1188 replies to this topic

[Riccardo_italy]

I think someone here might be interested....

 

https://www.altairas...IKRa4W8L_VNggt8

 

The ASCENT 102mm F11 ED Doublet refractor is optimised for visual observation and imaging of solar system objects. An evolution of the well respected "Red Tube Classic" Starwave 102 Achromat, now with ED optics and better mechanics!

 

[mic1970]

If I only had the money. 

[Erik Bakker]

Looks like a lovely and affordable visual scope. We'll have to wait and see how the actual quality and consistency of the image it forms of the planets is at high powers, but that scope looks promising.

[Astrojensen]

This was literally my first reaction: https://www.youtube....h?v=P3ALwKeSEYs

 

And this my next: https://i.imgur.com/eFfmdb3.jpg

 

Expect to hear more soon...

 

 

Clear skies!
Thomas, Denmark

[Astrojensen]

Ordered. Since I've been screaming about long-focus apochromats since forever, I guess it's only fair that I bought one, now that they are actually available again. 

 

I can put it on my massive Vixen Saturn mount and make my own poor man's Nikon ED 100/1200. 

 

 

Clear skies!
Thomas, Denmark

[Erik Bakker]

Great news Thomas!

 

Look forward to your assessment of that scope 

[Axunator]

Here’s hoping it’s a good ’un Thomas!

 

Now the only thing missing here are 20 pages of pointless rumination about the undisclosed glass type used in it 

[Far Star]

Here’s hoping it’s a good ’un Thomas!

 

Now the only thing missing here are 20 pages of pointless rumination about the undisclosed glass type used in it 

I think the ED glass is Chinese FK-61 (Considering the relatively low price of the telescope, Japanese FPL-51 glass would probably be too expensive.).

[Spikey131]

   

[Eric H]

Quite a bit more expensive but how about this one. 120mm F12.5 ED

 

http://www.frtelesco.../frt120ded.html

[stevew]

I think the ED glass is Chinese FK-61 (Considering the relatively low price of the telescope, Japanese FPL-51 glass would probably be too expensive.).

As the link to the web page does not state the type of ED glass your post is purely conjecture.

Not that it matters, as according to the Abbe numbers for both types of glass they are quote close in performance.

I have a 110mm ED that uses HFK61 and it is a great performer...

 

Steve

[Starlease]

At f11 any glass should be great.

Edited by Starlease, 08 January 2019 - 11:11 PM.

[Riccardo_italy]

I'm really looking forward for the review!!!

 

As the link to the web page does not state the type of ED glass your post is purely conjecture.

Yes, but FK-61 is the least expensive ED glass. So, having ED glass means at the very least having FK-61 or any better glass.

Edited by Riccardo_italy, 09 January 2019 - 02:35 AM.

[emilslomi]

At f11 any glass should be great.

Actually, the achromat version is great! Badly tempted, very badly ... will try to resist for 24h, but not much hope ...

 

Cheers, Emil

[Niklo]

Ordered. Since I've been screaming about long-focus apochromats since forever, I guess it's only fair that I bought one, now that they are actually available again. 

 

I can put it on my massive Vixen Saturn mount and make my own poor man's Nikon ED 100/1200. 

 

 

Clear skies!
Thomas, Denmark

Hi Thomas,

that sounds really interesting. I hope that you get  a good refractor. I am curious how good this refractor is and what you tell us.

A normal Vixen GP, Celestron ADM or similar should be fine. You probably don't need a Vixen Saturn. I have the achromat version with 4" f/11 and for me it works ond a ADM fine.

Clear skies,

  Roland

[Element79]

It's about time someone offered a long focus ED doublet.  And this one looks pretty good too with a dual speed focuser included.  And even if it uses one of the lesser ED glasses, at f/11 it should have a blur ratio of about 1.10 or so making it mostly color free.

 

I already have my next scope on order else I would jump on it...

[Jon Isaacs]

As the link to the web page does not state the type of ED glass your post is purely conjecture.

Not that it matters, as according to the Abbe numbers for both types of glass they are quote close in performance.

I have a 110mm ED that uses HFK61 and it is a great performer...

 

Steve

This is how I see it:

 

- At that price, it's unlikely it is FPL-53.  And in general, if it were FPL-53 or something similar, they would mention it. 

 

- Actually they're not that close.  FPL-53 can offer about twice the color correction of FPL-51.  I have owned a number of HFK-61 doublets, they're good, much better than an achromat but certainly chromatic aberration is visible without much difficulty.  The AT-102ED, I purchased 10 years ago was definitely colorful.  One night I made a comparison with the NP-101 on Venus, the 101 was color free, the AT-102ED definitely showed purple fringing.  The 110mm F/7 I looked through one evening did a good job.. Great is somewhere else. 

 

- In any event, this is F/11 and not F/7 so it should be quite good.  And there is more to a refractor objective than just color correction.  Hopefully Thomas will have a stunning performer on his hands.

 

Jon

[MortonH]

The split tube for bino-viewing is a great idea.  Can also help reduce the length for transport.

Edited by MortonH, 09 January 2019 - 05:46 AM.

[Astrojensen]

 

Now the only thing missing here are 20 pages of pointless rumination about the undisclosed glass type used in it 

No need for that. It's white and has a sliding dew cap, with a pretty logo on it. What more do you need? 

 

 

Clear skies!
Thomas, Denmark

[Astrojensen]

Hi Thomas,

that sounds really interesting. I hope that you get  a good refractor. I am curious how good this refractor is and what you tell us.

A normal Vixen GP, Celestron ADM or similar should be fine. You probably don't need a Vixen Saturn. I have the achromat version with 4" f/11 and for me it works ond a ADM fine.

Clear skies,

  Roland

Of course I don't need the Saturn for such a small and lightweight scope, but trying to recreate something like the Nikon 100/1200 ED could be a lot of fun. 

 

Here's a link to the Nikon that Markus Ludes currently has for sale: https://www.apm-tele...r-teleskop.html

 

The Vixen Saturn does resemble the Nikon mount quite a bit and the combination is going to be absolutely rock solid. The Nikon 100/1200 has been one of my dream telescopes ever since I read Ed Ting's review. 

 

 

Clear skies!
Thomas, Denmark

[RichA]

I think someone here might be interested....

 

https://www.altairas...IKRa4W8L_VNggt8

Depending on what ED glass they use, it may or may not be any different from shorter APO's.

[Astrojensen]

About the glass type(s), color correction and all that: The scope is a cosmetically different version of this scope:

 

http://www.kasai-tra...erius102ed.html

 

PRESUMABLY the optics are the same. And if they are, the color correction is QUITE good indeed, according to the chart on Kasai's site: http://www.kasai-tra...us102edab-1.jpg

 

If I'm reading the graph correctly, it has about the same color correction as Takahashi's FC 76! It has a TOTAL color defocus of 0.2mm, which is better than the TEC 140...! 

 

That is at least according to theory... What happens in practice is anyone's guess so far. Especially since we don't know whether the glass is the same as in the Nerius 102ED or indeed whether the Nerius is as good as theory or not. 

 

But we'll soon find out.

 

 

Clear skies!
Thomas, Denmark

[Astrojensen]

At f/11 and an ED, I'm actually more worried about spherical correction, zones, figure smoothness, pinching, astigmatism and collimation, than I am about false color.

 

 

Clear skies!
Thomas, Denmark

[KevH]

This is how I see it:

 

- At that price, it's unlikely it is FPL-53.  And in general, if it were FPL-53 or something similar, they would mention it. 

 

- Actually they're not that close.  FPL-53 can offer about twice the color correction of FPL-51.  I have owned a number of HFK-61 doublets, they're good, much better than an achromat but certainly chromatic aberration is visible without much difficulty.  The AT-102ED, I purchased 10 years ago was definitely colorful.  One night I made a comparison with the NP-101 on Venus, the 101 was color free, the AT-102ED definitely showed purple fringing.  The 110mm F/7 I looked through one evening did a good job.. Great is somewhere else. 

 

- In any event, this is F/11 and not F/7 so it should be quite good.  And there is more to a refractor objective than just color correction.  Hopefully Thomas will have a stunning performer on his hands.

 

Jon

The post you are quoting was in response to someone saying it was unlikely to be FPL51... not FPL53.  So, stevew is right in stating that it doesn't really matter as  FPL51 vs FK61 are nearly identical in terms of abbe number.  Obviously there's more to a scope than the just the ED element but this is almost certainly a Kunming United product and they seem to know what they are doing. 

Edited by KevH, 09 January 2019 - 12:20 PM.

[AaronM]

Hello Thomas,

 

congratulations for your order - hope the scope is as good as you want it ! Enjoy and report please !

Thanks a lot.

 

Michael Aaron