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Adding GoTo capability to a Porta II Mount?

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#1 pugliano

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Posted 10 July 2013 - 07:35 AM

I really want a 102mm refractor with GoTo, but, from my experience with an 80mm Meade DS, the mounts are terrible. What I'd really like is a 102mm refractor on a Porta II alt-az mount for stable viewing, but with the object locating capabilities of a goto as well. I thought about getting the Celestron SkyScout to add to the tube, but I think they've been discontinued.

Are there any options that would give me object locating capabilities as an add-on to the Porta II mount? I don't need a drive, I just want to be able to locate objects easily.

#2 SeattleScott

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Posted 10 July 2013 - 09:18 AM

Tracking yes. Goto I don't think so. You can always upgrade the tripod on a goto refractor if it isn't sturdy enough.

#3 WaterMaster

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Posted 10 July 2013 - 09:34 AM

If you're just looking for object location, and you have an android phone, check out SkEye is a great little app developed by one of our members that turns your android phone into a push-to object locator. All you need to do is mount your phone to the telescope, set the alignment, and away you go. I use it with my 15x70 binos on a p-mount and am quite pleased with it's performance and utility. Here's a link to how I mounted my phone.

#4 pugliano

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Posted 10 July 2013 - 09:50 AM

Thanks. Guess it's time for me to upgrade my phone. :)

#5 pdxmoon

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Posted 10 July 2013 - 11:38 AM

If you're just looking for object location, and you have an android phone, check out SkEye is a great little app developed by one of our members that turns your android phone into a push-to object locator. All you need to do is mount your phone to the telescope, set the alignment, and away you go. I use it with my 15x70 binos on a p-mount and am quite pleased with it's performance and utility. Here's a link to how I mounted my phone.


That's cool! Anything similar for a iPhone?

#6 Eric63

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Posted 10 July 2013 - 11:54 AM

Not Sure about the Porta, but my AZ4 has setting circles. I simply look up the coordinates using SkySafari on my Iphone and turn my scope manually to the right location. Works quite well and it keeps things very simple. Before my AZ4, I used a compass and a declometer on the tube (just remember that there is an offset between true north and magnetic north).

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#7 Jon Isaacs

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Posted 10 July 2013 - 12:08 PM

If you're just looking for object location, and you have an android phone, check out SkEye is a great little app developed by one of our members that turns your android phone into a push-to object locator. All you need to do is mount your phone to the telescope, set the alignment, and away you go. I use it with my 15x70 binos on a p-mount and am quite pleased with it's performance and utility. Here's a link to how I mounted my phone.


Steve:

How accurate do you find Skeye to be? I have tried Skeye as well as other programs and not found them sufficiently accurate for actual Pointing of the scope. The biggest problems are with the azimuth reading, i.e. the compass.

My phone is a HTC Incredible, I have used it with a tablet as well.

Jon

#8 WaterMaster

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Posted 10 July 2013 - 02:04 PM

I don't believe Harshad (the SkEye developer) has produced an iOS app yet and I don't know of any iOS app that has the same features.

Jon, I actually have good results with SkEye, but it takes a little prep. The compass is the problem and I get around that in two ways. First, I can't observe from my normal location in my backyard as it's too close to power lines. I have to move away at least 50' before I stop getting the 'unusual magnetic field present' warning. Second, I have to calibrate my phone's compass in close proximity to the mount and binos (haven't tried it on my scopes). It is accurate enough to get my target in the bino's FOV (4.3°), but as I haven't tried it on my scopes I can't speak to its accuracy with a narrower FOV. :shrug:

I recently upgraded to a new phone and purchased SkEye (rather than use the free version), and it seems to work better on the new phone (less lag when moving). I suspect that might be due to better accelerometers or perhaps a better compass in the new phone.

#9 galexand

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Posted 10 July 2013 - 03:52 PM

How accurate do you find Skeye to be? I have tried Skeye as well as other programs and not found them sufficiently accurate for actual Pointing of the scope. The biggest problems are with the azimuth reading, i.e. the compass.


I'll echo this...from one phone to the next there is a lot of variability, but it is generally hard to get them calibrated reliably. And if your OTA is metal, it's even harder. But it is very inexpensive if you already have the phone and can build a mount out of stone knives and bear skins..

I think the OP probably wants some sort of pushto setup, which is basically setting circles (like has been said). Don't know how easy that is to add to the porta II, though.

Though personally I'd recommend getting some 7x50 or 10x50 binocs. Their wide field of view makes it easy to learn the sky, and then when you want to find a specific object, you can use them to learn the neighborhood. Once you know the terrain a little, it should be a snap to find objects in the telescope as well, just start at a bright star and hop from there. The learning curve is kind of steep though -- frustrating at first.

#10 frito

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Posted 11 July 2013 - 10:02 AM

If you're just looking for object location, and you have an android phone, check out SkEye is a great little app developed by one of our members that turns your android phone into a push-to object locator. All you need to do is mount your phone to the telescope, set the alignment, and away you go. I use it with my 15x70 binos on a p-mount and am quite pleased with it's performance and utility. Here's a link to how I mounted my phone.


Steve:

How accurate do you find Skeye to be? I have tried Skeye as well as other programs and not found them sufficiently accurate for actual Pointing of the scope. The biggest problems are with the azimuth reading, i.e. the compass.

My phone is a HTC Incredible, I have used it with a tablet as well.

Jon


compass accuracy is more about the phone than anything else, in my experience with various android phones over the years is the same as yours its good enough for rough directions but not good enough for accurately pointing a scope. i do believe there is a way to try and calibrate the compass, just like you can calibrate in leveling apps but of course you would need a reference to calibrate to. if sky safari etc. would allow us to point a mounted phone at a target and then say you are now point at this, it would be able to compensate for the error after doing that on a number of objects, just like goto mount do really.

#11 frito

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Posted 11 July 2013 - 10:07 AM

OP i have seen tracking setups like this for them

http://www.optcorp.c...-ii-mounts.html

but never anything else. goto on Alt Az is usually something only found on mounts/scopes that come with it. another issue with the porta mounts is how their clutches have no release and are designed to slip easily for manual use, if you were to devise a goto setup it would be easy to knock it out of alignment due to them.

best bet to save cash is buy a used CG-5 AS-GT mount, they can be had for 400 or less now and will offer you everything you want except for portability, for that you got your porta mount :)

#12 Jon Isaacs

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Posted 11 July 2013 - 10:27 AM

I really want a 102mm refractor with GoTo, but, from my experience with an 80mm Meade DS, the mounts are terrible.



I do think that the Celestron Nexstar SLT and GT mounts are superior to the Meade DS's so you might find a possible compromise there. The tripods are definitely on the flimsy side so something is definitely needed there.

As far as the Portamount, I use a digital level to find Mercury and Venus when they are lost in the sunset. This combined with a basic knowledge of where the cardinal points of the compass are located is sufficient. Otherwise, it depends on the scope. My 4 inch has a 540mm focal length so I just use a widefield eyepiece that provides a 4+ degree TFoV and use the scope as a Superfinder.

Jon

#13 Starman1

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Posted 13 July 2013 - 04:10 PM

JMI makes an encoder installation kit for the Porta II mount
Image
With that encoder kit, a JMI, Sky Commander, or ArgoNavis computer can easily be added.
This would not provide full GoTo, but would allow you to find deep-sky objects easily. Tracking would then be up to you.

JMI also makes motors for the Porta mount that allow tracking, but I don't think they've tied both the computer and tracking together yet for that mount.
You might call them to get an idea of price and features.

http://www.jmitelescopes.com/index.htm

#14 pugliano

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Posted 14 July 2013 - 07:01 AM

Thanks, Don!






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