Need Pushto computer for Dob

[glend]

I have a 12" GSO dob, currently setup with azimuth setting circle on the base and an incline meter on the tube, which works great as a basic manual pushto system - as long as I know the exact co-ordinates of the object I am looking for in the sky. My problem is that azimuth alignment has to be carefully done, and my laptop (running Celestron's Skylight) has limited battery duration for giving me co-ordinates, and I find myself going back and forth between the scope and the laptop (often plugged in to the AC in the house or inverter in the camper). Also I would like to avoid having to bend down to the base each time I have to reset the azimuth (back suffers) but could live with that if I have to.

I have looked at Argo Navis (too expensive for me), and the JMI digitial setting circle system, and Sky Commander, but really only Argo Navis offers and off the self solution for the 12" GSO (again too expensive).

Is there a simple handheld computer that holds all the Azi/Alt co-ordinates for the NGC catalog, plus Messiers, etc so that I can keep it at the scope? I have a 7" Android tablet (but it doesn't have onboard GPS) so it would be great if there was an App for that - but don't mention Skeye - I have tried it and found it terrible in use. Maybe the Mobile Observatory app, any views on this?

All advice welcome.

[acropolite]

Keep an eye on the icetrade section, they come up every now and again for around $500 complete with encoders.

[Allan_L]

Hi Glen,

I had good success at our remote Bretti camp last week with my ipod touch.
I know its not android, but I am sure something is available there too.
Anyway, I had a version of stellarium and it gave the Alt/Az continually updating.

The thing about Alt/Az, is that it is continually changing as the Earth rotates, and it is relatively different for any given location from Earth. So a static list is not an option.

With no GPS, I needed to load the Lat / Long, local time, and time zone into it once.

I found it very accurate.

You still need to be able see the az scale on the base though.
But I can see mine OK when I turn on my red head light.

I will experiment with Android Apps with my new (dumb) tablet too, and let you know if I find one that is as accurate (FREE).

And, If you find something better, though, PLEASE let me know.

Al

[glend]

Thanks Alan, I have downloaded Mobile Observatory from Google Play to run on the Android tablet. I did have to input my home GPS co-ordinates (because there is no onboard GPS in the tablet) and would have to update the location fix whenever I go elsewhere. The feature I liked about Mobile Observatory is that it has a big catalog, and I just have to input the NGC# or M#, name, etc and it will tell me where it is and the direction to go relative to my last position in the sky (with a red arrow). It displays in Azi/alt format as well as Ra/Dec, so it suits my needs there. The menu is not exactly intuitive (took me a while to figure out how to search for an object) but it looks promising as a solution.

[PeterHA]

You could think about connecting a Astro Devices NEXUS with encoders to your Dobson and use a Android device with something like SkySafari.

[bojan]

Try David's Ek webpage..
http://eksfiles.net/digital-setting-circles/
http://eksfiles.net/digital-setting-circles/usb-digital-setting-circles/

[noeyedeer]

Skeye would be better then mobile observatory. I have both and skeye pro has the full ncg catalogue compared to parts in mobile observatory.

do a 3 star alignment with skeye and away you go. the difference between the two is dramatic. I use MO most of the time but for push to, nothing beats skeye.

I have the pro version the free version is just as good but I don't know how extensive the catalogues are with the free.

but for free ... its better than nothing and its designed for being a push to .. not just a free view
matt

[noeyedeer]

also there's lots of users using skeye for a push to and there's plenty of help on the net, specially from the developers

sorry for mentioning skeye :)

mobile observatory is accurate enough for using alt-az on your scope .. just don't forget to press "now" to keep up-to-date

[noeyedeer]

ps, most android apps can be found for "free" :)

maybe you need to reset your gyro by waving it in a figure 8 a few times ... you may need to do this each time you use the app or until north points to north etc. once its configured it is a good push to

mobile obs only had 2500 ncg objects

[glend]

What do people think of Astro Devices Nexus wifi system and Sky Safari combo? It seems very cost effective at less than $250 AUD, it's a local product, and interfaces to Android.

[CJ]

I found SkyEye far too jittery. I couldn't find a way of smoothing its response to movement. I found Sky Safari much calmer and the version I bought was darn nearly free. That and being able to tap an object and then read about it was amazing. An interactive directional book. The future is here!

[noeyedeer]

I agree with you cj, but once you reset the gyro it becomes a lot more stable .. you may have to do it a few times.

either way you're happy .. I'm happy :). just don't rule it out because most of the frustration is user level not the program. wiki can give me info if I want it ... plus who wants to download half a gig? I have ski safari pro and never use it because its too fancy for my likings. I prefer simplicity without the obstructions of over the top renders.

that's why I use mobile observatory almost 99% of the time ... but skeye as a push to is great

these are my main astro apps ....

[glend]

I will give SkySafari a try as well. Found out that the Nexus price does not include the encoders and cables (more $), and apparently the Alt bearing has to be modified to mount the ALT encoder (more $, some encoder suppliers will do the ALt bearing mod but only if you buy their system box).

I will wait on the encoders and other hardware and just get to know Skysafari and the other Apps that I have, and if they can give me 'at the scope' co-ordinates then that saves me time dealing with the laptop.

Thanks to all, consider this thread closed for now.:thumbsup:

[AG Hybrid]

Argo Navis Encoders + Astro Devices Nexus Wifi + Nexus 7 /w Skysafari Pro = SERIOUS WIN!

On my first night with it I found 40 new objects I had never seen before. From central Sydney. 40! I only spent 2 hours outside that night too.

[CJ]

This video showing a tablet mounted on a scope and using the gyro setting may be of interest. I'm going to try this myself. I have my doubts about its accuracy but, combined with a finderscope and a low mag eyepiece, I reckon it could be quite helpful. Certainly cheap if you already have a tablet!

http://www.youtube.com/watch?v=B2k_oWac-pk

[glend]

Thanks Chris, I have heard that tablet gyros and compasses are no better than a cheap device like an Astro-fix (locator) which is a non-ferrous compass and inclinemeter in a single box - which can get you close but lack the accuracy of encoders.

However, IMHO (as an old software engineer) the future of Pushto certainly seems to be headed for hand-held tablet based sky apps interfaced to the encoders via wifi or bluetooth. This negates the need for expensive dedicated purpose hardware/software systems (you fill in the blanks on who they are). Off the shelf multi-purpose tablets (Android or IOS), running low cost astronomy apps, interfaced wirelessly to the encoders is an optimal low cost package for consumers.

Anyone marketing that complete encoder/cable solutions kit which plugs into a Wifi or Bluetooth box would be well placed for the future. Unfortunately, there doesn't seem to be that sort of animal around in the market at the moment. Astro Devices Nexus seems like a good example of a wifi encoder destination box but doesn't come with the encoder bits packaged for end users (you still have to buy bits and pieces for your particular scope).

I am researching overseas suppliers of encoder equipment now, as the only local source I could find for a package suitable for my GSO wasn't willing to sell them to me unless I bought one of their hardware/software 'systems'.

[Barrykgerdes]

I can supply an old Magellan I (Meade) and two encoders (4096 bit) but I don't have any cables you will need to make them. Pick up required.

Barry

[mark3d]

It sounds like you are using the Cloudy Nights setting circles (http://www.cloudynights.com/ubbarchive/showflat.php/Cat/0/Number/937949/page/0/view/collapsed/sb/5/o/all/fpart/1) method of using a Wixey (digital) angle gauge for the Alt, and printed degree circles for Az.

In case you aren't aware, note there are two versions of the Az disc - one goes on the base plate, and requires you to align the scope itself to a known objects. The other version of the Az disc (counter-clockwise I believe, but you might want to check that), which I use, goes on the top plate, and instead of aligning the whole scope, the (movable) pointer can simply be aligned to the correct degree on the Az disc, based on the coordinates of a known object.

So, I can plonk the scope down in any orientation, point at a known object - fine-tune the orientation of the Wixey, and move my pointer on the base plate, so that my scope reflects the actual coordinates of the known object. Currently, the pointer is made from Lego (you can see I am going all-out on professional equipment here) and I just jam it between the base and the ground. I am going to make a better version which uses a red LED for the pointer. It's really easy when you just move the pointer.

SkEye is not perfect but it's bloody amazing really and I appreciate it. I would, however, pay for a specialised app that simply just provides a lookup for objects and then gives the Alt/Az coordinates, without the other stuff that SkEye does. Also, some info about the object would be fantastic... feel free to develop one, I'll buy it ;)

[glend]

Yes, I presently have a printed/laminated azimuth circle on the ground board with a pointer on the rotating base. It's setup to north obviously, and I do use a digitial inclinometer on the tube to get my Alt angle. This works ok, but I find I have to bend down to see the azi numbers and increments when setting that, and the inclinometer can only be seen from the side (has a magnetic base so sits on top of the tube.

I have found a US DIgital Alt encoder that looks good for my application as it does not require any complicated ALt trunnion modification - it simply mounts on the tube.

http://www.usdigital.com/products/inclinometers/incremental/t5

[mark3d]

Yes looking side-on to the angle gauge is not great, and it's not illuminated, I might shine a very dull red LED on to that somehow too.

[Hzadbhat]

I've built a cradle to hold a tablet which in turn attaches to the top ssection of my collapsable.
I use the free version of skeye.
But, i have a top of the line Samsung tablet with all the bells and whistles.
Therefore, the screen image settles quite quick.
If you use a cheap tablet, face north, hold your tablet in front of you at arms length and do 2 figure eights with as much rotation as your arms allow. Then repeat for east, south and west. Finally, do the same pointing straight up.
Then aim your tablet somewhere you know, the crux is easiest for most.
Once the image stops moving, start viewing, but SLOWLY.
Cheap tablets have cheap insides and if you move it too quick, it takes forever to align.
Try practicing this over a few times and you'll see what i mean.
The other option is take out a second mortgage and just buy top of the line gear. I can't do this myself, and thank the stars my job requires me to have the best technology available and is all supplied.
With good quality, you can also have a side screen which after calibration also details alt and az.

[Steve-hobart]

What sort of cradle attachment did you build? I have a nexus 7 tablet I could use but I would need to attach it somehow to the dob and then I was wondering whether the metal in the dob would throw out the magnetic sensor in the tablet.