Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1


Robert J. Bridges
 

Hi All,

 I would like to replace the sliding focuser on my Vario-Finder (10x60;  61x250 f/4.1) scope with a Crayford style focuser. 

Does anyone have a suggestion?

Thanks,
Bob

--
Robert J. Bridges
Professor
Physiology and Biophysics
Chicago Medical School
3333 Green Bay Rd
North Chicago, Il 60064
Office: 847 578 3273
Cell: 847-271-7944
bob.bridges@...


Robert Chozick
 

I put a ZWO 1.25 helical focuser on mine. It works great. 

Robert 


On Oct 14, 2020, at 2:37 PM, Robert J. Bridges <bob.bridges@...> wrote:


Hi All,

 I would like to replace the sliding focuser on my Vario-Finder (10x60;  61x250 f/4.1) scope with a Crayford style focuser. 

Does anyone have a suggestion?

Thanks,
Bob

--
Robert J. Bridges
Professor
Physiology and Biophysics
Chicago Medical School
3333 Green Bay Rd
North Chicago, Il 60064
Office: 847 578 3273
Cell: 847-271-7944
bob.bridges@...


Woody Schlom
 

Bob,

 

I don’t know about a Crayford style focuser, but Baader makes nice helical focusers for the Vario-Finder.  The one I have is a 1.25” eyepiece holder with helical focuser built into it.

 

Unfortunately I’m not home now and can’t give you the Baader part number.  But it’s NOT the stock one that comes with the Vario-Finder.  As I recall it’s T2 thread at the scope side – so it just threads on.  And unlike another 1.25” adapter for that scope from Baader, this one has a much longer 1.25” throat – so eyepieces or camera nosepieces don’t wobble nearly as much as Baader’s very short 1.25” adapter.

 

Woody

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Robert J. Bridges
Sent: Wednesday, October 14, 2020 12:31 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

 

Hi All,

 

 I would like to replace the sliding focuser on my Vario-Finder (10x60;  61x250 f/4.1) scope with a Crayford style focuser. 

 

Does anyone have a suggestion?

 

Thanks,

Bob

 

--

Robert J. Bridges
Professor
Physiology and Biophysics
Chicago Medical School
3333 Green Bay Rd
North Chicago, Il 60064
Office: 847 578 3273
Cell: 847-271-7944
bob.bridges@...


George
 

Bob,

 

As a reminder, the Baader finder uses the locking ring and lens as a fine focuser.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Woody Schlom
Sent: Wednesday, October 14, 2020 3:02 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

 

Bob,

 

I don’t know about a Crayford style focuser, but Baader makes nice helical focusers for the Vario-Finder.  The one I have is a 1.25” eyepiece holder with helical focuser built into it.

 

Unfortunately I’m not home now and can’t give you the Baader part number.  But it’s NOT the stock one that comes with the Vario-Finder.  As I recall it’s T2 thread at the scope side – so it just threads on.  And unlike another 1.25” adapter for that scope from Baader, this one has a much longer 1.25” throat – so eyepieces or camera nosepieces don’t wobble nearly as much as Baader’s very short 1.25” adapter.

 

Woody

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Robert J. Bridges
Sent: Wednesday, October 14, 2020 12:31 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

 

Hi All,

 

 I would like to replace the sliding focuser on my Vario-Finder (10x60;  61x250 f/4.1) scope with a Crayford style focuser. 

 

Does anyone have a suggestion?

 

Thanks,

Bob

 

--

Robert J. Bridges
Professor
Physiology and Biophysics
Chicago Medical School
3333 Green Bay Rd
North Chicago, Il 60064
Office: 847 578 3273
Cell: 847-271-7944
bob.bridges@...


Roland Christen
 

Adding a Crayford focuser will make the system unstable (flex) and defeat the purpose of the finder as a guide scope.

Rolando



-----Original Message-----
From: George <george@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Wed, Oct 14, 2020 4:21 pm
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

Bob,
 
As a reminder, the Baader finder uses the locking ring and lens as a fine focuser.
 
Regards,
 
George
 
George Whitney
Astro-Physics, Inc.
Phone:  815-222-6538 (direct line)
Phone:  815-282-1513 (office)
Email:  george@...
 
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Woody Schlom
Sent: Wednesday, October 14, 2020 3:02 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1
 
Bob,
 
I don’t know about a Crayford style focuser, but Baader makes nice helical focusers for the Vario-Finder.  The one I have is a 1.25” eyepiece holder with helical focuser built into it.
 
Unfortunately I’m not home now and can’t give you the Baader part number.  But it’s NOT the stock one that comes with the Vario-Finder.  As I recall it’s T2 thread at the scope side – so it just threads on.  And unlike another 1.25” adapter for that scope from Baader, this one has a much longer 1.25” throat – so eyepieces or camera nosepieces don’t wobble nearly as much as Baader’s very short 1.25” adapter.
 
Woody
 
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Robert J. Bridges
Sent: Wednesday, October 14, 2020 12:31 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1
 
Hi All,
 
 I would like to replace the sliding focuser on my Vario-Finder (10x60;  61x250 f/4.1) scope with a Crayford style focuser. 
 
Does anyone have a suggestion?
 
Thanks,
Bob
 
--
Robert J. Bridges
Professor
Physiology and Biophysics
Chicago Medical School
3333 Green Bay Rd
North Chicago, Il 60064
Office: 847 578 3273
Cell: 847-271-7944
bob.bridges@...


Robert Chozick
 

The helical focuser adds no extra length since you move the tube in further to accomodate it.  The tube ends exactly in the same place as before inside of the extension at the end and is much easier to focus.





On Oct 14, 2020, at 5:07 PM, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:

Adding a Crayford focuser will make the system unstable (flex) and defeat the purpose of the finder as a guide scope.

Rolando



-----Original Message-----
From: George <george@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Wed, Oct 14, 2020 4:21 pm
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

Bob,
 
As a reminder, the Baader finder uses the locking ring and lens as a fine focuser.
 
Regards,
 
George
 
George Whitney
Astro-Physics, Inc.
Phone:  815-222-6538 (direct line)
Phone:  815-282-1513 (office)
Email:  george@...
 
From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Woody Schlom
Sent: Wednesday, October 14, 2020 3:02 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1
 
Bob,
 
I don’t know about a Crayford style focuser, but Baader makes nice helical focusers for the Vario-Finder.  The one I have is a 1.25” eyepiece holder with helical focuser built into it.
 
Unfortunately I’m not home now and can’t give you the Baader part number.  But it’s NOT the stock one that comes with the Vario-Finder.  As I recall it’s T2 thread at the scope side – so it just threads on.  And unlike another 1.25” adapter for that scope from Baader, this one has a much longer 1.25” throat – so eyepieces or camera nosepieces don’t wobble nearly as much as Baader’s very short 1.25” adapter.
 
Woody
 
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Robert J. Bridges
Sent: Wednesday, October 14, 2020 12:31 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1
 
Hi All,
 
 I would like to replace the sliding focuser on my Vario-Finder (10x60;  61x250 f/4.1) scope with a Crayford style focuser. 
 
Does anyone have a suggestion?
 
Thanks,
Bob
 
--
Robert J. Bridges
Professor
Physiology and Biophysics
Chicago Medical School
3333 Green Bay Rd
North Chicago, Il 60064
Office: 847 578 3273
Cell: 847-271-7944
bob.bridges@...

Robert Chozick




CurtisC
 

Rolando: For a long time I used the Baader Vario-Finder as a guide scope with my TEC140ED (FL = 1035 mm with flattener).  The guider is an SX Superstar.  The Vario-Finder bracket (the one you sell) is mounted to the body of the focuser (Starlight Instruments 3545).  A brief email exchange with Howard a couple of months led me to go back to using the build-in OAG on my QSI 683 ("Why are you using a guide scope?").  As part of my re-evaluation of my guide settings and techniques and other matters, I've pored through hundreds of messages in this forum, going back to the forum's beginning in 2000.  There was some commentary about the Baader guide scope when you introduced it to the A-P product lineup back in 2013, but there hasn't been much since then.  What is your current feeling about using the Baader Vario-Finder as a guide scope?


Roland Christen
 


What is your current feeling about using the Baader Vario-Finder as a guide scope?
The Vario finder works great as a guide scope with most short focus refractors, like the TEC 140.

Rolando


-----Original Message-----
From: CurtisC via groups.io <calypte@...>
To: main@ap-gto.groups.io
Sent: Thu, Oct 15, 2020 6:24 am
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

Rolando: For a long time I used the Baader Vario-Finder as a guide scope with my TEC140ED (FL = 1035 mm with flattener).  The guider is an SX Superstar.  The Vario-Finder bracket (the one you sell) is mounted to the body of the focuser (Starlight Instruments 3545).  A brief email exchange with Howard a couple of months led me to go back to using the build-in OAG on my QSI 683 ("Why are you using a guide scope?").  As part of my re-evaluation of my guide settings and techniques and other matters, I've pored through hundreds of messages in this forum, going back to the forum's beginning in 2000.  There was some commentary about the Baader guide scope when you introduced it to the A-P product lineup back in 2013, but there hasn't been much since then.  What is your current feeling about using the Baader Vario-Finder as a guide scope?


CurtisC
 

Thank you. 

Unrelated to the question about the Baader, I tried your suggestion of running a couple of minutes unguided to see how the DEC axis "bobbles."  I wasn't sure what numbers I should evaluate: RMS?  Numbers from the running readout?  Eyeball the lines on the graph?


Roland Christen
 

Look at the P-P values. That will tell you how much the sky is moving around by itself, and you don't want to try to correct for this with your guider. It's impossible really to chase this motion because by the time the guide software has read it, the star has bounded to another value. So the idea is to set the Min Move to be just a bit above this peak value (1/2 of the P-P).

How to calculate the Min Move? At 1x the mount moves 1.5 arc sec per 0.1 seconds of time. So a Min Move value of 0.1sec will ignore all sky motions less than 1.5 arc sec.

Rolando


-----Original Message-----
From: CurtisC via groups.io <calypte@...>
To: main@ap-gto.groups.io
Sent: Thu, Oct 15, 2020 1:01 pm
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

Thank you. 

Unrelated to the question about the Baader, I tried your suggestion of running a couple of minutes unguided to see how the DEC axis "bobbles."  I wasn't sure what numbers I should evaluate: RMS?  Numbers from the running readout?  Eyeball the lines on the graph?


Roland Christen
 

One other thing I recommend is to use Guiding Assistant in PHD. It will help you to choose proper settings.

Rolando


-----Original Message-----
From: uncarollo2 <chris1011@...> via groups.io <chris1011@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Thu, Oct 15, 2020 1:21 pm
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

Look at the P-P values. That will tell you how much the sky is moving around by itself, and you don't want to try to correct for this with your guider. It's impossible really to chase this motion because by the time the guide software has read it, the star has bounded to another value. So the idea is to set the Min Move to be just a bit above this peak value (1/2 of the P-P).

How to calculate the Min Move? At 1x the mount moves 1.5 arc sec per 0.1 seconds of time. So a Min Move value of 0.1sec will ignore all sky motions less than 1.5 arc sec.

Rolando


-----Original Message-----
From: CurtisC via groups.io <calypte@...>
To: main@ap-gto.groups.io
Sent: Thu, Oct 15, 2020 1:01 pm
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

Thank you. 

Unrelated to the question about the Baader, I tried your suggestion of running a couple of minutes unguided to see how the DEC axis "bobbles."  I wasn't sure what numbers I should evaluate: RMS?  Numbers from the running readout?  Eyeball the lines on the graph?


Robert Berta
 

Huetech used to sell a nice helical focuser that didn't rotate the camera. You can lock down all of the adjustments with thumb screws so once locked down there is NO flexure or unwanted movement. I have had that setup (with a 50mm guide scope) since about 2005 and it works great with my 152mm and 80mm APO refractors. I have another 70mm guide scope with a longer focal length  and different focuser that I use with both the 152mm APO refractor and a 11" SCT. The trick is to eliminate ALL possible loose/soft connections....once you do you will get great guiding. 

I don't have the part number of that Huetech focuser anymore so can't help there. 


 

zwo also sells a helical non-rotating focuser, I'm not sure if it meets your specs

I think i have one of those hutech helical focusers i'm not using if that's the path you choose


Brian

On Thu, Oct 15, 2020 at 1:31 PM Robert Berta <biker123@...> wrote:
Huetech used to sell a nice helical focuser that didn't rotate the camera. You can lock down all of the adjustments with thumb screws so once locked down there is NO flexure or unwanted movement. I have had that setup (with a 50mm guide scope) since about 2005 and it works great with my 152mm and 80mm APO refractors. I have another 70mm guide scope with a longer focal length  and different focuser that I use with both the 152mm APO refractor and a 11" SCT. The trick is to eliminate ALL possible loose/soft connections....once you do you will get great guiding. 

I don't have the part number of that Huetech focuser anymore so can't help there. 



--
Brian 



Brian Valente


CurtisC
 

Thank you, Rolando.

"Guiding Assistant" in PHD or PHD2?

I've reviewed most of what you've posted about guiding in this forum, going back two decades.  That's not to say that maybe I haven't missed something important.  In the past I ignored the Advanced Settings in MaxImDL  I never looked at them.  I got what I got.  Having studied your advice, I believe my results have noticeably improved on nights of good seeing.  It's the nights of bad seeing, like the last few nights, that still trouble me.  Fiddling with the Min Move and aggressiveness, I've been able to get good results (= approximately round stars) on NGC 7293, which -- even for me at 33.5 deg N -- is pretty far south.  But guiding on something straight overhead, like M33, has been less successful.  That's where I ordinarily expect the best results.  So I'm still trying to get things worked out on nights of bad seeing.  As we speak, I'm still using the QSI's OAG.  But I may go back to using the Baader Vario-Finder again.  There are always guide stars, and I don't have to recalibrate if I rotate the QSI from landscape to portrait orientation.  But I assume the Min Move has to be increased significantly.


 

>>> "Guiding Assistant" in PHD or PHD2?


PHD2


On Thu, Oct 15, 2020 at 1:39 PM CurtisC via groups.io <calypte=verizon.net@groups.io> wrote:
Thank you, Rolando.

"Guiding Assistant" in PHD or PHD2?

I've reviewed most of what you've posted about guiding in this forum, going back two decades.  That's not to say that maybe I haven't missed something important.  In the past I ignored the Advanced Settings in MaxImDL  I never looked at them.  I got what I got.  Having studied your advice, I believe my results have noticeably improved on nights of good seeing.  It's the nights of bad seeing, like the last few nights, that still trouble me.  Fiddling with the Min Move and aggressiveness, I've been able to get good results (= approximately round stars) on NGC 7293, which -- even for me at 33.5 deg N -- is pretty far south.  But guiding on something straight overhead, like M33, has been less successful.  That's where I ordinarily expect the best results.  So I'm still trying to get things worked out on nights of bad seeing.  As we speak, I'm still using the QSI's OAG.  But I may go back to using the Baader Vario-Finder again.  There are always guide stars, and I don't have to recalibrate if I rotate the QSI from landscape to portrait orientation.  But I assume the Min Move has to be increased significantly.



--
Brian 



Brian Valente


George
 

Guys,

 

Use the Baader scope’s fine focus, not a helical focuser…flexure can enter into the guiding.    The point of the guidescope design was to eliminate all flexure.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Robert Berta
Sent: Thursday, October 15, 2020 3:31 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

 

Huetech used to sell a nice helical focuser that didn't rotate the camera. You can lock down all of the adjustments with thumb screws so once locked down there is NO flexure or unwanted movement. I have had that setup (with a 50mm guide scope) since about 2005 and it works great with my 152mm and 80mm APO refractors. I have another 70mm guide scope with a longer focal length  and different focuser that I use with both the 152mm APO refractor and a 11" SCT. The trick is to eliminate ALL possible loose/soft connections....once you do you will get great guiding. 

I don't have the part number of that Huetech focuser anymore so can't help there. 


CurtisC
 

George, what do you think of the Baader Vario-Finder for guiding?  I know in 2013 you seemed to have some success with it.  What have seven years of experience taught you?


George
 

It works great.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of CurtisC via groups.io
Sent: Thursday, October 15, 2020 3:55 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

 

George, what do you think of the Baader Vario-Finder for guiding?  I know in 2013 you seemed to have some success with it.  What have seven years of experience taught you?


CurtisC
 
Edited

Assuming you use MaxImDL, what is your Min Mov?  What is your guide camera?  I have the SX Superstar.  Back in 2014, when I was planning to buy the Baader, I was advised that the smaller pixels of the Superstar (compared to the version of the Lodestar available at the time) would be better suited to the Baader Vario-Finder.  Right now I'm inclined to think that one of the newer CMOS cameras with even tinier pixels might be the better bet.


Nick Iversen
 

I tried the Baader fine focus but in the end I bought a helical focuser which is much easier to use. Screwing and unscrewing the front lens to focus was a pain because it unlocks the lens which has to be locked again.

What is best practice for using the fine focus?