14 replies to this topic

[LukaszLu]

This model has already been presented on the forum. Since the thread dedicated to it has been closed, let me start a new one and show you my find, imported from Germany.

 

I was curious about this manufacturer, because I have never had the opportunity to test any refractor with the DK (or maybe KD?) logo.

 

The set lacks a mount, I will have to find a replacement. I do not know how the objective cell was originally tightened. The telescope arrived with a rattling cell screwed with too long screws with too short thread, falling into the light of the tube and deforming the strange, flexible collar made of black plastic. I replaced the screws with short sheet metal screws with a sharp tip, which perforated this collar and held it in place in a way, and I hope that it will regain its round shape, because at the moment it slightly obscures the light of the objective.

 

Attached Thumbnails

• 
• 

Edited by LukaszLu, 06 February 2025 - 12:55 PM.

[LukaszLu]

The worst thing I have discovered so far is the sloppy end of the tube. The tube is cut crookedly, the angle of the cut is not perpendicular to the axis of the tube, which means that after screwing on the focuser, its axis drops significantly in relation to the axis of the telescope. This is a fatal flaw that shows that the "JTII inspection" is just a marketing fiction - if anyone checked the quality of this instrument, it should never have left the manufacturer's warehouse. Honestly, it is hard for me to imagine that today any Chinese manufacturer could afford such sloppiness and incompetence.

 

So my first encounter with the Dai-Ichi Kogaku is a bit disappointing, but we will see what I can "squeeze" out of this instrument. I hope that ultimately its quality will be similar to the 60 mm Carton, which I value very much and which looks very similar in terms of construction and has the same optical parameters.

Attached Thumbnails

• 

[Augustus]

These things are really good optically, Celestron imported them.

[LukaszLu]

The objective is secured with a plastic ring, very easy to unscrew without the use of tools - the kind found in some later Vixen refractors. Unfortunately, this does not guarantee that the objective has not been removed many times, and the lenses separated and rotated relative to each other. But we will see - I am working on straightening the focuser and I hope that this refractor will surprise me positively yet :-)

Attached Thumbnails

• 

[LukaszLu]

Straightened using the "lazy" method. I was afraid to correct the edge so as not to tear the white varnish on the edges, so I simply enlarged one of the holes and tightened the focuser in a slightly bent upward position. If someone doesn't know what to look at, they won't notice that the pipe is cut incorrectly. I hope... :-)

Attached Thumbnails

• 

[deSitter]

The worst thing I have discovered so far is the sloppy end of the tube. The tube is cut crookedly, the angle of the cut is not perpendicular to the axis of the tube, which means that after screwing on the focuser, its axis drops significantly in relation to the axis of the telescope. This is a fatal flaw that shows that the "JTII inspection" is just a marketing fiction - if anyone checked the quality of this instrument, it should never have left the manufacturer's warehouse. Honestly, it is hard for me to imagine that today any Chinese manufacturer could afford such sloppiness and incompetence.

 

So my first encounter with the Dai-Ichi Kogaku is a bit disappointing, but we will see what I can "squeeze" out of this instrument. I hope that ultimately its quality will be similar to the 60 mm Carton, which I value very much and which looks very similar in terms of construction and has the same optical parameters.

I would cut the final part of the tube off with a hacksaw and make new holes for the focuser.

 

You wrap blue painter's tape around the tube and build up a channel to guide the hacksaw blade. I have made numerous cuts this way and they come out absolutely square to the tube.

 

-drl

[LukaszLu]

Unfortunately, I don't have much experience with this. Right now the cut edge is perfectly straight and nicely varnished. I'm afraid I wouldn't do it so cleanly. We're talking about a difference of 1-1.5 mm (~0.05'') - you can see it in the side view I showed in the photo, but in practice no one will look at this telescope like that. My faith in my own strengths is probably too small compared to the scale of the problem to take the risk :-)

 

In a word, I will behave like Rambo, who repressed the pain from his consciousness. I intend to repress this problem and start looking for some mount, because it is my main concern at the moment.

[LukaszLu]

And now the $64,000 question: what is it?? :-)

Attached Thumbnails

• 

[LukaszLu]

Today, despite the cold wind and icy hands, I did a quick comparison of the Polarex 114 and Dai-Ichi Kogaku.

 

Which one is better? Which one would I keep if I could only have one? Well - probably Polarex. Its image seems more natural, warmer, and obtaining a beautiful, sharp views does not require any special effort - at least that's the feeling. It is one of those telescopes that "draw you in" - create some feeling of pleasure from staring through it, even at a lamp post or chimney :-) The first time I felt something like that was with Royal Astro R-74. As if it grabbed you and held you to the eyepiece :-) I even moved away from it then, surprised what was going on...

 

On the other hand, Kogaku has noticeably less chromatic aberration. The image seems cleaner, more sterile. Today I observed the Sinus Iridum, for example. The shadow cast into the bay, towards the illuminated slopes of the rim, seemed to have a slightly purple tone in the Polarex. In Kogaku it was simply uncompromisingly gray.

 

I compared them using several eyepieces, including the Zeiss O-10 (91x magnification). At this magnification it is difficult to say which telescope gives better detail, in both it seems excellent. On Jupiter I had the impression that the Polarex more often provided an opportunity to spot some traces of a richer cloud structure beyond the main bands. Callisto, sliding just below the edge of Jupiter's disk, was visible well in both instruments. However, after changing the eyepiece to a modern TV giving 150x magnification, the Polarex showed its superiority. Even though at 60 mm diameter combined with high magnification the image became uncomfortable for me, becoming covered with traces of floaters and vitreous structure in my eye, with Polarex I still encountered moments of a richer cloud structure, and Callisto was still perfectly visible. In the Kogaku the image became clearly worse, Callisto was difficult to see, and an aberration appeared around Jupiter's disk, which I did not see in the Polarex.

 

To sum up today's first tests: if I had to choose, I would choose Polarex, but if I had to stay with Kogaku, I would have no reason to complain, because it began to give way to the Polarex in the range of magnifications that are uncomfortable for my eyes at this diameter anyway. The results are burdened by the fact that I was freezing terribly and had no motivation to delve methodologically into my comparisons...

[ccwemyss]

And now the $64,000 question: what is it?? :-)

Bears a bit of a resemblance to this:

 

https://www.cloudyni...eflector-mount/

 

Chip W.

[Kasmos]

Today, despite the cold wind and icy hands, I did a quick comparison of the Polarex 114 and Dai-Ichi Kogaku.

 

Which one is better? Which one would I keep if I could only have one? Well - probably Polarex. Its image seems more natural, warmer, and obtaining a beautiful, sharp views does not require any special effort - at least that's the feeling. It is one of those telescopes that "draw you in" - create some feeling of pleasure from staring through it, even at a lamp post or chimney :-) The first time I felt something like that was with Royal Astro R-74. As if it grabbed you and held you to the eyepiece :-) I even moved away from it then, surprised what was going on...

 

On the other hand, Kogaku has noticeably less chromatic aberration. The image seems cleaner, more sterile. Today I observed the Sinus Iridum, for example. The shadow cast into the bay, towards the illuminated slopes of the rim, seemed to have a slightly purple tone in the Polarex. In Kogaku it was simply uncompromisingly gray.

 

I compared them using several eyepieces, including the Zeiss O-10 (91x magnification). At this magnification it is difficult to say which telescope gives better detail, in both it seems excellent. On Jupiter I had the impression that the Polarex more often provided an opportunity to spot some traces of a richer cloud structure beyond the main bands. Callisto, sliding just below the edge of Jupiter's disk, was visible well in both instruments. However, after changing the eyepiece to a modern TV giving 150x magnification, the Polarex showed its superiority. Even though at 60 mm diameter combined with high magnification the image became uncomfortable for me, becoming covered with traces of floaters and vitreous structure in my eye, with Polarex I still encountered moments of a richer cloud structure, and Callisto was still perfectly visible. In the Kogaku the image became clearly worse, Callisto was difficult to see, and an aberration appeared around Jupiter's disk, which I did not see in the Polarex.

 

To sum up today's first tests: if I had to choose, I would choose Polarex, but if I had to stay with Kogaku, I would have no reason to complain, because it began to give way to the Polarex in the range of magnifications that are uncomfortable for my eyes at this diameter anyway. The results are burdened by the fact that I was freezing terribly and had no motivation to delve methodologically into my comparisons...

I've done most of my side by sides on targets during the day and while I might be mistaken, it seemed to show a clearer winner. It certainly showed how some are brighter than others or if they colored the view. Also, like your results many of them seemed to perform about the same.... until the power went up.

Edited by Kasmos, 09 February 2025 - 12:55 AM.

[deSitter]

I've done most of my side by sides on targets during the day and while I might be mistaken, it seemed to show a clearer winner. It certainly showed how some are brighter than others or if they colored the view. Also, like your results many of them seemed to perform about the same.... until the power went up.

Problem with day testing is your eye stopping down. I would wear my observing googles - safety goggles painted black with a hole saw aperture over my observing eye.

 

-drl

[LukaszLu]

It is a fact that daytime observations can reveal what is impossible to see at night. Today I tried. A dark, cloudy day and a tree against the sky. In other words, very demanding conditions because on the one hand there is a strong contrast of details against the sky, and on the other hand - details of the trunk and bark are poorly visible in poor lighting.

 

An additional drawback of Kogaku immediately came to light - an unblackened sleeve in the focuser, causing reflections visible in the eyepiece. Even on the Moon it was not visible, but during the day it was immediately obvious. Interestingly - it is noticeable only with a diagonal. Therefore, I conducted further observations without a diagonal, and I will have to repeat the night observations.

 

- It was confirmed that Polarex seems to find focus much easier and faster. You can do it "in one movement" while Kogaku requires experimenting "back and forth". I suspect that this feature is related to the quality of the optics - although I cannot say why. At around 100x magnification, both telescopes showed details of similar quality, but the pleasure of observing remains with Polarex.

 

- I expected that dark branches against the sky would be burdened with greater chromatic aberration in Polarex. CA is very clearly revealed in such conditions. To my surprise, this time I did not notice a clear difference. Perhaps Kogaku was slightly cleaner, but to a degree that made it difficult to issue a final verdict.

 

- I also expected that Polarex would cope better with the faintly visible details of the dark surface of tree trunks. Already in the case of my previous Polarex, I noticed that it had a strange ability to brighten dark areas and pick out details from them that are less visible in other refractors. The dark side of the Moon is a good example where this ability can be observed. It is a bit like HDR - shadows are "boosted" even though as a whole, the image does not seem brightened. And it was confirmed - dark branches against the dark gray, poorly lit trunk were perfectly visible, while in the case of Kogaku they were of course visible - but I would not use the term "perfectly"...

 

 

By the way, I had the opportunity to test the eyepieces that came with the telescope. According to the list I found in the original box, they should be HM 8, 12.5 and 20 mm eyepieces. Instead of HM8 there is H8 (at least that's what the inscription on the housing, which looks different from the other two, says), so maybe this eyepiece is not original, or maybe only the black frame was replaced. In any case, these are quite decent eyepieces, apart from the limited field of view.

 

If I had them, would I buy the Zeiss O-10 today, which I compared them with? I know I will upset Zeiss enthusiasts, but I will ask: Why? I did not see anything more with it... :-)

[LukaszLu]

While America wakes up for work and sips its morning coffee, the day is just ending in our part of the globe. The sun is already setting in the vicinity of Krakow, and in the east you can see the brightening disk of the Moon. In keeping with centuries-old tradition, local residents put up refractors in front of their homes to cool them down before night-time observations.

 

I put them up too. Today, Kogaku and Polarex were joined by the Carton T-620 - probably the closest to Kogaku in terms of design.

Attached Thumbnails

• 
• 

Edited by LukaszLu, 10 February 2025 - 11:36 AM.

[LukaszLu]

So how did yesterday's tests go? Well... in the freezing cold, on my knees to avoid the diagonals, with watery eyes from the cold and fingers like icicles. So it's no wonder that my motivation was getting weaker with every passing minute. Especially since I added the Carton T-620 to the test set...

 

Results? First of all, what I noticed previously was confirmed - none of the instruments tolerate exceeding the magnification resulting from the diameter of the lens, i.e. 120x. Or at least with the seeing quality we had near Krakow. The image becomes worse, details are less visible - mainly due to floaters and interference from the vitreous body in the eye. At higher magnifications they start to reveal themselves immediately - at least in my case. Today I tried both the TeleVue zoom at 6 mm focal length and the Baader Genuine Ortho 7 mm - neither showed as much as Zeiss 10 mm Ortho or Unitron/Polarex 9 mm SYM.ACH. The Moon and of course Aristarchus were in the crosshairs. I compared the visibility of the central peak and the dark stripes descending vertically down the crater slopes. A certain superiority of Polarex observed previously seems to be confirmed - these details were more visible. The tendency of the Polarex to tint the image was also confirmed - I don't know why, but it is visible on the Moon, and not on planets and during day tests.

 

But... both of these telescopes were left behind by Carton. Compared to Polarex and Kogaku, it produced razor sharp image, clearly brighter, more contrasting (although Carton does not have the "HDR" effect like Polarex). While in Polarex chromatism manifests itself in the coloring of dark areas, the minimal chromatism of Carton takes the form of micro-traces of a scale as tiny as the details that this telescope is capable of showing.

 

As I mentioned, the conditions did not encourage me to extend the tests, so I do not want to pass final judgment. But for now it seems that Kogaku did not turn out to be a brother design of Carton, which has all the features of an outstanding instrument. Maybe easy access to the lens in Kogaku means I should look for the correct mutual positioning of the lenses? Maybe it is more a matter of the example than the model? Especially since my Carton is difficult to treat as a product that meets factory standards. When it arrived to me, the lens was in poor condition, it had no spacers at all, and I made them myself, using self-adhesive aluminum tape. So there is no chance for precision in such work. Despite this, it gives crushing quality. Maybe another example of Kogaku would be just as good or better?