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Anyone use the Explore Scientific N208 CF Newtonian ?

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#1 GaryShaw

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Posted 08 April 2019 - 07:00 PM

HI All:

I'm primarily a DSO observer and am considering the above scope as a companion scope to my Schmidt Newtonian. Both would to be used for EAA and Visual observing.

 

I'd appreciate hearing anyone's opinion on the quality of the optics and the overall build as well as any comments on its EAA and visual use. 

Thank you for your input...

Gary


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#2 ICit2

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Posted 08 April 2019 - 07:58 PM

Here you go bud.

 

https://www.youtube....h?v=UPL5bidORT8

 

And for NV with this scope: https://www.youtube....h?v=6usKtqpVMi8

 

Dakota


Edited by ICit2, 08 April 2019 - 08:01 PM.

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#3 wcoastsands

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Posted 08 April 2019 - 09:46 PM

The N208CF is an amazing scope. It really is a quality scope, both in optical quality and build quality. Every bit of it feels absolutely solid. It’s easy to collimate. After performing star tests, I saw no visible sign of optical aberrations. There is no spherical aberration, and optics do not appear to be pinched at all.

 

Keep in mind that these do ship with the primary mirror clips over tightened to keep the mirror protected during shipment. They will need to be loosened before use. Video on this here.

 

I primarily use mine for astrophotography, but I have to say I was blown away when I saw the Trapezium of the Orion Nebula through an eyepiece with this scope. It looked like a 15” exposure at ISO1600. The nebulosity was so well defined, it took my breath away. This is the largest scope I’ve ever looked through, though.

 

Using the HR Coma Corrector, these are the kind of results you can expect as an imager when capturing with this scope.

 

This is the setup I’m using:

Explore Scientific N208CF 22.6lb Astrophoto Rig

 

Also, if you aren’t already aware, there is apparently a new version of this scope available. I just noticed it this morning on Bresser’s website. It’s called the Explore Scientific PN208 Carbon Mark II Hexafoc OTA.



#4 GaryShaw

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Posted 09 April 2019 - 11:45 AM

Here you go bud.

 

https://www.youtube....h?v=UPL5bidORT8

 

And for NV with this scope: https://www.youtube....h?v=6usKtqpVMi8

 

Dakota

PERFECT DAKOTA - THANKS!

GARY



#5 GaryShaw

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Posted 09 April 2019 - 11:51 AM

The N208CF is an amazing scope. It really is a quality scope, both in optical quality and build quality. Every bit of it feels absolutely solid. It’s easy to collimate. After performing star tests, I saw no visible sign of optical aberrations. There is no spherical aberration, and optics do not appear to be pinched at all.

 

Keep in mind that these do ship with the primary mirror clips over tightened to keep the mirror protected during shipment. They will need to be loosened before use. Video on this here.

 

I primarily use mine for astrophotography, but I have to say I was blown away when I saw the Trapezium of the Orion Nebula through an eyepiece with this scope. It looked like a 15” exposure at ISO1600. The nebulosity was so well defined, it took my breath away. This is the largest scope I’ve ever looked through, though.

 

Using the HR Coma Corrector, these are the kind of results you can expect as an imager when capturing with this scope.

 

This is the setup I’m using:

 

 

Also, if you aren’t already aware, there is apparently a new version of this scope available. I just noticed it this morning on Bresser’s website. It’s called the Explore Scientific PN208 Carbon Mark II Hexafoc OTA.

Thanks Nikkolai - very helpful information and links!

Gary


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#6 REC

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Posted 09 April 2019 - 01:30 PM

The N208CF is an amazing scope. It really is a quality scope, both in optical quality and build quality. Every bit of it feels absolutely solid. It’s easy to collimate. After performing star tests, I saw no visible sign of optical aberrations. There is no spherical aberration, and optics do not appear to be pinched at all.

 

Keep in mind that these do ship with the primary mirror clips over tightened to keep the mirror protected during shipment. They will need to be loosened before use. Video on this here.

 

I primarily use mine for astrophotography, but I have to say I was blown away when I saw the Trapezium of the Orion Nebula through an eyepiece with this scope. It looked like a 15” exposure at ISO1600. The nebulosity was so well defined, it took my breath away. This is the largest scope I’ve ever looked through, though.

 

Using the HR Coma Corrector, these are the kind of results you can expect as an imager when capturing with this scope.

 

This is the setup I’m using:

 

 

Also, if you aren’t already aware, there is apparently a new version of this scope available. I just noticed it this morning on Bresser’s website. It’s called the Explore Scientific PN208 Carbon Mark II Hexafoc OTA.

Wow, what a great shot of M42!


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#7 REC

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Posted 09 April 2019 - 01:42 PM

Here you go bud.

 

https://www.youtube....h?v=UPL5bidORT8

 

And for NV with this scope: https://www.youtube....h?v=6usKtqpVMi8

 

Dakota

Wow, nice review!



#8 wcoastsands

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Posted 09 April 2019 - 03:51 PM

Thanks! I think that’s my best attempt so far. I’m still hoping to add more data to it, but it’s starting to get pretty low in the western skies after dark now. I might end up waiting until next season before capturing any more on it.

Dakota’s review is the best. It was the only one I could find of the N208CF when I first started looking into it. Even so, I think it was what really sold me on this scope.

#9 jmiller1001

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Posted 09 April 2019 - 11:16 PM

I have one - it's a great scope.  I use mine primarily for imaging, but it's great for visual as well.  I replaced the stock focuser with a Moonlite one, but that's primarily for imaging reasons - with the stock focuser for visual it's fine.  I also re-center spotted the mirror as the original center spot was off by about 1/16".  Again, for visual, I can't imagine that making a huge difference.  Collimation is simple and mine holds it well.  I 2nd Dakota's review - it was the final kicker for me as well.  Great scope for the money imho.  Extremely portable - I use it as a grab and go occasionally.


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#10 wcoastsands

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Posted 10 April 2019 - 12:18 AM

I replaced the stock focuser with a Moonlite one, but that's primarily for imaging reasons - with the stock focuser for visual it's fine.  I also re-center spotted the mirror as the original center spot was off by about 1/16".

I haven't had the pleasure of using a Moonlite, yet. So I don't know what I'm missing. What motivated you to upgrade from the stock focuser to a Moonlite? Also, how were you able to determine that the center-spot was off center?



#11 jmiller1001

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Posted 10 April 2019 - 09:26 AM

I bought the Moonlite focuser because 1. I had tilt in my images (using CCD Inspector) and I suspected that I was getting tilt in the stock focuser (this was correct) and 2. I wanted a motorized focuser (which I got with the Moonlite).  

 

I had the mirror cell out cleaning it and I measured the center spot out of curiosity and it was off by about 1/16"  I had a Catseye center spotting kit laying around and I used it to re-center the mirror.  Does it make a difference?  I don't know honestly, but CCD Inspector shows almost zero tilt and collimation that is spot on....


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#12 iKMN

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Posted 10 April 2019 - 09:45 AM

I wish I’d had gotten one of these when they were $599. I do have a 6” MN and 10” dob so it doesn’t make much sense but I’ve always wanted one. Anyway, glad to see so many like it.

#13 GaryShaw

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Posted 10 April 2019 - 10:08 AM

I have one - it's a great scope.  I use mine primarily for imaging, but it's great for visual as well.  I replaced the stock focuser with a Moonlite one, but that's primarily for imaging reasons - with the stock focuser for visual it's fine.  I also re-center spotted the mirror as the original center spot was off by about 1/16".  Again, for visual, I can't imagine that making a huge difference.  Collimation is simple and mine holds it well.  I 2nd Dakota's review - it was the final kicker for me as well.  Great scope for the money imho.  Extremely portable - I use it as a grab and go occasionally.

Hi JM

I’m visual and EAA oriented so do you think the issues you raised would merit my taking similar steps?

 

Also, if you don’t mind, could you educate me on a few things you mentioned that I probably need to understand?

1. Tilt: what is this and what impact does it have on imaging?

2. Cateye: Sounds like a useful device but I’ve never heard of it. Can you add a bit on it as well?

3. Motorized focus: With a smooth course/fine focuser, what is the benefit of a motorized one? 

 

I appreciate your your time in answering any of the above 

cheers

Gary



#14 jmiller1001

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Posted 10 April 2019 - 10:49 AM

Sure - Here are the answers:

 

Also, if you don’t mind, could you educate me on a few things you mentioned that I probably need to understand?

1. Tilt: what is this and what impact does it have on imaging?

For imaging, tilt shows up as elongated stars across the image.  

2. Catseye: Sounds like a useful device but I’ve never heard of it. Can you add a bit on it as well?

Catseye - the king of collimation tools and resources.

3. Motorized focus: With a smooth course/fine focuser, what is the benefit of a motorized one?

For visual and EAA, it doesn't help.  For imaging, it autofocuses and compensates for thermal gradients in the imaging train and it compensates for filter to filter focusing variation.  For automated imaging, it's a must.

 

If you're doing visual and EAA, I can't imagine that you would benefit greatly from what I did my scope.  However, with a fast Newt like this one, collimation is key - even for visual!


Edited by jmiller1001, 10 April 2019 - 10:49 AM.

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#15 GaryShaw

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Posted 10 April 2019 - 02:03 PM

Sure - Here are the answers:

 

Also, if you don’t mind, could you educate me on a few things you mentioned that I probably need to understand?

1. Tilt: what is this and what impact does it have on imaging?

For imaging, tilt shows up as elongated stars across the image.  

2. Catseye: Sounds like a useful device but I’ve never heard of it. Can you add a bit on it as well?

Catseye - the king of collimation tools and resources.

3. Motorized focus: With a smooth course/fine focuser, what is the benefit of a motorized one?

For visual and EAA, it doesn't help.  For imaging, it autofocuses and compensates for thermal gradients in the imaging train and it compensates for filter to filter focusing variation.  For automated imaging, it's a must.

 

If you're doing visual and EAA, I can't imagine that you would benefit greatly from what I did my scope.  However, with a fast Newt like this one, collimation is key - even for visual!

Thank you JM. I’ll do some research on Catseye.

 

On motorized focusing, is this an automatic focusing that takes place as needed and without human involvement or is it used by the observer to remotely adjust focus when needed?



#16 jmiller1001

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Posted 10 April 2019 - 07:57 PM

The whole idea with autofocusing is no human intervention required:  SGP (Sequence Generator Pro), FocusPal and a number of other imaging programs automate this for you.  You have to perform an initial calibration and set-up and then you're good to go!



#17 wcoastsands

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Posted 11 April 2019 - 10:09 AM

Do you use a coma corrector with your Moonlite focuser? If so, I’m wondering if you had any trouble reaching the proper focal distance with it.

 

There’s another user with a Moonlite focuser who’s using the Explore Scientific HR Coma Corrector, but is unable to reach focus with the limited back focus of the Moonlite focuser. They’re currently attempting to add some sort of spacing between the HRCC and the end of the focus tube.

 

If this all sounds familiar to you, would you mind advising? Thanks!



#18 25585

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Posted 11 April 2019 - 10:45 AM

80mm secondary! :O

 

What are the primary collimation knobs like?

 

Very neat scope.


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#19 wcoastsands

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Posted 11 April 2019 - 10:56 AM

It’s even larger on the Mk II at 85mm. The focal length is also slightly shorter at 800mm, putting the focal ratio at f/3.8 instead of f/3.9.

#20 CCD-Freak

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Posted 11 April 2019 - 07:47 PM

I have a prototype of the ES8CF and it is a very capable astrograph.  I am testing to see which coma corrector is best with it.  At F3.8 it will be a great scope for EAA work.  

 

ES8-AP900 at CBSP_08.JPG

 

 

John Love

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Edited by CCD-Freak, 11 April 2019 - 07:48 PM.

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#21 wcoastsands

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Posted 11 April 2019 - 07:56 PM

Wow, I really like your setup. I never considered using an additional tube ring to mount the finder on. Really nice configuration.
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#22 CCD-Freak

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Posted 11 April 2019 - 08:18 PM

Here is a single 240 second EAA shot of NGC6992 with the ES8CF and an ASI-1600MC-Cool with a MPCC taken the same night as the above photo.

 

Single EAA NGC6992-sm.jpg

 

 

John Love

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#23 jmiller1001

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Posted 11 April 2019 - 10:22 PM

I'm using two different coma correctors: A TV Paracorr 2 and the ES HRCC - both require that the coma corrector be spaced way out on the Moonlite to achieve focus with a camera (ZWO071Pro).  I have not used them visually.

 

Edit: I have not decided yet which one works better with this scope.


Edited by jmiller1001, 12 April 2019 - 08:38 AM.

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#24 jmiller1001

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Posted 11 April 2019 - 10:24 PM

CCD-Freak - Curious, what are the fundamental differences/improvements of the ES8CF?  Thanks!


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#25 CCD-Freak

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Posted 12 April 2019 - 08:51 AM

I'm using tow different coma correctors: A TV Paracorr 2 and the ES HRCC - both require that the coma corrector be spaced way out on the Moonlite to achieve focus with a camera (ZWO071Pro).  I have not used them visually.

I  have the Baader MPCC (original version) A GSO and a Sky Watcher Quattro.  The EAA image was made with the MPCC.    If I can ever get some clear sky I want to test them all together to see which one gives the tightest stars.  The SW Quattro is touted to be very good.  Most require 55mm spacing and the GSO required 65mm if I remember correctly.  I haven't tried the ones you have but I know many people like the Paracorr.  

 

S20204 SW Quattro Coma corrector-1.jpg SW Quattro

 

John Love

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