Meade focal reducer f/6.3 question

[Emmanuel Marchal]

When I bought my Meade 10" ACF second hand, it came with a meade focal reducer/field flattener.

I'm now trying to get the correct light train including the reducer, a FLO OAG and a DSLR EOS 500D.

I've read in some post that there at least 2 generations of Meade F/6.3 reducers with different back focus.

My reducer box says

Series 4000 07545LF

f/6.3 Focal Reduce/Field Flattener

UPC 0709942001846

The reducer inscription says

CHINA MEADE SERIES 4000f/6.3 FOCAL REDUCER/FIELD FLATTENER MULTI-COATED

How could I tell which model I own and which backfocus I should work with?

[Merlin66]

Easy to check....

The "original" reducer had a focal length of 240mm and a back focus working distance of 110mm

The "new" (current) reducer is close to 110mm focal length with a working distance of only 45mm!!

Just focus and image of the sun on a wall/ card and measure the distance.

Hope this helps.

[Emmanuel Marchal]

Thanks Merlin66. Looks like I have one of the old one with 240mm FL. Glad it's this one as I understand the new model wouldn't work with a DSLR and its 55mm of back focus already in the camera.

Cheers. 

[lensman57]

When I bought my Meade 10" ACF second hand, it came with a meade focal reducer/field flattener.

I'm now trying to get the correct light train including the reducer, a FLO OAG and a DSLR EOS 500D.

I've read in some post that there at least 2 generations of Meade F/6.3 reducers with different back focus.

My reducer box says

Series 4000 07545LF

f/6.3 Focal Reduce/Field Flattener

UPC 0709942001846

The reducer inscription says

CHINA MEADE SERIES 4000f/6.3 FOCAL REDUCER/FIELD FLATTENER MULTI-COATED

How could I tell which model I own and which backfocus I should work with?

The information given by Merlin66 is quite correct, they redisgned the new Reducer as it was impossible with the old one, a filter wheel and a CCD to clear the top of the mount as the scope was pointing upwards so they reduced the backfocus to 45mm, my concern is however with the suitability of the oridinary series 4000 reducer for the ACF optics, this is something that you need to research yourself, you really do not want an £85.00 reducer spoiling the ACF field.

Regards,

A.G

[Emmanuel Marchal]

The information given by Merlin66 is quite correct, they redisgned the new Reducer as it was impossible with the old one, a filter wheel and a CCD to clear the top of the mount as the scope was pointing upwards so they reduced the backfocus to 45mm, my concern is however with the suitability of the oridinary series 4000 reducer for the ACF optics, this is something that you need to research yourself, you really do not want an £85.00 reducer spoiling the ACF field.

A.G

Good point A.G. I have that concern as well. I've read about the Field Flattener part of the meade reducer not being suitable for an ACF scope, but I've also read elsewhere (i think in SGL) that the FF effect would not be noticeable when used with an APS format DSLR which is what I am imaging with (eos 500D). So my hopes is that it will be ok.

I guess the only way to know is by taking pics and seeing how the star shapes look like.

clear skies!

[lensman57]

Good point A.G. I have that concern as well. I've read about the Field Flattener part of the meade reducer not being suitable for an ACF scope, but I've also read elsewhere (i think in SGL) that the FF effect would not be noticeable when used with an APS format DSLR which is what I am imaging with (eos 500D). So my hopes is that it will be ok.

I guess the only way to know is by taking pics and seeing how the star shapes look like.

clear skies!

Give it a go and good luck.

A.G

[Davey-T]

I use the 6.3 reducer on my 10" mainly with Atik 314 but also with DSLR more for the reducing than flattening effect as the stars look fine to the edge.

There is an Optec Lupus F/R designed for the ACF but lots of money and as far as I know no UK supplier.

Dave