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Sky Safari + Android for "push to like" assist?

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#1 StarCurious

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Posted 24 December 2012 - 10:36 PM

I am a complete newbie researching into my first telescope purchase. I purchased Sky Safari Plus Android to learn the sky and discovered that after selecting an object, pressing the Compass button, then Center button, Sky Safari Plus displays an arrow towards the target. This seems to work even when the field is smaller than 1 degree. Has anyone tried to mount a tablet (or smartphone) on a telescope, and use this feature to guide which direction to push - especially for a Dobsonian telescope? I have checked all boxes under Settings, Display (including Telrad). Thanks in advance

#2 Lane

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Posted 24 December 2012 - 11:31 PM

That will work on both Goto and Pushto mounts. It does require the skyfi wifi unit be connected to you hand controller and you will connect your tablet to that wifi. Make sure the RA/DEC are the same values in Sky Safari and your mount's hand controller and remember that you still have to do the initial alignment with you hand controller. After that you can just move the scope and watch the cross hairs in sky safari to find objects.

#3 StarCurious

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Posted 24 December 2012 - 11:55 PM

Thanks, Lane. I am sorry I did not ask the question properly.

What I really meant was if I don't have pushto or goto telescope, can I rely on the Pointer Display for guidance to manually push my OTA towards a target - assuming I have a tablet mounted firmly and aligned with the OTA.

I haven't bought my first telescope yet. It seems to me I don't need Azimuth, Altitude setting circles (nor RA, DEC for equatorial) at all since the only axis that matters ultimately is the OTA itself, pointing at the object.

What surprised me was when I held a 10 inch tablet with the elbow on a desk (with no telescope), I was able to control the tablet "axis" to the point that even within 1 degree FOV I was able to "merge" the object into the cross hairs of the Telrad view in Sky Safari Plus on the tablet. I am hoping this is "good enough" pushto without the computers and sensors on the mount.

#4 Lane

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Posted 25 December 2012 - 02:47 AM

Actually the iPad and sky safari are very good for finding things. Though i rarely use them as you describe. That method would let you find the general location for pointing the scope, but afterwards you would want to flip the view on the iPad to match the view in your eyepiece. Then you would star hop until you find the object.

Once you learn the constellations pretty good you would be able to skip the first step because getting your scope pointed roughly at an object is really pretty easy. You just find the location in sky safari of the object you want to view and note its relative position to some stars in a constellation, then you find the constellation and those stars in the sky. It is really easy once you learn the constellations.

The real problem is that some things are so faint they could be dead center of the eyepiece and still be overlooked. This is where using sky safari really comes in handy, because you can zoom in and work with more stars than you would have available in a paper atlas. When you match up the stars in the eyepiece with the ones in sky safari you can be certain the object is there. Then you can use adverted vision to try and see that object, or say with certainty that it was not visible on that night.

#5 StarCurious

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Posted 25 December 2012 - 01:06 PM

Lane,

Thanks for the insight and the tips.

#6 btschumy

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Posted 25 December 2012 - 06:20 PM

Curious,

The compass is not really accurate enough to replace digital setting circles. I find that I'm doing pretty good if I the compass is within 5 to 10 degree of actual.

The gyroscope is more accurate and in theory you can center a star in the scope and on the device and turn the gyro on. Then as you push the scope around, the display will show you where you are pointing. The problem is the gyro does drift over time so it loses its accuracy. We have hopes of eventually trying to correct for this to turn your device into digital setting circles. Just got to find the time to work one it,

#7 StarCurious

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Posted 25 December 2012 - 07:10 PM

btschumy,

Thanks, that's encouraging to hear.

#8 Sean Wood

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Posted 26 December 2012 - 08:09 AM

Sounds like what you are trying to do is an actual feature in the app Skeye. It has the ability to offset your devices magnometer and accelerameter to give you virtual "push to" functionality. There's both a free, it's fairly basic really no better than Google Sky Map, and pro version, full NGC catalog and and a filtering system to limit what's shown. If you've got a metal tube dob though I HIGHLY recommend having your tube demagnetized or it will interfere with the sensors on your device. It's not highly accurate but will get you fairly close. I find it best to do a star alignment within the constellation you're trying to find an object in before actually trying to find it. Decent results can be achieved if you're patient and willing to read and figure out the app settings and the adjustments you can make within the app to the sensor inputs. There's a manual and mounting ideas on the developers website, you can get there via the link on the app in the Play Store.

#9 StarCurious

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Posted 26 December 2012 - 03:58 PM

Thanks for the tip, Sean. I have the original ASUS 10-inch Transformer tablet. I already bought Sky Safari Plus but will look into Skeye. I found this user review via Google:

http://www.astronomy...let-phone-pu...

I am trying to decide whether to buy a pushto scope such as the Orion 8i, but I am hesitant, having read a few bad user experiences on CN with such headaches as warped rocker base that makes the Intelliscope feature inaccurate, as well as cold weather problems with the hand controller. This suggests to me that the quality control is not consistent, and since I am from Canada I would have more difficulty with returns and warranty issues. This is not a knock against Orion but my acceptance that it would be difficult to maintain flatness of a rocker base made out of wood.

Question: how would you demagnetize the OTA? Is there a mass produced Dob OTA not made of steel (e.g. aluminum)?

#10 Sean Wood

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Posted 26 December 2012 - 04:49 PM

Have you looked at the Bluetooth Push to option that Hubble Optics released here in the last couple weeks. It has the transmitting module, wiring and the encoders for $249, I don't really know how that stacks up cost wise to other similar products. I know they say it works with Sky Safari. It's designed for their Ultra light telescopes but if you're handy at all it doesn't seem as if it would be that difficult adapt the design.

http://www.hubbleopt...com/skyhub.html

#11 StarCurious

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Posted 26 December 2012 - 11:24 PM

No. I am not handy at all and wouldn't attempt to modify the rocker/base.

I think between Skeye and Skysafari Plus, I will wait for the tablet based push to solution to guide the scope well enough.

#12 Sean Wood

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Posted 29 December 2012 - 01:05 AM

Sorry just noticed your comment on the demagnetizing. I work in a tool and die shop so for me it was easy I just took the upper cage of my light bridge to work and passed it over our industrial demagnetizer it took like 15 seconds. Ha ha ha. It's pretty much a large AC electro-magnet. The alternating wave form rapidly changes from N to S and that's what demagnatizes the steel. I've found handheld old style bulk tape erasers on ebay for around $30 or so that would most likely do the job nicely if you can't find a machine/tool and die shop that doesn't have a de-mager or just plain isn't willing to help out.

The process is easy just pass the metal through the field going in the direction of the objects longest axis. If you use the handheld unit put a towel on your tube and run the unit the length of the tube making sure to go completely off each end and rotate the tube around till you go over the entire thing. It may take multiple passes around the tube depending on how strong the bulk tape eraser is. Make sure not to turn the handheld unit off in the middle of the metal as this will just magnetize the metal further. You may have to take breaks if the handheld unit over heats, and it will generate heat,it could fry the coil inside of it. If you can't touch it or you can smell it getting hot its prob best to let it cool down.

Edit: You'll want to be sure to remove all electronics from the tube prior to attempting this as the electromagnet could fry them.

#13 Ham Radio

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Posted 29 December 2012 - 09:36 AM

I have been reading this with interest and am wondering if there is a device I can attach to my 70's vintage C-8 that will let me use my Android tablet as a "virtual" setting circles? It doesn't have any kind of controller or such. I would like something that when I move the scope, it shows where it is pointing in Skeye or Ski Safari.

I do know that you can use Skeye along these lines, but it requires the tablet to be attached to the scope which is a little impractical on the C-8 unless someone can give me some ideas.

#14 fmhill

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Posted 29 December 2012 - 10:18 AM

QRZ de K1FH K

You ask an interesting question. This is a subject I have investigated and I fear the cost of adding encoders and control module for connection to a computerized device of any type will be higher than simply purchasing a new (or used) Go-To computerized mount such as the Celestron CG-5 or CGEM which will have the means (a serial port and encoders built in) to plug and play with any computer/tablet etc.

However, an online source you can check for a digital readout kit is http://www.jmitelesc...com/buy_ngc.htm (JMI)...

There are a number of places that sell parts and kits for adapting older mounts if you do a search online for Telescope mount digital readout encoders.

An interesting article with good information is here:
http://www.bogan.ca/...s/digtcrcl.html

Ultimately, after researching the subject of adapting my old mount, I ended up purchasing a new Go-To mount for about the same it would cost to adapt my old one. Since that point in time, my collection of gear has grown to include a Celestron GGEM DX, a Celestron CG-5 ASGT, and a Losmandy G11/Gemini II. The CG-5 is my grab and go for portable use, the CGEM DX is my mainstay for serious imaging, and the G11 I am just starting testing and evaluation following a major overhaul after 4 years of use... All three of these mounts I use via control from a laptop via serial ports with the exception of the G11 which has a built in TCPIP Ethernet port for mount control and go-to positioning via Stellarium planetarium software.

No more cold nights outdoors for me, I run my imaging from a Desktop PC while enjoying the warmth and comfort of being indoors...

73

Mitch...

#15 Ham Radio

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Posted 29 December 2012 - 10:27 AM

I don't need the tablet to control the scope, just to know where it is pointing. I am wondering if something like the skyfi wifi that just sends pointing data to the tablet so you can see where it is pointing.

#16 fmhill

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Posted 29 December 2012 - 10:49 AM

Before your mount can interface with any electronic device, it must have the means to electronically measure its position and have some type of electronics communications port to talk to a terminal device such as a tablet, Iphone, or laptop.

In this day and age of electronics devices with this type of capability, the manufacturers package as much functionality to increase marketability. You end up paying for the whole package whether you want it or not.

Therefore you will pay about the same for a digital readout kit as you will for a new mount with all the capability built in.

#17 Sean Wood

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Posted 29 December 2012 - 11:31 AM

Check out the link to the Hubble Bluetooth DSC's I listed earlier. They feed back in to an Android device and update the screen on SkySafari. depending on your set up they might be an option. The current config is for as Alt/Az set up. Maybe they can be configured for GEM if need be.

Also check out the SkEye website. Users have posted pics and ideas for mountings in the "Documentation" section. The manual/users guide is there also. There's some good info there.
http://lavadip.com/skeye/
My concern with using SkEye on an older scope like the older C-8 would be what metals the scope tube and or mount are made of. If steel or cast iron they would most likely interfere with your sensors so badly that accuracy would be squat.

#18 StarCurious

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Posted 29 December 2012 - 05:57 PM

Ham Radio,

I just bought Skeye Pro for $9 to support their development. You don't need wifi or anything to communicate with encoders and such. All you need is to attach the tablet to the OTA. Then you need to find a star in your scope, and correspondingly on the tablet you need to find the same star (use the search function) and press "Align".

I am still researching through this, and Sean already posted a link to how people attach the tablet to their OTA's. What is so smart is you don't have to align the axis of the tablet to that of the OTA. One option I am considering is to buy a set of tube rings with 1/4-20 adapter on top of the ring, and mount the tablet on this gadget from Orion:

http://www.telescope...er-for-iPadT...

If you already have the 1/4 20, then you just need the Orion kit.

It would hopefully keep the tablet far enough away from the OTA for magnetic interference to be detrimental. According to the Skeye site, even with magnetic interference, aligning by more than one star would mostly mitigate it. I suspect that after some alignment, it will become accurate enough, especially if you search a rather close by bright star (and align) just before you search for your faint target.

Read through till the end of the user review via the link from my earlier post - I am encouraged.

#19 StarCurious

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Posted 29 December 2012 - 05:59 PM

Ham Radio,

If you have Android phone or tablet, there is a free version of Skeye for you to try out - near your scope.

#20 Sean Wood

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Posted 29 December 2012 - 10:36 PM

Not to get off topic but if you like using Skeye. Try Starlog it's an astronomy logging app that allows you to make viewing lists and the full version ties into Skeye to find them. You just do an initial alignment in Skeye and then go to Starlog select your list item then hit a magnifier/search icon,it opens up Skeye on the object. You then have to do a search for the object in Skeye find the object in the scope and then hit the back button and it goes back to Starlog log your entry and move on to the next item. I know it sounds complicated but its really not and once your used it it goes pretty quick. I do know these 2 developers are going to try to work together to make each others apps work better with each other.






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