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Why no slow-motion controls on most alt-az mounts?

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#1 Mark9473

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Posted 12 March 2006 - 09:27 AM

I would like to understand why most alt-az mounts do not have slow-motion controls. Is it because these mounts are generally only used at low magnification where nudging the telescope is not that much of an issue?

Two mounts I'm in particular looking at, are the new William Optics Eazy-Touch mount, as well as a Universal Astronomics Macrostar mount.

#2 kfred

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Posted 12 March 2006 - 10:35 AM

I don't know the answer to your question however, I'am glad that WO, UA, Helix, to name a few have come out with some great mounting options.

For my Intes Micro Alter M603 6" F/10 Maksutov-Cassegrain about the only thing on the market that I liked and had slow-motion control was the Takahashi Teegul Altazimuth w/ Lapides Modification.


Fred

#3 celestial_search

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Posted 12 March 2006 - 11:41 AM

Well, I can propose one answer.

I was looking at the Vixen Porta mount (Alt-Az with slowmo controls). It cost over $150 more than my surveyor's tripod and Hercules Single Arm Alt-Az mount that does not have slowmo controls.

Price of the mount is probably a key factor.

Also, if the movement of the Alt-Az mount is smooth and you get used to the mount you probably don't need (although it would be nice to have) slowmo control.

I was viewing last night with my Mak 127mm and used a 12mm U.O. HD EP (128X) on a few objects and it was not too diffuclt to keep it in the FOV.

I also went with my set-up because Vixen specified 9 pounds as the max load weight (possibly a conservative rating), and the surveyor's tripod and Hercules can hold at least 2, if not 4 or 5, pounds more weight.

Trades offs including price.

#4 denodan

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Posted 12 March 2006 - 12:35 PM

It is because the Alt-Az you need to move in both RA and DEC to follow a star and generally is very hard to track by hand, they are not generally made for astronomy, but for looking at land objects, so the thinking is no need for slow motion.

An Equatorial mount set up and polar alighed only needs to be moved in RA, and maybe a little in DEC so hand guiding is possiable so these have slow motion controls.

The New SCT now have often come in Alt-AZ mounts, but are controlled by computer, so tracking is possible just.

#5 dvb

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Posted 12 March 2006 - 01:43 PM

It is a good question. I currently have the very inexpensive AZ3 for my F/9 ED100. It does have slo mo. I have taken off the azimuth cable, cuz it seems to get in the way, and i seldom used it. I use the altitude adjustment all the time, because the altitude bearing is very stiff, and it is really not possible to follow anything without the slo mo.

I have the WO EZ touch on order -- I am hoping the movements will be smooth enough that I won't need slo mo.

An the other hand, the stiffness of the AZ3 means I can give it some awkward balancing challenges -- a heavy (StellarVue F10) finderscope, a 2" Antares diagonal, and a 31mmT5 Nagler, and still have it balanced (with the tube way back in the rings.) I'll see how the EZ Touch handles that. I hope I don't have to rebalance as I change eyepieces.

#6 Phil Wheeler

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Posted 12 March 2006 - 02:14 PM

I would like to understand why most alt-az mounts do not have slow-motion controls. Is it because these mounts are generally only used at low magnification where nudging the telescope is not that much of an issue?


That's one reason. I use two mounts: A UA Microstar and a Bogen-Manfrotto 410 geared head. The latter has slo-mo knobs and can accept unbalance with ease .. so it is really good for looking at and tracking planets at higher magnifications and when making radical eyepiece changes. But the Microstar is much easier to use when I'm wanting to scan the skies at lower magnifications with a single (zoom) eyepiece.

Phil

#7 Mark9473

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Posted 12 March 2006 - 03:19 PM

thanks all, some pretty unexpected answers so that's a good thing.

A special thanks to Phil for suggesting the Manfroto 410 geared head; I was looking at that (online) earlier today. The only problem related to your suggestion is that I would like to do an "either or" instead of getting both.

Bogen says this head has a special feature to allow instant un-clamping / re-positioning / re-clamping or something like that. Could you clarify what this is and how it works for our use?

#8 LesB

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Posted 12 March 2006 - 10:00 PM

The best alt-az I ever had were the Unitrons for the 2.4" and 4" refractors. The Vixen alt-az for my 80mm in no way compares to the old Unitrons. I had those alt-az's for many years before getting an eq.

Owning an alt-az is like beating your head on the sidewalk: it feels so good when you stop.

#9 Phil Wheeler

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Posted 12 March 2006 - 10:46 PM

Bogen says this head has a special feature to allow instant un-clamping / re-positioning / re-clamping or something like that. Could you clarify what this is and how it works for our use?


You twist a collar which disengages the mechanism, letting the scope or camera move freely .. so one hand holds the payload and the other disengages the mechanism .. one axis at a time. It's spring loaded, so if you let loose of the collar it reengages.

I picked up mine used in a local camera store for a very good price. The new ones are a bit different in design .. and seem to operate a bit more smoothly.

Oh yes .. mounting is via a quick release plate, handy when switching from my PST to ZS80FD.

Phil

#10 williamoptics

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Posted 13 March 2006 - 01:06 AM

W.O. mount design is different from other alt-az mount.
The internal construction makes slow-motion controls not necessary on this mount. Its main characteristic is smoothness and ease of use. Even at high power, you can follow the stars very easily by pushing the scope with your hand without any problem of backlash or stability.

#11 CESDewar

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Posted 13 March 2006 - 02:15 AM

Also, if the movement of the Alt-Az mount is smooth and you get used to the mount you probably don't need (although it would be nice to have) slowmo control.

I often hear this comment, but I have to say this is not my personal experience. I have had several Alt-Az mounts and my main mount for my TeleVue NP-127 is a premium quality DiscMount DM-6, and for my 80mm WO SuperAPO - a Vixen Portamount with slow motion controls. I have to say that scopes aside, I really do prefer having slow-motion controls to track objects when working at higher magnifications. Nudging a scope simultaneously on two axes is not quite as easy as it it made out to sound, even if the motion is smooth. I also find that twiddling slow motion controls involves less disturbance to the image than physically grabbing the scope to move it.

Just my 2cts.

#12 darylf96

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Posted 13 March 2006 - 02:52 AM

For planetary work, I insist on slow mo controls. That is why I use the Orion Astroview for two of my smaller scopes as a grab-and-go mount. Also, for pointing at the zenith, a counterweight and slow mo controls make viewing so much more pleasurable, especially at high magnification. I have an AZ3 which does have slo mo controls, but it is impossible to balance a scope pointed near the zenith whith this type of mount and with no provision for locking the alt. nut (I made my own socket on a handle for this purpose), the scope wants to fall in your lap. Also, after awhile you must rewind the slow motion controls when they reach the end of the worm gear.

#13 Mark9473

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Posted 13 March 2006 - 03:23 PM

thanks all for your input! Seems like I'm going to have to try before I buy. But if I hear that even the DM6 is not optimal, I'm starting to see a tracking mount in my future...

#14 Herenomore

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Posted 13 March 2006 - 06:59 PM

One of the things I asked Tom Peters about before I got my DM-4 was the lack of slo-mo controls. He told me to just try the mount. Sure enough, as soon as I did, I realized how unnecessary they were and I haven't thought about it since. You really need to try the mount yourself to appreciate what I'm saying but its an *extremely* smooth mount and control by hand (in any direction) is so easy, precise, and natural that you forget the mount is even there when you're on the ep.

Tom

#15 Oldfield

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Posted 13 March 2006 - 11:06 PM

Imagine a stable invisible hand is holding the OTA for you while you're scanning around, you can push it wherever you want, need slow motion control?

#16 Larry Patriarca

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Posted 15 March 2006 - 05:47 PM

Every piece of equipment that you own/use is based on personal preference and even that can vary depending on current needs. Tracking can obviously be a must if imaging, sketching, or maybe for public observing. Slow motion controls on an alt-az can be helpful, especially with mounts that don't allow balance vertically and horizontally, or have too much backlash, or instability due to mount construction or the more popular culprit...insufficient legs. To concur with others here, any mount designed to allow proper balance, and offer minimal backlash, can be utilized to track manually, even at high power. Can this be acceptable for you? That again is up to your personal preferences and current needs for portability, quick setup, stability, and/or ease of use. Those who insist that only an EQ mount can fulfill high power needs, typically have not used a well built altaz, or are so used to having tracking or slo-mo controls, they can't get used to not having it, irregardless of how much longer it takes to set up an EQ or how much less portable it is. Those that insist an alt-az should at least have slo-mo control, have again, typically not used a well built altaz, or are so used to having tracking or slo-mo controls, they can't get used to not having it. For us at UA, the simplicity of the designs we build (MicroStar, MacroStar, UniStar product lines) do not allow the addition of slo-mo controls, not without increasing the size of the product or inflating the cost greatly. And, since my own personal preference is for quick and easy, I have never favored slo-mo controls over a nudging a superior design alt-az set on proper legs.

#17 Mark9473

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Posted 16 March 2006 - 02:28 PM

thanks for your insightful comments, Larry. I am determined to get an alt-az mount, otherwise I might just as well have kept the Vixen Super Polaris mount I had on my previous scope. But even within alt-az there are many options to investigate.

#18 Flavio Lemos

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Posted 08 August 2006 - 08:43 PM

I'm looking for a good alt-az for my TV 85. When I use a 22 t4 or a 13 t6, even a photographic head and tripod works, but when I switch to a 9mm with barlow at 133x it is a nightmare to follow Jupiter. I wonder if a good alt-az will let me be happy, or if they only work at low power.

#19 Phil Frederick

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Posted 08 August 2006 - 11:57 PM

Hello Flavio--

Many people dismiss AZ mounts with slo-mo controls in favor of an EQ where you only have to use one SM adjustment in order to track (if you're reasonably well polar aligned).

I have a CG5 EQ and an SVP EQ and both are very good mounts for visual observing. My preference for most visual observing however is to use my Tak Teegul (Lapides Modified)--have two of them-- with both my ZS80FD and Celestron C6SCT. The mounts are very solid (on the CG5, SVP and Bogen475 tripods)and the slo-mo controls allow very easy, smooth tracking. I've found most photo heads less than satisfactory and EQ's are a bit of a pain. I've used the the Tak Teegul at 200X (especially with Nagler's) and find that they work well.

Lots of opinions on this subject but this generally works well for me. good luck!

Phil

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#20 Tim2723

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Posted 09 August 2006 - 12:11 AM

I think that the desire for slo motion is indeed a very personal choice. I have tried a very good, expensive 'push around' mount (the TV Gibraltar), and I personally do not care for the motion. I much prefer my little AZ-3, but then again I have never had any of the problems with the altitude axis that so many report.

#21 krehmkej

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Posted 09 August 2006 - 08:25 AM

Mark,
I have been through the same search, going through the Meade version of the AZ3, and a modified GEM. Both suffered from limited movement ranges and the AZ3 was nearly impossible to use near zenith, even after modification with an adjustable clamping nut handle. Believe it or not, the $48 el-cheapo Meade alt/az sold in their closeour store is the best I've used, after being fitted with a heaver tripod mount and legs. It has smooth slo-mo movements and suits my AT66 nicely. Am sure that it is limited to light(>4 lbs)OTAs, however.

#22 TerryC

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Posted 09 August 2006 - 10:30 AM

Hi Phil,

Where did you get those slo-mo controls for your Teegul mount from?

I have a modified Teegul and it works well with mu Tak TSA-102

Terry

#23 Guest_**DONOTDELETE**_*

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Posted 10 August 2006 - 02:17 PM

I'm glad somebody asked this question as I was wondering myself. I once owned a 4" Unitron Alt-Az and I loved having the slo-mo cables. With practice, I grew very proficient at using them. It was easy to track objects and keep them centered for visual observation. I wish they still made this mount. It was solid and steady even with the 4" F/15 refractor and accessories. :refractor:

#24 Phil Frederick

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Posted 10 August 2006 - 09:44 PM

Hi Terry--

Try www.focusknobs.com. Also, I think that Scopestuff sells their stuff. The knobs are really great!

Phil

#25 jrbarnett

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Posted 10 August 2006 - 11:08 PM

Those knobs look GREAT! I gotta have some!

Thanks for sharing,

Jim






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