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Flip Mirror Focus problem with Canon 60D

Equipment Imaging
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#1 N2TU

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Posted 16 April 2021 - 03:08 PM

Am trying a new flip mirror on my Explore Scientific ED80 and having newbie problems. This is the one I am using...

 

https://www.amazon.c...ie=UTF8&psc=1  

 

Trying to focus the camera, I crank the ED80 focus all the way into the OTA.... I mean all the way...the focus is still not quite correct. It is close but not good. 

 

How can I work around the short focus distance? 

 

Thanks!.....

 

Lou

 

PS: Once I get past this, I have another question...but first things first!



#2 Joe1950

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Posted 16 April 2021 - 03:52 PM

Well, it would have been better if you had to rack it out and couldn’t reach focus. Then you could use an extender.

 

What kind of imaging are you going to use it for?

 

Wide field and DSOs at prime focus? Not much you can do.

 

Planets, moon? If you have a Barlow lens and would use it for a larger image scale, placing the nosepiece of the flip mirror into the Barlow and then the Barlow into the scope, would likely bring the focal plane out enough to focus. Or, some Barlow’s will unscrew from the main tube and you can screw it directly into the nosepiece of the flip mirror assembly. It would give you less amplification than the Barlow with its tube.

 

joe.

 

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#3 N2TU

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Posted 16 April 2021 - 04:11 PM

Hey Joe!.

 

Thanks for the reply....I just found my 'problem'...I ditched the T Ring adapter and screwed the camera directly onto the T-ring. 

 

Now I just have to get the EP on the other side of the flip mirror to focus....that should be just a matter of trail and error....

 

Thanks....or 73!

 

Lou

Well, it would have been better if you had to rack it out and couldn’t reach focus. Then you could use an extender.

 

What kind of imaging are you going to use it for?

 

Wide field and DSOs at prime focus? Not much you can do.

 

Planets, moon? If you have a Barlow lens and would use it for a larger image scale, placing the nosepiece of the flip mirror into the Barlow and then the Barlow into the scope, would likely bring the focal plane out enough to focus. Or, some Barlow’s will unscrew from the main tube and you can screw it directly into the nosepiece of the flip mirror assembly. It would give you less amplification than the Barlow with its tube.

 

joe.

 

N2TU de W2DI.


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#4 slepage

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Posted 16 April 2021 - 04:11 PM

The flip mirror is taking up to much back focus. Not to be mean or anything, but the best thing you can do for yourself is to ditch the flip mirror.  The vignetting that you are going to have will be unacceptable  considering that it only comes with a 1 1/4 nose piece.   The 60D will require a larger image circle.  Google 60D live view focusing.  This is the simplest and fastest way to get excellent focus considering that your scope has a focal length of 480mm and works at f/6.  You can also look up the Bahtinov focusing mask.

 

Steve


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#5 Joe1950

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Posted 16 April 2021 - 04:22 PM

Very good, Lou



#6 N2TU

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Posted 16 April 2021 - 06:54 PM

Steve,

 

You are fine...I appreciate the feedback and guidance. I am new at this and appreciate any and all information.

 

Lou


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#7 michael8554

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Posted 17 April 2021 - 06:40 AM

During the day get the 60D in focus on a distant landmark.

 

Unscrew the 1.25" fitting the eyepiece goes in, and try to find eyepiece focus with the eyepiece in your hand over the port in the flip mirror.

 

This will give you a rough idea of where the eyepiece needs to be.

 

If that is too close to use the 1.25" fitting then you're stuck, as you've run out of telescope focus.



#8 N2TU

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Posted 17 April 2021 - 11:31 AM

All...

 

Thanks for everything....Finally got the camera and the EP in focus. I had to add an extension on the EP...and screw the camera onto the flip mirror. Now I have enough focus range for both the camera and the EP.

 

Much appreciated...thanks for the suggestions!   waytogo.gif

 

Lou


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