Optimizing a small Maksutov.

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John Baars Netherlands
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Optimizing a small Maksutov.

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Post by John Baars »


There are several ways to improve the performance of a small Maksutov. The first two that I suggest make the biggest difference. There is no need to dissemble your optical parts with the first pair of suggestions. The second pair does. But for your comfort: The first two are by far the most effective.

1. Insulate the tube.
Turbulence inside the tube as a result of cooling down is a major problem in Maks. If you don't isolate you can count on severe inside seeing problems and a long cooling period. The key is to slow down the inside cooling proces. Light passes through a Maksutov tube three times and the first time right along the cold tube wall. If you insulate that wall most of your problems are over. All kind of isolation materials are allowed. No need to isolate the backside. You will be surprised by the calming effect it has on the image.

If your only goal is to see nice open clusters, you have already finished your upgrade.
DSC02097 (640x426).jpg

This is the "naked" telescope. A Skywatcher 102 mm f/13 Maksutov.


DSC02095 (640x426).jpg


The same telescope with his jacket on.

2. Apply a matte-black tube inside the long baffle. The shininess of it is well known. It diminishes the contrast you see on the Moon or bright planets like Jupiter and adds to the glare around bright double stars. Just shove a well fitting tube of black flocking material up the baffle. Take care that it is not all the way in. Otherwise it will work as a diafragm and cover the light that comes from the edge of the mirror. This for instance, is a good material:
https://www.fpi-protostar.com/flock.htm
DSC02792 (640x426).jpg
When you direct your telescope to the bright clouds you will see the difference immediately.
Met en zonder light-trap in Mak.png
Without and with a light-trap. Quite obvious differences.

So you are finished now. Cooling time as well as contrast on Jupiter , double stars and Moon are optimized by now.

Maybe you would like to take two steps further and take away all shiny surfaces in the telescope within your power.

3. In order to do so you will have to unscrew the corrector and the mirror holder. Mark the position of the outside corrector holder and mirror holder with a small sticker. Cut it through and afterwards you will find the exact position back.
IMG_1629 (326x640).jpg
Then apply the light-trap material inside the tube following the manual. Max. handling width of the adhesive strips is 3 inches.
IMG_1635 (640x480).jpg
Nice opportunity to clean all inside optical surfaces. (Don't if you don't know how)
IMG_1639 (640x480).jpg
4. Finally you can add light-trap material to the inside of the first baffle, the one that is attached to the corrector.
IMG_1637 (640x480).jpg
Now you can reassemble the telescope again. Maybe to your surprise you probably won't need to collimate. As corrector, primary and secondary are all spherical, there is no particular sweet collimation spot like in a parabolic one. But if your mirror is noticeably out of order, you can collimate it with the screws in the back. The big ones go all the way through into the next base-plate and need to be loosened. You can collimate with the small ones.

Yesterday evening I observed Jupiter with it. I was amazed by the amount of details I could see. It comes close to a 4 inch refractor. Of course I was helped by the good seeing.

Remember: steps one and two are the easiest ones with by far the most impact. The last ones will add the nearly unnoticeable last few percent.
The aperture stays the same. Don't expect to see DSO's you have never seen before, but the somewhat darker background gives a bit more contrast with the DSO.

Good luck and keep observing!
Refractors in frequency of use : *SW Evostar 120ED F/7.5 (all round ), * Vixen 102ED F/9 (vintage), both on Vixen GPDX.
GrabnGo on Alt/AZ : *SW Startravel 102 F/5 refractor( widefield, Sun, push-to), *OMC140 Maksutov F/14.3 ( planets).
Most used Eyepieces: *Panoptic 24, *Morpheus 14, *Leica ASPH zoom, *Zeiss barlow, *Pentax XO5.
Commonly used bino's : *Jena 10X50 , * Canon 10X30 IS, *Swarovski Habicht 7X42, * Celestron 15X70, *Kasai 2.3X40
Rijswijk Public Observatory: * Astro-Physics Starfire 130 f/8, * 6 inch Newton, * C9.25, * Meade 14 inch LX600 ACF, *Lunt.
Amateur astronomer since 1970.
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Lady Fraktor Slovakia
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Re: Optimizing a small Maktusov.

#2

Post by Lady Fraktor »


Some excellent improvements John.
A bit of light control can go a long way to improving the views.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
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Makuser United States of America
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Re: Optimizing a small Maktusov.

#3

Post by Makuser »


Hi John. A great collection of tips for Mak-Cass telescopes. Here is one that I put up last week on another thread, using inexpensive snack package storage clips for fine touch focusing, and is very easy to do.
MCT tip.JPG
Marshall
Sky-Watcher 90mm f/13.8 Maksutov-Cassegrain on motorized Multimount
Orion Astroview 120ST f/5 Refractor on EQ3 mount
Celestron Comet Catcher 140mm f/3.64 Schmidt-Newtonian on alt-az mount
Celestron Omni XLT150R f/5 Refractor on CG4 mount with dual axis drives.
Orion 180mm f/15 Maksutov-Cassegrain on CG5-GT Goto mount.
Orion XT12i 12" f/4.9 Dobsonian Intelliscope.
Kamakura 7x35 Binoculars and Celestron SkyMaster 15x70 Binoculars. ZWO ASI 120MC camera.
>)))))*>
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Ylem United States of America
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Re: Optimizing a small Maktusov.

#4

Post by Ylem »


Well done John :)
Clear Skies,
-Jeff :telescopewink:


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Orion 80ED
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John Baars Netherlands
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Re: Optimizing a small Maksutov.

#5

Post by John Baars »


[mention]Makuser[/mention] ,
Thanks for your addition!

I always use a clothespin, especially for focussing on Planets, Lunar craters and double stars :D Ugly as it seems, it is a useful solution for very fine focussing without having vibrations. The image crawls into focus without tremors. Funny enough, few know of this.

I keep mine in my observation-vest. Here it is:
wasknijper scherpstelling (480x640).jpg
Refractors in frequency of use : *SW Evostar 120ED F/7.5 (all round ), * Vixen 102ED F/9 (vintage), both on Vixen GPDX.
GrabnGo on Alt/AZ : *SW Startravel 102 F/5 refractor( widefield, Sun, push-to), *OMC140 Maksutov F/14.3 ( planets).
Most used Eyepieces: *Panoptic 24, *Morpheus 14, *Leica ASPH zoom, *Zeiss barlow, *Pentax XO5.
Commonly used bino's : *Jena 10X50 , * Canon 10X30 IS, *Swarovski Habicht 7X42, * Celestron 15X70, *Kasai 2.3X40
Rijswijk Public Observatory: * Astro-Physics Starfire 130 f/8, * 6 inch Newton, * C9.25, * Meade 14 inch LX600 ACF, *Lunt.
Amateur astronomer since 1970.
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Bigzmey United States of America
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Re: Optimizing a small Maksutov.

#6

Post by Bigzmey »


Nice mods John! If we can do it, why they can't incorporate better stray light control into manufacturing process.
Scopes: Stellarvue: SV102ED; Celestron: 9.25" EdgeHD, 8" SCT, 150ST, Onyx 80ED; iOptron: Hankmeister 6" Mak; SW: 7" Mak; Meade: 80ST.
Mounts: SW: SkyTee2, AzGTi; iOptron: AZMP; ES: Twilight I; Bresser: EXOS2; UA: MicroStar.
Binos: APM: 100-90 APO; Canon: IS 15x50; Orion: Binoviewer, LG II 15x70, WV 10x50, Nikon: AE 16x50, 10x50, 8x40.
EPs: Pentax: XWs & XFs; TeleVue: Delites, Panoptic & Plossls; ES: 68, 62; Vixen: SLVs; Baader: BCOs, Aspherics, Mark IV.
Diagonals: Baader: BBHS mirror, Zeiss Spec T2 prism, Clicklock dielectric; TeleVue: Evebrite dielectric; AltairAstro: 2" prism.
Filters: Lumicon: DeepSky, UHC, OIII, H-beta; Baader: Moon & SkyGlow, Contrast Booster, UHC-S, 6-color set; Astronomik: UHC.

Observing: DSOs: 3106 (Completed: Messier, Herschel 1, 2, 3. In progress: H2,500: 2180, S110: 77). Doubles: 2382, Comets: 34, Asteroids: 255
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