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MaxBright 2 setup confusion

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#1 Owk

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Posted 27 July 2020 - 09:10 PM

Hello Members,

 

I have never used binoviewers. I would like to buy the MB2’s. After many weeks of researching I’m confused!

 

My equipment:

 

Celestron C925, ES 102 CF APO, Baader Click lock 2in Diagonal, ES 2in dialectric diagonal.

 

My aims:

 

i would like to Binoview with both scopes, Primarily moon and planets but also widefield brighter DSO.

 

what do i need to make this work in addition to the binoviewer?

 

What GPC’s are needed/desirable to allow focus and offer different magnifications. Ideally to be able to use in both scopes.

 

Is a different diagonal needed/desirable?

 

Thanks in advance

 

 

Hemi

 



#2 swsantos

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Posted 27 July 2020 - 11:54 PM

I went through the same thought process myself a month ago. I have an 8” Edge HD, Televue 127 and Televue 85 and have been wanting to try binoviewing for a while now. I decided that I would build my binoviewer set up around the SCT to start with because it would give me the most light and might be the easiest to start off with because of the shorter moment arm.
 

Even though an SCT can come to focus without a GPC they seem to be highly recommended here for best color correction so I started with the lowest power one, the 1.25, to maximize the field of view. I already had one 24mm Panoptic so I bought the second one because they seem to be one of the favorites for the wide field viewing.

 

I really like my 2” Baader prism diagonal for mono viewing so I decided I would get the Baader T2 prism diagonal for the binoviewer to minimize the light path. Note that a T2 diagonal will provide a much shorter light path, so wider field of view, than a 2” diagonal.

 

I then figured I needed a planetary high power pair, so looking to get about 200X with the GPC, I got a pair of 12.5 mm Morphei. After using them and the 24mm Panoptics I will decide if I need something in between.

 

I did get the Universal Alan Gee II Telecompressor just to see what kind of wider field I might get with that but I have not yet tried it.

 

Once I get that all working with the SCT,  I will then see if the Televue 127 will come to focus with the 1.25 GPC and will then have to decide if I want to also use it with the binoviewer and if so what additional eyepieces and GPC, if any, I might then need. But I’m going to take it one step, one scope at a time.

 

Honestly, I am hoping that the Maxbright II on the 8” SCT give me all that I need from binoviewing. So far it has greatly exceeded my expectations!


Edited by swsantos, 28 July 2020 - 12:21 AM.

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#3 Owk

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Posted 28 July 2020 - 06:22 AM

Thanks SWS,

 

Im wondering why the 1.25 GPC and not the 1.8? 

 

If you keep the light path as short as possible, is there much correction required?

 

For wide field, you have the Alan Gee, thats fully corrected right?

 

sorry, if the questions are dumb, ive been observing and imaging for yrs but I cannot get my head around these BinoV setups.

 

....and finally how do you select eye pieces? there is a PHD thesis right there!

 

Cheers

 

Hemi



#4 swsantos

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Posted 28 July 2020 - 10:59 AM

I have read and it seems generally accepted that it is best to use a GPC even if the telescope can focus without it because it helps with color corrections needed because of the prisms in the binoviewer.

 

You can measure the back focus of your telescope then refer to the Maxbright manual to calculate that GPC you will most likely need in your setup. SCTs do not seem to need GPCs but benefit from them from what I have read and refractors often needs them.

 

The 1.25 GPC provides a wider field of view than the 1.8 and for me the name of the game is widest field of view with the lowest power through the 24mm Panoptics on the Edge. Remember that the GPC acts like a Barlow so the higher the number the higher the mag and the narrower the FOV.

 

For high power my skies are reliable to about 200X I normall observe with a 10mm Ethos with the 8" Edge 2000mm focal length for that 200X.

 

The 1.25 GPC will turn a 12.5mm eyepiece into 10mm so that is why I chose the 12.5 Morpheus.

 

The Alan Gee is designed to be used without a GPC but if I can I will try it with and without to see what happens. I am not even sure if both things can be chained together between the binoviewer and diagonal.



#5 Eddgie

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Posted 28 July 2020 - 01:45 PM

Hello Members,

 

I have never used binoviewers. I would like to buy the MB2’s. After many weeks of researching I’m confused!

 

My equipment:

 

Celestron C925, ES 102 CF APO, Baader Click lock 2in Diagonal, ES 2in dialectric diagonal.

 

My aims:

 

i would like to Binoview with both scopes, Primarily moon and planets but also widefield brighter DSO.

 

what do i need to make this work in addition to the binoviewer?

 

What GPC’s are needed/desirable to allow focus and offer different magnifications. Ideally to be able to use in both scopes.

 

Is a different diagonal needed/desirable?

 

Thanks in advance

 

 

Hemi

For the C9.25, you should use the Baader 1.25" T2 diagonal with the binoviewer connected directly to the top of the diagonal.    You can use that for general observing, and for the best planetary performance, you would want to put in the 1.25x or 1.7x GPC.  (1.7 is probably better).

 

For the refractor, for working at the widest field, you would probably once again want to use the T2 prism diagonal.  For planets but you may have to use a GPC to get it to focus but I can't tell you which one.  The 1.25" might work, but the 1.7x is a much safer bet.  

 

Again, you really only need the GPC for planetary observing where the goal is to get the best possible contrast.  For general observing it is not necessary, but I highly recommend that the T2 diagonal be used for the C9.25 with the BV directly attached.  The C9.25 goes into aperture reduction with much less flange to focal plane distance than the larger SCTs.  In fact, it is I think worse than the C8 with respect to aperture loss, so keep it short, and GPC up for planets.

 

If you were only doing planets I would recommend the Televue Bino Vue 2x amplifier. This would work fine with your 2" diagonal in both scopes and like the Baader GPCs, it fully corrects for spherochromatism. 


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#6 swsantos

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Posted 28 July 2020 - 09:27 PM

Trying the Panoptics on the binoviewer without the GPC for a wider field is next then finally trying the Alan Gee.

 

I am then planning on some planetary viewing still without the GPC then finishing up by putting it back on again to see for myself the effects of using or not using the GPC.



#7 Owk

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Posted 29 July 2020 - 07:16 PM

Thanks again guys,

 

Is it better to get the prism or mirror diagonal? And BBHS coatings or not?

 

my current thoughts are to go with

 

1. Baader zeiss bbhs T2 prism diagonal 

2. GPC in 1.25 ( wide field for the APO) and 1.7 (planets in the sct and apo)

3. Alan Gee 2 for wide field in the sct

 

have not even considered EP’s, but might have to get budgets initially....any recommendations here?

 

best

 

hemi



#8 swsantos

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Posted 30 July 2020 - 09:35 AM

I got the Baader T2 Zeiss BBHS and I like it a lot.

 

My Televue NP127 will not come to focus with the 1.25 GPC using the 12.5mm Morphei but will focus with the 24mm Panoptics so GPC 1.25 is borderline at least with that refractor. You might need the 1.7 GPC for your APO too and as always YMMV. I measured the backfocus on the NP127 and knew it was going to be close would recommend you measure your backfocus its easy.

 

The Alan Gee Universal that I got is OK. It does widen the SCT's field to just over 1 degree, similar FOV to a 21mm Ethos in mono mode (not AFOV rather the amount of space you are seeing about 1.05 degrees), but it is not as nice as the widefield I get with the NP127 and no Alan Gee. I would say I am glad I have it but its going to be for special occasions. My default wide field configuration with my SCT will be 24mm Panoptics without GPC only using the Alan Gee when I need more FOV for something specific.


Edited by swsantos, 30 July 2020 - 09:36 AM.


#9 Eddgie

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Posted 30 July 2020 - 09:56 AM

Thanks again guys,

 

Is it better to get the prism or mirror diagonal? And BBHS coatings or not?

 

my current thoughts are to go with

 

1. Baader zeiss bbhs T2 prism diagonal 

2. GPC in 1.25 ( wide field for the APO) and 1.7 (planets in the sct and apo)

3. Alan Gee 2 for wide field in the sct

 

have not even considered EP’s, but might have to get budgets initially....any recommendations here?

 

best

 

hemi

The primary difference between a prism diagonal (any prism diagonal vs any same size mirror diagonal) is the light path distance will be less for the prism.  This is because light slows down in glass so this has the effect of making the path appear shorter than it is physically.

 

For example, the Badder standard prism has a light path of about 39mm.  Due to the slightly larger prism, the Zeiss diagonal (is this still made) was about 43mm or something (I forget) and the mirror was something like 48mm.

 

The next difference, not really important for general observing, is that the prism will induce spherochromatism, but this is generally not much of an issue on slower telescopes.




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