Discovery 17.5” Split Tube Dobsonian Telescope
Yesterday, 08:20 AM by clay1022
REVIEW OF SUMERIAN OPTICS ALKAID 16” TRAVEL SCOPE
Nov 26 2015 04:38 AM by alexvh
Astrotrac TP3065 Pier Review
Nov 20 2015 07:03 AM by James Waters
Apo-tmosphere: Gutekunst ADC Review
Sep 23 2015 10:18 AM by pbsastro
Optolong LRGB Filter Testing and Comparison wit...
Sep 22 2015 12:41 PM by turbo399
First Light Review: Teeter Custom TT Planet Kil...
Sep 04 2015 11:57 AM by Zellmer
The Baader Planetarium Morpheus
Aug 20 2015 09:45 AM by wapaolini
Book Review: Astro-Imaging Projects for Amateur...
Aug 15 2015 09:08 PM by Kenny2004
University Optics Konigs
I've tried both TV plossl and UO Konig 32mm eyepieces, head to head, and the biggest difference is the eyecup on the TV. Optically, neither I nor the several others who looked through them could see a difference in a 10" f/5.6 Dob. They are both top quality choices in this category.
I've also read that Konigs should work better in slower scopes, showing sharper images at the edge of the field. Having collected a set of UO Konigs, 8, 12,16, 24 and 32mm, I have the following observations on their use in a 10" f/5.6 Orion Dob and an 80mm f/11.2 Parks refractor.
1) The 8 to 24 mm focal length Konigs, with 60-65 degree apparent fields, do suffer from edge blur. The 16mm seems to have the smallest sharp-focus field, perhaps because it has the widest apparent field. The discontinued 8mm seems the best in this regard, but its eye relief is so short it's hard to see the edge.
2) The well focused area in these eyepieces is roughly equivalent to a comparably priced plossl, say a 26mm Celestron Silvertop. I like the wider field, even if the additional apparent field is not as sharp, but then, I'm a star hopping DSO hunter, for the most part.
3) I've not found Konig edge sharpness to be sensitive to focal ratio as I've been told; I don't see any difference in edge sharpness, f/5.6 to f/11, and I've looked for it using stars, the Moon and sunspots. Your experience (and telescope) may differ.
4) Given that the 1.25" format restricts a 32mm eyepeice to about 50 degrees, one would expect the 32mm Konig to be sharp right to the edge of the field, and it is - if these were 50 degee apparent field eyepieces, we wouldn't be having this discussion!,
5) In planetary applications I was surprised to see just as much detail and contrast on Jupiter with the 8mm Konig as with 7 and 9 mm Orthos, considering magnification differences. Complex, wide field designs, such as an 8.8mm Meade UWA, suffer noticable loss by comparison, even if they make Dobsonian tracking less of a chore.
6) When hunting faint, deep sky objects, I find the 16mm Konig provides detection thresholds superior to a 15mm
Panotic. There's just a bit more contrast, the difference between a confirmed, independent sighting and wiggling
the scope, breathing deeply, or using field stars to tell if an object is present. I suspect this may hold true
for quality plossls, but I have no evidence to that effect.
This is not to say that there aren't optimum observing experiences to be had with UWA's and Nalgers, Panoptics and Super Wides, or even the ubiquitous plossl. In the end, every eyepiece has strengths and weaknesses. Matching an eyepeice's characteristics and cost to your scope, observing habits and budget is part of the fun of amateur astronomy. Just remember that you don't need a second mortgage to get some really fine glass.