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  #1  
Old 15-06-2009, 07:09 PM
Maplesyrup (Josh)
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How Do you find objecst with Altazi?

With Altazimath mounts, is there an accurate finding of objects? Like with a equatorial mount you can use declinations and such, what do you do to find objects you cannot see?
Also can they track?
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  #2  
Old 15-06-2009, 08:11 PM
Maplesyrup (Josh)
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am I being an idiot?
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  #3  
Old 15-06-2009, 08:21 PM
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duncan
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Hi,
No you are not. Sometimes it takes a while for people to find and reply to a post. As for me i'm new at this as well so can't really help
Cheers
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  #4  
Old 15-06-2009, 08:27 PM
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jjjnettie (Jeanette)
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I've got 2 Alt Azi mounts, both are goto. So when I want to find something, I just press a few buttons on the controller, and it goes to it. Yes, they both track too.
I have the iOptron Cube and the iOptron Mini Tower.

Last edited by jjjnettie; 15-06-2009 at 08:51 PM.
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  #5  
Old 15-06-2009, 08:30 PM
Wavytone
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I use starhopping on my altaz mount - from a map. I have the Orion SkyView and for casual observing at low to medium power its fine. As for a map I use StarMap Pro on my iPhone, or Sky Atlas.

Some mounts - "push to" - have digital setting circles (Argo Navis or Sky Commander, you decide what you want to look at and the controller tells you which way to go to get there - you push the scope.

And yes there are "goto" altaz mounts like the iOptron Cube and the latest one-arm fork Celestron has with a C6 on it; Skywatcher is also selling a small one arm fork with a 90mm Maksutov on it (rather small).

Most of these require calibration using the two star method to achieve accurate "goto"s.

Personally I think it is worth taking the effort to star-hop from a map for two reasons:

a) you will learn your way round the constellations. I am constantly disappointed by people who are so used to goto scopes they have no idea where anything us, or what else is nearby.

b) using a map you can see what else is nearby at a glance. Worth knowing IMHO.
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  #6  
Old 15-06-2009, 08:34 PM
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Robh (Rob)
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Josh,

I have a Dob which is basically altazimuth. I find everything by using maps and star hopping but you need a decent finderscope, say 8x50 (cost about $100). I know some people use an Argo Navis but I think that will cost you around $1000.

Regards, Rob
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  #7  
Old 15-06-2009, 08:54 PM
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jjjnettie (Jeanette)
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Let me add that I did my apprenticeship on a 60mm refractor then a 10" dob before going to go to.
Star hopping is the only way you'll learn the night sky.
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  #8  
Old 15-06-2009, 08:59 PM
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dannat (Daniel)
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O mostly use medium big binos, which are on goos sturdy tripods, and i also use star maps but i would not call it star hopping but the geographic method.

What i do is find a really bright star or constellation marker which i can easily see with the naked eye. With the binos (or good finder - like 8x50, not a crappy 6x30 which is hard to see with).
I then look at the star map to work out how far need to go in degrees up/down and left/right. I use the fov of my findee to move ie if i'm fifteen dgrees away i accurately move across three finder diameters..
i have found it easier than satr hopping, as when i look i see heaps of stars and gt lost on which star i should be looking at.
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  #9  
Old 15-06-2009, 09:55 PM
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JethroB76 (Jeff)
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Many with alt/az newts use manual setting circles very successfully. Such systems need a lappy or PDA to provide up to date coords for your chosen objects...
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  #10  
Old 16-06-2009, 07:36 PM
Maplesyrup (Josh)
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ok so there is a way of measuring degrees and such of constellation/guide stars. Great thanks for all your help!
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  #11  
Old 16-06-2009, 09:41 PM
astro_nutt
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Hi Josh!!
Ahh!!!...no...you're not an idiot..but as with most of us we learned using a planishpere or starmap and by using the bright...or key stars in the colstellations..then it's a case of trial and error..sweeping the sky through the eyepiece until....having setting circles on your scope and using one of the many software/freeware which can give you the altazi co-ordinates on the night you wish to view..and if you have a laptop..even better!!
At the moment I'm finishing a experimental converter from R.A. Dec to altaz..(fingers crossed!!)
Cheers!
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  #12  
Old 16-06-2009, 11:53 PM
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JethroB76 (Jeff)
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What type of scope do you have?

This is the style of system I mentioned, shown here on a dob

http://www.iceinspace.com.au/63-434-0-0-1-0.html
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  #13  
Old 17-06-2009, 12:04 PM
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erick (Eric)
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Try starhopping, Josh.

M104 is a good star-hopping target - come on, you can do it!

http://www.iceinspace.com.au/forum/s...ad.php?t=21935
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  #14  
Old 18-06-2009, 01:50 PM
Barrykgerdes
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Hi

Finding objects from the Alt/Azm co-ords is not an easy task because they are continually changing. However with a bit of practice and a conversion RA/Dec to Alt/Azm bearings program it can be done. I did this with my Dobsonian mounted telescope when I first got it

The first thing to do is get accurate scales for the Alt and Azimuth axes. I did this by making these circles in AutoCad and printing them out in as large a scale as I could paste on the associated surfaces.

The Altitude was calibrated by leveling the base and pointing the OTA vertical using a spirit level. A pointer to 90 degrees on the scale was placed on the stationary surface so that I could read off altitude.

The azimuth was calibrated by first locating an object on the horizon at true north by using trigonometry and a compass. The OTA was then swung down and the base moved so that the north object was centered in the eyepiece. I then fixed a pointer to the rotating box that pointed to 0 degrees azimuth.

All the above was done to get the telescope into a position where the true alt/azm could be read out.

From there I used a program I wrote in Basic that converted RA /Dec into Alt/Azm. Most planetarium programs these days will do the same by reading out both RA/Dec and Alt/Azm for the current date/time and location.

Using a wide-angle eyepiece that will give you about a 1 degree FOV you should be able to find most of the well known objects by pointing the OTA to the instantaneous Alt/Azm positions as read off from the computer.

Below are a couple of photos of how I made these scales for my 16” lightbridge

Barry
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  #15  
Old 20-06-2009, 05:00 PM
Maplesyrup (Josh)
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Great thanx alot everyone, now ive just gotta save some pocket money to get a scope.
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