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B400 for visual observation?

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#1 paulsky

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Posted 15 January 2020 - 11:32 AM

Hello,
Really in a Lunt LS50 have the B400 for visual observation (strictly) there is much difference with a B600 in this same solar telescope?
Thanks in advance.
Regards.
Paul.

 



#2 demorcef

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Posted 15 January 2020 - 11:51 AM

Hello Paul.

 

I have a LS50 and a B600. I think the B600 is more comfortable for visual because it gives you an extra 2mm vs the 400. It makes it easier to find the sun because you have a slightly larger field of view.


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#3 Eddgie

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Posted 16 January 2020 - 09:26 AM

Hello,
Really in a Lunt LS50 have the B400 for visual observation (strictly) there is much difference with a B600 in this same solar telescope?
Thanks in advance.
Regards.
Paul.

The full disk will fit in the field of the BF400 and the amount of detail you can see will be identical to what can be seen in the BF600.  While the BF600 will make the sun easier to find, a good solar finder will typically do the same thing and in my experience, the sun is pretty easy to find. 

 

The BF-600 will provide quite bit more field around the sun.  The BF600 will perhaps give you a bit more money on re-sale but that is totally a neutral because you will pay more up front for it. 

 

Both will perform identically on the amount of detail you can see on and around the solar disk though.  

 

 

In the LS50, the solar disk will be slightly over 3.2mm at the focal plane.

 

Forgive the crude art work, but this represents the scale.  While one could argue that the sun is a tight fit in the 4mm, one also argue that there is a lot of wasted space in the 6mm.

 

solar disk.png

 

I have no recommendation.  Money is money and we each make our decision based on how important the difference in cost will be in terms of benefit we receive.

 

This drawing can show you the difference though. Hopefully it will be useful in helping understand the cost/benefit argument for each option. 


Edited by Eddgie, 16 January 2020 - 09:27 AM.

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#4 WilburTWildcat

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Posted 22 January 2020 - 05:26 PM

Great illustration! I've been mulling all this myself and the concentric rings help.

 

Does more space around the disc lead to increased contrast for prominences?



#5 dhkaiser

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Posted 22 January 2020 - 05:51 PM

Another consideration is what mount you will be using.  The wider field of view can be desirable for a non tracking mount.



#6 George9

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Posted 23 January 2020 - 03:49 PM

A huge prom could miss as the Sun becomes active, but you can always just shift the prom to the center of the field.

 

If you ever plan to use a binoviewer, you need the B600. A binoviewer would improve the view.

 

George




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