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DevonSkies

Switch from Porta II to AZ4

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I've been using an ST102 f/5 refractor on a Vixen Porta II mount for a couple of years now as a grab and go. Nice and light, but the incessant vibration at high magnifications was driving me mad, particularly for planetary viewing. Last week I was attempting to observe Saturn at 100x and the vibration just wiped out all the detail.

So, I decided to "upgrade" to the heavier AZ4 (I say "upgrade" in quotes, as the AZ4 is actually a cheaper mount and lacks the slo-mo controls). Well, I'm pleased to report that the difference is tremendous. The AZ4 is solid as a rock, and there is no hint of vibration even when focusing. Best of all, when I turned the scope onto Saturn I could immediately see the Cassini division and some surface detail for the first time ever!

The moral of this story - something as simple as improving the mount has made my humble ST102 work like a whole new scope!

The only negative so far of the AZ4 is significant "stiction" in the altitude axis. I find I have to nudge the scope up and then down again to make small adjustments in altitude. I'm hoping this will smooth out in time... The azimuth axis is nice and smooth.

Next job - save up for the 100ED I've been lusting after!

:-)

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Good result! Did you only change the mount, or is the tripod also new? The tripod of my EQ3/2 is prone to vibration, sticking it on a modded tripod with stiffer legs improves that a lot

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Great report. Have you reviewd balance and then tightness of the altitude bolt re the stiction you experienced?

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1 hour ago, michael.h.f.wilkinson said:

Good result! Did you only change the mount, or is the tripod also new? The tripod of my EQ3/2 is prone to vibration, sticking it on a modded tripod with stiffer legs improves that a lot

Yes, the tripod is also new - the AZ4 comes with a pretty heavy steel tripod, much better than the aluminium legs of the Porta II. To be fair to the Porta, the mount itself is nice, it's really the lightweight legs that are the problem.

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1 hour ago, happy-kat said:

Great report. Have you reviewd balance and then tightness of the altitude bolt re the stiction you experienced?

Yes, I did adjust the altitude tightness as loosely as I could without the scope starting to slip. I'll see how it goes over the next few weeks.

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Just now, DevonSkies said:

Yes, the tripod is also new - the AZ4 comes with a pretty heavy steel tripod, much better than the aluminium legs of the Porta II. To be fair to the Porta, the mount itself is nice, it's really the lightweight legs that are the problem.

Can you mount the Porta-II on the AZ-4 tripod? Maybe that would be best of both worlds

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1 minute ago, michael.h.f.wilkinson said:

Can you mount the Porta-II on the AZ-4 tripod? Maybe that would be best of both worlds

I haven't tried that yet, but yes it would be worth a try! Not sure if they're compatible, but I'll have a look. Thanks.

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I use my Porta II on HEQ-5 tripod when it's not in use. It is then rock solid.

I had to cut a notch in the Porta II to clear the Azimuth peg on the tripod but it was easy enough to do.

David

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My AZ4 came with a tripod with round legs rather than the two hollow aluminum side-by-side legs. But this changed recently. What does the AZ-4 that's working so well for you have for legs?

I also have a Vixen Porta II which I find more stable over the AZ4 I bought over here in the US. If the legs my AZ4 came with here are the same as what you have there in the UK, I'll put those on my Porta II mount and see what happens regards stability. Perhaps that will actually be "..... be best of both worlds" as Michael proposed.

The AZ4 over here carries the Orion (USA) brand and is called the "VersaGo II." The legs on the mount were recently changed to the two hollow-aluminum ones shown in their recent catalog here:

http://www.telescope.com/Mounts-Tripods/Altazimuth-Mounts-Tripods/Orion-VersaGo-II-Altazimuth-Telescope-Mount/pc/-1/c/2/sc/35/p/10105.uts

This is getting very interesting to me!

Thanks all,

Dave

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51 minutes ago, Dave In Vermont said:

My AZ4 came with a tripod with round legs rather than the two hollow aluminum side-by-side legs. But this changed recently. What does the AZ-4 that's working so well for you have for legs?

I also have a Vixen Porta II which I find more stable over the AZ4 I bought over here in the US. If the legs my AZ4 came with here are the same as what you have there in the UK, I'll put those on my Porta II mount and see what happens regards stability. Perhaps that will actually be "..... be best of both worlds" as Michael proposed.

The AZ4 over here carries the Orion (USA) brand and is called the "VersaGo II." The legs on the mount were recently changed to the two hollow-aluminum ones shown in their recent catalog here:

http://www.telescope.com/Mounts-Tripods/Altazimuth-Mounts-Tripods/Orion-VersaGo-II-Altazimuth-Telescope-Mount/pc/-1/c/2/sc/35/p/10105.uts

This is getting very interesting to me!

Thanks all,

Dave

Hi. My AZ4 has the heavy, round steel legs. I think it's sometimes called the AZ4-2, distinct from the AZ4-1 which has the lightweight aluminium legs (same as the AZ3 I think, and similar to my Porta II). The steel legs on the AZ4-2 look the same as those on the the EQ5.

Hope that helps!

Edited by DevonSkies
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Yes - it helps, thank you! And anything related to the AZ3 is a disaster in my book! :p I've usually heard this described by words unprintable in a family forum!

I'll keep hunting for more. I'm looking for ways to improve both the AZ4, as well as the Porta II's out there - for little £££$$$.

Enjoy!

Dave

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I also use an AZ4 with my ST102 at the moment. Similar to yourself, I found alt stiction to be a bit annoying (especially at higher magnification when nudging more often). I stripped the head down and regreased which did help a bit....but I think my issue is that I don't seem to have the scope very well balanced. Found it a bit difficult with the short tube length - once I have Revelation diagonal and X-cel eyepiece in it's difficult to keep the tension right as I increase alt. Maybe I'm being stupid and missing something though!

Out of interest, have you done anything special (weights, etc) to help balance the ST102? 

Cheers :-) 

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On ‎13‎/‎07‎/‎2017 at 12:01, DevonSkies said:

Yes, I did adjust the altitude tightness as loosely as I could without the scope starting to slip. I'll see how it goes over the next few weeks.

May sound counter intuitive but try tightening it not loosening it. Yes the movement is stiffer buy you have more control over the movement and no sticktion, which is the main culprit for over shooting and having to yoyo to your target. This works perfectly for me and I use the larger ST120 for solar and night observing on mine. 

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1 hour ago, davyludo said:

I also use an AZ4 with my ST102 at the moment. Similar to yourself, I found alt stiction to be a bit annoying (especially at higher magnification when nudging more often). I stripped the head down and regreased which did help a bit....but I think my issue is that I don't seem to have the scope very well balanced. Found it a bit difficult with the short tube length - once I have Revelation diagonal and X-cel eyepiece in it's difficult to keep the tension right as I increase alt. Maybe I'm being stupid and missing something though!

Out of interest, have you done anything special (weights, etc) to help balance the ST102? 

Cheers :-) 

When I had an AZ-4 I found that having the scope balanced slightly nose heavy worked best. The dovetail fitting makes it fairly easy to slide the scope forward a bit "on the fly" if you are putting a lot more weight on the back end.

It should be perfectly capable of handling an ST102 or an ST120 for that matter.

The AZ-3 works OK with short tubes such as the ST80 and 90mm mak-cassegrains. I've even had a TAL 100 on an AZ-3 but it was not wonderful !

 

Edited by John

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24 minutes ago, John said:

When I had an AZ-4 I found that having the scope balanced slightly nose heavy worked best. The dovetail fitting makes it fairly easy to slide the scope forward a bit "on the fly" if you are putting a lot more weight on the back end.

It should be perfectly capable of handling an ST102 or an ST120 for that matter.

The AZ-3 works OK with short tubes such as the ST80 and 90mm mak-cassegrains. I've even had a TAL 100 on an AZ-3 but it was not wonderful !

 

Thanks for the response John. 

The heads of the bolts that are on my dovetail stick out a bit, so unfortunately that limits the amount of travel I have :hmh: It certainly feels like I could do with weight being a bit further forward thought. It's not a massive issue...just feel that stiction would be less noticable if I could get the weight a bit further forward and have things better balanced.

The AZ4 is a great mount and I love the ease and freedom of using an alt-az. I bought a cheap 2nd hand AZ3 really just to try to slow motion controls - I've had the ST102 on this a couple of times, it's not great but it's fine for a quick look between gaps in the clouds. I did have to replace the alt nyloc nut as it kept coming lose and causing me issues. Works fine with my wee 76mm newt which weighs nothing.

Holding out for more information on the AZ5 for now! 

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The stiction issue I found was eased quite a lot with the strip down/ regreasing that you mentioned. What grease did you use? I've used a high quality Teflon grease bought from a local bike shop. It doesn't cure it all together, I found if the mount hadn't been moved for a while there was that familiar little resistance, but after that it moved very smoothly during any session of use.

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The CG5 tripod is so I believe a compatible, no mods required fit for a vixen porta II mount. I changed to a wooden tripod, though the stock tripod was quite alright at least for using my 76mm F6.3 refractor.

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Hi. I had a huge problem with stiction, as you put it, and I was always stressed by pushing it up too far and then pulling it down again. I feel I have much better control now and I assume it's just muscle memory. I wondered how I was going to ever track Jupiter and now I feel fine about it nearly all the time. I tend to keep the altitude quite tight now as I hate it when it swings free and if it's tight, the balance doesn't need to be so perfect. It just seems that I got used to it since I got it in March. Hope you do too.

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I've got both these mounts. The porta 2 I prefer due to the slow motion controls but it does take longer to stabilise than my az4 (aluminium legged).

I've also got an Az 3 but that never gets a look in any more.

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13 hours ago, Alfian said:

The stiction issue I found was eased quite a lot with the strip down/ regreasing that you mentioned. What grease did you use? I've used a high quality Teflon grease bought from a local bike shop. It doesn't cure it all together, I found if the mount hadn't been moved for a while there was that familiar little resistance, but after that it moved very smoothly during any session of use.

Hi Ian, 

I originally used general purpose lithium grease that I had lying around (which made quite a difference compared to the original stuff that was on there). However after speaking to some people on SGL I was advised to use teflon grease so bought a tube of superlube. Again, this made a difference over the lithium (only slightly though). 

After reading the link posted by happy-kat, I think I may have applied too much grease....because I put grease on EVERY surface I could (including the teflon surfaces). I did notice that I needed to have everything done up tighter after applying the superlube as the mount was more prone to drooping (which I assume is because my scope wasn't properly balanced). 

I think I might remove some of the grease and try keeping the alt a bit tighter (rather than setting it so that it's only just holding the scope in place).

 

I'd like to point out that the mount is in no way unusable...the grease has made a massive improvement over how it originally felt. I'm being really pernickety here and really just looking for minor ways to improve things - I understand that there will probably always be some amount of stiction to overcome (without spending a fortune on a fancy mount).

At the moment I'm not getting the telescope out much....so tinkering with things is keeping me out of trouble!!

 

Cheers, 

Davy

 

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58 minutes ago, davyludo said:

I'd like to point out that the mount is in no way unusable...the grease has made a massive improvement over how it originally felt. I'm being really pernickety here and really just looking for minor ways to improve things - I understand that there will probably always be some amount of stiction to overcome (without spending a fortune on a fancy mount).

Hi Davy, likewise, I frequently find myself tinkering to improve stuff. To misquote an old saying, "cloudy nights find work for idle hands"! The balance issue is a significant one (as with any scope) but I've found the ED100 is pretty easy in that respect so I'd not considered that as  a particular problem. All things considered though, I think the AZ4 is a really good,useful work horse of a mount, particularly mounted on the steel legged tripod.

Edited by Alfian
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On 24/07/2017 at 15:14, davyludo said:

I also use an AZ4 with my ST102 at the moment. Similar to yourself, I found alt stiction to be a bit annoying (especially at higher magnification when nudging more often). I stripped the head down and regreased which did help a bit....but I think my issue is that I don't seem to have the scope very well balanced. Found it a bit difficult with the short tube length - once I have Revelation diagonal and X-cel eyepiece in it's difficult to keep the tension right as I increase alt. Maybe I'm being stupid and missing something though!

Out of interest, have you done anything special (weights, etc) to help balance the ST102? 

Cheers :-) 

If you feel that you need a bit more weight at the front of the tube (the reverse is usually the case, ie, tubes can be "front heavy", especially on larger apertures-but yours is a short focus scope) it might be worth sourcing a spare tube ring (or even a pair of them), which you could then put just behind the dewshield and adjust backwards until you get good balance.

They should be easy to find online for not much cash?.

Dave

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