just too inexperienced to be able to make the best choice for my needs..

hey heres an idea, anyone wanna set up an eyepiece comparison test out on the field? i'm sure it would be very useful for all the beginners like me.. people who are willing could volunteer their eyepiecs.. then we can see the difference between different type of eps like orthos, plossels, kellners, naglers and different brands within the same type of ep.. maybe a nagler vs pentax vs meade SWA or something like that?
what you people think?

Oooh, that's quite a lot of work but not really an impossible task.
We can organize one, but have to wait until we get better weather over here.

harlequin2902 · Post by **harlequin2902** » Tue Oct 07, 2003 10:55 am

hmm... is it safe to buy? like what if you buy an eyepiece from some guy in the US, and when it arrives find a huge scratch on the lense or something? i mean.. you never know.. oh and whats the shipping costs like?
thanks

eu-wen

The Americans are generally OK. And they do take very good care of their equipment (same with the Japanese...used items can be kept and maintained in excellent-near mint condition). So far, those I dealt with have been very honest and responsive.

Shipping one single eyepiece (standard sized ones....not hand-grenade types) from US by standard air parcel (insured) costs US$15.00 Takes about 4-10 days to arrive. The nearer the person lives to a large US city with it's own airport, the faster it'll arrive in Singapore.