50 replies to this topic

[Jeff B]

 

 

Test your color vision -- http://www.xrite.com...-test-challenge

 

Man that test is hard!

 

I scored 15 and in the 60-69 bracket.  The bluer end was where I tended to miss.

 

Jeff

 

 

 

FACT: 1 out of 255 women and 1 out of 12 men have some form of color vision deficiency.

 

Did you know that?

 

 

Sorry, I didn't see that.

[KaStern]

Hello Jeff,

 

it must have been 7 years ago that I performed that test the first time.

I took the time to do it again and, fortunately, the result is the same than before:

0

Male, from 50 - 59 years old.

 

But I guess the graphics card, the settings and the monitor

along with the brightness (a bit low here) might influence the test results... 

 

Cheers, Karsten

[doctordub]

I scored a 0 and a 4 previously. I think the monitor has some effect on score. I owned the Astro Telescope version of this Kumming Optical scope and was pleased by its performance. The CA on Jupiter, Venus, Sirius  and the Moon was evident, but the sharp image it produced with the Chromacor was stunning. If I did not have the Tak FS-152, I would still own this scope.

CS

Jonathan

[jrbarnett]

Hello Jeff,

 

it must have been 7 years ago that I performed that test the first time.

I took the time to do it again and, fortunately, the result is the same than before:

0

Male, from 50 - 59 years old.

 

But I guess the graphics card, the settings and the monitor

along with the brightness (a bit low here) might influence the test results... 

 

Cheers, Karsten

Very true.  Here at work on my HP 1600x900 older monitor running on Intel HD4400 graphics, defaulted to whatever color scheme the Intel drivers and control software select I score worse than I do at home on my MacBoo Pro Retina with Intel Iris integrated graphics and whatever defaults color balance OS X with the OS X Intel chipset drivers select.

 

Key to getting a higher score is to first do a gross sort moving every obviously hued square to the correct half of the screen before discriminating between adjacent chips.  I score 20 here at work and 10 at home.

 

- Jim

[raal]

Nice test!

I score between 3 and 4, color calibrated monitor.

 

Speaking of fast achros, I have a barride optics 6" f/5 and I needed the prescription for it for modeling barlows and field flattener for it, so I went through the hassle of making a spherometer with ball feet, calibrated it the best I could with Jo Blocks, etc., measured the glass volume and density by immersion method...

With help of Mike I. Jones, who pointed me out to CDGM glass catalog, without any doubt, the glasses Barride used for this are H-K9L and C-F4.

Knowing the exact Back focal length for best polychromatic focus, I nailed the prescription accurately enough.

 

Now, the thing with that f/5.9 doublet is that it is obviously corrected for d line (588nm).

 

My Barride is corrected for e (546nm). The difference is smaller spherochromatism for f-line and above, which is producing smaller purple halo.

here is the plot for LSA (for the same lines and same 76mm aperture radius)

 

and here is the chromatic focal shift

 

On bright stars there is a small indigo halo and much larger, dimmer, purple halo.

When stopped down to 100-110mm, it is very easily bearable on the Moon at 150x mag. I'll get an EP to bump the mag up to 200, it feels like it can bare that much, and stop there with that scope.

 

Anyhow, about that purple halo business, correcting a fast achro for e line, it seems like a much more usable thing to do than correcting it for d line and let 430nm go too wild.

Edited by raal, 22 December 2015 - 07:53 PM.

[Derek Wong]

Test your color vision -- http://www.xrite.com...-test-challenge

 

This is an interesting test but I think your score depends partly on strategy and your monitor.  I scored 0, age 50-59 but I don't think I have better color vision than many other people.

 

However, the statistics on color vision deficiency are true, and that plus the aging cornea and our perceptual filtering system accounts for the wide variety of perception of color in various scopes. Many people who don't see color aren't color blind, they just ignore it (filter it in their brain).

 

Regardless of how much color one sees, there must be a substantial reduction in contrast on planets unless filters are used.  This scope would be great to use as a low to medium power binoscope, though...

 

Derek

[glend]

Resurecting this thread to ask a question.  The TS version seems to have a fairly good focuser for imaging, add their flattener and it would seem to be a good option for narrowband imaging. I had a Bresser 152 achro with the rear mounted corrector, and it was a nice narrowband scope, i am sorry i sold it now. The only problem with the Bresser was the focuser and the rear corrector prevented the use of a flattener.

Anyone using this scope for narrowband imaging?

A good achro can be a good narrowband imager.

[nicknacknock]

Yes, it can be good for narrowband imaging. See this thread.

[photoracer18]

Interesting. With my new cataract lenses installed in late 2015 I scored a perfect 0 in the hue test at 70 years old. Don't think I could have done that before the surgery.

While working at Hands On Optics I considered buying one of the 150 F5.9 scopes but having already experienced APOs I passed on it.

Edited by photoracer18, 05 September 2017 - 03:29 PM.

[glend]

Yes, it can be good for narrowband imaging. See this thread.

Ha ha, i started that thread back when i was imaging with my Bresser.

[Simoes Pedro]

Hi Bill,

 

looking at the spherochromatism chart you provided, the green to F/C focus error is about .550 to .600 mm. Which translates to a chromatic error of 1/1500 to 1/1650 of the focal length. This is actually worse the standard achromat, which is 1/1800 to 1/2000.

 

The reason to being worse is spherical aberration at such short focal ratio. Notice how F lines bends to the right and C lines bends to the left. This means that to achieve an overall aberration balance, F needs to focus coloser and C longer, leading to a greater error than on a long focus achromat.

 

To sum up color correction will be terrible, possibly even worse than on a standard 150 f8.

 

There is nothing "false" in the advertisement. A BK7/SF2 achro may actually have worse color at such short focal ratio.

 

Regards,

Edited by Simoes Pedro, 06 September 2017 - 11:50 AM.

[garret]

This low cost optical design could be used for a interesting low-cost 150mm binocular...

 

2x TS (Germany) 152mm refractors:  Euro 2200.= total

1x EMS/ Matsumoto 1.1/4"  Erecting Mirror System: Euro 1400.= total

Heavy duty  Video Head with counter weight: Euro 1000,=

Some hardware: Euro 400,=

Total Euro 5000,=

 

I have already a adjustable Pier-Tech pier and eyepieces: 22 LVW, 17.5 Morpheus, 12 Delos, 9mm Delite for my APM 100 ED binocular.

The 17.5mm Morpheus gives 51x magnification, 1.45 degree field and nearly 3mm exit pupil.

The near perfect 12mm Delos 75x ;  0.95 degree field, 2.0mm exit pupil.

 

btw, my hue/ color score is 2 (age 50-59) https://www.xrite.com/hue-test

 

Garrett

Edited by garret, 10 May 2018 - 03:25 AM.

[Thaellar]

In my late 50s, I scored a 10, but I'm red green colorblind.

[RichA]

This is an interesting test but I think your score depends partly on strategy and your monitor.  I scored 0, age 50-59 but I don't think I have better color vision than many other people.

 

However, the statistics on color vision deficiency are true, and that plus the aging cornea and our perceptual filtering system accounts for the wide variety of perception of color in various scopes. Many people who don't see color aren't color blind, they just ignore it (filter it in their brain).

 

Regardless of how much color one sees, there must be a substantial reduction in contrast on planets unless filters are used.  This scope would be great to use as a low to medium power binoscope, though...

 

Derek

I scored zero same age group and male, but according to what I've read, most women can divide down colours into about twice the number of shades as men.

[gnowellsct]

 

 

6. TS ships worldwide and since you are based in the US, you don't pay VAT so reduce the selling price you see by 19%.

 

 

DHL will hammer you with additional fees and taxes.  Your effective rate, including shipping, will be the same as the European VAT price without shipping.

 

GN

[jragsdale]

This thread just can't die! Well, I came into possession of the Astro-Telescopes version of one of these scopes and have been doing narrowband imaging with it for a few months. I can say the results have been OUTSTANDING. I even use a .8x reducer/corrector and installed an autofocuser on the stock crayford (which I intend to replace). This is a 16h shot with an ASI183MM:

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[Sarkikos]

I good alternative is a Celestron Omni XLT R f5 with a TSFlat2 to flatten the field.

 

Mike

[photoracer18]

Well I had minor cataract issues in my right eye only so my eye doctor scheduled surgery back in 2016. Did not notice a lot of difference afterwards because it had not progressed that far.

[petersmeadelx6]

Here is a size comparison of the CT152 with a 3" focuser - next to a Orion ST80.

This post is a few years old but I just picked up a C.T 152 5.9 and am having trouble finding any "how to" or specs. Can you tell me the minimum focus for this beastie? I was testing out on some scenery and couldn't focus on trees 250 feet away without drawing the ep up from the diagonal. seems long but could be normal? Any advice on centering the focuser as there seems to be lots of play between the focusing inner face and ota outer face.

 

 

Thanks for any advice you may have. 

[fsphotography]

This post is a few years old but I just picked up a C.T 152 5.9 and am having trouble finding any "how to" or specs. Can you tell me the minimum focus for this beastie? I was testing out on some scenery and couldn't focus on trees 250 feet away without drawing the ep up from the diagonal. seems long but could be normal? Any advice on centering the focuser as there seems to be lots of play between the focusing inner face and ota outer face.

 

 

Thanks for any advice you may have. 

Not sure what you mean by the''focusing inner face and outer face'', are you referring to the point where the focuser rotates?  Don't know about the minimum focus distance,i don't look at trees with mine.

 

Frank.
 

[petersmeadelx6]

Not sure what you mean by the''focusing inner face and outer face'', are you referring to the point where the focuser rotates?  Don't know about the minimum focus distance,i don't look at trees with mine.

 

Frank.
 

Yes, the inner face of the focuser (female end) and the end of the ota (male end). Pictures attached. No, I don't look at trees with mine either but was checking focus in daylight as the evenings have been cloudy lately, as it is this evening. Focusing on shiny objects, like distant hydro transformers is also a way of gauging c.a. 

 

Another cn member provided some tips re centering the focus, which I figured, but I was curious about whether there was an intermediate piece missing as I have never handles one of these and info seems scarce. 

 

Peter B.

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[fsphotography]

Hi Peter,that is what i thought you were talking about. I'm not seeing the large white teflon washer/spacer that belongs between the mating surfaces,but it might just not be in the pictures. The long bolts and nuts don't belong,originally

in their place were three grub screws.But the bolts can be used in their place,i'm guessing the previous owner was have a problem with the grub screws becoming loose after rotating  the focuser a few times. If you are going to retain the long screw/bolts you need to shorten them,or buy shorter ones, round off the ends so they are nice and smooth and don't bite into surface they contact with when the focuser is rotated. The bolts need to be very   finely adjusted so they still allow rotation but remove any slop, once that's achieved lock them gently but firmly with the nuts. Also use a washer under the nut to avoid any paint damage.  Using the bolts as they are will only cause damage to the mounting flange. Having said all that,the rotating feature is less than perfect so do what i did,

just nip up the bolts and nuts(or replace them with the correct grub screws,the bolts look ugly),so it doesn't rotate and forget about that feature. Good luck and enjoy the scope.

 

Frank

Edited by fsphotography, 11 January 2021 - 04:27 AM.

[petersmeadelx6]

Thanks. I will replace the hardware. As for the nylon spacer, that's a bummer as I don't want to hunt for obscure items. had I known, I might not have purchased or asked for a small adjustment in $$$. Not being stingy but how much time will I be using up to find or make a suitable spacer???

 

Clear skies to you. 

[Mitrovarr]

That reviewer stated that there was no false color on the lunar surface.  How is that possible?  False color was readily apparent with my old 4" f11 as well as my old Stellarvue 80ED... both also made by Kunming.  That is a magical 6" f5.9 scope!

I've heard that before with 6" achromats. My guess? The overwhelming brightness of the moon blows out their night vision and it's too faint for them to see.

[junomike]

I've heard that before with 6" achromats. My guess? The overwhelming brightness of the moon blows out their night vision and it's too faint for them to see.

Yes, there's gobs of CA when pointed at a bright object.  Most users tend to keep away from the Terminator as inside Craters show lower to no CA.