13148 replies to this topic

[StarDust1]

I just hope they do a better job with the FSQ replacement than with the FCT-65D: While the scope itself has vey nice optics, the reducer introduces strange star aberrations. According to Takahashi, that is by design and can not be fixed. Of course, it still has the same mediocre focuser/mechanics as the other small Taks. Very disappointing for a 65mm scope for 2k€.

If you want it for imaging, don‘t buy. In my case bad weather unfortunately prevented me from testing and returning it before the return period elapsed.

 

Some users report no issues with unusual star aberrations or flaring. You can find their reports in the comment section of Astrobin user images for the FCT-65D. I’m delaying my purchase until I can confirm the issue is fixed or a reliable solution is available.

 

Here is one example:

https://app.astrobin...QrkQ==&i=uyhzc8

[psienide]

Finally got first light with the FS128 last night. Started with some imaging of m101 just to see what i'm working with. It's definitely better corrected than my svbony ED doublet. Luminance did not show the excessive star bloat I was expecting. I'm sure some is there, but this is promising at the very least.

Moving on to visual, the views of jupiter were pleasing and rivaled my 8" reflectors in sharpness and contrast. I could not see any false color at high mag, but admittedly i'm not really accustomed to looking for it in visual.

 

One gripe I have is the lens spacers protrude a bit causing newt lens-clip like diffraction patterns on bright stars. It seems that this is a common problem with older Taks unfortunately. Has anyone tried to solve for this? Any strategies to share?

Edited by psienide, 16 March 2025 - 10:10 AM.

[Live_Steam_Mad]

I just hope they do a better job with the FSQ replacement than with the FCT-65D: While the scope itself has vey nice optics, the reducer introduces strange star aberrations. According to Takahashi, that is by design and can not be fixed. Of course, it still has the same mediocre focuser/mechanics as the other small Taks. Very disappointing for a 65mm scope for 2k€.

If you want it for imaging, don‘t buy. In my case bad weather unfortunately prevented me from testing and returning it before the return period elapsed.

A guy I know in Japan said to me ;- "now Takahashi anounces request for recall of all ‘65D FU Reducer 0.65×’ and ‘60CP FU Reducer 0.65×’.

 

Is your reducer included in this recall? I wonder if the recall is because of optical issues (maybe wrongly assembled, elements flipped or something) ?

 

Regards.

[payner]

I'm not an imager, but Tak has made a recent reducer recall: https://takahashijap...&_x_tr_pto=wapp.

Edited by payner, 16 March 2025 - 01:10 PM.

[Rasfahan]

A guy I know in Japan said to me ;- "now Takahashi anounces request for recall of all ‘65D FU Reducer 0.65×’ and ‘60CP FU Reducer 0.65×’.

 

Is your reducer included in this recall? I wonder if the recall is because of optical issues (maybe wrongly assembled, elements flipped or something) ?

 

Regards.

The reducer recall is only for a mechanical issue of some of the reducers, because it can hamper the rotator movement. No recall for optical issues. I verbatim quoted the official Takahashi statement regarding the optical issues above: The issues are due to design and cannot be fixed.

 

Sorry to vent but it‘s really frustrating: It seems impossible to buy a defect-free telescope except if one gets lucky by accident. Maybe you can get one regularly from CFF, TEC and AP but they have long waiting lists and don‘t produce small scopes anymore.

Edited by Rasfahan, 16 March 2025 - 11:45 AM.

[davidc135]

Finally got first light with the FS128 last night. Started with some imaging of m101 just to see what i'm working with. It's definitely better corrected than my svbony ED doublet. Luminance did not show the excessive star bloat I was expecting. I'm sure some is there, but this is promising at the very least.

Moving on to visual, the views of jupiter were pleasing and rivaled my 8" reflectors in sharpness and contrast. I could not see any false color at high mag, but admittedly i'm not really accustomed to looking for it in visual.

 

One gripe I have is the lens spacers protrude a bit causing newt lens-clip like diffraction patterns on bright stars. It seems that this is a common problem with older Taks unfortunately. Has anyone tried to solve for this? Any strategies to share?

In 'Telescope-Optics.net', page 11.19, Vla Sacek studied mirror clips on a 200mm Newt and thinks that they can't cause noticeable diffraction spikes even if they measure 18x9mm. But he's talking visually, maybe it's different in imaging.

 

David

Edited by davidc135, 16 March 2025 - 01:01 PM.

[edif300]

Some users report no issues with unusual star aberrations or flaring. You can find their reports in the comment section of Astrobin user images for the FCT-65D. I’m delaying my purchase until I can confirm the issue is fixed or a reliable solution is available.

 

Here is one example:

https://app.astrobin...QrkQ==&i=uyhzc8

An optical issue due to design, reproduces the pattern with each optical device… seems this is not the case.

[psienide]

In 'Telescope-Optics.net', page 11.19, Vla Sacek studied mirror clips on a 200mm Newt and thinks that they can't cause noticeable diffraction spikes even if they measure 18x9mm. But he's talking visually, maybe it's different in imaging.

 

David

Definitely an imaging thing. Imagers create mirror masks to mask out the clips because the patterns show up everywhere. I suppose I just need to look into masking the area of the spacers. Or just live it, or just consider this my visual only scope.

[dan_hm]

Some users report no issues with unusual star aberrations or flaring. You can find their reports in the comment section of Astrobin user images for the FCT-65D. I’m delaying my purchase until I can confirm the issue is fixed or a reliable solution is available.

Here is one example:
https://app.astrobin...QrkQ==&i=uyhzc8

The stars in that image have clear issues if you look at them, especially on the left side of the frame. I’m one of the commenters in that post and the imager told me his copy did indeed have issues.

I have not seen anyone who has not had issues with the reducer, myself included. Another owner I’ve been in contact with has a Photon Cage on his and is going to see if the problem is just sensor tilt, but for now it seems to be an inherent defect present in every copy of the reducer.

It will be embarrassing for Tak if they have to recall the reducer a second time but it will really be the right thing for them to do. An issue like this is unacceptable especially for a premium scope.

[dan_hm]

I just hope they do a better job with the FSQ replacement than with the FCT-65D: While the scope itself has vey nice optics, the reducer introduces strange star aberrations. According to Takahashi, that is by design and can not be fixed. Of course, it still has the same mediocre focuser/mechanics as the other small Taks. Very disappointing for a 65mm scope for 2k€.

If you want it for imaging, don‘t buy. In my case bad weather unfortunately prevented me from testing and returning it before the return period elapsed.

Where did Tak say this?

Edited by dan_hm, 16 March 2025 - 01:49 PM.

[Rasfahan]

Where did Tak say this?

It‘s from an email I got forwarded from my vendor after I asked them if my reducer was eligible for replacement. After the hassle I had with my FSQ-85 and my Epsilon 160 (both needed replacement due to bad optics straight from factory), this definitely was my last Takahashi purchase.

[Rasfahan]

Some users report no issues with unusual star aberrations or flaring. You can find their reports in the comment section of Astrobin user images for the FCT-65D. I’m delaying my purchase until I can confirm the issue is fixed or a reliable solution is available.

 

Here is one example:

https://app.astrobin...QrkQ==&i=uyhzc8

The stars in that image are atrocious: They show flaring, halos and blue/red fringing (due to CA? bad postprocessing? Who knows…). My FRA300 has far better rendition than that, both on- and off-axis.

[StarDust1]

The stars in that image are atrocious: They show flaring, halos and blue/red fringing (due to CA? bad postprocessing? Who knows…). My FRA300 has far better rendition than that, both on- and off-axis.

Upon reviewing images captured with the Askar FRA300, I've noticed that bright stars exhibit aberrations, including a "lighthouse" effect. Could you confirm if your FRA300 unit displays these same aberrations?

 

Please refer to the sample image provided on the Telescope Service website:
https://www.teleskop...strograph-14818

[dan_hm]

It‘s from an email I got forwarded from my vendor after I asked them if my reducer was eligible for replacement. After the hassle I had with my FSQ-85 and my Epsilon 160 (both needed replacement due to bad optics straight from factory), this definitely was my last Takahashi purchase.

Wow, that’s ridiculous. I bought it after Tak USA heaped praises on it but then saw the optical issues in the official Tak Japan posting. I figured they could have been user errors but if Tak privately admits it’s an inherent defect that’s inexcusable.

I’ve done extensive backfocus adjustments on mine and have seen no improvement, so what you’re saying confirms my suspicions that it’s inherent to the design. Crazy. I’ll have to do some thinking about whether to return it. I guess I could have an aperture mask made for the purpose of gathering star data but that’s a bit annoying.

[jap201]

Sorry in advance if I've posted this to the wrong place, please feel free to move this if its in the wrong forum/thread.  

 

I've got my first real telescope, a takahashi tsa120.  Love the scope and learning.  But I found these 2 pieces in the box, there's no identifying marks, in english and I can't seem to find them on the system diagram.  They're about 2" long (50.8mm), a little less wide.  Just a hollow threaded short piece if threaded tube.  If I attach them to the drawtube ahead of the rest of the light train, I cannot get focus.  

 

Does anyone know what these are for?

 

thanks for your time

Joe

 

Edited by jap201, 16 March 2025 - 05:27 PM.

[Ncraw]

It seems most issues with Taks are in their imaging scopes (especially with all the new high resolution imagery) while they really excel in the visual ones. They pumped out one legendary scope after another from the FC50 all the way to the TSA 102/120 and everything in between. 

 

Can't some of these well tested and proven scopes like the FC-50, FC-60, FOA-60, FS-76DS, FC-76DCU, FC-100, TSA-102/120 be used for imaging with flatteners? Even the FC-76 Classic comes with dedicated flattener and reducer.

[dan_hm]

It seems most issues with Taks are in their imaging scopes (especially with all the new high resolution imagery) while they really excel in the visual ones. They pumped out one legendary scope after another from the FC50 all the way to the TSA 102/120 and everything in between.

Can't some of these well tested and proven scopes like the FC-50, FC-60, FOA-60, FS-76DS, FC-76DCU, FC-100, TSA-102/120 be used for imaging with flatteners? Even the FC-76 Classic comes with dedicated flattener and reducer.

I think it’s more accurate to say issues are common with Tak’s *fast* scopes (f/4 and below). The new FC-76DP with its dedicated f/4.8 reducer doesn’t appear to have issues. Maybe that’s a better option for someone looking to buy one from the new line. A fair bit slower and a narrower FOV but at least it doesn’t seem to have major optical defects.

[Rasfahan]

Upon reviewing images captured with the Askar FRA300, I've noticed that bright stars exhibit aberrations, including a "lighthouse" effect. Could you confirm if your FRA300 unit displays these same aberrations?

 

Please refer to the sample image provided on the Telescope Service website:
https://www.teleskop...strograph-14818

The sample image is quite a bit sampled down. What I‘m seeing is some lighthouse effect on Sadr and the neighboring star. These two are very bright. I can‘t confirm the FRA300 will not show diffraction effects on Sadr or other very bright stars <3mag. All of my other scopes do.

 

In the fields I shot with the FRA300 I can see some slight CA in the corners of a full-frame field (IMX410). No lighthouse effect, flares or any such things. The slight CA is in agreement with the published spot diagrams. But I know there‘s bad samples out there, too, so it’s certainly a lottery.

 

The much more complex FCT-65D+flattener system should offer better performance in comparison. Unfortunately I haven‘t seen a good image. I preordered on faith expecting the usual impeccable Tak optics (and to eventually replace the focuser).

 

I‘m preparing some DPAC tests of the FRA300 and FCT-65D, with and without the reducer and the multi-flattener. Will take me some time to set everything up.

[StarDust1]

Here’s the FC-76DP paired with the 76DP FU 0.64× reducer, tested using the ASI6200MC Pro camera. I’m quite pleased with the results, but I’ll let you be the judge.

 

https://starbase.hat...25/02/19/193000

Edited by StarDust1, 16 March 2025 - 06:09 PM.

[Rasfahan]

I think it’s more accurate to say issues are common with Tak’s *fast* scopes (f/4 and below). The new FC-76DP with its dedicated f/4.8 reducer doesn’t appear to have issues. Maybe that’s a better option for someone looking to buy one from the new line. A fair bit slower and a narrower FOV but at least it doesn’t seem to have major optical defects.

That is the „old“ FC-76D doublet in a new housing with a slightly better performing reducer than before. It is still not up to full-frame imaging with modern sensors. I have the FC-76DCU and like it a lot for its versatility but for imaging-only applications there are better scopes out there.

[StarDust1]

The sample image is quite a bit sampled down. What I‘m seeing is some lighthouse effect on Sadr and the neighboring star. These two are very bright. I can‘t confirm the FRA300 will not show diffraction effects on Sadr or other very bright stars <3mag. All of my other scopes do.

 

In the fields I shot with the FRA300 I can see some slight CA in the corners of a full-frame field (IMX410). No lighthouse effect, flares or any such things. The slight CA is in agreement with the published spot diagrams. But I know there‘s bad samples out there, too, so it’s certainly a lottery.

 

The much more complex FCT-65D+flattener system should offer better performance in comparison. Unfortunately I haven‘t seen a good image. I preordered on faith expecting the usual impeccable Tak optics (and to eventually replace the focuser).

 

I‘m preparing some DPAC tests of the FRA300 and FCT-65D, with and without the reducer and the multi-flattener. Will take me some time to set everything up.

Thank you, Torben! I’m looking forward to it.
 

[Rasfahan]

It seems most issues with Taks are in their imaging scopes (especially with all the new high resolution imagery) while they really excel in the visual ones. They pumped out one legendary scope after another from the FC50 all the way to the TSA 102/120 and everything in between. 

 

Can't some of these well tested and proven scopes like the FC-50, FC-60, FOA-60, FS-76DS, FC-76DCU, FC-100, TSA-102/120 be used for imaging with flatteners? Even the FC-76 Classic comes with dedicated flattener and reducer.

Unfortunately the flatteners and especially the reducers are not up to the needed specs. The demands of the modern sensors are quite high and it’s also desirable to have a low focal ratio for imaging. In principle, the FCT-65D is the right direction: Premium triplet with a large, multi-element flattener for a well-corrected and illuminated field.

 

The FC-76D with the 1.04x flattener is very good out to APS-C (and I‘ld expect the FC-100 to be, too) but also quite slow. The TSA-120 also looks good with its flattener, but not for full frame. The FS-60CB is too colourful and shows serious corner aberrations already on M4/3 with the flattener. The TOA are exceptional (probably best in their aperture) with the flattener and still very good with the reducer. I can‘t say anything much about the vintage scopes because I haven‘t owned or tested one and it‘s not easy to get the specs.

 

Many Chinese designs forego good correction and produce round stars by introducing high spherical aberration. Tak does not which makes aberrations visible that would otherwise be hidden by fat, round stars. (The design of the Askar FRA300 is a rare exception from that norm).

[dan_hm]

Here’s the FC-76DP paired with the 76DP FU 0.64× reducer, tested using the ASI6200MC Pro camera. I’m quite pleased with the results, but I’ll let you be the judge.

https://starbase.hat...25/02/19/193000

Actually, that image shows similar flaring to the FCT-65D reducer. Guess I take back what I said about the 76DP being the only one that doesn’t have issues.

**** is Tak up to?

[Rasfahan]

Here’s the FC-76DP paired with the 76DP FU 0.64× reducer, tested using the ASI6200MC Pro camera. I’m quite pleased with the results, but I’ll let you be the judge.

 

https://starbase.hat...25/02/19/193000

The image is very much downsampled and the stars have been stretched and masked to hide possible aberrations. They are still visible, including some flaring and what appears to be coma.

[StarDust1]

The image is very much downsampled and the stars have been stretched and masked to hide possible aberrations. They are still visible, including some flaring and what appears to be coma.

Are the stars not according to the Spot diagram in FC-76DP + 76DP FU reducer 0.64× shown on the page? The stars in the center appear sharp and well-defined, while those in the corners seem to exhibit some noticeable aberrations.