DENK "BINOTRON" - FIRST LIGHT
Posted 17 February 2013 - 05:13 PM
Posted 21 February 2013 - 05:13 PM
Posted 21 February 2013 - 08:06 PM
The Maxbrights with a T2 required a 1.5x GPC to reach focus in my 6" APO.
But when I went to the Mark Vs (same prism), I could no longer reach focus with the 1.5x configuration, and I am not even sure that the 1.7x would work because these seem to be actually only 1.6x, and I only had about 2mm of in-focus left when using the Maxbrights.
If I went to a 2x configuration to be sure of reaching focus, I would increase my magnification 75%.
Some of this would be offset because I could use a bigger eyepiece in the Mark Vs.
If I went to a giant bino with a light path that was another 20mm or so, I might need even more magnification to reach focus.
In the SCT, it is not as bad, but past 200mm, and the C14 looses aperture.
So, If I went to a 2" diagonal to support a giant prism bino, I would have to add so much back focus that the system would loose a lot of aperture.
In fact, even with the standard Denkmeier Supersystem used with a 2" diagonal, the scope was already only working at 13.2" of aperture.
With my current configuration (Baader Clicklock, Baader T2 Standard prism, and Mark Vs, (total back focus of about 198 mm of back focus).
This gives a focal length of about 4000mm, but full aperture (My scope starts to cut off the light cone right at 200mm).
A big bino though, using a 2" diagonal but with a light path of 140mm, would have a total of perhaps 270mm of back focus (maybe more).
In this case, the C14 would be working at about 4300mm focal length, but the aperture would be reduced to about 13 inches or less.
You can overdo it on the prism size for refractors or SCTs. The bigger the prism, the more Barlow or back focus you need, and in the SCTs, you would almost for sure loose aperture (except C11).
I did some quick calculations, and in almost every case for refractors, if the change from a Maxbright size bino to a Mark V required a step up in GPC, the advantage of the bigger prism would be almost completely negated.
In other words, you could get the same size true field from the Maxbrights using a 20mm Explore Scientific as you could get from a Mark V using 24mm Panoptics if the Mark Vs required one step up in GPC strength.
And if you had a 2" with a big enough prism to use a big 2" eyepiece like a 27mm Pan, you might need even more GPC, so that in the end, you might wind up with no bigger true field than the Maxbrights.
Light path is the the great evil of binovierwers. Unless one is willing to modify a telecope that cannot reach focus without a GPC or OCS, it is very difficult to get a wider field by going to a bigger aperture bino for refractors, and many SCTs will experience aperture loss when giant prisms are used, unless they use an OCS of course, but then what would be the point of the bigger prisms?
I went to the Mark Vs for the C14 because the increase in field size in this case was enough to justify it, but I wrote off the notion of using them in the 6" APO.
Think about it this way..... If I had to use 2x in the 6" APO to reach focus, that would give me 2430mm of focal length.
Heck, I can use them on my EdgeHD 8" and get 2350mm with a brighter field that is every bit as sharp? What would be the point?
I simply abandoned the idea of using the binoviewers with the 6" APO when I realized I could get a bigger, brighter true field out of the EdgeHD 8". It did not make any sense at all to pursue getting the Mark Vs to work on the 6" APO.
Posted 21 February 2013 - 10:00 PM
Posted 22 February 2013 - 12:29 AM
It's very well explained but also completely due to the longer tube on Eddgie's scope. I'm actually considering keeping my MkVs when the B27's arrive just for the spectacular view they render in my 6" APO at 1X with Pan 24s or Brandon 32s.
Keep 'em both. There are times when I am sooooo glad I have two sets of binos.
Posted 03 March 2013 - 02:37 AM
The sheer size of the 45s resulting in a light path so long that the 20s might be performing as 12s...
What on Earth does does this mean?
The Multipurpose OCS may require an extension or more infocus than the Newtonian OCS (it does when I am at lowest LL power mode of dual power switches). If you require an extension it would change the focal length of the system. If it is just infocus (without an extension) I don't know what he is talking about either?
I knew exactly what all the powers were with just one power switch. Adding the second one (reducer/multiplier) increased the length and changed all the powers a little.
I only know the LL and HH for sure provided by Russ, and had to estimate multiplying the powers of both power switches in series.
I guess we could do the drift time measurement to know for sure.
Posted 03 March 2013 - 09:47 AM
Keep 'em both. There are times when I am sooooo glad I have two sets of binos. [/quote]
Posted 03 March 2013 - 10:44 AM
With my IPD (67mm) I only use 1 1/4 eps....the largest fieldstop for 1 1/4 is 27mm (24mm Pans) so 30mm and more is not needed
The Baader Hyperions have a 28mm field stop.
When measured with a caliper, I got 28mm.
The Televue 40mm Plossls were 27mm.
Is 1 millimeter a big deal?
Well, yes and no I suppose. On one hand, I very much like to see a very sharp field stop in my eyepieces with zero softness. For many this is not important at all and while it is cosmetic, it is what I personally like. The 24mm Hyperions have a very sharp field stop.
And as for the difference, well a 3% wider field in a binoviewer is a 3% wider field in a binoviewer.
And if you are using a C14, it all adds up.
I have no investment in what other people buy. Only trying to say that there are bigger field stops in 1.25" eyepeices.
Does it matter to you or to anyone else? Maybe not.
Juat a fact so I though I would introduce it.
Posted 23 March 2013 - 08:04 PM
Posted 24 March 2013 - 06:34 PM
Had my Binotrons with Denk 21's out a fews days back hooked up to my Tak TOA 130. The conditions were much better than my first night out and WOW did they perform. The moon was amazing. The Tak by itself is great on the moon but with the binoviewers the view was breathtaking. Razor sharp and beautiful subtle coloring of the lunar surface. Jupiter was also a wealth of detail and the moons perfect tiny disks. What is really amazing to me (and I know most binoviewer users already know this but it is new to me) is how relaxing it is to view with two eyes instead of one. I can't wait to bring them to a really dark site and put them in my Dob. This night was in my yard which is kind of dark -(I don't know the darkness scales but I can see the milky way from my yard but not distinct light and dark areas within it - it is just a hazy band of light.). The binos really performed beyond my expectations.
Posted 24 March 2013 - 08:11 PM
Posted 24 March 2013 - 09:21 PM
Posted 28 March 2013 - 03:19 AM
Posted 28 March 2013 - 04:03 PM
Spoke to Russ and I'm on the list. I can't wait.
E-mail from Brown says Monday.
Posted 29 March 2013 - 10:05 AM
Mine shipped today!
Do you know what your order number is? I'm on the list and still waiting (2094).
Posted 29 March 2013 - 06:27 PM
Posted 02 April 2013 - 09:07 PM
Posted 03 April 2013 - 10:45 AM
Spoke to Russ and I'm on the list. I can't wait.
E-mail from Brown says Monday.
Got mine and a preliminary report using my APM 6" F8 triplet.
1. Wonderfully made, love the rubber coating.
2. Light weight, much appreciated
3. Wonderful coatings
4. Cool collimation feature
5. Deeper collet allows eyepieces with longer barrels to sit flush with top.
6. Best for last, very sharp, no tint differences between R/L.
Not so good:
1. Requires ~ 10mm more backfocus due to collimation feature. Bad for my APM 152 F8, can't get to focus sans OCS with power switch attached.
2. Speaking of the power switch, arms are very stiff and when using sans OCS with refractors, barlow side has annoying "glow" at focus. Older version switches do not. Glow eliminated with OCS so new switch can only be used with OCS, a limitation.
3. Two inch nose piece on new switch is longer than old one and with OCS attached, entire viewer sticks up out of diagonal ~10mm. Not good.
So, a mixed impression so far. More later.
Posted 04 April 2013 - 01:26 AM
Posted 04 April 2013 - 08:01 AM
My refractors are all "bino-friendly" and all, save the APM 6" F8, can swallow the extra 10mm of backfocus but that does limit my eyepiece selection considerable and, to me, represents a loss in capability and flexibility of the product with those scopes.
When I get the time, I'll contact Russ about this.
Posted 05 April 2013 - 02:27 AM
Posted 10 April 2013 - 06:33 AM