Baader Maxbright Binoviewer

[Franklin]

On 02/05/2023 at 16:02, Space Hopper said:

Sorry if i gave out wrong information with regard to 1.7x GPC placement on the Max 2.

I was confused by all of this as well. There are two versions of the 1.25x and 1.7x GPC, one for fitting in the top of the diagonal and one for fitting into the Zeiss Micro Bayonet dovetail on the binoviewer. These models are differentiated by the letter "Z" for Zeiss at the end of their respective product codes. The lens element in each is a cemented doublet and as you say, it is possible to unscrew the retaining ring and flip the element over. Baader states that this is not advisable for the 2.6x GPC as it is not a cemented doublet and this is why it is always placed in the diagonal top. Whichever configuration you place the 1.25x and 1.7x GPC in, the convex side of the element needs to be pointing skyward.

I found all this out today whilst playing around with my new MBII, I ordered the 1.25x GPC with the "Z" at the end because it's all they had in stock at FLO. Not having a Quick Changer to use it with the Zeiss Micro Bayonet I had to reverse the element which went well and all is working as it should. I was hoping the 1.25x GPC would allow me to reach focus when in the diagonal top position but unfortunately it is a little short. Placing the GPC in the diagonal nosepiece top allows focus with some drawtube to spare which is a result although I am not quite sure how placing it here affects the amount of amplification. I think I will just get the 1.7x GPC when they are back in stock at FLO because I know that will work fine in the diagonal top position and the amplification will be much smaller than using just a regular 2x barlow, mine is the 2.25x Q-Barlow and seems to give crazy high magnifications when used with this set up.

[ukskies]

Just a quick update.

First, many thanks to all of you for your helpful contributions to this thread, you helped me decide.

I now have in my possession one Maxbright mk II binoviewer and I have ordered another Baader mkIV zoom (I already own one) and a 2.6 glasspath corrector which will be delivered when the GPC comes into stock, this should be within two weeks.

I feel that having the zooms will give me a great magnification spread whilst I'm experimenting to find what works best for me and offers a low cost option too. I can change the adjustable eye cups with the plain rubber ones that come with the zooms.this will give me another 10mm of additional clearance for my nose and about 18mm space altogether.

[Franklin]

18 minutes ago, ukskies said:

I now have in my possession one Maxbright mk II binoviewer and I have ordered another Baader mkIV zoom (I already own one) and a 2.6 glasspath corrector which will be delivered when the GPC comes into stock, this should be within two weeks.

That will be an awesome set up with your FC100, a mag range of about 80x to 240x with the MK IV zooms, nice!

Edited May 11, 2023 by Franklin

[ukskies]

Hi again everyone, a quick update.

The 2.6x GPC held things up a bit but I told FLO that i would wait for it to arrive and they could send the (second) zoom and another BST 5mm all together. In the meantime I fitted the More Blue 12 to 1 MEF unit and removed the helical focuser and screwed the Binos straight onto the T2 diagonal, the Maxbright case is designed to hold the viewers and T2 diagonal whilst attached.

This meant that I couldn't do much with the binoviewer except cover it to keep the drool off until my second delivery arrived. Well it arrived on Wednesday.

Working Thursday meant no late night Wednesday so I decided to wait until Thursday (last) night for a play hoping the clouds would give me a break. 

Thursday evening, Luna was up way before dark so I thought this ideal for my first play with the Maxbright as I would be able to see what I was doing. Got the frac out on the old vixen mount, pointed it at the Lunar terminator and powered up the drives.. This meant i wouldn't be far off the target once I was ready to view.

I have a 2" nosepiece on the T2 and this went into the Tak 2" tube adapter so no loss of inward focus travel. I then popped in the 2.6 GPC and slid the scope forward almost all the way through the clamshell, added the two zooms and checked the balance. It was close but very slightly back end heavy though not by much so I figured the motors would cope with it and they did.

Next it got frustrating!

Both zooms set on 24 and I could not reach focus. With the focuser wound fully in there was simply not enough inward travel to reach focus. Checked the Maxbright manual and yes I've got the GPC in as shown facing into the diagonal but it wouldn't quite reach focus. out comes the GPC and yes the zooms just reached focus but the focuser was racked out only a half mm I'd guess. I tried the zooms at various settings but at the 8mm setting I could not achieve focus.

Finally I tried the two 5mm BST's. Focus was achieved with less than 2mm of outward travel but I was now able to set the diopters for the sharpest image in both eyepieces.

I decided to spend some time viewing now as it was getting dark and I had the moon up and visible though bits of cloud were now interfering (normal service) so I had 148X mag in both eyes for the first time and I attempted to be subjective about the view. The seeing from my town garden looking west over a block paved area that's six feet above scope level and with houses behind that after a very sunny day was not the best, Luna was constantly rippling in the unsteady air. There was however something about the Bino viewing that I liked, It was certainly very comfortable and relaxing compared to the Cyclops view I'm used to.

It wasn't simple, change of target now had the added issue of getting the two eyepieces into a position where I could see an image in both, never mind seeing the full field. Unlocking the T2 ring to re adjust the angle often resulted in me altering my carefully set inter pupillary distance and the angle I found was quite critical at this (148X) magnification as I only had a 0.68mm exit pupil and two pupils to line up.

I fiddled and cursed and cursed and fiddled but eventually went back to Luna at 148X and just drank in the view. There was definitely something to this new crazy, extremely expensive experiment.

The positives are viewing comfort, once correctly positioned it is just so relaxing on the eyes. this is a huge plus. The view I think was a bit more detailed and dimmer by a small margin but with a target like the moon dimmer is a positive and more detailed is always a positive. The conditions were not conducive to drawing any meaningful conclusions and I was denied any higher powered viewing and subsequent smaller exit pupils by the lack of focus travel though the seeing would not have allowed more anyway.

The negatives well we won't mention cost so I think the issue is keeping two small exit pupils in line with your own pupils whilst pointing the scope at various different bit of sky is 🤔 ...challenging. It may get simpler with practice and I may be doing things wrong so far but I'm pretty sure the EQ mount, Binoviewer and me are not a marriage made in heaven and unless one of you kind people can tell me a better way I'm thinking the Vixen EQ will have to go. an Alt Az mount would make things so much more straightforward in operation.

I also have the lack of infocus issue to get around too and maybe I can swap out the 2" Tak adapter for a Baader Clicklock and gain a few mm more, maybe I should change the nosepiece to a 1 1/4" one and put the GPC before the diagonal. Any ideas anyone?

I'm waffling so all the best and clear skies.

 

EDIT: I've just revisited Malcolm's pictures and detailed description and from Baader specs for the 2.6 GPC it looks like I  may need an extension for more back focus and not infocus as I thought. I'll report back after trying this.

 

Edited May 27, 2023 by ukskies
possible incorrect information in post

[ukskies]

Update number 2! 🙈

Yes, I'm stupid, I worked the optical path out to mean I was short of infocus. I wasn't, in fact I didn't have enough outward travel to reach focus and now I fully understand how this works.

When I re-read Malcolm's excellent explanations with pictures I realised my mistake. The optical path length of the 2.6x glasspath corrector is quoted as -120mm and the optical path length of the binoviewer is 110mm so in effect they almost cancel each other out bar minus 10mm.

If I took both GPC and binoviewer away and used the T-2 zeiss prism diagonal with a normal eyepiece I would require the Tak 2" extension piece (that comes with the DF) attached to the scope before the diagonal. as the Binoviewer and GPC cancel one another out I need the extension with these fitted also!

It's so simple I can't believe I got it wrong.🤷‍♂️

Tonight, well before dark the moon was up so I got everything set up in the daylight so I could see exactly what I was doing. I fitted the Tak extension and built and balanced everything on the Vixen mount and with the Moon in the finder crosshairs powered up the mount. The binoviewer was on with the 2.6 GPC in the diagonal and the two Baader Mk IV zooms in the holders. I adjusted the inter pupillary distance to close enough. Then I looked in the eyepieces with the zooms both set on 24mm. Pale cream light filled the view as I turned the More Blue coarse focuser and suddenly I saw detail appear and disappear! Ha I was close!! On to the fine focus wheel and back in slowly, suddenly the Moon was in super sharp focus sat in a blue sky surround and lacked the contrast a dark sky provides but it was sharp and detailed nonetheless. I then viewed for a while trying different magnifications on the zooms and at all settings when I tweaked the focus the Moon was pin sharp and the view was very comfortable and looked amazing.

I had left the T-2 ring that holds the Binos to the diagonal very slightly loose so I could turn them in relation to the diagonal and thus get the angle right for my eyes. This I struggled with on my previous update as it was too tight. Tonight it was free of play but did allow rotation of the unit and was easy to do.

As the view was quite steady I popped in the two 5mm BST's for nearly 400X and not expecting much I was surprised when the focus snapped in. The Copernicus crater was sharp with very detailed crater walls. The shadows weren't black and the usual contrast was lacking but it was still an hour before sundown and the view was very sharp. I was elated, the small 0.26mm exit pupils were very comfortable to view with and I'm sure I've not seen as much variance in shades on the Lunar surface as I was noticing tonight.

Work tomorrow so I pulled the scope in early and I won't be out again until Thursday evening if the clouds stay away but if so I will wait for full dark.

In conclusion I'm very pleased with this setup now and a huge thank you to all who contributed to this thread and helped convince me to get the Bino's they are brilliant.

[Paz]

Well done getting over the hurdles of binoviewing, it can be a bit of a process of trial and error and ongoing problem solving!

[takurrito]

I absolutely can relate with your frustration trying to get the binoviewers to reach focus. I binoview with 4 different scopes (60mm, 76mm, and 100mm refractors, and a 10" SCT), and trying to remember which scope combo requires the 1.7 GPC and which require an extension tube can be an exercise in frustration. To make matters worse, my 60 and 76mm scopes can be configured with the Takahashi extender CQ 1.7x that screws in-between the objective and focuser, meaning that I have to try and remember how to set the binoviewer up in 60mm f/5.9, 60mm f/10, 76mm f/7.5 and 76mm f/12.6 modes. 

Just yesterday I sent @mikeDnight a message asking about how he was able to reach focus without the GPC on his FC100DZ, because I swore I couldn't reach focus with mine, but after his assurance I tried again and sure enough, I could reach focus with in-focus to spare! Clearly I confused my DZ with my 76mm scope 🥲.

[ukskies]

1 hour ago, takurrito said:

I absolutely can relate with your frustration trying to get the binoviewers to reach focus. I binoview with 4 different scopes (60mm, 76mm, and 100mm refractors, and a 10" SCT), and trying to remember which scope combo requires the 1.7 GPC and which require an extension tube can be an exercise in frustration. To make matters worse, my 60 and 76mm scopes can be configured with the Takahashi extender CQ 1.7x that screws in-between the objective and focuser, meaning that I have to try and remember how to set the binoviewer up in 60mm f/5.9, 60mm f/10, 76mm f/7.5 and 76mm f/12.6 modes. 

Just yesterday I sent @mikeDnight a message asking about how he was able to reach focus without the GPC on his FC100DZ, because I swore I couldn't reach focus with mine, but after his assurance I tried again and sure enough, I could reach focus with in-focus to spare! Clearly I confused my DZ with my 76mm scope 🥲.

I can relate to you trying to remember what configuration goes with which scope amidst so many different setups. I can remember when I had a memory but now I need to write stuff down.

With all those I'd have to make a spreadsheet! 🤣

[ukskies]

10 hours ago, Paz said:

Well done getting over the hurdles of binoviewing, it can be a bit of a process of trial and error and ongoing problem solving!

Thank you Paz, Kind of you to say. From the views I was getting it was worth figuring it out. I'm already a convert and it's that @mikeDnight that started it, he's to blame! 😆

[MalcolmM]

Very pleased you got them working @ukskies. They really are a black art when you start trying to use them. I spent quite a bit of time, effort and money on first, the WO ones, and then the Maxbrights, but when it all comes together you really do get a 'wow moment'

Malcolm 

[ukskies]

8 minutes ago, MalcolmM said:

Very pleased you got them working @ukskies. They really are a black art when you start trying to use them. I spent quite a bit of time, effort and money on first, the WO ones, and then the Maxbrights, but when it all comes together you really do get a 'wow moment'

Malcolm 

Thanks Malcolm, it's thanks to your excellent pictorial that i figured out how to get the issue sorted.

I thought I had my head around it but I was wrong there. Once the penny dropped I thought OMG I can't believe I got it wrong. Without your posts I would still be wondering so thank you so much again for those posts.👍