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Binoviewing issues

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#1 kenza

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Posted 12 October 2019 - 11:45 AM

Hi all!

 

Recently i acquired a new baader mark V bino to use with my CFF 140 after reading many great reviews here, especially the ones concerning the 2x pan 24mm combo for wide field. I also got the baader 1.25x GPC thinking that would be enough to reach focus. Unfortunately i was wrong. I am using a TV everbrite diagonal which eats up a lot of light path. I then switched to a TV powermate 2.5x and finally reached focus. So my final setup is TV everbrite 2” diagonal, TV powermate 2.5x , mark V bino and 2x pan 24mm. 

 

Then when i finally turned to the double cluster to test this combination i saw a huge amount of distortion starting from about 2/3 from the center and worsening towards the edges. The stars in the center were fine and sharp. What i mean by distortion is something resembling field curvature. The stars were elongated. When i tried viewing with the baader zooms there was  less distortion but that was probably because of a narrower field of view. I am baffled.

 

Any ideas?

 

Aleksandar



#2 kenza

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Posted 12 October 2019 - 12:37 PM

Could it be that because i am not using the baader gpc for mark V but rather a powermate that i get this spherical aberration?



#3 Eddgie

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Posted 12 October 2019 - 01:27 PM

Could it be that because i am not using the baader gpc for mark V but rather a powermate that i get this spherical aberration?

No, I don't think so.  I have used the 2.5x without any problem down to f/7, but I have not used eyepieces with field quite this wide. I know of others that have used the 2.5x with no problem as well.

 

You would not use both the GPC and the powermate.  One of the other.  In fact, I was going to ask if you were positive that you took out the GPC before installing the powermate. 

 

I am not at all sure what the problem is and I am not saying that it has nothing to do with the 2.5x, but I have used it with BV and it worked fine.  If one does not already have the 2.5x powermate, I think the Televue 2x binoviewer amplifer is the better way to go, but I have used both and they both worked well for me.

 

Wish I could help more.  Try using the BV in straight through mode on a terrestrial target like a distance car bumper glint to see how it works. 



#4 StarAlert

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Posted 15 October 2019 - 10:34 PM

No, I don't think so.  I have used the 2.5x without any problem down to f/7, but I have not used eyepieces with field quite this wide. I know of others that have used the 2.5x with no problem as well.

 

You would not use both the GPC and the powermate.  One of the other.  In fact, I was going to ask if you were positive that you took out the GPC before installing the powermate. 

 

I am not at all sure what the problem is and I am not saying that it has nothing to do with the 2.5x, but I have used it with BV and it worked fine.  If one does not already have the 2.5x powermate, I think the Televue 2x binoviewer amplifer is the better way to go, but I have used both and they both worked well for me.

 

Wish I could help more.  Try using the BV in straight through mode on a terrestrial target like a distance car bumper glint to see how it works. 

Will viewing with binoviewers be correct side up and right/left correct for terrestrial viewing? Or does one need an amici prism?



#5 Eddgie

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Posted 16 October 2019 - 07:31 AM

Will viewing with binoviewers be correct side up and right/left correct for terrestrial viewing? Or does one need an amici prism?

Standard binoviewers use no lenses of any kind so the image will be the same as it would for an eyepiece.


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#6 BillP

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Posted 16 October 2019 - 01:13 PM

Time for process of elimination.

 

Is diagonal the issue -> First try the original setup in you CFF but without the diagonal you used (target near the horizon so easy on neck).

 

Is Powermate the issue -> try the original setup in you CFF but without the diagonal you used and without the Powermate (you should be able to reach focus)

 

Is CFF the issue -> Then the original setup in your C11 (including the CFF's diagonal) so you eliminate the CFF140 (although may be too much magnification, but try).

 

I all the above show same problem, then its the binoviewer.


Edited by BillP, 16 October 2019 - 01:19 PM.


#7 kenza

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Posted 18 October 2019 - 03:52 AM

Update:

 

I am glad to say that the problem has been resolved. I already mentioned that I couldn't reach focus with the 1.25x Baader GPC and TV Everbrite because the large diagonal ate up too much light path so I had to use only the 2.5x powermate. A couple of nights ago a friend borrowed me his Baader T2-BBHS Sitall Diagonal mirror which has the shortest light path available so I was now able to use the GPC. I tried the pans 24 on the double cluster and it was perfect! No distortions were present and also the view was sharper. I tried also the zooms on Saturn and the planet was much sharper than when I used the powermate. My conclusion is that the Baader Mark V bino should be used with the dedicated Baader GPCs for best results. 

 

I also tried using the GPC and Powermate together ( in this scenario the GPC was placed before the diagonal) and although you get much more magnification the image  is a lot darker. I then tried two different setups: just the GPC with a high power eyepiece and just the powermate with a lower power eyepiece. In the end the magnifications were nearly the same, but the image with the powermate was clearly still darker. The image with the GPC was on the other hand was sharper and I could see more detail on Saturn. 

 

So in the end yes, it is possible to use both the GPC and powermate together but for best results it's better to use just the GPC and a higher power eyepiece or buy additional Baader GPCs (1.7x or 2.6x ). 



#8 Eddgie

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Posted 18 October 2019 - 10:39 AM

Well, I am surprised.  I have used the Powermate, and it worked fine, but I only recommend the powermate for people that already have the 2.5x powermate.

 

If people can reach focus using the GPCs and T2 diagonal, they are in my opinion the absolute best way to BV.

 

For a Dob, where it is not possible to reach focus with the GPCs, I recommend the Televue 2x as a better choice than the powermate, but if you don't already have a powermate and the use is going to only be for BV, then the Televue 2x is the best choice.



#9 rob.0919

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Posted 18 October 2019 - 11:32 AM

I would look at getting a Baader Prism as well if you can source one.

I personally would avoid using a powermate, and stick with the GPCs or maybe get a Barcon.

 

Remember both the 1.25 and 1.7x screw into the end of the Mk 5

If you get the 2.6 that (only that) goes in the diagonal

 

Good video here from Daniel.....

https://youtu.be/VUszP3-23P0




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