Baader Maxbright Binoviewer

[ukskies]

On 30/04/2023 at 22:38, mikeDnight said:

I've never used a gpc but have used a 2X barlow on the nose of the binoviewer. 

Mike when you say Barlow do you mean a conventional Barlow or a more specialised one, like this William Optics one for example?

https://www.firstlightoptics.com/binoviewers/william-optics-binoviewer-2x-barlow.html

 

[Space Hopper]

If its of help, the focusing range using the Baader binoviewers / gpc's on refractors is about 65mm.

ie the point where / if you can focus natively without a gpc to where you can focus using the 2.6x gpc.

This is important if you have a focuser with limited range. The secret is to try and reach focus sans gpc with the focuser almost fully racked in.

Native focus is tricky to achieve though when you add up the lightpath of both the binoviewer and diagonal. Not many scopes will offer this, but usually something optimised for imaging will get you close.

If you can't focus, the 1.25x , 1.7x and 2.6x gpcs will give you back 20mm, 35mm and 65mm respectively.

[Franklin]

I've used a MaxB1 with a T2 32mm prism diagonal and 1.7x gpc and could reach focus, though there wasn't a lot of drawtube out if memory serves me. I've got a MaxB2 on order and when it arrives I'm hoping to be able to reach focus with the 1.25x gpc though only an extra 20mm might be pushing it. My plan is to purchase the 1.25x gpc from FLO and if it is insufficient to take advantage of their excellent returns policy and swap it for the 1.7x gpc, which I used to own and should never have sold.

[ukskies]

33 minutes ago, Space Hopper said:

If its of help, the focusing range using the Baader binoviewers / gpc's on refractors is about 65mm.

ie the point where / if you can focus natively without a gpc to where you can focus using the 2.6x gpc.

This is important if you have a focuser with limited range. The secret is to try and reach focus sans gpc with the focuser almost fully racked in.

Native focus is tricky to achieve though when you add up the lightpath of both the binoviewer and diagonal. Not many scopes will offer this, but usually something optimised for imaging will get you close.

If you can't focus, the 1.25x , 1.7x and 2.6x gpcs will give you back 20mm, 35mm and 65mm respectively.

It's a dark art Rob.🤣

Thanks, I think I'm gradually beginning to understand the mechanics of it and thanks again for all the help.

The back focus measurements will be especially helpful.

Edited May 2, 2023 by ukskies

[ukskies]

14 minutes ago, Franklin said:

I've used a MaxB1 with a T2 32mm prism diagonal and 1.7x gpc and could reach focus, though there wasn't a lot of drawtube out if memory serves me. I've got a MaxB2 on order and when it arrives I'm hoping to be able to reach focus with the 1.25x gpc though only an extra 20mm might be pushing it. My plan is to purchase the 1.25x gpc from FLO and if it is insufficient to take advantage of their excellent returns policy and swap it for the 1.7x gpc, which I used to own and should never have sold.

That's going to be an interesting comparison then, please update us later with how that works out.

[MalcolmM]

2 hours ago, ukskies said:

Just looking at your setup picture and wondering so I thought I'd just ask instead. 😆

When you are in focus on the above setup how much of the drawtube is extended? No need to measure Malcolm just approximate please if you can, it would help me understand the back focus a bit.

With the Tak 28mm Erfles in, the focuser is racked out about 14mm. Total range is about 30mm

Malcolm 

[MalcolmM]

@ukskies, to come to focus with the 1.7 GPC, I put a 15mm extension between the prism and the nosepiece. Now the focuser is racked out about 11mm.

Here's the 1.25 setup:

And here's the 1.7 GPC setup.  Note the T2 extension attached between the prism and it's nosepiece. Hope this all makes sense! It's a bit of a black art!

I don't have the 2.6 GPC but it would probably require a longer extension. You could work it out from the respective light path gains the 2.6 gives you w.r.t. the 1.7 and 1.25

Malcolm 

[MalcolmM]

And just for completeness (I'm enjoying this 🙂and it's good to record it all), here's the native setup, no GPC. Note the Tak coupling has had to be removed to shorten the light path enough!

I don't really like doing all this screwing and unscrewing in the dark, so I try to set it up before observing, depending on what I'm observing!

Malcolm 

[ukskies]

Malcolm, thank you for posting these detailed pics they are brilliant and a great help.

I now understand it all. It really helps that we have the same scope plus I want the Clicklocks too. A picture is worth a thousand words eh?

[Paz]

1 hour ago, Franklin said:

I've used a MaxB1 with a T2 32mm prism diagonal and 1.7x gpc and could reach focus, though there wasn't a lot of drawtube out if memory serves me. I've got a MaxB2 on order and when it arrives I'm hoping to be able to reach focus with the 1.25x gpc though only an extra 20mm might be pushing it. My plan is to purchase the 1.25x gpc from FLO and if it is insufficient to take advantage of their excellent returns policy and swap it for the 1.7x gpc, which I used to own and should never have sold.

I can get to focus with the 1.25xgpc and the t2 baader prism diagonal using my 102mm f7 scope but I have to place it in front of the diagonal which ups the magnification a bit and also creates enough headroom to get to focus. The 1.7x and 2.6x gpc's I can use in the right place or place them further forward out of choice for more magnification or for more infocus if I'm using other contraptions that take up more light path that have to be allowed for.    

[MalcolmM]

4 minutes ago, ukskies said:

A picture is worth a thousand words eh?

Totally agree! Now all we need is for someone to come along with a better way of doing it! So I set it up a certain way and then change eyepieces to change magnification. I think @Stu does something slightly different for example. He uses the same eyepieces, but changes Barlows and/or adds extension tubes ... I think!

Malcolm 

[mikeDnight]

3 hours ago, ukskies said:

Mike when you say Barlow do you mean a conventional Barlow or a more specialised one, like this William Optics one for example?

https://www.firstlightoptics.com/binoviewers/william-optics-binoviewer-2x-barlow.html

 

I use a 2X Ultima SV Barlow at present, but I have used a Skywatcher Deluxe 2X Barlow and had amazing views. The SW Deluxe can unscrew so you can then screw the Barlow lens directly onto a 1.25" nose piece of the binoviewer, or use it attached to its Barlow body to give a little extra magnification. I prefer using the full Barlow. It is still only short and so doesn't pause any issues.

 There's a 2X Ultima SV for sale on ENS at the moment. I think most modern Barlow are optically very good though!

[Paz]

6 minutes ago, MalcolmM said:

Totally agree! Now all we need is for someone to come along with a better way of doing it! So I set it up a certain way and then change eyepieces to change magnification. I think @Stu does something slightly different for example. He uses the same eyepieces, but changes Barlows and/or adds extension tubes ... I think!

Malcolm 

I started out by changing gpc's and keeping the eyepieces the same but I find it is not an easy operation changing gpcs in the field, plus the way they change the optical path length means having to rebalance the scope. These days I usually pick one gpc and stick with it for a session, and change eyepieces for different magnifications once I'm out in the field. I'll also make use of extensions or change the placement of a gpc to adjust magnification but again I'll decide on that when setting up and won't usually change it during a session. 

[ukskies]

21 minutes ago, mikeDnight said:

I use a 2X Ultima SV Barlow at present, but I have used a Skywatcher Deluxe 2X Barlow and had amazing views. The SW Deluxe can unscrew so you can then screw the Barlow lens directly onto a 1.25" nose piece of the binoviewer, or use it attached to its Barlow body to give a little extra magnification. I prefer using the full Barlow. It is still only short and so doesn't pause any issues.

 There's a 2X Ultima SV for sale on ENS at the moment. I think most modern Barlow are optically very good though!

Many thanks Mike, that's more great info, are you still using the helical focuser with this setup too? I've got one on my T-2 prism and like it for mono viewing, it's just so smooth and it seems more intuitive to find in the dark too.

 

 

 

 

 

i

[ukskies]

43 minutes ago, Paz said:

I can get to focus with the 1.25xgpc and the t2 baader prism diagonal using my 102mm f7 scope but I have to place it in front of the diagonal which ups the magnification a bit and also creates enough headroom to get to focus. The 1.7x and 2.6x gpc's I can use in the right place or place them further forward out of choice for more magnification or for more infocus if I'm using other contraptions that take up more light path that have to be allowed for.    

Thanks Paz, this is more excellent info and a big help.

[Stu]

1 hour ago, MalcolmM said:

I think @Stu does something slightly different for example. He uses the same eyepieces, but changes Barlows and/or adds extension tubes ... I think!

Yes, I do it differently because I’m a little bit weird 🤪🤣.

For starters I use a Feathertouch focuser with 2.5” travel. Not sure how that compares with either the DC or DF, or whether it changes the amount of back focus available. I think on the DC there is the removeable green section which gives more; there’s a few threads somewhere on the forum with details if anyone needs that.

Because I find changing the two eyepieces and then balancing focus again a bit of a faff, for years now I have stuck with 25mm ortho eyepieces with a x1.7 GPC, and the Barlow element from an AP Barcon on the nose of the binoviewer. Then I can add extensions using T2 QuickChangers to vary the mag. It can lead to a long stack which is a little unwieldy, and I would not necessarily recommend it to anyone sane, but it works for me.

I do now have some more eyepiece pairs; 20mm Vixen LVs, and 10mm and 6mm BCOs which work well.

One comment on using them. With a single eyepiece, especially a wide field one, you can look around the field to take in what is there. With binoviewers you tend to lose one channel or the other if you do this, so observing is best done on axis, and just pan the scope if you want to see something else. As a result, I’ve never really seen the point in using widefield eyepieces, and tend to stick with orthos or plossls. Most of my binoviewing is high power solar or lunar so that works well for these targets.

Obviously others may have different, and equally valid views. One thing is for sure, and that is binoviewers are a very personal experience in that some love them, some just don’t get in with them, and others like myself take a long time to train their brains to use them, but now do love them.

[Franklin]

8 hours ago, Paz said:

I can get to focus with the 1.25xgpc and the t2 baader prism diagonal using my 102mm f7 scope

That's good to hear. Do you think the 1.25xgpc in the diagonal nosepiece position gives more or less amplification than the 1.7xgpc in it's native position just before the binoviewer?

[mikeDnight]

9 hours ago, ukskies said:

Many thanks Mike, that's more great info, are you still using the helical focuser with this setup too? I've got one on my T-2 prism and like it for mono viewing, it's just so smooth and it seems more intuitive to find in the dark too.

 

 

 

 

 

i

  Yes, I mainly use the helical focuser with the Baader prism, though I have a 2" click lock that I can also use on it, but i think that adds a bit more length to the system, and with the FC's that can sometimes be a problem. At times I also use the Tak prism which has a slightly shorter light path than the Baader. 

[Highburymark]

13 hours ago, Stu said:

Yes, I do it differently because I’m a little bit weird 🤪🤣.

For starters I use a Feathertouch focuser with 2.5” travel. Not sure how that compares with either the DC or DF, or whether it changes the amount of back focus available. I think on the DC there is the removeable green section which gives more; there’s a few threads somewhere on the forum with details if anyone needs that.

Because I find changing the two eyepieces and then balancing focus again a bit of a faff, for years now I have stuck with 25mm ortho eyepieces with a x1.7 GPC, and the Barlow element from an AP Barcon on the nose of the binoviewer. Then I can add extensions using T2 QuickChangers to vary the mag. It can lead to a long stack which is a little unwieldy, and I would not necessarily recommend it to anyone sane, but it works for me.

I do now have some more eyepiece pairs; 20mm Vixen LVs, and 10mm and 6mm BCOs which work well.

One comment on using them. With a single eyepiece, especially a wide field one, you can look around the field to take in what is there. With binoviewers you tend to lose one channel or the other if you do this, so observing is best done on axis, and just pan the scope if you want to see something else. As a result, I’ve never really seen the point in using widefield eyepieces, and tend to stick with orthos or plossls. Most of my binoviewing is high power solar or lunar so that works well for these targets.

Obviously others may have different, and equally valid views. One thing is for sure, and that is binoviewers are a very personal experience in that some love them, some just don’t get in with them, and others like myself take a long time to train their brains to use them, but now do love them.

Just to be aware Stu - unlike the Baader MkIV and MkV, the 1.7x GPC is supposed to go in the diagonal with the MBII, not in the binoviewer. Alternatively, you can reverse the elements within the GPC and continue using it inside the binoviewer. Otherwise, images will probably be slightly soft - that’s what I found.

[Paz]

6 hours ago, Franklin said:

That's good to hear. Do you think the 1.25xgpc in the diagonal nosepiece position gives more or less amplification than the 1.7xgpc in it's native position just before the binoviewer?

That's a good question, I think less from memory but I can measure it directly, clouds permitting, and feed back.

[Stu]

50 minutes ago, Highburymark said:

Just to be aware Stu - unlike the Baader MkIV and MkV, the 1.7x GPC is supposed to go in the diagonal with the MBII, not in the binoviewer. Alternatively, you can reverse the elements within the GPC and continue using it inside the binoviewer. Otherwise, images will probably be slightly soft - that’s what I found.

Thanks Mark. I’m pretty sure I’ve reversed the element so it is correct but will check. You can’t reverse the x2.6 so I always use it with the flat surface towards the binoviewers.

Question though, why would the orientation of the elements be different between a Mark IV/V and a MaxBright II? I’m a bit confused by that.

[Franklin]

Only had the MB 1 up to press and all the gpc's could go in the diagonal top, inside the T2 thread or inside the diagonal nosepiece which used the plastic ring to center it. Should have my MB 2 by the weekend so will see how different it is then. I see FLO list model-specific gpc's so it looks like the MB 2 will be different.

[ukskies]

Maxbright II is inbound. Whilst posting and reading this thread I was keeping a close eye on FLOs stock levels and suddenly last night it was on 1 so impulsively I ordered it! 🤣

[Highburymark]

9 hours ago, Stu said:

Thanks Mark. I’m pretty sure I’ve reversed the element so it is correct but will check. You can’t reverse the x2.6 so I always use it with the flat surface towards the binoviewers.

Question though, why would the orientation of the elements be different between a Mark IV/V and a MaxBright II? I’m a bit confused by that.

Good question - and I don’t know the answer. It was only playing around with the 1.7x indoors (I mainly use the 2.6x now for solar and lunar) that I realised it was not producing the super sharp views it had in the past - and it was a CN thread that pointed out the change, which I had failed to pick up on when I bought the MBII.

[Paz]

16 hours ago, Franklin said:

That's good to hear. Do you think the 1.25xgpc in the diagonal nosepiece position gives more or less amplification than the 1.7xgpc in it's native position just before the binoviewer?

I've checked and the 1.25x in front of the t2 prism diagonal does give less magnification than a 1.7x at the rear of the diagonal. I eyeballed it with a microguide eyepiece on the moon and the difference in magnification looked to be roughly in correct proportion to their relative stated magnifications. That was with a 1.25" nosepiece into the scope from the diagonal.

I should add I can get to focus with the 1.25x behind the diagonal but that means using a 2" to t2 straight into the diagonal  which I don't like to do as it means having to mess with the 2" twist lock on the scope to rotate the binoviewer and I hate twist locks (!).  It also entails winding the diopter adjusters on each side most of the way inwards to make it to focus.

Here's how the moon looked through the clouds!

Edited May 3, 2023 by Paz