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Barlow for lunar astrophotography on small refractor?

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#1 Sonauer

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Posted 21 February 2020 - 12:41 PM

Hello everyone, I've used this forum plenty of times to improve my astrophotography but this is my first time posting! So first of all thank you very much.

 

I have an Orion 80ED, Celestron AVX mount, Orion mini deluxe autoguider package and a modified Canon 3Ti. I use my equipment mostly for DSO. I have also taken pictures of the moon and I was thinking maybe I could improve these using a barlow between my scope and my DSLR. My question is, since the Orion 80ED is only 600mm (FL), a 2x or 3x barlow still wont provide enough magnification to photograph much detail of the moon. Is it possible to use a 5x barlow on a scope like mine, to take pictures of the moon? Will the image be clear enough?

 

I ask this because I know the use of barlow for magnification has its limits, specially with small apertures and focal lengh like mines. So will this be a problem even with a bright moon and doing astrophotography? Is this a good idea? If not, how can I estimate or calculate the max barlow I should use before the image is worthless?

 

Thank you very much for your help.



#2 bobzeq25

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Posted 21 February 2020 - 02:07 PM

I did it with an 80ED and a 3X.  It worked OK, not great.


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#3 Sonauer

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Posted 23 February 2020 - 06:53 PM

Thank you for your answer, if I may ask, in what way not great? I'm new to this. Do you think using a 5x will be pushing it too much?



#4 bobzeq25

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Posted 24 February 2020 - 02:53 PM

Thank you for your answer, if I may ask, in what way not great? I'm new to this. Do you think using a 5x will be pushing it too much?

I wouldn't go 5X, unless your seeing is routinely excellent.   My image was not as sharp as I hoped, probably a combination of seeing and only 80mm.  Still worthwhile.



#5 KLWalsh

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Posted 24 February 2020 - 07:34 PM

I think if you do the calculation, for a Canon 3Ti and an 80 mm aperture, Nyquist sampling would imply a focal length of around 1200 for maximum resolution, which you’d get with a 2X barlow. Maybe on a superb night you’d get a bit more detail with a 3X barlow.
You’d want to shoot a high resolution video, then do image stacking with RegiStax or AutoStakkert.
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#6 Sonauer

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Posted 26 February 2020 - 12:50 PM

Thank you both, I'll go max 3x then, probably 2x since skies here are not the best.


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