6mm Radian, Delos Shootout
Posted 02 October 2011 - 05:55 PM
--The 6mm Radian: I started here. Jupiter looked quite nice at 254X, and an exit pupil of 1.3. Being fairly low above the horizon, bands and festoons came and went as the atmosphere fuzzed out the details. However, sharp views also appeared. I enjoyed the views, both on and off axis. Its weight of 9 oz offered no balance challenges.
--The 6mm Delos: I was surprised how noticeably better the view was both on and off axis. When times of better seeing came, Jupiter looked more contrasty and sharp. The belts were better defined. Focus snapped in better than with the Radian. The adjustable height eyepiece guard worked fine. The 72 degrees of AFOV was a nice bump up over the Radian. Its 15.5 oz of weight offered no balance challenges.
--The 12mm Nagler with a boost from a 2X TeleVue Powermate. This was a surprise! The views with this combination were only slightly less sharp and contrasty the views through the Delos, both on and off axis . This combination provided noticeably better views of Jupiter than with the Radian. This given that there are additional lenses for the light to travel through, resulting with some light loss and contrast. However, Jupiter is quite bright, and some light loss won’t affect the views much. That might be another matter on dimmer deep sky objects. Also, its 39 oz of weight might cause some balance issues. There is the additional inconvenience of switching out eyepiece units into and out of the Powermate.
My conclusions: the 6mm Delos definitely won the shoot out. Its sharp, contrasty views, reasonable weight, excellent construction, and large eye relief sold me. The extra 10 degrees of AFOV is a plus over the Radian, which has 60 degrees. In fact, the more I use the Delos, I am beginning to prefer a 72 degree AFOV field over others.
I have posted in other places on Cloudy Nights that I changed my eyepiece strategy to only buy eyepieces that had enough eye relief to use while wearing glasses. All eyepieces used in this test easily met that criteria.
The 12mm Nagler coupled with a 2X TeleVue Powermate came in a strong second. I have a new respect for the Powermate. I don’t like to use a Powermate or Barlow all that often because I prefer the view and less hassle that a single eyepiece provides.
The Radian, with its good images, placed third.
They will be sold and replaced with Delos as additional eyepieces become available in that line.
Posted 02 October 2011 - 06:05 PM
Posted 02 October 2011 - 08:18 PM
Posted 02 October 2011 - 08:40 PM
Posted 02 October 2011 - 09:05 PM
Posted 02 October 2011 - 09:48 PM
Having read many of your previous posts on how much you like the Radians I'm pleased to hear how much you like the Delos. Must be good if you're going to sell your Radians. I'm a little surprised that the 12mm Nagler/Powermate combination came in second. If I needed the eye relief I would definitely be looking at the Delos.
With eyepiece choices, one has to decide which factors are most important, then live with the trade-offs. Some may be a little sharper, but have narrow field of view, or short eye relief. The type of telescope and F number are factors. The amount of money a person can afford to spend is an important factor. Wearing glasses while viewing was important for me. I found that Radians performed very well, especially when moving into the high power ranges, with the factors important to me. Now, through continuing to develop new eye piece designs, TeleVue brought us the Ethos and Delos. They do different things. The Delos hit the areas important to me
--high power, long eye relief, sharp, contrasty images when viewing planets.
Posted 02 October 2011 - 10:03 PM
Gene, did you swap back and forth several times when comparing each eyepiece as Jupiter was getting higher in the sky? I certainly can't say I am blessed with good seeing conditions very often, but of the times I have compared my 8mm Radian to my 8mm Ethos, or my 6mm Radian vs my 6mm Ethos, or my 5mm Radian to 5mm Nagler T6, the Radians hold their ground quite well. I mean I have went back and forth between the 8mm Radian and 8mm Ethos over and over, just trying to find the slightest difference. The best I can come up with is a slight color tone difference. Obviously the Delos is a different animal than the Ethos, but I don't expect the difference is much between the two considering the similar design. I am glad you like your new eyepiece, but I would give it another go over several sessions before I condemned the Radians..Ken
I am not condemning the Radian. It gave good views. To conduct this experiment, I had the eyepieces close by, and loaded them one at a time, viewing in my Portaball with a Tom O Platform. That made it easy to switch out the eyepieces since Jupiter remained in the field of view. I did not have to 'refind' the object. I rotated the eyepieces in sequence. As I noted, the views slipped in and out of fuzziness, with times in each eyepiece when the image cleared up. Others have posted that the Delos gave a slightly sharper image on Jupiter (the operative word is slightly) than the Ethos. I did not have an Ethos to throw into the mix. I always recommend that people conduct their own experiments when it comes to comparing optics.
Posted 02 October 2011 - 10:46 PM
I think TV needs to send you free of charge each of the new Delos as they come out. You probably just made them a lot of money with a highly respected opinion. How about it TV, here is one of your very strong supporters!!!!
Posted 02 October 2011 - 11:22 PM
I think I would favor the Delos over the Ethos, because of the better ER.
Chesmont Astronomical Society - www.chesmontastro.org
Deep Space with Refractors - http://tech.groups.y...ewithrefractors
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos
Posted 03 October 2011 - 11:39 AM
It's interesting to see how the Delos perform against the Pentax XW's.
Posted 03 October 2011 - 01:11 PM
The king is dead long live the new king! But why is the extra 10 degrees of AFOV a pre?...when you observing the planets? I never think my radian AFOV is too narrow when observing the planets.
It's interesting to see how the Delos perform against the Pentax XW's.
When doing high power work on the planets or other objects such as double stars, 60 degrees was fine. I was impressed that TeleVue was able to bump up the Delos to 72 degrees, and produce a lens system that, in my opinion, was sharper on an extended object like Jupiter than my Radian. The additional 10 degrees of AFOV will equate to the view hanging longer for people with no tracking, and easier to find objects when they slip out of view. With the Radians, I had to sometimes find the object with a wider field eyepiece, such as a 31 or 22mm Nagler, then replace the eyepiece with the Radian. The 72 AFOV of the Delos made it that much easier to find the object from the get-go, without having to make it a two step operation.
Posted 03 October 2011 - 01:19 PM
I rotated the eyepieces in sequence. As I noted, the views slipped in and out of fuzziness, with times in each eyepiece when the image cleared up.
The time was 10 p.m. October 1st. Jupiter was high enough above the horizon to perform this experiment. However, I would have liked it better if I could have done the shoot out at 11 or 12 O'clock. When the image cleared up, it did so for 30 seconds or so, plenty of time for it to register in my mind before I switched in a different eyepiece. I changed out the eyepieces every few minutes, leaving them in long enough to ensure I was getting the optimum view.
Posted 03 October 2011 - 01:28 PM
I would give it another go over several sessions before I condemned the Radians..
I have always advocated living within one's means in the pursuit of this great hobby. There are eyepieces that perform quite well that are moderately priced. However, I am now an old guy of 68 years. My kids are educated and financially self sufficient .
Astronomy is the only hobby in which I indulge myself. So, I will sell my Radians and replace them with Delos in the high power ranges of 8, 6 and 4mm. My wide angle eyepieces include 31, 22 (my most used wide angle eyepiece on a 12.5 inch Dob) 17 Naglers and a 12mm Nagler, a mid power eyepiece. All my Naglers also have enough eye relief to be used while wearing glasses. I was tempted to go with Ethos in the mid to wide angle ranges. However, their 15mm of eye relief meant that I would have to view through with my glasses off. If I viewed without wearing glasses, then I would have purchased the Ethos eyepieces.
Posted 04 October 2011 - 07:24 AM
Posted 04 October 2011 - 09:46 AM
Posted 04 October 2011 - 12:21 PM
A very nice report! I wish you alot of enjoyable views with the Delos eyepieces as you acquire them.
Thanks again for sharing your experience,
Posted 05 October 2011 - 02:09 PM
Posted 14 October 2011 - 05:12 PM
Posted 15 October 2011 - 07:11 PM
Posted 17 October 2011 - 10:36 PM
I had clear views hanging in there for 20-30 seconds at a time, so I felt confident in my conclusions. The Radians are excellent eyepieces, however I will be replacing them with Delos as they are issued.
Posted 18 October 2011 - 01:35 AM
What was an altitude of the Jupiter? 15-20 degrees over Horizon? Was not 250x too much in the conditions? Let's suppose that seeing (taking into account atmosphere dispersion) was close to 2". After magnification 250x it shall be 530" for eye. Or 9 angular minutes - atmospheric spot for observer.
...It was done on an F/5, 12.5 inch Portaball. Jupiter was not well placed since it had just risen for about an hour before I did the test...
It is interesting is it ever possible to distinguish fine difference in aberration balance of Radian and Delos on so bad background? That means that aberration spot of Radian shall be much more (or at least compatible) to that 9 angular minutes, including central part of field.
Posted 18 October 2011 - 01:49 AM