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Tracking Scope mount question

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7 replies to this topic

#1 ParagPA

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Posted 17 October 2019 - 10:08 AM

Hello,

 

I normally use an ED80T w/ a Canon EOS80D.

 

However, I want to image the NA nebula with a new AP-modified T3i I just received, with a 50-120mm lens (I think - don't have lens in front of me) instead of using the ED80T, so I can get a larger field of view.

 

What are my options for mounting a guide scope? I still want to do long, guided exposures. 

 

Thanks!

Parag

 



#2 SilverLitz

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Posted 17 October 2019 - 10:12 AM

Mount lens and guidescope side by side:

 

Samyang135_03.JPG

 

Samyang135_02.JPG


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#3 Hesiod

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Posted 17 October 2019 - 11:28 AM

If the astro mod is just an improved IR cut filter, at 50mm f/5.6 or less it is very doubtful you will ever need the guide, as the most basic devices can get you 5-6' subs (at these exposures risk already to burn brighter areas of the target, and definitely stars, at least those visible by naked eye) .
Even at 100mm can avoid the guide rather easily (I usually takes 2 or 3' subs at 200mm with a simple low end tracker. I do not try longer ones because would "burn" the picture!).

Otherwise I suggest too the side-by-side arrangement: take a dovetail bar and place a quick release clamp at either end (can use Vixen type clamps, or even ARCA ones, which are smaller and lighter)

#4 ParagPA

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Posted 18 October 2019 - 07:00 AM

If the astro mod is just an improved IR cut filter, at 50mm f/5.6 or less it is very doubtful you will ever need the guide, as the most basic devices can get you 5-6' subs (at these exposures risk already to burn brighter areas of the target, and definitely stars, at least those visible by naked eye) .
Even at 100mm can avoid the guide rather easily (I usually takes 2 or 3' subs at 200mm with a simple low end tracker. I do not try longer ones because would "burn" the picture!).

Otherwise I suggest too the side-by-side arrangement: take a dovetail bar and place a quick release clamp at either end (can use Vixen type clamps, or even ARCA ones, which are smaller and lighter)

 

Thanks! It never occurred to me that the tracking mount itself would be good enough. I’m using a CEM40 mount, which tracks well. I’ll try that and keep it to 2-3 minute subs. 



#5 NuclearRoy

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Posted 18 October 2019 - 12:53 PM

If you do need to guide, I second SilverLitz's answer.

Attached Thumbnails

  • 600mm with dew controller.jpg
  • 600mm with dew controller side.jpg


#6 ParagPA

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Posted 18 October 2019 - 02:03 PM

If you do need to guide, I second SilverLitz's answer.


Looks like I'd need to rotate the saddle plate 90 degrees to make this work - but I assume that's possible on the CEM40

#7 View2

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Posted 18 October 2019 - 02:45 PM

Btw.. I love your counterweights. I've been there.

#8 SilverLitz

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Posted 19 October 2019 - 09:32 AM

Looks like I'd need to rotate the saddle plate 90 degrees to make this work - but I assume that's possible on the CEM40

Absolutely NO PROBLEM rotating any saddle 90deg.  

 

I setup my G11 (using its integrated bubble levels) getting its home position by leveling both the RA and Dec bubble levels, with saddle in the normal position.  I set the Dec setting circle to 0deg, and then rotate the saddle 90deg, lining up with the Dec setting circle at 90.




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