Second eyepeice choice

[timmo567]

Hi everyone,

I recently purchased a Meade 16mm SWA EP from the trading section and after using it, I am no longer able to use the EP's that came with my telescope :P So I effectively only have one eye piece at the moment and have found 3 that I am interested in for a second one.

I have a 10" dob which has a length of 1200mm at F4.7 and I also have a 2x Barlow. So with the 16mm I currently have magnifications of 75x and 150x. I'm looking for something in between these, so 11mm-12mm. I don't wear glasses and have never had a problem with eye relief. The three contenders are:

12mm Edmund RKE
12mm (or is it a 12.5mm) University optics ortho HD
11mm Televue plossl

The university optics website lists the HD ortho as 12.5mm but in the picture it clearly says 12mm. If it is 12.5mm then its too close to my other EP for me and it's down to the other two.

I'm interested mainly in planetary viewing with these EP's and they seem somewhat similar to me but I had some specific questions. Out of the three, are there any which would not be recommended in a F4.7 scope and which would not barlow well?

The 12mm's plus my 16mm with barlow gives
75x, 100x,150x,200x

The 11mm plus my 16mm with barlow gives
75x, 109x,150x,218x

Any advice would be appreciated ;)

[Suzy]

Tim, have a look at my thread posted recently, "The best 5mm EP under $200". Though this isn't the size that your looking for, there is a lot of very useful info on there regarding good quality eyepieces for planetary viewing and suggested fov for eyepieces for dob users. Barlowing also is a big topic in that thread.

[MikeyB]

I think you've hit the nail on the head when you say these three are "somewhat similar", Tim and for med/high magnification planetary viewing I'd doubt that there's much to choose between them in terms of sharpness, contrast, etc.

They all share the same usability deficiencies, though: small eye lens, short eye relief and narrow fields of view (45 degrees for the UO and the Edmund, and 50 degrees for the TeleVue). After the pleasure you're finding from using a Meade Super Wide Angle, any of these three may feel like you're peering through a keyhole. You'll also find a need for constant tweaking of the dob position to keep the target centred, especially when using a barlow. On the other hand, a barlow will improve the eye relief somewhat, so it's not all bad news.

That thread that Suzy mentions is a VERY good place to do some further in-depth research:

The Best 5mm EP under $200 (http://www.iceinspace.com.au/forum/showthread.php?t=59484)

[dannat]

go for the edmund RKE, only 3 lens elements usually counts to better transmission - check cloudy nights eyepiece forum for many fans - keep in mind you will be bumping the dob frequently to keep objects in the fov.