Baader VIP, Baader/Zeiss barlow

[Piero]

While observing in my garden last night, I also tried some combination with the Zeiss zoom I have. Hope this findings will be useful. Sorry if the discussion is a bit Baader-centric! 

 

Zoom eyepieces (like the high-end Leica and the Zeiss zooms) can be very good tools for observing. They can be even more powerful when connected with a good barlow. 

My Zeiss zoom (25.1mm-6.7mm) uses a manually modified Baader adapter (Diascope Okularbajonett 2; # 2454502) which reduces the inward travel quite a lot compared to the standard 2" Zeiss adapter for telescopes. The additional benefit of using this adapter is that it can accept 2" filters and Baader T2 connections. 

 

The Baader VIP can be used successfully with this zoom. After a few testing, the configuration that I seem to use the most is as follows:

Zeiss zoom with Baader adapter + 15mm spacer + 2"-to-1.25" reducer adapter + M48-to-T2 ring + VIP nosepiece (which should work at about 2.23x trasforming the zoom into a 11.26mm-3.00mm). 

Advantages: 

-  it does not hit the diagonal mirror so it can be used on refractors with a 2" focuser;

- the focus position doesn't change much compared to the Zeiss zoom in 2" mode without VIP barlow.

Disadvantages:

- it is a rather tall combo. 

 

Having a Baader/Zeiss barlow, I was curious to see how it performed with this Zeiss zoom. The Zeiss barlow nosepiece can be screwed onto the Baader bajonet adapter via T2 connection and this should work as 2x. This would get all the above advantages, while also reducing the length of the combo. Unfortunately, this configuration does not reach focus on the TAK when used in 2" mode. It would require an extension tube. Same if spacers are added. It does reach focus when used in 1.25" mode, but this eyepiece is rather tall and heavy for 1.25" in my opinion. 

 

In line with this,

1) Zeiss zoom + 2" bajonet adapter + 1.25" nosepiece on a 1.25" diagonal, required a couple of cm inward travel. Similarly when the 1.25" nosepiece was replaced with the 1.25" VIP nosepiece. 

2) Nikon zoom + Baader / Zeiss barlow is nearly parfocal to Nikon zoom without barlow. 

 

In conclusion, it seems to me that the Baader VIP and Baader/Zeiss barlow were preferably conceived to work in 2" and 1.25" mode, respectively.

[John]

Very interesting Piero

I'm still getting my head around all the possible combinations that my VIP barlow provides with my Leica ASPH zoom and other eyepieces as well.

I agree that the combos needed to get a full 2x from the VIP do lead to a very tall "stack" sticking out of the focuser. 

[Piero]

Thanks John,  

Yes, Baader solutions are really versatile. Because of this one might need to spend some time to find out how to use his equipment, I feel. 

After recent tests, these barlow combos work well for me: 

- Zeiss zoom + VIP (as described above)  [ Tak / Dobson (nighttime, planets) ]

- 24 Pan, Nikon zoom + Zeiss barlow (2.86x - using the native 1.25" clicklock, 15mm spacer borrowed from the VIP, 40mm spacer) -  [ Tak (solar), TV60 (nighttime, solar) ]

- Docter permanently fitting a Baader pushfix (2") + Zeiss barlow nosepiece (2x) + 2"-to-1.25" reducer adapter - [ Tak / Dobson (planets), Tak (solar) ] 

 

It would be great to have a Baader variable spacer which can be manually adjusted. Then, take a 2"-to-1.25" reducer adapter on one side (or just a M48-to-T2 ring for 2" eyepieces), and the VIP on the other side, and you get a VIP zoom tool. This could get us a Docter Zoom eyepiece!!  

 

Which VIP combos do you use the most?

[jetstream]

I shouldn't say this but, I'm thinking of trying one of these or similar once I get a chance.

http://agenaastro.com/baader-1-25-t2-eyepiece-holder-helical-microfocuser.html

So, what do you think Piero?

 

[Piero]

7 minutes ago, jetstream said:

I shouldn't say this but, I'm thinking of trying one of these or similar once I get a chance.

http://agenaastro.com/baader-1-25-t2-eyepiece-holder-helical-microfocuser.html

So, what do you think Piero?

Considering this 

"I shouldn't say this BUT", "SO".. very bad English Gerry! LOL!       Just joking of course! 

 

 

I think that is the idea, but the travel is too short to work as a zoom (28.7mm - 35.3mm (1.13" - 1.39"), focus travel of ~6.5mm (0.26")). I think we would need 30mm at least. 

[John]

3 hours ago, Piero said:

It would be great to have a Baader variable spacer which can be manually adjusted. Then, take a 2"-to-1.25" reducer adapter on one side (or just a M48-to-T2 ring for 2" eyepieces), and the VIP on the other side, and you get a VIP zoom tool. This could get us a Docter Zoom eyepiece!!  

 

Which VIP combos do you use the most?

Baader do variable length T2 extension tubes:

https://www.firstlightoptics.com/adapters/baader-varilock-46-lockable-t-2-extension-tube.html

Maybe that would be suitable ?

Most of my use of the VIP has been at or around 2x so I've used combos that give a 64mm spacing between the eyepiece field stop and the top of the barlow element.

[Piero]

I was aware of the Baader Varilock, but don't know how much it stays in place without locking it. 

[John]

1 hour ago, Piero said:

I was aware of the Baader Varilock, but don't know how much it stays in place without locking it. 

I should have tried one when I was at the astro show yesterday. I was too busy eyeing up equipment that I could not really afford

 

[Piero]

20 minutes ago, John said:

I should have tried one when I was at the astro show yesterday. I was too busy eyeing up equipment that I could not really afford

That's the good thing of going to a show!  

Was it interesting? 

[John]

31 minutes ago, Piero said:

...Was it interesting? 

Yes - £8.50 plus some fuel well spent I think. Good to see some up and coming stuff for real. It would be easy to spend a silly amount of money though - they pitch the show discounts at just the right level to get you reaching for your wallet

In the end I just went for a dew shield extension for the ED120 and a replacement dust cap for the top of my 12" dob. Last of the big spenders !

[Piero]

All the following text assumes the equipment used in 2" mode.  The VIP can be used in 1.25" mode but this requires additional inward travel which may not be available.

 

Here are a two configurations I find quite interesting:

1. 15mm spacer + Baader/Zeiss nosepiece locked inside a 2"-to-1.25" reducer + M48(Male)-to-M48(Male) 
2. 15mm spacer screwed onto the Baader VIP 1.5x  

 

The two combinations share a T2 thread on top, which can be used as connector with T2 adapters. This can be useful for attaching the Zeiss Zoom 25.1-6.7mm using the Baader bajonet adapter. 

The double locking required for the Baader/Zeiss Barlow (1) (2"-to-1.25" reducer, 2" clamp) is possibly less safer than the single locking required for the VIP (2) (2" clamp). 

Whilst on Newtonian telescopes, the two are somehow interchangeable, the former can be desirable on refractors when: 

• 2" filters are used. The VIP can accept 2" filters and these can be screwed between the ring above the nosepiece and the 2"-to-1.25" reducer. Depending on the filter cell, there is a chance that the VIP nosepiece hits the diagonal mirror. A OIII or UHC filter can be useful when opening up a planetary nebula with a zoom eyepiece at high power. 
• observing the Sun with a 2" solar wedge (e.g. Baader Herschel Wedge). Solar wedges include a ND3.0 filter at the bottom of the eyepiece clamp. The nosepiece of the VIP hits the ND3.0, whereas the the former solution does not. Also, (1) allows additional filters (e.g. single polarising filter) to be used if needed.

 

Minor differences: 

• (1) sits slightly higher. As consequence it requires 2-3mm inward travel compared to (2).
• (1) barlow is slightly longer than (2), therefore it magnifies slightly more (possibly ~2.25x vs ~2.1x).

 

The weight between the two is comparable. None of them requires weird inward or outward travel to reach focus.

[Piero]

I spent a couple of hours observing the sun and testing the two combinations and the Zeiss zoom. On axis the details were indistinguishable to my eye. These are the best barlows I have ever used. 

The VIP nosepiece would hit the ND3 filter in the Baader Solar wedge, so I changed the configuration for the VIP a bit. The flexibility of the VIP is really amazing! 

What I did was to play with the VIP and the M48-toM48 that I have. The latter is by Lacerta, possibly a clone of an equivalent Baader Adapter. Externally, it has 2 positive M48 threads. Internally, it fits a negative T2 on one side and a negative M36.4. The VIP nosepiece was detached from the 2" to 1.25" reducer and screwed onto the T2 of this M48 to M48 adapter. Now, this adapter can be attached to the 2" to 1.25" reducer in two ways. On way is with the nosepiece down, which enables the VIP to be used with 1.25" focusers or with 1.25" eyepieces. The other way is with the nosepiece inserted in the reducer from the bottom, which enables 2" filters. This second option moves the VIP few millimetres up.

This latter solution allows one to use the VIP with T2 heavy equipment (e.g. zooms), mount 2" filters, fit the VIP onto 1.25" focusers, and use the VIP with 1.25" eyepieces. Reversing the ring is trivial.

 

 

 

 

 

And here is the adapter :  http://www.365astronomy.com/M48-M48-Positive-Converter-with-T2-and-M36.4-Negative-Threads.html  

[John]

The VIP barlow has almost endless configuration options - it's mind boggling !

I used my low cost 7.2mm - 21.5mm zoom in my LS50Ha again today. It works so well I can see that I'll just keep using it as a "one eyepiece" solution for that scope. Simples

 

[Piero]

Zooms can be very effective IMO.   

[25585]

Prefer eye piece turret as can keep better eye relief for shorter fl eps. I believe Baader make one.....

[John]

4 minutes ago, 25585 said:

Prefer eye piece turret as can keep better eye relief for shorter fl eps. I believe Baader make one.....

I'll try a turret someday. Might have issues with inwards focus travel though - the turret eats up a chunk of that.

[25585]

Reading a description of the Astro Physics barlow  https://www.teleskop-express.de/shop/product_info.php/language/en/info/p472_ASTRO-PHYSICS-BARADV-2--Advanced-2fach-Barlow.html it seems the same as a Baader VIP. Chicken and egg like the dielectric diagonal I guess.

[John]

5 hours ago, 25585 said:

Reading a description of the Astro Physics barlow  https://www.teleskop-express.de/shop/product_info.php/language/en/info/p472_ASTRO-PHYSICS-BARADV-2--Advanced-2fach-Barlow.html it seems the same as a Baader VIP. Chicken and egg like the dielectric diagonal I guess.

I think you can get the same effect by altering the spacing between the barlow lens element and eyepiece field stop with all barlow lenses that have a removiable lens element. Not with the optical quality of the VIP or Astro Physics though, perhaps.

 

[25585]

I was wondering if the AP, VIP or another with smallish magnification, would boost the eye relief of longer fl eps, without losing much TFOV.

For example a 31mm Nagler with er of 19mm (according to TV), boosted to 25. Such Barlows would be more useful than larger mags, and could be stackable if need be.

[John]

Barlows tend to vignette when used with longer focal length eyepieces. Telextenders, Powermates etc don't but you don't get the eye relief extension you seek. It's a bit of a conundrum