Making the most of eyepieces with Baader

[F15Rules]

Hi all,

I haven't done much observing lately for various reasons as well as short nights, cloudy spring etc etc..

But I have been doing a few bits of experimentation in my mancave to make my actual sessions more rewarding and dare I say, efficient?😁

My accessories setup ie eyepieces, diagonals, binoviewer etc have been stable for a little while now and consist of ;

Fixed focal length eyepieces for Cyclops viewing: Pentax XL 10.5mm, Pentax XL SMC 8-24mm zoom, Celestron Axiom LX23mm and 31mm..usually used in 2" mode. I can also Barlow the zoom and 10.5mm to achieve higher magnifications with no loss of eye relief.

For Binoviewing I have an excellent set of Maxbright IIs which I use with pairs of Tak Abbe Ortho 12.5mm, WO wide angle 20mm and Meade 4000 32mm. I also have a Baader 1.7x GPC, Baader Hyperion Zoom Barlow 2.25x and W.P 1.6x nosepiece for higher powers.

I have just two diagonals but they are good ones: Baader Zeiss BBHS T2 prism and Astro Tech 2" Dielectric mirror diagonal.

I do definitely tend to see the Baader BBHS prism as my preferred diagonal lately, as it's so versatile. The BBHS version has a 34mm clear aperture and, if I attach a 2" click lock to the prism eyepiece side (I use a Baader short 2" nosepiece threaded into a basic 2" click lock body, see photos below), I can use all the above cyclops eyepieces in 2" mode.. all of them have field stops under 34mm apart from the big 31mm Axiom, and even this one works great with the prism..if there is any vignetting, I can't see it..and the whole rig feels very solid.

I use the two Pentax eps, which are technically 1.25" eps,  with Revelation 2" to 1.25" self centering adapters. These add some weight to the eps, meaning that there is little, if any, re-balancing of the OTA needed, no matter which cyclops eyepieces I'm using.

For binoviewing, all 3 eyepiece pairs are quite small and light, so swapping in a session between cyclops and binoviewing mode is just a one or two minute job👍.

In case it might help someone else, or just be of interest, I thought I'd just share below a few photos of the configurations I use😊.

Thanks for reading.

Dave

Baader Zeiss prism with 2" nosepiece, left, and barebones 2" click lock, also with 2" nosepiece which threads onto the prisms' M48 male eyepiece side thread, see below.

Above setup with 2" uncloaked Axiom 23mm in the click lock.

Above with Pentax zoom and 2" self centering adapter. Below with Pentax stack ready for insertion into Tak's 2.7" focuser.

 

 

[John]

It is always interesting to hear and see what gear others are using and how they are using it - thanks for posting this Dave 👍

I'm thinking of using my  Baader Zeiss T2 in 2 inch mode so it is useful to see how you approach that.

The Pentax 8-24 zoom is quite a lump isn't it 🙂 

[Louis D]

4 hours ago, F15Rules said:

the big 31mm Axiom, and even this one works great with the prism..if there is any vignetting, I can't see it

You'd need to take a photo of an evenly illuminated field in the daytime with that combo and then use photo editing software to sample pixel brightness across the field to accurately determine the amount of vignetting.  I've done this with the Meade 5000 SWA 40mm in my 127 Mak which has only 27mm of clear aperture at the rear port:

 

[F15Rules]

That's very interesting, but I am very happy with the overall low power, wide angle views that my setup provides🙂.

Dave

[F15Rules]

10 hours ago, John said:

It is always interesting to hear and see what gear others are using and how they are using it - thanks for posting this Dave 👍

I'm thinking of using my  Baader Zeiss T2 in 2 inch mode so it is useful to see how you approach that.

The Pentax 8-24 zoom is quite a lump isn't it 🙂 

Thanks John👍.

The Pentax is a good size but not too heavy..here are the dimensions from the Flo website (I bought my first one of these from them in 2016 and you can read my review on their site..):

Weight: 550g (1.2lb)
Length: 114mm (4.5")
Width: 69mm (2.7")

The setup for these bigger eyepieces isn't back focus critical when using them in cyclops mode (and they're too big to even contemplate using them in binoviewers).

However, when using the binoviewers with the FS128 and smaller eyepiece pairs, I can simply use the provided knurled ring on the Maxbright IIs body to thread the Zeiss BBHS prism straight onto the prism itself, so guaranteeing the shortest possible light path.

On my scope, I can get native focus of all my eyepiece pairs with no OCS or Barlow this way..although I understand that some scopes can't do this, depending on their tube length and focuser.

Having used a fair few binoviewers in the past, I can say that ergonomically and optically the MBIIs are a real step up and a joy to use by comparison.

Dave

Edited June 28, 2023 by F15Rules
Additional text info

[omo]

Never thought of using a 2" nosepiece to screw onto the diagonal, i can see how it could be useful though.

I'm sure someone could write a quite lengthy book on Baaders multitude of adapters and possible ways of screwing them all together

[omo]

4 minutes ago, F15Rules said:

However, when using the binoviewers with the FS128 and smaller eyepiece pairs, I can simply use the provided knurled ring on the Maxbright IIs body to thread the Zeiss BBHS prism straight onto the prism itself, so guaranteeing the shortest possible light path.

 

You can with the right adapters thread the bino directly to the T2 diagonal slightly shorter i think - never tried it as i use the HD T2 quick changers, you cant use a GPC before the diagonal like this though