Old 07-08-2017, 08:09 AM
Nino (John Peacock)
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Meade Acf

Good morning, I have a 10inch Meade lx200 F10 Acf and I'm starting to get into deep sky photography, I think I read somewhere that I won't need my 6.3 focal reducer is this correct? Cheers John
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Old 07-08-2017, 09:17 AM
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Shano592 (Shane)

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Hi John.

I have the same setup as you. I also have an F/6.3 reducer.

The reducer can be used, but to use it with a camera, the optical train needs to be shortened, in order to reach focus. Pretty much the same as visual, I guess.

I use a Canon 50D with mine, and the only setup that works with the reducer is this one:

telescope>reducer>2-inch adapter>t-ring>camera

Anything else, and focus can't be reached.

You don't need the reducer at all if doing deep sky. The reducer will give you a wider field of view, at the expense of zoom. The same item at f/10 is a lot "closer" in the image/eyepiece than at f/6.3.

One thing I have noticed with my reducer (which is not a corrector)... due to the fact that the ACF optics are flat to the edge of the field, having the reducer on for imaging, causes vignetting of stars at the edge of the images.
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Old 07-08-2017, 02:31 PM
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astronobob (Bob)
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Hey John,
There are two main reasons why a 6.3 reducer is used, visually & photographically,
1) as mentioned by Shane - it will produce a 'wider field'
2) the scope will be 'faster' meaning, quicker exposure times, by about 30% - ball park estimate, give or take 10 %

Another advantage is, the wider the field, the less critical Guiding, Focus, Backlash etc will be, , Hence, the smaller the field, the more critical.
Is why the more experienced 'imagers' out ther have such good quality mounts !

Just my Bob's worth :-)
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Old 07-08-2017, 05:49 PM
Nino (John Peacock)
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Thank you Bob and Shane, over the coming weeks I will try with and without and see what results I get. Cheers
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Old 07-08-2017, 11:03 PM
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redbeard (Damien)
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Hi John,

I mostly use a focal reducer as to speed things up and get a wider view. For example, I use a Canon 450D with a Meade 10" GPS, Celestron 6.3 reducer/flattener. With the above rig at 6.3, I can fit
much of the Orion nebula in, but at F10, zoomed in a lot more. Other nebula are quite large and some way larger than what 6.3 can see. Don't get me wrong though, if going really deep,
(well as deep as the scope will allow), and you have good tracking/guiding and an EQ mount, then F10 all the way.

Another thing to consider if you were to use a focal reducer, is there needs to be the correct distance between the focal reducer and the sensor in your camera, to work at the rated F6.3. On my scope the distance is about 105mm, not sure on yours, should be similar, but as you have the flat field ACF, ensure you have the best reducer. There are a few to choose from, some better than others as usual. But hey, you can always crop your images!

If you are using a DSLR, then the sensor gets hotter the longer the exposure so faster is better. If you have a good CCD, then your laughing either way.

If you don't mind me asking, what sort of camera/mount/guiding rig do you have?


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Old 08-08-2017, 12:38 PM
Nino (John Peacock)
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Hi Damien

I have a 10 inch Acf Meade LX200, it is still fork mounted, My guide scope is a orion 80mm short tube guider. I use a Nixon D5200 and a Prostar lunar planetary and guide ccd. So far I have only photograph the Moon, Saturn and Jupiter. I intend on starting Deep sky photography when this full moon leaves the night sky. Cheers
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