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Binotron 27 Super System on the way! A couple questions

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#1 Blueox4

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Posted 10 January 2024 - 08:36 AM

After chatting via email with Russ over the last week or so and reading all I could here on the Binotron I have a Binotron 27 SCT Super system on the way! As Russ explained to me the SCT system works with refractors too which is how I will use it. The system comes with Denkmeier 1/10th wave diagonal, binotron body, power switch and OCS corrector. Also a matched pair of D21 eyepieces. So glad I went with the Binotron and Russ. It’s obvious Russ has a passion for what he does and what he makes. He added an adapter so I could also use my Baader 1.25” Zeiss spec prism diagonal with the binotron if I wish. I’ll be using the binotron with the following scopes:

 

AP155 EDT f/9

AP130 GTX

AP Stowaway

TOA-130NS w/ 3.5” FT focuser

 

with the power switch I think I can use fewer sets of eyepieces. With the D21’s and the above scopes what would be another useful pair of eyepieces to acquire? 



#2 bigdob24

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Posted 10 January 2024 - 08:56 AM

You may look at a pair of zooms. With the power switch you will have an assortment of usable magnifications to fit the conditions and you may never use a single power eyepiece againwaytogo.gif

Im happy with a set of Baader 8/24. I only observe our day star no experience with deep sky.


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#3 Eddgie

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Posted 10 January 2024 - 09:59 AM

 

 

AP155 EDT f/9

AP130 GTX

AP Stowaway

TOA-130NS w/ 3.5” FT focuser

 

 

 

The D21s are good eyepieces, but I am not sure that they are the best choice. In fast reflectors, I would recommend the D21s because at faster speeds, there is some noticeable vignetting using 24mm wide fields.  At f/5 in my 12" dob, I found the vignetting of 24mm wide fields a bit too much for me, but the D21s were fine. 

 

If you are using these refractors and have to use the OCS to reach focus, then you may get by with something wider than the D21s and possibly even 24mm Panoptics.  The shallower light cone of the refractors will probably not give the same kind of vignetting you would get with the 24mm Pans in a faster reflector.

 

The great unknown though, is how much you may be concerned with the uneven illumination of the field. This is influenced by your observing conditions and your own personal prefernece.

 

As I said, I think the D21s are perhaps the best choice possible for a fast dob, but with slower scopes, usually there is a desire to maximize true field, and the D-21s are going to steal some of that from you.   


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#4 Nerd1

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Posted 10 January 2024 - 12:13 PM

That is an impressive list of scopes you have,  I just sent back a pair of Williams Optics to Highpoint. There was so much wobble in the diopter, they were unusable.  I just bought a used pair of Denks, they should be in tomorrow.  I just bought a pair 18.2 Delites and 7mm Astrotech UWAs to go with them.  I would think a nice set of 32mm possls or maybe 11mm  Delites would be a good choice. On a night of exceptional seeing when you can really up the magnification. 


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#5 Blueox4

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Posted 10 January 2024 - 01:49 PM

When Russ and I discussed eyepieces he said he recommended the D21’s based on the fact I did not want to exclusively view the moon and planets and my viewing conditions. When it arrives and we get a clear night  will see. I’m not sure what the power switch will bring to the table  with the D21’s. I see me using the binotron mostly with my 155 f/9. Eddgie, what would you recommend for use in that scope? 



#6 betacygni

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Posted 10 January 2024 - 07:27 PM

With scopes of that quality I’d go with Takahashi TPL eyepieces. I’ve tried nearly every binoviewer friendly option (zooms, Delites, Brandons, panoptics, Morpheus, Masuyamas, Naglers, tak orthos, various plossls, etc) and they have become my favorite. They have the best planetary image quality and superb ergonomics for binoviewing. The 18mm, 25mm, and soon to be 33mm never leave my binotrons.

Edited by betacygni, 10 January 2024 - 07:30 PM.

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#7 lookoutmtn17

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Posted 10 January 2024 - 10:01 PM

I would suggest using the D21's for a while with the power switch and see how you like the different views before adding additional eyepieces. The D21's offer very good views and are light weight. I do like the pair of Morpheus 12.5mm eyepieces that I added, but they add a bit more weight than the D21's (8 oz total vs 24.4 oz total). 


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#8 BCEagleScope

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Posted 20 January 2024 - 04:11 PM

After chatting via email with Russ over the last week or so and reading all I could here on the Binotron I have a Binotron 27 SCT Super system on the way! As Russ explained to me the SCT system works with refractors too which is how I will use it. The system comes with Denkmeier 1/10th wave diagonal, binotron body, power switch and OCS corrector. Also a matched pair of D21 eyepieces. So glad I went with the Binotron and Russ. It’s obvious Russ has a passion for what he does and what he makes. He added an adapter so I could also use my Baader 1.25” Zeiss spec prism diagonal with the binotron if I wish. I’ll be using the binotron with the following scopes:

 

AP155 EDT f/9

AP130 GTX

AP Stowaway

TOA-130NS w/ 3.5” FT focuser

 

with the power switch I think I can use fewer sets of eyepieces. With the D21’s and the above scopes what would be another useful pair of eyepieces to acquire? 

Hi, I just bought a Binotron 27 set up for use in my 16" Teeter Dobsonian. I was interested to hear about your experience using them this past year. I have the binoviewer, ocs 45, powerswitch, collimation tool, and two 24mm panoptics. I don't anticipate switching the eyepieces out given the power switch magnification options. 


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#9 Eddgie

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Posted 20 January 2024 - 10:32 PM

 Eddgie, what would you recommend for use in that scope? 

While I think Denk may have slightly rolled down the actual power factors (these were the factors for the Denk 11, but the B27 has about 15mm longer light path so the powers should be slightly higher) let's go with the 1.3x because while you can always get higher powers with shorter length eyepieces, the #1 concern with most BV users is the small true field limit imposed by 1.25" eyepieces.

The D21 has a field stop size of 24.4mm (as I recall). With the 1.3x OCS, your effective focal length is going to be about .77 degree true field.

 

While it does not sound like much, using 24 Pans will open that up to .85 degrees. Again, that is a very small improvement, but as I said, the narrow true field is about the most common complaint you will ever hear about binoviewers. The Pans also have a slightly wider and more immersive apparent field of view.

 

The Panoptics also have excellent ergonomics. The Explore Scientific 24s have an even larger true field (just shy of .86 degree) but the ES eyepieces are quite fat at the top and have short eye relief, so even though they have one of the largest true fields, they also have the worst ergonomics so I don't recommend them.

 

At the top end, the D21s have a actual focal length of 21.6mm, so your high power would be about 200x while the 24 Pans will be only about 180x so the D21 would likely give a high power that had a bit smaller exit pupil and give a little better planetary reach. That being said, if you routinely use higher powers, you are going to be swapping out the eyepiece anyway. 

 

The strengths of the D21s are that they are very light, and while they have a narrower apparent field, the have almost zero pincushion distortion. I personally don't mind pincushion distortion, but some people that like to pan around dislike it.  Also, while the apparent field is bit smaller, it is actually easier to take in the entire field. With the Pans,  you feel more like you have to move your eyes side to side or up and down to explore the whole field, but for some reason, with the field just seems to be there in front of you in the D21s and even a very slight left/right/up/down movement of the eye is required to feel like you are getting all of the field. 

 

Not that you would be interested, but currently I use a pair of 25mm Celestron X-Cel eyepieces, and I actually love them. They have a narrower apparent field than either of the above choices but they are even better than the D21s when it comes to the ability to simply look in and feel as if you are enjoying the entire field without having to roam your eyes around. Apparent field simply does not seem so important when you are using both eyes as it does when using one eye, and if the D21s offer you the ability to take in most of the field with very little eye movement, the X-cels are even better. There is zero distortion and the apparent field is wide enough to still give some immersion, but you just seem to see all of the field rather than most of the field. The field stop is 26mm, so they offer almost as big a field as the 24mm pans, and they have excellent eye relief. They are also very light. Not that it looks like cost is a factor for you, but the 25mm X-Cel is my top recommendation for an inexpensive low power binoviewer eyepiece for use in refractors.  

 

There are no bad choices among these. The 25mm X-cel is a surprisingly good low power binoviewer eyepiece at a great price and a good compromise between wide true field and natural view.  The D-21s offer a bit wider apparent field that strikes a great balance between the X-cel and 24mm Pans, and the Pans offer the widest true field, the widest apparent field, and outstanding ergonomics, but at the penalty of some extra weight. 

 

I will say it once again though: If you spend any time at all on the binoviewer forum, you will find that number one complaint interviewers get is the narrow true field. If you don't usually use your scope for larger objects and instead do a lot of doubles, galaxies, small clusters, planetary nebula, and planets, the D21s are probably the best choice here, but that small difference in true field that you get with the 24mm Pans while small, is still big enough, that combined with the extra apparent field and the bit bigger exit pupil, gives maybe the most immersive field of these. 

 

I know that this is not actually advice on which of these is "best" and I don't like to really to make that kind of judgment as to what the "Best" choice because I can't really know what is most important to you, but I can tell you that any of these are great choices. Pick the characteristics that you think best suit your observing needs and preferences.

 

And whatever you get, please share your observing experiences when you have had a chance to use them.

 

Have an epic time! 


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