On the Initialise window it also has a "Test" button, but don't use this one if you have a technical difficluty it may produce incorrect information suggesting it works fine.
Hello everyone, I am outside and testing the EK box setup and it works perfect! Every time the object is in the center of 32 mm eyepiece! After an hour an a half it was a bit out of the center. I need to find out fine tuneup with Cartes du Ciel. Things like refresh rate or something else, still learning the program cos I use Starry Night.
I will post the pics of the setup as soon as I can.
I would like to thank everyone but especially to Bojan and Simon! Bojan fixed the circuit and Simon made the circuit board for me
Thanks Malcolm as well for good instructions how to get encoder resolutions.
IT WORKS!!!
After an hour an a half it was a bit out of the center.
Hi Bob, those are good news
Discrepancies you are mentioning could be for variety of reasons, most likely one is non-orthogonality of your mount axis, or the whole thing was out of level.
If you ever go with Mel Bartels software in the future, you can compensate those imperfections - there are semiautomatic routines that will analyse your mount, calculate the necessary parameters and store them on your disk to be used next time
One thing I found there is not a lot of room underneath a 12" DOB so my direct drive is very difficult to implement on the centre axis.
I have though successfully created a direct drive from the outer DOB plate but my encoder resolution is way too high now, something in the range of 200,000 steps so it is off to get a lower res encoder. I will consider the ones purchaced recently but I am also looking at some new selectable PSR encoders so I can adjust them. It cannot be mounted directly like other encoders as it has a floppy centre axis. To resolve this I am also going to make a encoder mount making is fully mountable on most DOB's both centre axis and outer axis without major mods.
The big pulleys are made from trolley wheels I bought at Bunnings for $2.50 each. I cut the groove with grinder into the rubber wheels so the belt sits in nicely. Since its hard rubber on both pulleys the chance for belt to slip is minimal
Arrow #1 is showing the wing nut with short tube to tighten when everything lines up.
Arrow #2 showing Az wheel with groove cut in
Arrow #3 showing 2 piece of alloy plates with holes cut that way so adjustments can be made, both up and down and left and right.
Arrow #4 showing the pieces of wood I had to put under big wheel to keep the same distance between base and wheel. I put some grease in between so the friction is minimal.
I put piece of fuel hose on encoder shaft (first pic arrow showing the groove i cut). Before that I cut the groove with grinding stone while the piece was spinning on drill, so its centered as much as possible. I used the same way to cut groove into big wheels.
The belts are timing belts from old printer/scanner and are inverted (teeth out).
As you can see, its all simple and rough but it works fine, and the main thing is there is not slip errors at all
Malcolm,
I had the same problem with my dob. Not enough space between scope and base.
What would be the minimum speed of laptop I need to run Cartes du Ciel smootly. New laptop dont have serial ports. I know I could buy USB to serial adopter but can buy laptop as little as $150 bucks with serial port.
I have one old Fujitsu 1000 Stylistic, 100MHz pentium, and it is VERY slow with CdC. However, I think it is mainly because there is not enough RAM (only 4MB).
But if I do not load Tycho catalogue, it is *just* adequate.
On the other hand, my Dell Latitude D610 (1GHz) lap is quite OK for the task. The main issue here is available RAM: more the better.
The belts are timing belts from old printer/scanner and are inverted (teeth out).
Hmm.. When I mentioned "teeth out" in one of my previous posts, I meant something else.. When I was playing with the concept, I used a tightly mounted (glued) timing belt on a wheel with teeth out, so that effectively this forms a timing pulley with rubber teeth.
Then, I used larger timing belt of the same pitch, with much smaller timing pulley (from Small parts) on the encoder shaft.
The way you made your assembly, there may be some slippage between pulleys and belt, that could partly explain those small discrepancies you mentioned earlier.
I understand now what you meant with inverted belt
But the good news is it works like it is. You might be right about that micro slips. I thought that would be registered with the software because it says "0" errors, but that might be for something else.
I am happy as long as it helps me find things on the sky.
Now, regarding catalogs, Tycho catalogue you mentioned, is that one you would recommend?
OK, as long as it works.
After all, microslippage will be more detrimental if the resolution is much finer.. this way, it is probably not significant at all.
Tycho catalogue is just one of them (down to mag 10). You also have UCAC cat, this one goes down to mag 16, but it is HUGE...
Perhaps for you, Messier, NGC, SAC etc are more interesting for the start as they contain nebulae and star clusters.
Quote:
Originally Posted by bobson
I thought that would be registered with the software because it says "0" errors, but that might be for something else.
micro slipping will not be registered because the encoders are only source of information for your computer, so comparison is not possible and of course CdC assumes there are no errors from PIC side.
Not sure what "0 errors" mean, probably there were no errors?
Perhaps for you, Messier, NGC, SAC etc are more interesting for the start as they contain nebulae and star clusters.
Yes, I am interested in major things for now. I assume all those would be in the program already? Since I dont see any catalog just for Messier or NGC etc.
I downloaded Tycho 1 but link for number 2 is broken
Messier is not.. you have to get it separately: http://www.stargazing.net/astropc/external.html
Then after installation, you have to enable it.
Click Preferences - Catalogs and preferences - Size
There are some ticks to click ("show this catalogs").. also in "show" column you have to type "1" "2" etc.. depend on how many calalogs you want enabled. In "file" column you have to navigate to where Messier catalogue is (it will be in cat\externes\messier\marathon.txt)
Basically, you should download all catalogues, including search indexes. It is a lot of files, but it is worth it.
Installed Messier catalogue, works fine. Pity version 3 beta doesnt work properly on my computer, it doesnt recognise system time. Otherwise I think its better and easier to use.
Regarding USB to serial port adopter. Does it work straight without any virtual serial port needs to be created, or some software installed? On jaycar web they mention some driver that comes with the cable?
I have new Toshiba laptop but without serial port on it. So I was thinking if USB to serial port adopter would work I dont need to buy second hand laptop with serial port.
Essentially my USB to serial converter is built into the cable and look like a regular USB cable and it solders into the EK box. I found it a bit restrictive which is why I want to get the Bluetooth version working as quick as possible. I would suggest at this stage to just consider USB to serial adapator.
With that I am redesigning the board to accomodate the Bluetooth module and using modules for all parts to allow for easy upgrade without junking the whole unit and starting again.
As far as drivers I believe VISTA and Windows 7 will have inbuilt generic driver. I have not tested it on XP ATM. I expect the drivers are for earlier versions of Windows but unsure of Jaycars converter (ask Mr B). The USB to Serial convertor I originally tested was annoying and has a bright blue external high intensity flashing LED's that show communications. Light up the whole dark sky area.
On another point I found the optical encoders draw hefty current. I hope to have some good news on some encoders that I got for trial. So far I have been a bit disappointed with them but I have an idea. If it is successful then it may allow the whole EK box to run on USB power instead of a power pack or batteries. Most optical encoders are not very efficient.
But if I go to Bluetooth I will have to go back to external power again.
Thanks Malcolm, I left PM to Simon regarding USB to Serial adopter.
Yes, encoders draw hefty current, thats why Bojan told me to consider other options for power supply cos for now I use 9V battery. I have car battery ready for it but that introduces extra cables as well Bluetooth would be nice solution.
Is it Simon or Malcolm? 
