10" dob, stepper motor for focus and movement

[netwolf]

Here is a program i was looking at before on sourceforge. For a Three axis mount. Alt Alt Az.
http://threeaxis.sourceforge.net/simulator.html

Tracy Wilson has website has more information on what the above program is being wriiten for. He has two systems one is a Thre axis platform that adresses field rotation and the other is a Three axis mount.
http://www.c2optical.com/

[netwolf]

Dave,

One other problem with PC controll is that windows is not really a RTOS, so will you be using a dedicated box to do Siderail tacking etc.

[davidpretorius]

RTOS = real timeoperating system i assume????

for siderial time, i intend to get the program to access the internet, grab the gmt, add the users + 10 UMT and then use it work with siderial time.

for guys that may not have internet access, i would think that you get them to check their clock at beginnning of the night, adjust if neccessary and then i can't see the windows clock being a long way out.

[davidpretorius]

nice find on those simulators by the way. i have the maths 50% of the way their in terms of co-ordinate systems, but had not coded it yet. this will help!


thanks

[asimov (John)]

Hey Dave?? Guess what?? IT WORKS IT WORKSSS!!!! AAAHHaaAAaaaAAAAAaaaaa!!!!




The DRIVE!!! THE DRIVE!! 2 ****** years....total cost FREEE! woop woop!!!!!!!!!!!!!!!!!!!!!!! it clunks away like an olg grandfather clock, but who gives a RATSS! what a relief!

Can you tell I'm slightly happy, or what!??

[davidpretorius]

so she tracks smoothly thru the scope???

i am very happy for you!

well done

[asimov (John)]

when I first hooked it up (at it's lowest speed) which is about one step per second, thru the EP there was a definite 'back & forth' motion of jupiter seen. I thought 'oh heck! it doesn't work!!' Then I realized it was tracking too slow, so I spent time getting it tracking at the perfect rate...another look thru the EP & no detectable movement of the object (jupiter) even at 212X! I dare say still no good for astrophotos...but hey! When I set out to do this, it was only for visual use really. I just wanted to keep the object in view for a few minutes.

This is a dream come true. A few bugs to be ironed out, that'a all...It WORKS!! thats the main thing! If I could perhaps half-step this setup, it might be ok for photography, but only short time exposures at a guess..

[Starkler (Geoff)]

In the design of eq platforms, I have read that its desireable to keep steps to 1 arc second maximum to avoid seeing the steps at the eyepiece.

This translates to a minimum of 15 steps per second whilst tracking at the right rate.
It sounds like you some need extra gearing.

[davidpretorius]

let me know i i can do anything in regards to sorting out the mechanics of the steppers.

i would love you to spend another $79 and buy the Williams Optics adapter and then you and your camera will be splitting all the double stars and imaging!!!

woo hoo,

it is exciting!!!!

[netwolf]

Asimov, great news congrats.

Dave, by RTOS i mean real time response from the connected device to commands you send. Given the nature of Windows and access to drivers, I would think this would affect response times. I belive this is why Mel has his scope.exe run from a MS-DOS system.


I would think it would best to have the siderail tracking outside the computer control. I belive this is how it is doen on most EQ Mounts, there is a motor control circuit with a simple handpad to which you can add a Autostar like handpad for goto information. The motor control circuit maintains the siderail tracking.

[asimov (John)]

Sorry Geoff, I can't see 2 steps per sec. at the eyepiece at 212X..? My eyes are'nt that bad either. I've also read that, but I've just busted that myth!? and I'm not sure how or why!

I'm one happy chappy!!

I just GOTTA thank all you guys on here that helped with advise etc! Namely Laurie for the controller plan. Raff at AOE for building the controller. a 1980 something electronic typewriter for the stepper. My wife for putting up with my foul moods when the last 1/2 dozen designs failed. And you Davo for being just as chuffed at my success as I am!!

[netwolf]

Dave,

Microstepping for about US $18, 1/2 step and 1/8 step.
http://www.thsengineering.com/products/products.html

It uses the new A3977 IC designed for microstepping.
http://powerelectronics.com/mag/powe...g_motor_drive/

Wow. I just joined Scope-drive talk about information overload..

PS: above chip is available from PartsVault in NSW, I have requested a price on there website. A3977SED as used in circuit above. Note I am geting pricing for 4 but maybe cheaper to buy in bulk.

[davidpretorius]

the grumpy old man of the forum is now the excited teenager about to have initmate relations for the first time!!!

yippee!

i was about to say where are the photos, but as you said to me, just enjoy looking!

[davidpretorius]

thanks for the links netwolf.

i have finally after talking with the maker of the usb stepper motor controller, got it linking into my .net program. I will now go about working out full step, half step and fingers crossed, micro steps.

[asimov (John)]

Well, at least we can work out why I've been grumpy for the last 2 years..

I've already got plenty of pics thru that scope Dave. Mainly of objects not needing tracking, of course. And even one of the orion nebula. The camera is where I need to up-grade now. (The drive would not take to photography the way it is anyway) I've taken the kodak to it's limits & beyond. (max. time exposure, 4 secs)

[netwolf]

Dave,

I am not sure if you have already joined scope-drive yahoo groups or not. But they have an excelent maths doco about ra/dec to alt/az coversion
http://groups.yahoo.com/group/scope-...files/Math%20/

[davidpretorius]

i better go and join!!

thanks mate

[davidpretorius]

i have joined yahoo..... so yahoo!!

[davidpretorius]

how do you join scope drive, do i need to be invited?

[netwolf]

no, you need a yahoo mail acount. Click join this group. It will ask you for you to sign in. Use your yahoo email to sign in and then select your signup options for the group. I usualy opt for no email, this way my yahoo inbox is not clutered with emails from the group.

I found the same doco on the following url by Keith Burnett
http://bodmas.org/kepler/altaz.html
This is his main page, he has a few coding examples to for various things.
http://bodmas.org/kepler/index.html#top