Alt / Az mounting my OMC140

Tell us about those other projects you are working on.
Post Reply
User avatar
John Baars Netherlands
Co-Administrator
Co-Administrator
Articles: 5
Online
Posts: 2723
Joined: Sat May 11, 2019 9:00 am
4
Location: Schiedam, Netherlands
Status:
Online

TSS Awards Badges

TSS Photo of the Day

Alt / Az mounting my OMC140

#1

Post by John Baars »


My OMC140 ( 140mm Maksutov) was actually always a tad heavy for the Alt/Az mount my GrabnGo 102mm Maksutov normally sits on.
The little 102mm Mak has an quiver time of less than half a second when focusing. Moving into Alt or Az is very smooth, with no noticeable vibrations.

The little Mak on Alt/Az
IMG_1202 (375x640).jpg

The almost double-weighted OMC140 makes that just two seconds. The Alt/Az movements are still smooth. But that depletion time is crippling for fun focusing on planets, for example. Too bad.

Until I started thinking logically and mounted the arm from which the telescope hangs upright on the tripod. This way the telescope does not "hang" behind the vertically running Azimuth axis (see above), but is balanced exactly above it.
OMC op Alt Az.JPG

OMC140 is balanced here, all brakes released.

The extinction time decreased by more than 1 second and sits just above half a second. Logical actually. Planet-worthy, even on Jupiter. At least now I can see that during focusing, the planet "clicks" into focus. Alt/ Az movements are still smooth. Really GrabnGo it's all not, of course, but I still catch a suddenly appearing Orion Nebula among the clouds. One drawback is that for zenith observing there is not enough space between zenith mirror and mount. In that case, a shorter zenith mirror mount and prism must be fitted.

Next to it hangs a clever 50mm viewfinder with Amici prism that can be transformed by changing eyepieces from 8X50, via 14X50 to 18X50. The latter is no superfluous luxury in my location.

Edit: With the 102mm Mak mounted this way, I hardly notice any vibration during focusing.
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.
User avatar
Bigzmey United States of America
Moderator
Moderator
Articles: 8
Online
Posts: 7548
Joined: Sat May 11, 2019 7:55 pm
4
Location: San Diego, CA USA
Status:
Online

TSS Awards Badges

Re: Alt / Az mounting my OMC140

#2

Post by Bigzmey »


Well done John! I do the same with ES Twilight 1 when observing with 8" SCT, improves observing considerably. Unfortunately, it does not work with refractors.

Like your wrap to.
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
User avatar
Lady Fraktor Slovakia
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 9860
Joined: Mon Apr 29, 2019 9:14 pm
4
Location: Slovakia
Status:
Offline

Re: Alt / Az mounting my OMC140

#3

Post by Lady Fraktor »


Very nice John, good that a simple rearrangement has worked well for you.
Vrolijk kerstfeest en een gelukkig nieuw jaar :)
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
The only culture I have is from yogurt
My day was going well until... people
Image
User avatar
John Baars Netherlands
Co-Administrator
Co-Administrator
Articles: 5
Online
Posts: 2723
Joined: Sat May 11, 2019 9:00 am
4
Location: Schiedam, Netherlands
Status:
Online

TSS Awards Badges

TSS Photo of the Day

Re: Alt / Az mounting my OMC140

#4

Post by John Baars »


Bigzmey wrote: Sat Dec 24, 2022 5:54 pm Well done John! I do the same with ES Twilight 1 when observing with 8" SCT, improves observing considerably. Unfortunately, it does not work with refractors.

Like your wrap to.
Yes, pity it doesn't work with my 4 inch refractor. Can't get to the zenit unless in the old configuration. Too much torque in the wind-->trembling too..
Lady Fraktor wrote: Sat Dec 24, 2022 7:47 pm Very nice John, good that a simple rearrangement has worked well for you.
Vrolijk kerstfeest en een gelukkig nieuw jaar :)
I had never thought of rearranging. Was looking for a way to do it for my 4 inch refractor. It worked, but not enough. Mind the weight under the mount for better performance too.
Šťastné sviatky a bezpečný, krásny nový rok!
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.
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

Return to “Other "Do It Yourself" projects”