Advice on converting Dobsonian to GOTO.

[Donwendy]

Hi,

I have a Sky Watcher 250px dob and was wondering what is the best way to convert it into a GOTO and what sort of work/cost would be involved? Any pointers or advice would be gratefully received.

Thanks

Don

[knobby]

Skywatcher sell a kit to convert a Dob to goto... But not in the UK

Theres a thread on here about it somewhere

[Lenny147]

One word, Expensive. Im sure it works out cheaper to change the scope completely

[knobby]

http://teleskopy.pl/product_info.php?products_id=2220&lunety=Upgrade_Kit_GoTo_do_Dobson_10%27%27_Sky-Watcher

[dtr42]

£536 plus p and p for that kit

[ronin]

To put that OTA on an equitorial mount would mean an NEQ6 at least which is in effect £1K.

If the scope is the flex tube then not sure that you could actually get rings to go in the right place, could work if the solid tube variety.

[Lenny147]

Basically it is a change of scope

[Naemeth]

How about a big Dob EQ mount:

http://www.equatorial-platforms-uk.co.uk/

[Scooot]

http://www.equatorial-platforms-uk.co.uk/

Have a look at IDOL on here, this will find things like a goto, you just have push the scope to the object.

Richard

[Donwendy]

Thanks guys, I will take it under advisement lol.

[Joseki]

It's not what you're asking but I think it's worth considering whether a push-to system would do what you want. I thought about converting to goto option but in the end what I want (easy way to find targets) is actually satisfied by a setting circle, a digital inclinometer and a computer (possibly a smartphone), which I already have.

[DeepThought]

It's not what you're asking but I think it's worth considering whether a push-to system would do what you want. I thought about converting to goto option but in the end what I want (easy way to find targets) is actually satisfied by a setting circle, a digital inclinometer and a computer (possibly a smartphone), which I already have.

I had a similar thought on this.

If you could find a way of securely strapping your smart phone to your OTA then surely someone smarter than me could write an app that uses the inclinometer and built in compass to steer you to an object based on a two star alignment.

I'd buy it anyway.

[Eastridge]

I have decided to do what DeepThought suggests and mount smartphone to OTA running SKeye. Have been using the app 'handheld' for a year or so now but once mounted and magnetically shielded ( if your device needs this) it can be aligned and used as Push To.

http://lavadip.com/skeye/documentation.html

Just need to get around to seeing which of our phones ( hubbies or mine) is less sensitive to the magnetic fields and getting a sturdy mount, based on ideas from link above.

[cantab]

I've seen brackets that will hold a smartphone to a scope, but I'm not sure its sensors would be precise enough for push-to. Plus it would kill your night vision.

But yeah my understanding is that the cheap way is an angle gauge for elevation (typically a Wixey), an angle scale on the base, and look up the alt-az co-ords on computer.

[DeepThought]

Wow, I didn't realise someone had already done this.

Look forward to giving this a try.

[freeflyjay]

It's not what you're asking but I think it's worth considering whether a push-to system would do what you want. I thought about converting to goto option but in the end what I want (easy way to find targets) is actually satisfied by a setting circle, a digital inclinometer and a computer (possibly a smartphone), which I already have.

not tryed it but heres some info on skeye (i donn`t have a smart phone

http://lavadip.com/skeye/

[Eastridge]

I've seen brackets that will hold a smartphone to a scope, but I'm not sure its sensors would be precise enough for push-to. Plus it would kill your night vision.

But yeah my understanding is that the cheap way is an angle gauge for elevation (typically a Wixey), an angle scale on the base, and look up the alt-az co-ords on computer.

If I use it 'handheld' in red eye mode it doesn't seem to impact my night vision too badly, so that doesn't seem too much of an issue for me. How do you see the setting circle angles on the dob base without light - presumably you use a red torch so don't see that there is much difference. Is there?

re Sensitivity we will see but googling seems to reveal many ( mainly US) who are doing it and seem to be happy so I am not dismissing it so easy. It may not get the object dead centre in a high mag eyepiece but if it's there or about I am happy to do the final bit manually.

[DeepThought]

After reading this thread, I decided to make good use of the inclement weather and put together a device for attaching my phone directly to my OTA.

I had lying around one of those armband phone holders that joggers use and with some minor alterations to lengthen the strap I have found that this is absolutely ideal for holding the phone firmly to the tube.

I can also confirm that if your OTA is made of steel then don't waste your time.

I kid you not, my scope has such a good magnetic field that I'm surprised it doesn't align north all by itself.

Back to the drawing board.

[autonm]

Ingesting post. I have also been following a post about the same question 200p oat onto a heq5pro mount...which has been done by several people. I will find and post the link tomorrow.

[autonm]

take a look at this - http://stargazerslounge.com/topic/170143-200mm-skywatcher-dob-remount/

[Eastridge]

After reading this thread, I decided to make good use of the inclement weather and put together a device for attaching my phone directly to my OTA.

I had lying around one of those armband phone holders that joggers use and with some minor alterations to lengthen the strap I have found that this is absolutely ideal for holding the phone firmly to the tube.

I can also confirm that if your OTA is made of steel then don't waste your time.

I kid you not, my scope has such a good magnetic field that I'm surprised it doesn't align north all by itself.

Back to the drawing board.

Based on what I have read I'm not surpised you had issues with it held straight onto steel OTA.

Presume you did the 'figure of 8 ' action to try and resolve as per his website (link I posted above)? Did it put out 'Magnetic field warnings' when held against the OTA? Hubbies Galaxy Ace does much of the time but my Galaxy Note doesn't so am wondering if it's better shielded.

His site does say to try and use a holder that keeps it away from the OTA for exactly this reason + one of the posters has found that using a non slip mat between phone and OTA helps.

I have phone ( Note) ready to go with a jerry rigged set up - car luggage strap holding OTA polysyerene packing onto it, with non slip mat between and cut out ready to hold phone into packing with tape ( have checked phone touch still works thru clear tape.) It doesn't give any magnetic field warnings with this set up.

Just need a clear night to try it out, last night was due to be clear but clouded over.

I'm not giving up until I have tried it for myself taking into account all the tips etc. I have found online. If it works for many others seems daft not to give it a go.

[DeepThought]

Based on what I have read I'm not surpised you had issues with it held straight onto steel OTA.

Presume you did the 'figure of 8 ' action to try and resolve as per his website (link I posted above)? Did it put out 'Magnetic field warnings' when held against the OTA? Hubbies Galaxy Ace does much of the time but my Galaxy Note doesn't so am wondering if it's better shielded.

His site does say to try and use a holder that keeps it away from the OTA for exactly this reason + one of the posters has found that using a non slip mat between phone and OTA helps.

I have phone ( Note) ready to go with a jerry rigged set up - car luggage strap holding OTA polysyerene packing onto it, with non slip mat between and cut out ready to hold phone into packing with tape ( have checked phone touch still works thru clear tape.) It doesn't give any magnetic field warnings with this set up.

Just need a clear night to try it out, last night was due to be clear but clouded over.

I'm not giving up until I have tried it for myself taking into account all the tips etc. I have found online. If it works for many others seems daft not to give it a go.

Oddly it didn't give a warning, but I knew something was wrong when it would only show objects in one direction.

I believe the "figure 8" technique would only work if I did so whilst it was attached to the OTA, which would take some doing on a dobsonian.

I have managed to overcome the problem by using a couple of inches of foam between the phone and the OTA, this is just far enough away to avoid the problem.

It still needs some field testing though, but that's out of my hands until the weather improves.

[knobby]

Good excuse to upgrade to a large truss dob , no magnetic field in between the trusses!

[Eastridge]

OK - managed a field test last night, full details below but in summary – based on what we did it works well enough for us, not 100% accurate but gets you to having object in finderscope and we can go from there ourselves.

WHAT WE DID:

Checked location co-ordinates in SKeye app accurate

Check clock setting on phone accurate ( free Clocksync app)

Did 'figure of 8' move to sort magnetic field distortions right by where phone will be held.

Phone ( Galaxy Note) held with sticky tape onto polystyrene packing for OTA and that held to OTA with car luggage strap, non slip mat between as that has been mentioned elsewhere as being good for disrupting magnetic field.

Aligned as per instructions ( linked to above) to Jupiter, Betelgeuse & Rigel ( only south portion of sky visible from location due to garden landscaping works). As this was just a test we were not overly precise about this put object in cross hairs of finder and then confirmed it was ‘centrish’ in 8mm EP.

Couldn’t get to the mentioned ‘Insta align’ function so did all 3 manually.

Using ‘push to’ searched for M42 – when SKeye showed it as centred it was toward bottom of finderscope view.

Used ‘push to’ for Pliédies – again there but toward bottom

Used ‘push to’ for back to Jupiter – again slightly off to the bottom , which seems odd as we used it as the first alignment object, but the system is using averaging.

I wonder if we knocked the scope slightly at some point during aligning or something but it still ‘did the job’ if not with perfect accuracy.

We are now happy enough that we will buy some bits and bobs to get a less cumbersome phone mount, a cheap case and some foam to pack below to keep it from rocking + to reduce magnetic field issues.

When we have access to a fuller portion of the sky that will give the ability to choose more diverse alignment points which I would assume would make it more accurate as well.

I am also going to start this as a new thread as the title of this one is not directly appropriate any more.

Hope this helps anyone thinking about trying it for themselves,

[michaeldurban]

I also tried skeye..made an extra mount for it on my truss tube..

but, it is just soo twitchy and inaccurate, i also tweaked all the

settings..nothing really works.

the only real thing that works is a good setting circle and a digital

inclinometer..and then make sure the scope is super level.

and then..wham!!..right in the middle of the eyepiece..every time..

I promise this..you will find every object, every time using stellarium

(making sure your coords and time are set correctly..)