Focal Reducer for SCT - ACF

[ab6110]

Hi all,

I've been looking into focal reducers for my LX200 10inch (ACF). Every f/6.3 reducer I find seems to also correct the image aswell. All I'm looking for is a focal reducer that only widens the fov and provides a faster aperture. Any ideas?

Thanks 

[ollypenrice]

Here's some information if you scroll down the page to the LX200 bit. http://www.franskroon.nl/equipment.htm

Frans has been one of our regular guests for years and I can promise you that he knows what he's talking about.

Olly

Edited July 14, 2015 by ollypenrice

[Astroboffin]

Hi all,

I've been looking into focal reducers for my LX200 10inch (ACF). Every f/6.3 reducer I find seems to also correct the image aswell. All I'm looking for is a focal reducer that only widens the fov and provides a faster aperture. Any ideas?

Thanks

What would you not want to correct the field too, once the reducer has done its job you will get a large amount of field curvature issues and you will need them corrected by the flattener.

If you really don't want to correct the errors, then if you get a Meade or celestron f6.3 you have two sets of lens in them, and you can remove the one nearest to the camera and that is the flattener, and just leave the reducer in place......simples..

Regards

AB

Edited July 14, 2015 by Astroboffin

[sharkmelley]

I found the F6.3 reducer to to very disappointing because it did not correct the image properly for an APS-C DSLR size sensor.  So if you really want reduction without proper correction (and I don't understand why you would want that) then  the standard F6.3 reducer might fit the bill.

Mark

[michael8554]

As I understand it, compared to the old Meade SCT's,  the ACF is already "coma corrected", so the standard Meade, Celestron etc F6.3 focal reducers are not suitable and will only worsen the images.

So ab6110 is asking for a FR only without coma correction, there are a couple of brands who make special reducers for the ACF.

Michael

[ronin]

Someone on CN about a year back added a coma corrector to one of these and really upset the image. As the scope is corrected all they managed was to add back in more coma. It was one of those "Doh" moments that Homer would be proud of. :grin:

I suspect that getting a flattener that does not upset the already present coma correction at least in a small amount may be a bit of a problem.

[Davey-T]

These are supposed to work.

Ian King may supply them.

Dave

http://optecinc.com/astronomy/catalog/lepus/index.htm

Edited July 16, 2015 by Davey-T

[ollypenrice]

I found the F6.3 reducer to to very disappointing because it did not correct the image properly for an APS-C DSLR size sensor.  So if you really want reduction without proper correction (and I don't understand why you would want that) then  the standard F6.3 reducer might fit the bill.

Mark

I think the point s that the ACF does not need flattening. It has, like the Celestron Edge, a natural flat field. The OP just wants to reduce the FL without messing up an already flat field by re-flattening it and renderng it curved.

Olly

[sharkmelley]

Ignore my earlier comment - I hadn't spotted that you were talking about the ACF

[Astroboffin]

Ignore my earlier comment - I hadn't spotted that you were talking about the ACF

Yes me too, sorry

Should read the post properly before answering...

Regards

AB

[Astroboffin]

You could do what I sugested in my first post, and remove the field flattener lens from a Meade or celestron reducer, it is very very simple to do, when you unscrew the locking ring, stand up on a piece of cloth and the lens comes out in two pieces with a small plastic spacer between, lift the top lens off ( this is the flattener, it is nearest the camera end) and then the little spacer, then put the casing back over the reducer lens and put the locking ring back in.....simples, now you just have an f6.3 reducer.

I have removed a few of them to fit into a 2" cell so they would fit inside my 2" focuser, rather than have to screw on the back with the SCT threads, but I kept the flattener in also.

Can't see why it would not work, and a much cheaper option.

AB

[antaeus]

On 17/07/2015 at 11:50, Astroboffin said:

You could do what I sugested in my first post, and remove the field flattener lens from a Meade or celestron reducer,

Hi,

I know it is an old post, but I have the same problem with an ACF 8 inch and the Antares f6.3 focal reducer. Does anyone know if the same operation of lens seaparation can be applied to Antares focal reducer?

Cezar

Edited May 15, 2019 by antaeus

[kirkster501]

I have the AstroPhysics CCDT67 for my 14" ACF.  I have yet to try this reducer since I bought it off of ABS two weeks ago due to other projects and cloud out.

Others have used this same reducer on the ACF 10" scope successfully.  I can't think why the 14" should be any different so I have taken a punt on it.

https://astrojolo.com/gears/acf-10-and-ccdt67-telecompressor/

[bjaffa]

On 17/07/2015 at 02:50, Astroboffin said:

You could do what I sugested in my first post, and remove the field flattener lens from a Meade or celestron reducer, it is very very simple to do, when you unscrew the locking ring, stand up on a piece of cloth and the lens comes out in two pieces with a small plastic spacer between, lift the top lens off ( this is the flattener, it is nearest the camera end) and then the little spacer, then put the casing back over the reducer lens and put the locking ring back in.....simples, now you just have an f6.3 reducer.

I have removed a few of them to fit into a 2" cell so they would fit inside my 2" focuser, rather than have to screw on the back with the SCT threads, but I kept the flattener in also.

Can't see why it would not work, and a much cheaper option.

AB

I know that this is an older post but I hoping someone can help me.

I have a old meade f/6.3 focal reducer/flattener. I used it with a meade 10"  LX90  SCT (non ACF) in a moonlite 2.5 cml focuser.

I now have a meade 10" LX200-ACF  SCT and want to use the moonlite  focuser with a focal reducer (non field flattener). From the post above it sounds like it is possible to remove the field flattener lens..

The moonlite focuser draw tube is for a meade focal reducer so it is important that I either use a compatible focal reducer or remove the field flattener lens so it will work in the moonlite focuser.

If I remove the lens does anyone have experience with what the new back focus will be (the original back focus was 104 mm)?

Or can someone suggest a better focal reducer which would be compatible with the moonlight focuser draw tube?

 

Any help or suggestions would be appreciated.   Thanks  Brent

[lhm4000]

On 17/07/2015 at 04:50, Astroboffin said:

You could do what I sugested in my first post, and remove the field flattener lens from a Meade or celestron reducer, it is very very simple to do, when you unscrew the locking ring, stand up on a piece of cloth and the lens comes out in two pieces with a small plastic spacer between, lift the top lens off ( this is the flattener, it is nearest the camera end) and then the little spacer, then put the casing back over the reducer lens and put the locking ring back in.....simples, now you just have an f6.3 reducer.

I have removed a few of them to fit into a 2" cell so they would fit inside my 2" focuser, rather than have to screw on the back with the SCT threads, but I kept the flattener in also.

Can't see why it would not work, and a much cheaper option.

AB

I did this with one of my Celestron f/6.3 reducer/correctors.  I took off the lock ring and flipped the entire piece over.  The reducer glass is on the bottom, a 2mm tall plastic spacer, and finally the corrector (field flattener) is on top.  If you just put the focal reducer glass back in, there is nothing to prevent it from flopping around in the housing.

Since I don't have a 3D printer I found a place online that would print a 43mm outer diameter, 1mm thick, 9mm tall spacer ring.

I just got it today in the mail and it fits perfectly.  It holds the focal reducer glass in place (where it always has been) very well.  This should not change any characteristic of the reducer since the glass is still in the same location in the housing.  I just put in the new spacer, put in the focal reducer glass, and then tightened down the lock ring.

 

Edited August 14, 2020 by lhm4000

[jcannady]

On 14/08/2020 at 15:39, lhm4000 said:

I did this with one of my Celestron f/6.3 reducer/correctors.  I took off the lock ring and flipped the entire piece over.  The reducer glass is on the bottom, a 2mm tall plastic spacer, and finally the corrector (field flattener) is on top.  If you just put the focal reducer glass back in, there is nothing to prevent it from flopping around in the housing.

Since I don't have a 3D printer I found a place online that would print a 43mm outer diameter, 1mm thick, 9mm tall spacer ring.

I just got it today in the mail and it fits perfectly.  It holds the focal reducer glass in place (where it always has been) very well.  This should not change any characteristic of the reducer since the glass is still in the same location in the housing.  I just put in the new spacer, put in the focal reducer glass, and then tightened down the lock ring.

 

What 3D service did you use?

 

jim

[lhm4000]

1 hour ago, jcannady said:

What 3D service did you use?

jim

Hi Jim,

I went with CraftCloud3D:  https://craftcloud3d.com/

I was able to get 4 of the rings printed (in ABS black) and shipped to me for $9.99.

It was the same cost to get 1 or 4 printed and same total shipping.  So I have a few spares and can use them with my other reducers if necessary.

Hope that helps,

Lamar