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TMB Planetary II

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#26 SpaceRooster

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Posted 08 May 2013 - 10:12 PM

I did another comparison between my P-II 7mm and my TV 11mm plossl barlowed x2 last night, and found the same results as you did. The first few times I compared them, it wasn't that huge of a difference. But last night Saturn's details popped out much more in the TV combo than the P-II (specifically the cassini gap, which was a bit muddier in the P-II).

#27 Jon Isaacs

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Posted 08 May 2013 - 10:39 PM

Gregory93, I tried the TMB II 9mm in my TV NP127 which is f/5.2. There was very significant field curvature so it was no good in my scope. Keep in mind though, the TV scopes are very demanding on eyepiece design and quality, and I only have my own eyes to go by... Cheers, Fox


I have a set of TMB Planetary eyepieces and I frequently use the 9mm, the 6mm and the 4mm in my NP-101. They all exhibit what appears to me to be off-axis astigmatism. If my memory is correct, I cannot get them to focus at the edge of the field. Using them with the front section of a 1.25 inch GSO Barlow which provides about 1.5x magnification and a shift in the effective focal ratio from F/5.4 to about F/8.1 really cleans up the astigmatism, a tight double can drift past the field stop still nicely resolved.

For the money, they are quite good eyepieces... Last night I was using the 9mm in my NP-101 from my light polluted backyard to view M65 and M66. I could see both galaxies but they were not easily seen. I switched to the 9mm Nagler, both were slightly easier to see.

Jon

#28 FoxTrot

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Posted 09 May 2013 - 11:46 AM

Hi Jon, agreed. I think they are a very nice eyepiece for the price with excellent construction, great eye relief, very nice action with the eyeguard, and good field of view. But about 10 to 20 percent of the outer edge field of view would not reach focus whilst the on-axis image was in focus (in my scopes). Fox






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