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NP101 & NP101is

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#1 hongxu chen

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Posted 14 July 2019 - 06:35 AM

Except the focuser, what is the difference between Televue NP101is and non-is version? I notice that Starlight has NP101 focuser upgrade scheme. Will the Feather Touch improve the non-is version to as good as IS version?

#2 Jon Isaacs

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Posted 14 July 2019 - 06:45 AM

Except the focuser, what is the difference between Televue NP101is and non-is version? I notice that Starlight has NP101 focuser upgrade scheme. Will the Feather Touch improve the non-is version to as good as IS version?

I believe the difference between the NP-101 and the NP-101is is the diameter of the optics of the rear "Petzval" lens.  This essentially functions as a perfectly matched flattener/reducer.  The IS has larger diameter optics and is thus capable of illuminating a larger field of view.

 

Jon 


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#3 Spikey131

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Posted 14 July 2019 - 07:01 AM

For visual use, the NP101 is as good as the NP101is.

 

As Jon wrote, TV improved the optics in the “is” version to give a wider view for imaging.


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#4 hongxu chen

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Posted 14 July 2019 - 09:01 AM

I believe the difference between the NP-101 and the NP-101is is the diameter of the optics of the rear "Petzval" lens. This essentially functions as a perfectly matched flattener/reducer. The IS has larger diameter optics and is thus capable of illuminating a larger field of view.

Jon


I am using 16200 CCD. Is the non-is good enough for me?

#5 HydrogenAlpha

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Posted 14 July 2019 - 11:35 AM

I am using 16200 CCD. Is the non-is good enough for me?


The 16200 has a fairly large chip and is rather heavy. You should get the IS

#6 allen g

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Posted 14 July 2019 - 03:18 PM

I asked that question to David Nagler when I was purchasing the np101.  He said for visual viewing there is no difference. 



#7 hongxu chen

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Posted 14 July 2019 - 10:11 PM

The 16200 has a fairly large chip and is rather heavy. You should get the IS


I bought the NP101 ten years ago for visual viewing. Now I have a chance to get a good price 16200 CCD. So I am planing for astrophotography. I don’t know whether my scope is suit for that CCD or not. I would accept improve it like change the focuser to fully use this CCD, but not trade in it for an IS version or even a TAK. If my scope can not hold this CCD, I will just stop doing anything. Or I would not help myself to burn money to upgrade the scope to match this CCD after buying it. Then burn money to upgrade the CCD to match the new scope. Endless cycle, until sell my soul to this devil hobby.

#8 HydrogenAlpha

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Posted 14 July 2019 - 10:45 PM

I bought the NP101 ten years ago for visual viewing. Now I have a chance to get a good price 16200 CCD. So I am planing for astrophotography. I don’t know whether my scope is suit for that CCD or not. I would accept improve it like change the focuser to fully use this CCD, but not trade in it for an IS version or even a TAK. If my scope can not hold this CCD, I will just stop doing anything. Or I would not help myself to burn money to upgrade the scope to match this CCD after buying it. Then burn money to upgrade the CCD to match the new scope. Endless cycle, until sell my soul to this devil hobby.

If you eventually intend to upgrade to the NP101IS, you can look for a used unit so you don't need to spend too much on the upgrade. The price difference between a used NP101 and NP101IS is not unreasonably large. 

 

Also, you don't need to upgrade the CCD just to max out the image circle. There are many people happily using FSQ106s with small sensors, despite having the 88mm image circle. 

 

By the way, how much experience do you have with astrophotography? Shelling out for a 16200 is already quite a substantial investment, given that there are many other more affordable options (CMOS-based cameras) in the market. 




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