Jump to content


Photo

Compression ring visual back?

  • Please log in to reply
25 replies to this topic

#1 Kon Dealer

Kon Dealer

    Viking 1

  • -----
  • Posts: 692
  • Joined: 05 Jan 2011
  • Loc: Cambridge UK

Posted 14 February 2013 - 06:26 PM

Really don't like the horrible screws holding my EPs in my 6 and 8SE.
Would love a visual back with a compression ring instead.
Would this do?
http://agenaastro.co...ual-back-t-2...

Anyone got experience with this?

#2 zippeee

zippeee

    Ranger 4

  • -----
  • Posts: 332
  • Joined: 27 Dec 2010
  • Loc: Alberta, Canada

Posted 15 February 2013 - 01:12 AM

I think you may need this one.

sct clicklock

I love the clicklock, it beats thumbscrews any day!

#3 Bob Griffiths

Bob Griffiths

    Getting Grouchy

  • *****
  • Posts: 10601
  • Joined: 10 Oct 2005
  • Loc: Frederick Maryland

Posted 15 February 2013 - 08:33 AM

LOL... I removed he compression rings and drilled out a second hole and now use nylon set screws..

I HATE COMPRESSION RINGS ... especially when some of your most used eyepieces have barrel cut barrels... Royal PIA to remove sometimes...

To each his own ... LOL

Bob G.

#4 zippeee

zippeee

    Ranger 4

  • -----
  • Posts: 332
  • Joined: 27 Dec 2010
  • Loc: Alberta, Canada

Posted 15 February 2013 - 08:48 AM

The clicklock isn't your normal type of compression ring, I've never had an issue with undercuts or anything getting caught. As long as you have the ring in the open position you're guaranteed to have a smooth open bore with maximum clearance. And it can be operated with one hand in about a second!

#5 Mark9473

Mark9473

    Cosmos

  • *****
  • Posts: 8606
  • Joined: 21 Jul 2005
  • Loc: 51°N 4°E

Posted 15 February 2013 - 09:04 AM

http://agenaastro.co...ual-back-t-2...

Anyone got experience with this?


I think you may need this one.

sct clicklock


The 1.25" version works great as an eyepiece holder on top of a Baader T2 diagonal; the 2" version is what you'd put on your scope to slide the diagonal into and allow easy rotation or exchange with other accessories.

I have one of each (2" clicklock + T2 diagonal + 1.25" clicklock) on each of my scopes and will never give them up.
(note in the image there's a T2 extension ring and a helical focusser between the diagonal and the 1.25" clicklock clamp - it doesn't need to extend this high)

Attached Files



#6 Kon Dealer

Kon Dealer

    Viking 1

  • -----
  • Posts: 692
  • Joined: 05 Jan 2011
  • Loc: Cambridge UK

Posted 15 February 2013 - 01:11 PM

@Mark9473
Is this a 2" adaptor?
I really need a 1.25" one- all my diagonals/EPS are 1.25s.
I don't really want to add too much weight- and particularly length to the end of by SCTs.

#7 zippeee

zippeee

    Ranger 4

  • -----
  • Posts: 332
  • Joined: 27 Dec 2010
  • Loc: Alberta, Canada

Posted 15 February 2013 - 02:04 PM

The thread on your SE's rear cells are 2" SCT. Baader doesn't (to my knowledge) make a VB that goes from 2"SCT to 1.25". You'd need a standard 2"-1.25" adapter to use your 1.25 diagonals.

#8 Mark9473

Mark9473

    Cosmos

  • *****
  • Posts: 8606
  • Joined: 21 Jul 2005
  • Loc: 51°N 4°E

Posted 15 February 2013 - 03:43 PM

Like I said, the one at the top is the 1.25" for eyepieces, the one at the scope end that says 2" on it, is the 2".

#9 JBOU

JBOU

    Sputnik

  • -----
  • Posts: 27
  • Joined: 11 Jan 2011
  • Loc: Canada

Posted 15 February 2013 - 11:05 PM

I was looking into soltions to this as well. I don't want to minimize the back focus distance by going to 2", but the standard 1.25" visual back leaves a bit to be desired.

I was looking at the 1.25" click-lock and combining it with either:
Baader T2 to SCT Adapter
or
Blue Fireball sct adapter

for a cheaper solution, I was also considering this:
Blue Fireball Eyepiece holder

with the blue fireball adapter above.

Has anybody tried this?

#10 Eddgie

Eddgie

    Voyager 1

  • *****
  • Posts: 12546
  • Joined: 01 Feb 2006

Posted 16 February 2013 - 09:43 AM

The shortest light path I think you can get in an SCT adapter with compression ring is the Televue Shorth SCT adapter (ACS-0004).

The Baader SCT to 2" ClickLock has well over 40mm of light path, and by the time you add a 2" to 1.25" adapter, you are looking at well over an inch of additional back focus, which can add about 110mm of focal lenght to the telescope.

The Televue is about 1" of back focus, but once again, if you add a 2" to 1.25" adapter, most of these add about 10mm to 15mm to the light path.

The absolute shortest possible light path would be to use the Baader diagonal with the short SCT adapter. This threads into the T2 diagonal and then attaches directly to the SCT port, and is only about 10mm long (something like that). But... It doesn't rotate.

There is an in-between step, which is a Baader connector that acts like a standard SCT diagonal where you can loosen it and rotate it, but it is not as convenient as a compression ring type 2" adapter and using the compression ring to rotate the diagonal.

I think for someone wanting the shortest light path that sill offers the ability to easily rotate the diagonal, the Televue short SCT adapter is the way to go.

You can get the biggest possible field in a 1.25" format by using the Baader coupler, or get a bit more usability by using the longer Baader using that allows some rotation, but these are just not going to be as easy to use as the Televue Short Adapter with a short 2" to 1.25" adapter.

As much as I like the clicklock, I am thinking about going to the Televue short adapter for binoviewing because in binoviewing, every millimater is precious. The Clicklock works fine, but is is indeed a much longer solution than the Televue Short.

One issue with the Televue Short though is that some 2" to 1.25" adapters may not fully seat. I believe the TV short allows about .9 inch of depth. I have a couple of 2" to 1.25" adapters that are longer than this and only one that is this short.

But if it is going to be dedicated to the scope, you only need one.

In fact, my Mark V binoviewers have a 2" nose and that is only .9 inch long, and once again, I may replace the Clicklocks on EdgeHD 8" and long 2" adatper on my C5 with the Televue shorts.

Anyway, the Televue short with a 2" to 1.25" and a 2" adapter is about the least amount of back focus (shortest focal lenght) you can get for a standard SCT.

If you want to do even shorter, you have to move to the Baader T2 diagonal with the Baader short (10mm) or long (15mm?) SCT adapter.

But since this can allow the scope to work at very close to stated focal length (most SCTs are working above the stated focal lenght when used visually) or even less, the Baader approach might be the ticket. Hard to rotate the diagonal though.

I think for someone that is Alt-Az mounting am SCT and doesn't need to rotate the diagonal, the Baader T2 with 10mm SCT connector would give you perhaps less than stated focal lenght.

In the near future, I plan on buying one of each (Televue Short and the Baader SCT adapter for T2).

Will try to post the result here and binoviewer forum when I can.

The Clicklock is long though, and for those wanting to keep the lowest possible focal lenght when using 1.25" stuff, the Televue short or the Baader with T2 are going to be the best solutions.

#11 Eddgie

Eddgie

    Voyager 1

  • *****
  • Posts: 12546
  • Joined: 01 Feb 2006

Posted 16 February 2013 - 09:47 AM

Regarding my previous post, I have not seen the Fireball T2 to 1.25" and the Fireball SCT to T2.

I don't have lenghts, but this does ineed appear to be perhaps shorther than the Televue Short.


For someone that may go to a Binoviewer in the future though, I would still go with the Televue short. The clamping force on the 2" adapters are going to be much better than on the 1.25". Not a factor for 1.25" diagonals, but for binoviewers, could be.

#12 JBOU

JBOU

    Sputnik

  • -----
  • Posts: 27
  • Joined: 11 Jan 2011
  • Loc: Canada

Posted 16 February 2013 - 09:19 PM

Kon, I just noticed the Baader click-lock you're pointing to has a focuser. Are you looking to use this with a diagonal? I'd think there would be issues with it rotating due to the moment caused by the diagonal, depending on diagonal orientation and eyepiece weight.

Though, I can see how a fine focuser can be helpful w/ the C6.

#13 Mark9473

Mark9473

    Cosmos

  • *****
  • Posts: 8606
  • Joined: 21 Jul 2005
  • Loc: 51°N 4°E

Posted 17 February 2013 - 04:52 AM

JBOU what you describe is not happening in practice.

#14 Kon Dealer

Kon Dealer

    Viking 1

  • -----
  • Posts: 692
  • Joined: 05 Jan 2011
  • Loc: Cambridge UK

Posted 17 February 2013 - 11:11 AM

Blue Fireball Eyepiece Holder (1.25") with T / T2 Female Thread (T2 Visual Back) # E-10

This looks like what I want.
Unfortunately I do not think it is sold in the UK :mad:

#15 Pete-LH

Pete-LH

    Messenger

  • *****
  • Posts: 414
  • Joined: 25 Mar 2009
  • Loc: Wilmington, DE

Posted 17 February 2013 - 02:20 PM

Another vote for Baader Click-Lock. I am gradually switching everything over where I can to this mechanism. I have one on my TAK FS-102 and here on my new/olde C-8.

Attached Files



#16 Dunkstar

Dunkstar

    Mariner 2

  • -----
  • Posts: 249
  • Joined: 26 Mar 2012
  • Loc: Under the sky

Posted 17 February 2013 - 03:54 PM

How about one of these?

http://agenaastro.co...r-diagonal.html

Alternatively, Baader make a locking ring for Nexstar to connect their 2" clicklock diagonal to a 2" SCT thread. Not an inexpensive option though.

#17 Dunkstar

Dunkstar

    Mariner 2

  • -----
  • Posts: 249
  • Joined: 26 Mar 2012
  • Loc: Under the sky

Posted 17 February 2013 - 03:57 PM

Sorry, missed your location - this looks identical

http://www.telescope..._Quartz_LX.html

#18 JBOU

JBOU

    Sputnik

  • -----
  • Posts: 27
  • Joined: 11 Jan 2011
  • Loc: Canada

Posted 17 February 2013 - 07:31 PM

If you want to stick with 1.25", don't mind the extra length and cost, maybe one of these:
Baader click lock reducer
or
Baader deluxe reducer

with:

Baader sct to T2 adapter

Jim

#19 aa6ww

aa6ww

    Viking 1

  • *****
  • Posts: 936
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 18 February 2013 - 01:06 AM

I use the Starizona virtual view for my 2" SCT's visual backs because the back piece rotates without loosening or tightening anything. It can easily support a 2" diagonal and 31 Nagler with no slippage, yet it rotates glassy smooth when you need to reposition the eyepiece.

http://starizona.com...Standard-SCT...

I don't like the long thumbscrews so I replaced mine with headless screws from Lowes so the back of my scope looks very clean. Once the unit is adjusted once, its adjusted for the life of the unit.
That with a feather touch micro focuser is a killer combination, provided you do not have any noticeable image shift.
If your SCT has a sloppy image shift problem, and it bothers you, a Crayford type 2" focuser would the the only solution since high power viewing would drive you nuts.

The Baader visual back looks very nice however, but does it rotate easily without loosening anything?

...Ralph

#20 Pete-LH

Pete-LH

    Messenger

  • *****
  • Posts: 414
  • Joined: 25 Mar 2009
  • Loc: Wilmington, DE

Posted 18 February 2013 - 08:54 AM

The Baader Click-Lock has to be loosened. Once you get familiar and confident to it, it only takes a light adjustment. But I had not seen that Starzona design. Looks very nice. But I have not been completely happy with some brass compression ring designs in that I have experienced from a little to a lot of play in a 2" diagonal (especially when the secure groove in the barrel(nosepiece) does not exactly match the width and placement of the compression ring)so that it can wiggle a little and in one case completely fall out. Also a compression ring can mar the anodized finish on some diagonal barrels(nose piece) The Click lock is the most secure and well centered mechanism that I have encountered so far.
I had very good service lately from Starzona in the supply of an adapter for the feathertouch to the particular model of C8 that I have.

#21 Heitman

Heitman

    Mariner 2

  • *****
  • Posts: 241
  • Joined: 26 Jan 2007
  • Loc: Reeds, NC

Posted 18 February 2013 - 09:05 AM

Ralph,
Could you tell me the length of the Virtual View? I've been looking at this unit as a possible visual back for my C8. Right now I use a standard 2" visual back, but it's a real pain to have to loosen and tighten it to move the diagonal to different positions.
Thanks, Tim

#22 zippeee

zippeee

    Ranger 4

  • -----
  • Posts: 332
  • Joined: 27 Dec 2010
  • Loc: Alberta, Canada

Posted 18 February 2013 - 09:33 AM

The Click lock is the most secure and well centered mechanism that I have encountered so far.


Without a doubt. Remember this picture?

Posted Image

If anything was to fail, my bet would be on the T2 threads pulling out of the diagonal.


--

#23 Kon Dealer

Kon Dealer

    Viking 1

  • -----
  • Posts: 692
  • Joined: 05 Jan 2011
  • Loc: Cambridge UK

Posted 18 February 2013 - 05:30 PM

I'm really puzzled:question:that Celestron etc. have not seen a market for visual backs with compression rings for fitting diagonals/EPs- like there are on any half-decent refractor.

#24 watcher

watcher

    Vanguard

  • *****
  • Posts: 2120
  • Joined: 21 Nov 2007
  • Loc: St. Louis, MO

Posted 18 February 2013 - 08:31 PM

I still can't grasp why they move the primary mirror to focus instead of putting a real focuser on them.

#25 mclewis1

mclewis1

    Thread Killer

  • *****
  • Posts: 10808
  • Joined: 25 Feb 2006
  • Loc: New Brunswick, Canada

Posted 19 February 2013 - 10:02 AM

I still can't grasp why they move the primary mirror to focus instead of putting a real focuser on them.

Joe,

So the scopes can offer huge amounts of focus travel. Depending on the SCT model it can range from 6 to more than 11". This makes them very versatile scopes without requiring additional cost items to bring various optical configurations to focus.

The design has been commercially popular since the 60s ... they must be doing something right.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics