First view with a binoviewer - Eddgie's fault!!!
Posted 11 September 2013 - 06:24 AM
Reading the Binoviewers Forum just to keep an eye on things, I came accross a lot of sagely advice from Eddgie on a variety of topics. His enthusiastic support for binoviewers tipped the scale and I got me a Burgess Binoviewer with 1.9 OCA and 2x WO 20mm eyepieces for $100 on CN Classifieds to try out. So I thought to swing my Stellarvue 90mm APO smack on the double cluster to see what it's all about.
I first popped the binoviewers in and focused the eyepieces. Nothing much there, just some stars. Turned the scope to the double cluster and aimed with my RDF as it is a naked eye object at my location. A lot of words beginning with the letter f came streaming out of my mouth. I was gob smacked. First time I used binoviewers and I had no issues with merging the images immediately.
In a matter of milliseconds, I found myself literally dropping through the eyepieces into a rich 3D field which framed the double cluster perfectly. The feeling was literally one of falling into a void full of sparkling jewels. I could clearly "see" depth of field. What amazing tricks the mind plays on us!
Those 10 - 15 minutes I invested in observing the double cluster were full of pure joy. I felt exactly like back on 06 December 2010 when I walked out of my apartment at 04:15 am armed with my Celestron XLT150 on a CG4, a Celestron 8-24 zoom and a huge mug of coffee, determined to see Saturn for the first time.
It was love at first sight and the same happened with the binoviewers. It is time to seriously attack the moon with those babies this weekend and take a moonwalk baby!
So, Eddgie, my sincere thanks for the time and effort in promoting binoviewing plus your detailed explanations on so many aspects of using binoviewers. My bank account will not be so thankful as I plan to get a better unit now, but what the heck, you only live once
Posted 11 September 2013 - 07:55 AM
I am so very pleased that your first experiecne with binoviewers was so positive, but your experiences have only just begun. I can't wait until you look at the moon the first time!
Binoviewer equipment is the most complex of all equipment purchases I think, but buying something like the Burgess units is a great way to get your feet wet with an almost risk free investment (If didn't like it, you could sell them for mostly what you paid for them).
We are all looking forward to some of your first impressions when you look at the Moon or even the Sun (white light solar has become very interesting to me becasue of the binoviewers making the sun look so much more like a ball. Silly, but true. The sun looks more like a ball than a flat circle).
Again, I am thrilled that you enjoyed the view, and I hope that you continue to enjoy binoviewing.
Posted 11 September 2013 - 08:50 AM
Recently I just picked up a Celestron 102g and can't wait to use the WO on it for the moon this week. The moon is in prime time viewing right now.
Question, did you have to use the 1.9x OCA to get it to focus? Is this pretty much making your 20mm EP's perform like a 10mm now?
Have fun with them and check out Saturn before is heads over the hills.
Posted 11 September 2013 - 08:55 AM
And yes, it makes it perform like a 10.5mm eyepiece. However my SVR90t has a focal length of 630 so I got like 60-62x yielding 1 degree TFOV.
Posted 11 September 2013 - 09:35 AM
Posted 11 September 2013 - 09:56 AM
Posted 11 September 2013 - 10:10 AM
Posted 11 September 2013 - 02:49 PM
A friend of mine brought his Denk IIs that had been modified by Denk so that the WO dielectric diagonal directly attached to the BVs without the top eyepiece barrel.
Fitted onto my TMB 130 with FT3545 focuser, this shortening of the light path allowed me to get relatively WF views at 1x without an OCS. Focusing with 24 Pans, I still had 30mms of in-focus remaining!
I'm used to viewing through a 100mm binocular telescope and I have to say I was impressed with the views through the BV'd 130mm. Sweeping the MW was a treat with views very similar to the BT but I have to admit, the stars were a bit more pinpoint in the refractor. The 24 Pans provided 38x and a 1.72° FOV. Nice!
I also tried 19mm and 12mm eyepiece pairs on MW targets and the views were also great, albeit getting a bit dim with the 12mms at 76x.
Will have to try this combo out at higher mags. for lunar/planetary where i'm hoping my floaters will have less negative effects.
I'll have to consider a BV of my own in the future; doubling up on eyepieces is freaking me out a bit, I confess. I wonder if the Power Switch assy. would still work out with the additional 30mm of inward travel the FT still has left...
I also want to thank Eddgie and all for a lot of insight into BVs on this forum!
Posted 11 September 2013 - 06:17 PM
Posted 11 September 2013 - 08:20 PM
Congrats...now onto the eyepiece forum...see you there!
Posted 12 September 2013 - 01:37 PM
I had a 2" diagonal and with the 1.9 OCA I had about 3-4 mm available in focus travel. So no go without the OCA, that's for sure!
And this is always the issue with binoviewers... Most refractors will not reach focus without some kind of OCS.
If on the other hand, you keep the light path very short, you might be able to reach focus, but if you can't, then you need less GPC.
This is what makes the Maxbright and T2 Prism so attractive. I keep promoting these because in most cases, you will be able to get as large a true field with the Maxbright as you will with a bigger prism unit because you can get buy with less OCS.
If you can reach focus with the 1.9 GPC, then there is a chance that you could reach focus with the Maxbright/T2 Prism with a 1.25X GPC.
Even though the prism is smaller, the fact that you need less OCS means that in the end, you come out with the same size true field as you do with a Denkmeier or Mark V!
Sure, these units have bigger prisms allowing the use of lower power eyepeices, but you are soaking all of that lower focal length by having to go up in OCS.
And if you can reach focus with the Maxbright with no OCS, then you are in Binoviewer heaven.
At some point, you are going to want the extra true field, and that is when it gets very complicated. Make sure you do the math though.
A lot of people think the Maxbrights are overpriced for the aperture, but you have to look at it like this: Baader sells a "System" approach that is highly adaptable. The Maxbright T2 Prism makes it the shortest possible light path in a conventional binoviewer, and the more you do the numbers, the more you realize that light path really does matter.
Don't get me wrong. I love my Mark Vs.
But for a third of the price, you can put together a complete Maxbright system that will probably give the same size true field in most refractors without cutting the tube as you could get in the Mark V because of the higher OCS required.
Baader did their homework.
As an aside, in the past, there was a lot of discussion as to why the 21mm Hyperoin only had a 65 degree AFOV vs the 68 in all of the rest.
As it turns out, the 21mm Hyperion has a 22.5mm field stop.
Now funny thing is, that is almost exactly the size of the aperture in the Maxbright.
See? I think Baader thinks about these things, and I think the 21mm Hyperion is the "Denk D21" eyepiece for the Maxbright. My bet is that it was tweaked to allow the widest possible field without vignetting in the Maxbright in the same way that the D21 is perfectly matched to the low power mode of the Denk Supersystem.
Or maybe it was a coincidence, but the more I work with Baader stuff, the more convinced I have become that Baader is 100% "System" oriented. It all has to work perfectly together. No one does it like Baader.
Posted 13 September 2013 - 12:07 AM
The Maxbrights are definitely on my short list of astro gear. So basically 1.25" eyepieces with a field stop of 22 - 22.5 will not produce any vignetting, correct?
I wonder if anybody ever made a list of current EPs available with their field stops. Don Pensack made one. Now if only I can find it...
As for refractors, I can always find a binoviewer friendly model (Stellarvue SV110ED-BV used), or try Teleskop Service in Germany. They have up to 90mm APOs with detachable tube parts which allow for a really shirt light path, or alternatively I can ask them to make a Newt which is binoviewer friendly.
I am kicking myself now because I am about to receive a 6" Newt custom made from them and when I ordered it they gave me the choice to get the model suitable for astrophotography and add a 35mm extension on the focuser for visual and I said "thank you very much but I don't want to use an extension".
If only I had tried the binoviewers a couple of months ago! Still, one learns from one's mistakes...
I guess for such a project I would have to ask for a slightly larger secondary and for the primary mirror to be mounted higher in the tube, but that is for much later. For the time being, I have a date with the moon this weekend.
Posted 13 September 2013 - 07:27 AM
I have though, used the ES 20mm 68. This eyepiece has 22.8mm field stop and with this eyepiece, one barrel of the Maxbright had a very tiny bit of vignetting in one part of the field.
I used 19mm Pans though, and they did not, and they have a 21.3mm field stop. And by the way, you can often find the field stop sizes by just typing in the eyepiece and "Field Stop Size".
Anyway, the fact that the 19mm worked fine but the 20mm with the bigger field stop had a tiny amount of light cutoff in one part of the field kind of gave me the feeling that the 21mm Hyperion with its 22.5mm field stop was "Tuned" to the Maxbright. I don't know this for sure, but otherwise it would be odd that all of the other Hyperions are 68 degree AFOV, and the 21mm is 65 degree.
Once again though, I have not tried it, but based on what I have tried, I think it would be a good match.
Maybe someone that has tried it will chime in because I had thought about getting a pair.
Posted 14 September 2013 - 08:26 AM
Reading threads like this are moving my purchase to sooner rather than later!
Posted 14 September 2013 - 08:45 AM
I have read a lot of good reviews on the 19 in BV
Posted 14 September 2013 - 09:31 AM
I'm considering the D21's, I've been chewing over the cheaper es20-24's as well. I doubt the es's are quite as cool for binoviewing though, they look pretty chunky at the top and it seems the D21's will give you that little extra down the eyepiece...
Binoviewers are pretty complicated though, so I often feel like I'm making it up as I go along.
Posted 14 September 2013 - 01:23 PM
I would go with the Denk 21s though. They really are the best eyepecie for the low power arm in the Binotron I believe.
Russ told me that the focal length of the D21s is actually 21.6mm, but he can't call them "22mm" or some people might complain.
And the 19mms are going to give way to much power in your scope with the high power I think.
Remember when you use binoviewion, the view is a but dimmer. You may find that powers you used to use in mononvision are not too high. Maybe not, but I sure do.
But I see more detail at lower powers with binoviewers than I did with higher powers in monovision, so this is not a factor to me. Can't say your result will be the same as mine, but I find that the loss of brightness can be compensated for just by using a bit lower magnification.
Anyway, that would be my advice.. Bite the bullet and get the D21s if you are going to use the low power arm of the Binotron.
A bit less expeinsive option is a pair of 20mm ES 68s. I used these with the Binotron and they worked great, but you loose a bit of true field vs the D21s (22.8mm field stop for the ES vs 24.7 for the Denk, so and 8% bigger field for the Denks. Expensive, but bigger). Remember though that this makes the high power arm very high. Don't forget that binoviewers make the C11 more like 6000mm focal length in high power (much more than this in medium power) so the difference with the D21s is a more manageable 277x, vs 300x with the 20mm ES eepeices. Don't forget the binoviewer dimming when you think about using such a small exit pupil AND a binoviewer.
Posted 14 September 2013 - 03:53 PM
Posted 14 September 2013 - 05:12 PM
What the Mark Vs don't like though is the cone taper on the ES 24s.. I hate them. I really hate them. I mean I love the performance, but I have trouble getting them to center in the Mark V because they want to tilt, and when you tighten, they straighten, but don't bottom, so they come to rest at different heights and not always against the top of the diopter.
I have considered replacing them with 24 Pans but the 24 Pans cost to much.
I hate that taper. I hate it. I am sure that it is find in a 1.25" compression holder, but I hate that I have to fuss with them in the Mark V a lot.
Posted 14 September 2013 - 05:48 PM
Posted 14 September 2013 - 06:13 PM
Posted 15 September 2013 - 08:42 AM
Posted 15 September 2013 - 05:08 PM
The views of the moon and planets are truly amazing.