Wixey gauge

[BeerMe]

Anyone ever used one of these before? 

I have one coming my way with a 250px I'm buying from off here, and I was wondering how you would zero the gauge in order to use it? 

At a guess, I'd have thought that you needed to identify an object through the scope that is crossing the Celestial equator, then zero the gauge?  Or do I have a flawed understanding of how they work? 

[Star Struck]

You simply zero it on a horizontal surface you know to be level. i do mine on a window ledge. a wixey is not an astronomical tool. it should come with instructions.

very useful tool, i use mine with reflectors and refractors.

[acey]

The Wixey is an inclinometer - it measures angles with respect to horizontal. So you can use it to measure the angle of a target above the horizon (i.e. altitude). That is completely different from its declination. What you suggest would give declination only for targets on the meridian. To use the  Wixey as a "goto" you also need a way to measure the azimuth of the target, then use an app to convert altitude-azimuth to declination-RA.

Otherwise use the Wixey (with telescope) as a sextant - i.e. measure stellar altitudes. Or in place of as a spirit level when putting up shelves.

[Cosmic Geoff]

I bought a Wixey gauge to help find objects with my 203mm Newtonian. I zeroed the Wixey on a kitchen worktop. TBH I found the exercise a bit of a disappointment, as while I could set altitude accurately enough to find objects at low power it did not help much overall. Definitely no substitute for GoTo or electronic setting circles. I ended up buying an expensive GoTo scope of the same aperture.

[BeerMe]

I don't understand why you would zero it on a horizontal surface to be honest (although this is where my understanding may be flawed...).

I thought the altitude bearing for an object was how many degrees above the celestial equator that object is?  Since the celestial equator is not horizontal from my position at 54°N but rather around 36° above the horizon, surely I need to zero it at the ~36° mark if I want to use the altitude reading of an object to locate it?

[BeerMe]

2 hours ago, acey said:

The Wixey is an inclinometer - it measures angles with respect to horizontal. So you can use it to measure the angle of a target above the horizon (i.e. altitude). That is completely different from its declination. What you suggest would give declination only for targets on the meridian. To use the  Wixey as a "goto" you also need a way to measure the azimuth of the target, then use an app to convert altitude-azimuth to declination-RA.

Otherwise use the Wixey (with telescope) as a sextant - i.e. measure stellar altitudes. Or in place of as a spirit level when putting up shelves.

I was referring only to the altitude of an object, declination is something completely different and beyond my comprehension to be honest. 

As I said above, surely I need to take in to account the angle of the celestial equator from my horizon.  If a celestial object is showing 1° alt and I'm at 56° (not 54 as I said earlier sorry), then from my perspective I need to position the altitude of my scope at 34° + 1° from level to be at the same altitude as the object?

[BeerMe]

3 hours ago, Star Struck said:

[....]a wixey is not an astronomical tool. [...]

very useful tool, i use mine with reflectors and refractors.

To do what exactly, if not in an astronomical sense?  I've read a few blogs this morning that swear by the Wixey as a great astronomical aid, used with setting circles it basically allows your scope to become a PushTo. 

[Cosmic Geoff]

7 minutes ago, BeerMe said:

 I've read a few blogs this morning that swear by the Wixey as a great astronomical aid, used with setting circles it basically allows your scope to become a PushTo. 

They may say that, but I tried using the Wixey for that purpose on a mount with setting circles and it was pretty much a waste of time.  Setting circles on equatorial mounts are also a waste of time unless they are the size of dinner plates, which the circles on amateur-sized mounts sold today aren't.  GoTo and digital setting circles (no cheaper than GoTo ) are the superior modern solutions.

The reason you have to zero the Wixey is hard to explain concisely, but it's a common feature of electronic instruments that they need to be zeroed or calibrated somehow before use.

[BeerMe]

28 minutes ago, Cosmic Geoff said:

They may say that, but I tried using the Wixey for that purpose on a mount with setting circles and it was pretty much a waste of time.  Setting circles on equatorial mounts are also a waste of time unless they are the size of dinner plates, which the circles on amateur-sized mounts sold today aren't.  GoTo and digital setting circles (no cheaper than GoTo ) are the superior modern solutions.

The reason you have to zero the Wixey is hard to explain concisely, but it's a common feature of electronic instruments that they need to be zeroed or calibrated somehow before use.

It doesn't have to be sitting level to be zeroed surely?  This is the point I'm trying to make...my scope sitting horizontal will actually be pointing at objects 34° below the celestial equator, but if I zero the gauge on a level surface then I will need to raise the scope til the gauge reads 35° in order to be at the same altitude as an object whose current location is given as 1° alt.

Surely it would be easier for me to zero the gauge when my scope is pointed at the celestial equator?  Future readings then wouldn't need me to do calculations for every object of x + 34°?  How did you calculate the angle that the scope should be pointed at, using the gauge? 

[acey]

1 hour ago, BeerMe said:

I was referring only to the altitude of an object, declination is something completely different and beyond my comprehension to be honest. 

As I said above, surely I need to take in to account the angle of the celestial equator from my horizon.  If a celestial object is showing 1° alt and I'm at 56° (not 54 as I said earlier sorry), then from my perspective I need to position the altitude of my scope at 34° + 1° from level to be at the same altitude as the object?

What you are saying would make sense if the celestial equator was a circle running parallel to your horizon right round the sky (at an altitude, let's say, of 56 degrees). But it isn't. If you look south then the equator is 56 degrees above horizon This is declination zero. Turn and look north and the thing you'll see 56 degrees above horizon is Polaris, which has a declination of 90 degrees. The Wixey tells you the altitude of things above horizontal. The celestial equator is tilted with respect to the horizon.

Declination and Right Ascension are fixed co-ordinates on the celestial sphere that "rotates" around us, carrying the "fixed" stars. Altitude and azimuth are the positions of ("moving") stars in the sky, with respect to the horizon and the meridian (the north-south line). If some app tells you the alt and az co-ordinates for an object at your location and time, you could use the Wixey to tilt your scope to the relevant altitude, and a home-made gauge on your dobsonian (or other alt-az) could be used to turn the mount the appropriate amount in azimuth. If everything is accurate and you do it quickly enough (before the target "moves") you'll get where you want. I know of some people who've tried this sort of approach, perhaps someone will comment on its effectiveness. I got a Wixey for fun a few years ago because they're cheap. I've never used it for astronomy (and prefer a spirit level for shelves). I star-hop with a good map.

As to zero-ing the Wixey, putting it on a known horizontal surface and checking the reading is a good idea. I can't remember but presumably it can be manually zeroed if necessary.

Hope this all helps. Once you've got the thing and tried using it you'll quickly figure it all out, and understand why it has little real usefulness in astronomy. A sextant or a protractor stuck to the side of the alt-az mount would do the same job.

[BeerMe]

4 minutes ago, acey said:

What you are saying would make sense if the celestial equator was a circle running parallel to your horizon right round the sky (at an altitude, let's say, of 56 degrees). But it isn't. If you look south then the equator is 56 degrees above horizon This is declination zero. Turn and look north and the thing you'll see 56 degrees above horizon is Polaris, which has a declination of 90 degrees. The Wixey tells you the altitude of things above horizontal. The celestial equator is tilted with respect to the horizon.

Declination and Right Ascension are fixed co-ordinates on the celestial sphere that "rotates" around us, carrying the "fixed" stars. Altitude and azimuth are the positions of ("moving") stars in the sky, with respect to the horizon and the meridian (the north-south line). If some app tells you the alt and az co-ordinates for an object at your location and time, you could use the Wixey to tilt your scope to the relevant altitude, and a home-made gauge on your dobsonian (or other alt-az) could be used to turn the mount the appropriate amount in azimuth. If everything is accurate and you do it quickly enough (before the target "moves") you'll get where you want. I know of some people who've tried this sort of approach, perhaps someone will comment on its effectiveness. I got a Wixey for fun a few years ago because they're cheap. I've never used it for astronomy (and prefer a spirit level for shelves).

As to zero-ing it, putting it on a known horizontal surface and checking the reading is a good idea. I can't remeber but presumably it can be manually zeroed if necessary. Hope this all helps. Once you've got the thing and tried using it you'll quickly figure it all out.

 

Yes, of course, that's exactly where my flawed understanding comes in!!  So I'd have to do a manual calculation of the angle of each object from the horizontal and then use the Wixey to get me that angle?  So my next question would be... how do I calculate that angle from the alt information for an object that I get from an app?

Thanks for that detailed explanation above by the way :-)

[acey]

3 minutes ago, BeerMe said:

So my next question would be... how do I calculate that angle from the alt information for an object that I get from an app?

 

http://www.convertalot.com/celestial_horizon_co-ordinates_calculator.html

http://star-www.st-and.ac.uk/~fv/webnotes/chapter7.htm

[Peter Drew]

What you can do with a Wixey or perhaps better still a decent size Declination circle, is to set an alt-azimuth telescope accurately due South, lock the azimuth axis and then wait for an object of known declination to enter the field of view. Once it centres set the declination to its known angle. From that time each object that is rising from the East will pass through the field of view as it crosses the central meridian provided that you raise or lower the telescope to the objects declination. You can plan ahead for the objects you wish to see in order of Right Ascension. You will only view the object for as long as it takes to cross the field of view but if it is of sufficient interest to move the telescope to follow it you just subsequently perform the original setup procedure.  

[BeerMe]

5 minutes ago, acey said:

http://www.convertalot.com/celestial_horizon_co-ordinates_calculator.html

http://star-www.st-and.ac.uk/~fv/webnotes/chapter7.htm

Thank you, for both the information AND patience ;-)

[BeerMe]

54 minutes ago, acey said:

http://www.convertalot.com/celestial_horizon_co-ordinates_calculator.html

http://star-www.st-and.ac.uk/~fv/webnotes/chapter7.htm

On convertalot, I've put in the following information for when Jupiter is crossing the meridian due South tonight, but it's giving me an error for the observers input fields...can you tell me how I should be inputting the info?

Edit: found the error and got it working thanks acey :-)

 

[LukeSkywatcher]

I bought a Wixey a few yrs ago with the intention of using it with my Dob to find the elevation of objects i wanted to find. All it has done for me is to prove to me that there is no level surface in my house.

[astronymonkey]

I Use a wixey and a rotary encoder as the push to system on my 16 inch dob and have never had any problems. There are some basic things to get right though ie as long as you have an alt az mount as with an eq mount it will get difficult. With an alt /az mount imagine your scope as a big cannon, with an up/down and left/right and the wixey will deal with the up/down bit as this is the Alt reading that you mention ...... completely different to declination , which with a wixey you dont need to worry about.

FIrst off , download a bubble level app and use this to get the base level ... try to get within 0.2 degrees of level , and I manage to do this 75% of the time.

Next , amd THIS IS THE MOST IMPORTANT BIT ake sure your chosen app has an accurate location for you and an accurate time.... even a small difference here has a big impact.

Next , pick a known star and check its alt from your app and get it in the centre of the fov and zero the wixey .... then lower the tube in alt until it reads the same alt as the object , but with a minus figure, then zero again.... you will then be dead level. So as an example, find polaris, zero the wixey, then lower the tube to read -56degrees and zero again .... this is your artificial horizon.

Now go hunting, choose an object and point within the rough direction as best you can, now find the current alt of the object and raise the scope until the reading is the same as the target abject then sweep left and right til you hit the object. This is easier when the object is to the south as it is not rising or settimg so the alt angle isnt changing very quicky,

SO, tHe concept is simple and accurate, if an object is 35degrees above the horizon and your levelled scope is pointing towrads the sky at a 35degree angle, as long as it is in the right direction then you will see the object. Using a low powered eyepiece will help iron out any minor inaccuracies though.

Cheers

 

 

[Stub Mandrel]

Wixey will work fine as part of an Alt-Az setup.

[BeerMe]

@astronymonkey do you use the website linked above, using the RA and DEC of an object to get the altitude above the horizon for it? 

I use SkEye, but as far as I know that only shows the altitude above the celestial equator? 

[Bart]

I also have a 16" Dob and use Astrononkeys methodology exactly. It is surprisingly accurate, most of the time....

I'd be lost without it. 

[Bart]

3 hours ago, BeerMe said:

@astronymonkey do you use the website linked above, using the RA and DEC of an object to get the altitude above the horizon for it? 

I use SkEye, but as far as I know that only shows the altitude above the celestial equator? 

Try SkySafari, it's excellent. Go for the plus version, or pro if you're flush. 

[dobbie]

I've used astromonky 's method for years using a alt/az mount +low power ep, still do. And I've  beaten  goto mounts on quite a few occasions down at the astro club . John. 

[Gazabone]

I use this occasionally and it works really well. With regard to zeroing it, yes, it must be zeroed on a level surface; altaz coordinates work from degrees above (or below) the horizon. 

If using a Dob, you can add an azimuth circle in the base;

http://www.skyatnightmagazine.com/feature/how-guide/how-make-azimuth-setting-circle

 

you will need to use a program like Stellarium to get the coordinates of the object you're looking for AT THE TIME YOURE LOOKING FOR IT, unlike celestial coordinates, altaz coordinates change as objects move across the sky.  You'll need to calibrate the azimuth setting circle before looking for your target object.  

Happy viewing. 

[BeerMe]

3 hours ago, Bart said:

Try SkySafari, it's excellent. Go for the plus version, or pro if you're flush. 

Does SkySafari show the altitude of an object above the horizon?  I really like SkEye, but if any app added a functionality to allow you to see the altitude above the horizon, I'd switch to it :-)

[Stu]

3 minutes ago, BeerMe said:

Does SkySafari show the altitude of an object above the horizon?  I really like SkEye, but if any app added a functionality to allow you to see the altitude above the horizon, I'd switch to it :-)

Yes it does. Just search for the object and show its information page and all you need is there. Otherwise centre the object (press the centre button with the object selected) and the altitude and azimuth will show at the top.