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Any Intes MC & MN fans?

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#176 Arief M.

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Posted 26 April 2020 - 12:36 PM

My newer MN56 comes with screw-on baffled metal dew shield. The older one is part of the upper tube?

#177 scrane

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Posted 26 April 2020 - 01:57 PM

I think it’s removable, but I’ve never had it off. I think it requires the removal of several screws. It’s the only way I can explain the discrepancy in OAL.

#178 TG

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Posted 26 April 2020 - 03:39 PM

Looking at Venus in the daytime. MN "160 f5.5" on iOptron AZ Mount Pro + iOptron portable pier.

 

iiTrebch.jpg


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#179 luxo II

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Posted 27 April 2020 - 02:21 AM

Well that's novel, haven't seen an Intes MakNewt with a rotating topend like that before. 

 

Seems Intes/Intes Micro were as inconsistent with their designs as the British were with steam locomotives - rarely two the same, most with variations here or there...


Edited by luxo II, 27 April 2020 - 02:23 AM.


#180 n2068dd

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Posted 27 April 2020 - 03:25 AM

Hi,

 

 It took about one year to try out AP system of my Intes 10" for the first light,  though still in progress.

I find so many issues on it.

 I replaced Takahashi 90S mount to the Vixen Atlux(original) mount. May be, this is the least combination, it was too heavy for the 90S.

Sorry 90S!

Though, my Atlux is in the progress of modification.1. Replace bearing housing 2. Replace motor controller to Power flex 3. Make stable high rise Pillar for Atlux.

I find alignment issue somewhere in the optic. Must do overhaul.

Here, my set up temporally.

backyard.jpg

 

Regards

Hiromu


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#181 Arief M.

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Posted 27 April 2020 - 10:42 AM

I saw an ad for that "Perseus" Mak on Yahoo Japan auction site last year. Lucky new owner! Is Intes popular in Japan? 



#182 n2068dd

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Posted 27 April 2020 - 01:27 PM

I saw an ad for that "Perseus" Mak on Yahoo Japan auction site last year. Lucky new owner! Is Intes popular in Japan? 

Hi, Arief

Exactly, that is.

I did not expected 10" would appear in the market. It was indeed lucky.

 

At the days of INTES first imported 1993? it was rather budget MK compared to Zeiss or Quester.

Importer was Kasai, and also Star base in Japan had sold MK-65 around $1000.

Many young observer might purchased, I suppose.

Though, it was the day of the film, many were tend to select more fast APO.

 INTES F10 seemed not so popular as 300mm F2.8APO  or Schmidt F1.5 or Pentax F4.

I too select FCT-100 F4.5.

For the planet observing, It was said 8" Newtonian was the least end. Takahashi MT-200 around $2600 was the standard. despite Intes 8" was rather expensive $ 3700 in Japan.

In that aperture range, TEC MK was rather popular, I thought.


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#183 photoracer18

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Posted 27 April 2020 - 02:57 PM

The MN56 used two different style focuser base plates and of course I ordered the wrong one. Ron at MoonLite is now exchanging mine, and I will post some photos soon. I bought the red focuser to commemorate the Intes-Micro's political origins.

 

About ten years ago I returned home one day to find that someone had broken in and stolen, among other things, a recently purchased Alter m603. Discouraged by that and the general hassle of dragging around and setting up a Losmandy GM8 I drifted into other interests. My new iOptron AZ Mount Pro has reignited my interest in moving my lazy butt out of bed at 2AM. I am lucky to have skies worthy of making the effort.

 

The other night I put an old refractor on the iOptron and was amazed to find whatever target I commanded to magically appear centered in view. I am jealous of those people who can walk around the sky unaided. I am not one of those people. 

 

So, once I get the little Mak-Newt up and running I plan on returning to M13 and all those tiny little stars that I remember. 

On mine it had a JMI EV-1 mounted when I got it. It had the base with the 2 slotted screws. I just happened to notice that the 4 base focuser mounting holes also lined up with a Feathertouch with the flat Newtonian base, which I had laying around. Now I just need to find a long thin threaded knobbed screw that will fit in one of the FT angle adjustment set screw holes to make it fully rotatable like the JMI.

That gave me FT 2" focusers on both my Intes Micro MN56 and my Intes MK-67.


Edited by photoracer18, 27 April 2020 - 02:59 PM.

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#184 luxo II

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Posted 27 April 2020 - 08:51 PM

it was rather budget MK compared to Zeiss or Quester.

It has what counts where it matters, though. How do you find the focussing ?

 

IMHO the MK assemblies are much better built than the later Inter-Micro Alter Mxxxx versions.


Edited by luxo II, 27 April 2020 - 08:53 PM.

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#185 n2068dd

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Posted 28 April 2020 - 01:32 AM

Yes, it's interesting.

 

In the meantime, I like the Russian optics. rather my most favorite 28mm lens is Orion 28mm F6.0. and 50mm F1.5 Zonar copy. from '80s I had been using their M42 mount lens. They are very low priced, very sharp, so many variants,and occasionally had fake. I must check their optics. 

 

My first impression of MK-63 was,....' Exactly it's Russian!'

It both had ultra sharp optic and poor( rather to say individual ) milling metal processing. I could not screw in the standard diagonals nor MK-65 diagonal. Screw dimension was slightly different. That's same of my beloved Orion 28mm. At first, I could not screw it in the Leica. That all hand made milled tube construction of early MK was incredible! I loved tricky finder reticle system. I feel so many human foot print or hand print on them. Maybe, MK-63 was the only spherical optics, next MK-65 introduced aspherical curve and I confirmed MK-65 was better.

 

That feeling or characters were disapeared till MK-67 or 69 and parted Intes-Micro was for me another company. STF looked keeping same feelings though more sophisticated.

 

For about Zeiss MK, some our club member once purchased 18cm Zeiss Makustov priced $20000! brand new at that time. Though he say It was terrible optics, he refused to accept it. It was returned to Germany. I am thinking to now, Russian is superior for the Makustov design and production than Zeiss. Anyway, Intes optics and related company is my treasure.

 

DSCF1930.jpg

 

Regards

Hiromu


Edited by n2068dd, 28 April 2020 - 01:42 AM.

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#186 luxo II

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Posted 28 April 2020 - 02:32 AM

Hi Hiromu, indeed IMHO scopes with Intes glass are indeed treasures, though poorly recognised as such.

 

All the examples of russian optics I've seen (I can count 7) have been consistent - Intes and Intes Micro really did guarantee 1/6 wave P-V (standard) and 1/8 wave for the deluxe models - and they supplied a test certificate with the scope serial number to back that up. Likewise Santel and more recently APM which sourced optics from Intes-Micro and Santel, though it appears they were all using the same test laboratory. This is something no other manufacturer ever did. Not even Questar. 

 

By the way, the dovetail base on that scope doesn't look parallel to the OTA, right ?


Edited by luxo II, 28 April 2020 - 02:40 AM.

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#187 scrane

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Posted 02 May 2020 - 08:15 AM

When I went to mount my old MN56 on the iOptron AZ Pro Mount I found the dovetail plate an unusual size. About 2.5" spread. Bigger than the Vixen and smaller than the Losmandy. Does this sound familiar to anyone?

 

Also, I did mount the MoonLite dual speed focuser on the older MN56 and it looks and functions great!


Edited by scrane, 02 May 2020 - 08:18 AM.


#188 JohnH

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Posted 02 May 2020 - 10:30 AM

When I went to mount my old MN56 on the iOptron AZ Pro Mount I found the dovetail plate an unusual size. About 2.5" spread. Bigger than the Vixen and smaller than the Losmandy. Does this sound familiar to anyone?

Also, I did mount the MoonLite dual speed focuser on the older MN56 and it looks and functions great!



My M809 came with an oldball dovetail plate
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#189 luxo II

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Posted 02 May 2020 - 05:51 PM

So did the MK91... replaced it with a Losmandy one.
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#190 n2068dd

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Posted 02 May 2020 - 09:30 PM

Hi Hiromu, indeed IMHO scopes with Intes glass are indeed treasures, though poorly recognised as such.

 

All the examples of russian optics I've seen (I can count 7) have been consistent - Intes and Intes Micro really did guarantee 1/6 wave P-V (standard) and 1/8 wave for the deluxe models - and they supplied a test certificate with the scope serial number to back that up. Likewise Santel and more recently APM which sourced optics from Intes-Micro and Santel, though it appears they were all using the same test laboratory. This is something no other manufacturer ever did. Not even Questar. 

 

By the way, the dovetail base on that scope doesn't look parallel to the OTA, right ?

Hi, luxo II

 

Yes, not parallel. Cause, when I orderd custom made adapter, I just did not noticed Vixen  screw hole and bracket are not orthogonal.

Later,when I prepared corrected adapter (parallel direction), I did not replaced, rather set it as there. No problem so far.

 

Same test labo?

It's very trusty for us. Their optical standard looks high and the Polishing is impressively fine compared to other MCT company.

 

 

 



#191 luxo II

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Posted 18 May 2020 - 02:09 AM

Yes the mirror polishing is... a surprise. I bought a Howie Glatter laser collimator and I was surprised to find the holographic pattern is totally invisible on both the primary and secondary of the MK91. Placing wax paper over the corrector I can see the cross projected straight through from the baffle, as well as the reflected cross from the primary and secondary... and they are aligned perfectly and concentric with the secondary.

 

Likewise  on the APM 10" mak, not visible on either mirror, though the same (wax paper) solution worked.

 

The collimator instructions say it should be visible on each mirror, but no, completely invisible.

 

It is visible on the mirrors of a SW 180mm mak, though.


Edited by luxo II, 18 May 2020 - 02:34 AM.

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#192 stuart keenor

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Posted 18 May 2020 - 01:45 PM

Same on the Zen couldn’t see it

#193 Jeff B

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Posted 18 May 2020 - 05:49 PM

I thought I'd show you a DPAC image of my MN 76.  The one edge of the mirror a clipped due to the small secondary and the DPAC soruce and viewing being slightly off axis so I have "upper half and lower half" for the outside of focus images.  See the nice straight lines and at focus, some mild circular zones and faint "spokes" (see how small the secondary is), but also very smooth.    Remember though, double pass got its name because the beam bounces through the system (meniscus, secondary and primary) twice so errors are doubled.  

 

This is a very good optic system and it shows at the eyepiece with sharp views...when collimated of course, like any Newtonian.  I personally think the MN76 is the sweet spot in the Intes MN line with its larger aperture and manageable size/weight.   

 

Waiting (somewhat) patiently for Mars.

 

Jeff

Attached Thumbnails

  • MN76 b.jpg
  • MN76 DPAC Holder.jpg
  • MN76 In DPAC.jpg
  • MN76, DPAC, Outside Focus, Rightside Up.jpg
  • MN76, DPAC, Outside Focus, upside down.jpg
  • MN76, DPAC, White, At Focus.jpg

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#194 Tony Owens

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Posted 20 May 2020 - 11:17 AM

I'm a Mak fan myself. I have an early MN76 Mak-Newt with some sensible modification for easier collimation and more accurate focusing, and a Sitall MN86 with remarkable image quality. That one has had some mods too to improve optical equilibration performance for critical planetary imaging.

See thermographic video of cooldown here:

https://www.dropbox....oldown.mp4?dl=0

 

Note the excised rear portion of the mirror cell in the image below.

 

mirror_cell_radiation.jpg

 

While good on planetary imaging, I'm focusing more on deepsky imaging for the next couple of years, given my location and planetary positioning. 

I am thinking more about what sort of astrograph I can provide for deepsky use, in the 1000-1500mm FL range. I have a small 80mm F5 APO but dont want another bigger one. I'd like to try the MN for this, but am concerned about an insufficiently flat and uniformly illuminated field to suit the APS-C sized sensor I'd like to use. But, I haven't either measured (CCD Inspector) or raytraced the MN86 optical system so don't really know the scale of the problem.

If anyone has been in this situation before me, and has done practical testing, knows of a suitable field flattener, or can help, please do so!

 

cheers

Tony Owens

 


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#195 Far Star

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Posted 22 May 2020 - 11:23 AM

You do not need a field flattener.

 

Here is a photo (single frame, ISO 6400, 15 seconds exposure time) taken last night with my 180/1120 mm Matthias Wirth / Intes Micro Maksutov-Newtonian (without field flattener; the camera was a Canon EOS 800D with APS-C sensor):

 

3330-beschriftet-Sigma-Draconis-20200521


Edited by Far Star, 23 May 2020 - 02:12 AM.

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#196 Tony Owens

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Posted 24 May 2020 - 06:05 PM

I decided to take a closer look at my smaller Mak-Newt, the MN76 to understand the astroimaging potential better. This is a 180mm aperture instrument with 1100mm or so EFL (i.e., F6.1). The MN76 model is a little different from the MN86 in that there is a bit more backfocus. My MN76 has (123.0 minus the focuser height) mm worth of backfocus. That seemed interesting, as it exceeds the 55mm that is commonly provided in refractors equipped with field flatteners.

I removed the corrector in its cell, and mechanically profiled the concave and convex surfaces to estimate radii of curvature using best-fit spherical curves, and also determined the centre thickness. I checked the various optical element spacings and apertures (I needed to clean the instrument in any case due to extended storage) and cross-checked the data against the original optical layout. Agreement was close. I plugged the data into my lens design software, defined the corrector to be made of LZOS K8 crown glass, the most likely type used in the instrument, and tweaked-up the corrector ROC's via optimisation. The deviations of the optimised ROC's from my measurements were gratifying small. Spot diagrams and images looked very decent across a 6 mm diameter fully-illuminated image circle.

Next, I allowed the secondary (diagonal) mirror to grow from 40mm minor axis diameter (the size of the upgraded quartz diagonal in my MN76) to 53mm, based on the maximum obscuration I was willing to accept (30%) and assuming a 0.5mm edge bevel. I determined the nominal field of the scope to be approx 1.4 deg. based on a larger 34mm fully-illuminated image diameter - enough for APS-C. I also set up a requirement for broader wavelength range than visual scopes are designed with, i.e., 435 - 852 nm. This is more in keeping with narrowband and more advanced imaging uses. To allow for reasonable near-IR performance, I switched from protected aluminium mirror coatings to protected silver, which makes sense in a closed tube astrograph. I expect to recoat the mirrors anyway, so might as well choose a coating more suitable for imaging use. Finally, I replaced the Russian crown glass spec assumed for the corrector material with Schott N-BK7, and checked to see whether there was a perceptible difference in optical behavior. There was no significant difference. So I kept that change, as using N-BK7 made it easier to perform light transmission calculations, and the glass types are known to be very similar.

Finally, with these alterations, I determined the optimum curvature of the 34mm diameter image surface using optimisation. After some work I found that the field curvature depended strongly on the size of the diagonal used. If a minimum-sized diagonal is used, the image surface ROC and convex-to-the-primary sign is similar to the calculated Petzval radius, using analytic methods. However, with larger diagonals and field angles, the optimum ROC increases, i.e., becomes flatter. And, the image quality off-axis is very decent, at the slow F6 ratio of this instrument.

For the curious and the optically-literate nerd, here is a much more detailed report on the instrument, the reverse-engineering, and the raytracing analysis:

https://www.dropbox....lysis.pptx?dl=0

 

Tony Owens


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#197 luxo II

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Posted 24 May 2020 - 09:02 PM

Tony,

 

There's another possible arrangement for a low-profile focuser, in which there is no traditional in/out focuser at all - instead an eyepiece holder is mounted on a slider that moves lengthwise along the OTA. The slider also carries the diagonal mirror and using one or two curved vanes diffraction spikes from those can be eliminated.

 

There's a nice pic in another CN thread if I can find it again.

 

The difficulty is this would have to be a custom machining job, but a lot more compact and far lighter than that monster Clement focuser.


Edited by luxo II, 24 May 2020 - 09:17 PM.

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#198 Tony Owens

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Posted 25 May 2020 - 04:03 AM

Tony,

 

There's another possible arrangement for a low-profile focuser, in which there is no traditional in/out focuser at all - instead an eyepiece holder is mounted on a slider that moves lengthwise along the OTA. The slider also carries the diagonal mirror and using one or two curved vanes diffraction spikes from those can be eliminated.

 

There's a nice pic in another CN thread if I can find it again.

 

The difficulty is this would have to be a custom machining job, but a lot more compact and far lighter than that monster Clement focuser.

There's less backfocus on my MN86 hence the choice of the 76 for this study. It seems to have enough to accommodate an imaging train using most of the obvious focuser types. I want to study a helicoid a bit more before I do anything. Motorised focus is essential on an aluminium tubed scope with snappy focus like this, and I'd want a neat solution.

I have a Protostar quartz 66 mm m.a. Diagonal so might give that a try first with the Feathertouch and a base adapter. Just to encourage myself, as it were. Though as @Farstar has conclusively shown with his APS-C image, the only real issue with deepsky imaging with the 76 appears to be vignetting versus growth in CO!

Tony



#199 Jeff B

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Posted 25 May 2020 - 10:59 AM

I decided to take a closer look at my smaller Mak-Newt, the MN76 to understand the astroimaging potential better. This is a 180mm aperture instrument with 1100mm or so EFL (i.e., F6.1). The MN76 model is a little different from the MN86 in that there is a bit more backfocus. My MN76 has (123.0 minus the focuser height) mm worth of backfocus. That seemed interesting, as it exceeds the 55mm that is commonly provided in refractors equipped with field flatteners.

I removed the corrector in its cell, and mechanically profiled the concave and convex surfaces to estimate radii of curvature using best-fit spherical curves, and also determined the centre thickness. I checked the various optical element spacings and apertures (I needed to clean the instrument in any case due to extended storage) and cross-checked the data against the original optical layout. Agreement was close. I plugged the data into my lens design software, defined the corrector to be made of LZOS K8 crown glass, the most likely type used in the instrument, and tweaked-up the corrector ROC's via optimisation. The deviations of the optimised ROC's from my measurements were gratifying small. Spot diagrams and images looked very decent across a 6 mm diameter fully-illuminated image circle.

Next, I allowed the secondary (diagonal) mirror to grow from 40mm minor axis diameter (the size of the upgraded quartz diagonal in my MN76) to 53mm, based on the maximum obscuration I was willing to accept (30%) and assuming a 0.5mm edge bevel. I determined the nominal field of the scope to be approx 1.4 deg. based on a larger 34mm fully-illuminated image diameter - enough for APS-C. I also set up a requirement for broader wavelength range than visual scopes are designed with, i.e., 435 - 852 nm. This is more in keeping with narrowband and more advanced imaging uses. To allow for reasonable near-IR performance, I switched from protected aluminium mirror coatings to protected silver, which makes sense in a closed tube astrograph. I expect to recoat the mirrors anyway, so might as well choose a coating more suitable for imaging use. Finally, I replaced the Russian crown glass spec assumed for the corrector material with Schott N-BK7, and checked to see whether there was a perceptible difference in optical behavior. There was no significant difference. So I kept that change, as using N-BK7 made it easier to perform light transmission calculations, and the glass types are known to be very similar.

Finally, with these alterations, I determined the optimum curvature of the 34mm diameter image surface using optimisation. After some work I found that the field curvature depended strongly on the size of the diagonal used. If a minimum-sized diagonal is used, the image surface ROC and convex-to-the-primary sign is similar to the calculated Petzval radius, using analytic methods. However, with larger diagonals and field angles, the optimum ROC increases, i.e., becomes flatter. And, the image quality off-axis is very decent, at the slow F6 ratio of this instrument.

For the curious and the optically-literate nerd, here is a much more detailed report on the instrument, the reverse-engineering, and the raytracing analysis:

https://www.dropbox....lysis.pptx?dl=0

 

Tony Owens

Thanks for the analysis Tony, I really enjoyed the read. 

 

I've both the MN86 (an APM/MW OTA) and the Intes MN 76.  I've always felt the MN76 was, for me, the mint chocolate chip ice cream of the line.

 

Jeff



#200 stuart keenor

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Posted 25 May 2020 - 11:10 AM

Very interesting thread thanks for sharing 👍


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