7 replies to this topic

[Emanuel]

Another Cat is coming??

Any more info on this? 

 

http://k-astec.cocol...ost-447c52.html

[hughesthompson]

The Ultra Cat series seems to be an answer to Askar's quintuplet scopes which have very good specs.  William Optics was a leader in fresh optical designs with the original Redcat 51 but now they have to catch up.  Not sure what the limit is with scopes getting as complicated as camera lenses.

 

Just bought a RedCat 61 so I'm hoping four elements are enough!

Edited by hughesthompson, 20 June 2025 - 04:46 PM.

[Emanuel]

I'm curious about it.

I've been looking around for a possible replacement of the Samyang 135mm lens .

The fact that lenses are always problematic with star shapes on the corners, most of the times, has always made me think of small refractors, instead of lenses for astrophotography. 

You can , of course, do fantastic imaging with lenses, the Samyang/Rokinon 135mm is a very good example of that.

But, it's a struggle to get everything right. Long exposures for your target, short exposures for your stars, try F/2, try F/2.8, F/3, F/4, etc, you know what I'm talking about,  right?

On top of that, calibration exposures for every set, and you go mono, it's even more  job to do.

I wish there was more option on this department. 

A scope, not a lens, for very wide field , even for the milky way.

Askar have the 180 FMA and the 135. But, excuse me for saying this, I just can't pass the fact that when the lenses of a scope are not specified of what they are made, for me it's strange.

Anyway,  I don't see this 56 ultra cat on William optics website, or in European dealers, only at K-astec blog.

Is it still beeing tested, and not available yet, or what?

[hughesthompson]

I have an Askar FMA180 and it's one of my sharpest scopes.  The UltraCat 56 will be about 270mm focal length so it's not really in the Rokinon 135 range.  It looks like it will also be expensive.  The scope that is in that range is the MiniCat 51 at f3.5 and 178mm.  It's a 6 element design.  It's been controversial with some issues with corner stars on a full frame sensor.  William Optics even issued a disclaimer stating that the issue can be fixed in processing.  Not their best moment.  Other reviews with APS-C cameras are better.

[Emanuel]

Yes, totally agree with you.

The mini cat 51 also came into my mind, beeing a 178mm, F/3.5, that would be a great option.

But, like you said , I also saw, not so good reviews about it, and the William optics solution to the problem,  it's frankly very poor.

How good is the FMA 180, with a full frame camera? Or is it better to stick with a APS-C camera?

Edited by Emanuel, 21 June 2025 - 06:48 AM.

[hughesthompson]

Yes, totally agree with you.

The mini cat 51 also came into my mind, beeing a 178mm, F/3.5, that would be a great option.

But, like you said , I also saw, not so good reviews about it, and the William optics solution to the problem,  it's frankly very poor.

How good is the FMA 180, with a full frame camera? Or is it better to stick with a APS-C camera?

Until recently I've used the FMA180 with a 4/3 sensor.  An example is on my AstroBin here: https://app.astrobin...=ojfi4p#gallery

 

Recently did some star tests with my APS-C camera and center stars are very good but I'm seeing some CA and misshaped stars in the corners.  Nico Carver (Nebula Photos) recently did a comparison of lightweight scopes on YouTube and liked the FMA180 ver much.  It's so light it even works on a star tracker like my MSM Nomad with an ASI585MC (non-cooled).

[Emanuel]

Yeah, I saw that video from Nico Carver. And he was very excited about the FMA 180. Not so much about the other telescopes that he compared,  but the Askar was the one for him.

Your Heart and Soul nebulas photo is very nice, for just a little over 2 hours of exposure. 

I guess at the end, no matter the glass used on manufacturing the lenses, what really matters is the end result.

Edited by Emanuel, 21 June 2025 - 10:06 AM.

[Momerath]

Think Ill Stick with the AT65EDQ. Tho it is a interesting addition