Baader prism diagonals and f7 scopes

[Moonshane]

Well I have sold a few more 'bits' and have now got a Baader Zeiss prism plus 2.6x GPC in my box plus side pair of Baader Maxbrights , a 2" nose plus a 1.7x GPC on the way soon.

Just need a 1.25" eyepiece holder for cyclops mode plus another BGO for using in the BVs to get started. Mark's frac when collected at SGL 12 will be yummy as will the 120ed

[John]

Shane, you are developing "fracitis"

Never thought I'd see the day ........

Which frac are you collecting from Mark BTW ?

 

[Moonshane]

Lol.  still only 3:3

It's Mark's 102mm f7 As troth which will be my caravan scope replacement for the 80mm.  I concluded I agree with you re minimum aperture

[John]

21 minutes ago, Moonshane said:

Lol.  still only 3:3....

 

I'm at 4:1 here so I have it worse

102mm ED F/7 is a really useful scope

[Moonshane]

I forgot that my pst mod had a baby so it's 4:3 after all

 

[A McEwan]

22 hours ago, Moonshane said:

I forgot that my pst mod had a baby so it's 4:3 after all

 

There's something quite sinister looking about that setup. Maybe it's the long thin blackness, or the danger-red mount head. Or the helical-ness. I don't know. It's just scary.

[Moonshane]

I have bought a dedicated Baader t2 prism (the non Zeiss version) for my PST mod as it will reduce the optical length of my set up (after the etalon) substantially.

I am in the process of getting an adapter made which could be t2 - M33 x 0.75 (what I believe the PST eyepiece holder thread to be) however, I notice that there's a thread inside the T2 ring which might allow a smaller adapter to be made. Anyone know what the thread is please? It looks like it might me M34/35?

cheers

Shane

 

[YKSE]

It's M34, for threading in the GPC.

BTW, the new Baader site has added many specifications for Baader stuff, might worth a visit when needing some details.

http://www.baader-planetarium.com/en/accessories/optical-accessories/prism-and-mirror-star-diagonals/baader-prism-diagonal-t-290°-32mm.html

[Moonshane]

ahh, thank you. that makes sense. for this purpose, I will be using a nose from a pst so won't need the GPC thread as I'll be inserting them in the (shortened) nose and it may be easier to make a M33-M34 adapter to leave on the eyepiece holder 'permanently'.  I'll see what's what tomorrow night when I chat with my friend who is doing the machining for me.

[Moonshane]

Here's my before and after shots on the business end of my pst stage two mod. How's that for additional available back focus?

The shorter optical length and secure screwed connections were my main reasons for choosing this unit. I'd estimate a reduction of 132mm

 

[Moonshane]

Can anyone comment on this post? I thought it best to start a new thread as we are more into the realms of PST modding than prisms!

 

[YKSE]

If comments wanted about binoviewer or not with this 132mm shortened OTA, I'd say it is a very binoviewer-friendly, you should be able to do binoviewing without any OCS.

Tha backside of coin is, you're most likely not able reach focus for quick cyclops peek (unless your focuser has more than 132mm focuser travel).

[Moonshane]

My main question was about whether the aperture will effectively be clipped as I am bringing the BF forward so far. I suppose I should be able to try it out soon enough!

I 'll be sorting out a suitable T2 extension to take up the slack for cyclops viewing. I have to really leave the focuser drawtube in a fixed position (+/- 2mm or so) to ensure the etalon is correctly placed.