Attempting reverse psychology on mother nature
Posted 16 June 2013 - 02:16 PM
I'm going to try reverse psychology on mother nature by seeing if a big purchase will turn the weather from bad to good. I exchanged an email with Russ @ Denkmeier, and ordered up a Binotron-27 bino head only and a pair of D21 eyepieces.
I've had my Denk S2 Power x Switch diagonal for over a year, and it is a great thing for my CPC1100 (each pair of eyepieces becomes 3, bino or mono). I have been using my WO bino viewer and some Agena SWA eyepieces up until now, almost exclusively. The plan, originally, was to get a Denk-II this year, but with the new Binotron-27 introduction, I figured I should go ahead and get that instead. I also decided that it was past due for me to get some good glass to go with it.
I figure I'll either turn the weather into cooperative, or I'll curse the entire summer. Time will tell...
The WO and Agena eyepices will join my NexStar 5 setup at the house for grab & go usage. The Denk setup will stay with my CPC1100 at the farm (darker skies, open horizons).
Time to wait, and see if the bad weather curse turns already bad weather into good weather.
Posted 17 June 2013 - 06:46 PM
Posted 22 July 2013 - 06:35 PM
On the Binotron itself, I've got some thoughts already just playing around with the unit & D21s... The diopter adjustments are excellent; very easy to adjust but not so loose that it would change by itself. The fact that the eyepiece doesn't rotate with the diopter change is awesome. Same with the eyepiece locking ring, super smooth with "just right" feel to the movement where it is neither too fast nor too slow. It puts my WO to shame from a build-quality standpoint, though this is as it should be given the difference in price. The Binotron has some heft, but not enough that I'll have to make big changes to my counterweighting to balance the CPC1100. The rubber "armor" on the outside is great, as it allows you to make a good grip. The resistance on the IPD is also "just right", taking some effort, but not so much as to be concerning.
The D21's are pretty light for eyepieces of such size. I can't say much else about them yet, as I'll have to wait for first light. I'm pretty excited to try out the new gear, however.
The case the D21 pair and Binotron-27 head only shipped in is a nice addition; there's some room in there for other stuff, which is good since my regular eyepiece case is over full and this will free up some space.
Posted 24 July 2013 - 06:03 AM
The good news: The Binotron-27 binoviewer is a marvel of ergonomics & build quality. The eyepiece clamping, diopter focusing, and anti-reflective coatings are superb! The binoviewer was collimated such that I had an instant merge with my D21s and Agena SWA 15s & 20s with the barlow switch in on my Power x Switch S2 diagonal. I saw no reason to mess with good collimation, because the merge was actually instant.
The bad news: I need a dovetail adapter to use the reducer arm of my S2 Power x Switch diagonal. The Binotron-27's large prisms add just enough to the light path that I am about 1 turn from reaching focus with the reducer in with my D21s. I had about a half turn of focuser travel left after reaching focus on the WO. I've got an email on the way to Russ to get a dovetail adapter and see about the possibility of putting a "shorty" nose or IVB nose on my existing S2 Power x Switch diagonal to free up some focuser travel. I'm hooked on Power Switching, not just for binoviewing, but mono as well. Less futzing with eyepieces means more time viewing.
I did some quick comparisons to the Agena SWA (15 & 20mm pairs)/WO binoviewer setup, and the new Binotron/D21 combo and have some thoughts...
The WO binoviewer produces a halo around bright objects like Vega or Saturn or the moon in my C11 (it does to a lesser extent in the C5 as well); the WO binoviewers are not collimated as well as the Denk Binotron-27 either. The WO merge ok, but there is just enough offset between the eyes that you don't get the instant merge that I hadn't noticed it until I used the Binotron-27 and experienced zero merge time. There is a slight color & brightness difference between the 2 sides on the binoviewer; not objectionable, but plainly obvious after using a binoviewer that does not share that trait.
The Agena SWA eyepieces show some false color on the moon as well, and also exhibit ghosting (as did the WO 20mm eyepieces that the WO binoviewer came with). The combination works well on globs and decent enough on planets, but just doesn't have the snuff for the really bright objects. The WO/Agena combo also shows UGLY edge of field aberrations, mostly astigmatism; they are clean out to the point where you're only looking with 1 eye because you have to look sideways to see it as 70 degree fields appear to be enormous in a binoviewer.
The Binotron is color free on the moon, and does not give halos on bright objects like Vega; the anti-reflective coatings are truly excellent. Color between the left and right eye is close enough that I could not see a difference. Maybe test equipment can, but no color change from side to side is detectable by my ol' Mk1 eyeballs. The view through the Binotron seems is a bit brighter than through the WO, irrespective of what eyepieces are used, but true transmission comparison is best done on fainter objects with dark skies and not a full moon.
The D21s are very well corrected all the way to the edge of what looks to be a totally flat and distortion free field, have excellent eye relief, and exhibit no ghosting/halos around bright objects. The D21s provide an immersive field of view in a binoviewer. The field stop is razor sharp while mono or binoviewing.
I also got first light on my TV55 plossl. I can see the shadow of my secondary on the moon, and the sky is blue when using it away from the moon (expected with a >5mm exit pupil and a full moon). This bad boy was acquired for OIII/UHC nebula and max TFOV, and proper testing will have to wait until the sky is dark again. Eye placement is somewhat finicky, but I think I'll get used to it when I can actually use the eyepiece for real viewing once the skies get dark again.
When I get a dovetail adapter, I think I'll be quite happy. I was already maybe 85-90% binoviewer only, and I don't see that changing now that I've got premium glass. I crunched some numbers with my handy-dandy spreadsheet and just can't see the benefit of another pair of eyepieces for the binoviewer as the seeing doesn't justify it, and anything wider is best done with big-honking 2" eyepieces anyway.
In summary, I'd like to say that the Binotron-27 binoviewer is a fine piece of equipment. From the large color free and reflection free prisms, to the rubber coating on the outside, to the marvelous diopter focus adjustments, to the slick eyepiece clamping mechanism and the ability for us amateur astronomers to collimate them at any time, this binoviewer is truly world class.
The D21 eyepieces, which are priced in line with other premium optics, hold up their end of the premium price with premium performance from their excellent baffling and anti-reflective coatings to generous eye relief and lack of visible distortion throughout the flat field all the way to the razor sharp field stop. The sky was too lit up my the moon to make detailed transmission comparisons, but I have no complaints about their performance based on the 5 hours I spent with them tonight.
Posted 24 July 2013 - 08:10 AM
Thank you for such an excellent report, particularly the differences between the WO and Denk Binotron-27 BVs.
Posted 09 August 2013 - 10:08 PM
Posted 09 August 2013 - 10:43 PM
That was an interesting review. I guess it answered my question in a previous post about using the W.O. Binoviewer. However, can I use the W.O. Binoviewer with the Power/Filter switch diagonal on a CPC 1100?
That is how I was running before I got the binotron. The power switch diagonal accepts 2" or 1-1/4" eyepieces with an adapter. I put the WO into the adapter just like a 1-1/4" eyepiece and was up & running. Make no mistake, the binotron is well worth the higher price...