russellhq

Thanks Dave. That's how I wired it up, power directly to the stepper board. I've ordered a new stepper (£4) just in case this one is faulty. If not, then I think I'll need to look at the focuser tension and then consider pulleys. For the pulley, I'm considering putting a big pulley on the fine focus shaft so I get an even greater reduction.

Yes, you are correct. I've connected to pin 29 and 27 which are GND & 5V. I think Vin is only for supply power? http://arduino.cc/en/uploads/Main/ArduinoNanoManual23.pdf

Here's a photo of the connections. I'm pretty sure it's wired up as per your schematic. The lights flash when the motor is on low speed. When it's high, it's very hard to see them flashing. when it's stopped, they are off. The exception was when it was on separate power, in that case, when it was stopped, that lights stayed on. I tried 12v from my 10A supply and it didn't seem to make a different to the torque. The only difference was the motor got quite hot. Had to turn it off before it got too hot to touch. I can't see this being able to turn the focuser knob with the pulley. Think I might try buying a new one, maybe this one is knackered

I should have pointed out, the direct drive is connected to the 11:1 fine focus spindle, so should already be getting an advantage. I'll try with the 12v and see what happens, though I'd rather not run another cable just for the focuser.

Thanks guys, I did try a 9V batter, but same issue. I notice the board states 9-12V. Maybe I could run a 12v line from my power supply, that might give it more grunt?

Struggling a bit here. The parts arrived today and I got everything wired up, except I'm not using a switch. I first tried with the 5v source from the nano, and then with a fresh 9v battery. The stepper would turn but was pretty gutless, I'd say it couldn't pull the skin off a rice pudding! Have I got a duff stepper or am I doing something wrong? Here's a short video of the parts:

Of course, sorry I'm not very good with this programming malarkey Temperature is one of the properties of the Focuser class, so it would make sense that the Client requests it from the driver!

Yes, work does have a bad habit of getting in the way! I was reading the ASCOM documentation and I guess you would have to set up a timer in the driver to poll the focuser for the temperature. I don't think it's possible for the focuser to notify the driver of a change in temperature.

Maybe I've answered my own question, looks like these guys use a temperature probe that you attach to the telescope tube: http://www.optecinc.com/astronomy/catalog/tcf/tcf-s.htm And at $800 a piece, that's a professional piece of kit who's designer has probably done their homework.

This may be a silly questions, but why does a change in temperature change the focus? I assume it's because it causes the OTA to contract and expand, if that's the case then would it be better to mount the temperature sensor somewhere on the OTA, or is air temperature sufficient? What do the professional do? The reason I ask, it's a trivial task to mount a DS18B20 sensor anywhere you want. So let's get it in the best place.

It's not ASCOM, but APT reports humidity but that normally requires a separate sensor. The bracket was made with nothing more than a cordless drill and a C clamp.

While I'm waiting on the rest of the parts to arrive, I thought I'd give making the bracket a go. Turned out OK, just hope it's well aligned!

I'm not sure how useful it would be for a focuser, but if you're going to have an arduino on the mount anyway, then it would be handy to have a humidity sensor on it to monitor viewing conditions.

Sounds good. Also, I knew nothing about arduino programming but was able to get a TEC cooler program up and running quite quickly, the arduino site is very helpful. The common temp sensor is the DS18B20 and there's a good example on the arduino website: http://playground.arduino.cc/Learning/OneWire Also, the DHT22 is a good, cheap temperature and humidity sensor that works well with arduino. Though you might have to get the humidity outside of the focuser driver?

Would it be much extra work to include temperature monitoring? I know it's pretty straight forward, and cheap, to add a sensor to the arduino. I'm just not sure about the ASCOM driver side of things!

Well that's the parts bought, let's see what happens when they turn up! I decided to go for a direct drive rather than timing pulley. The shaft on the focuser is only 2.5mm, so it was difficult to find something with the correct bore. But I found these 2.5mm bore collars that are 8mm OD. And I found a 5mmx8mm flexible coupler, so hopefully they all fit together! http://www.amazon.co.uk/gp/product/B00J995ZQM/ http://www.technobotsonline.com/zinc-collets-2.5mm-pk-4.html

Has anyone carried this out on an ED80? I'm scratching my head for mounting options and belt length. Don't want to reinvent the wheel if it's been done already Also, not having the right tools I'm struggling to find info on the diameter of the focuser rod.

I think you just enjoy doing things the hard way!

I checked with my multiprobe and it seems to connect to the other ones marked green. Do you think it would cause a problem if you used it to bring the connections instead of using wire? I quite liked the idea of using conductive paint but I don't know enough about electronics to say either way.

Looks good, although why didn't you take advantage of the common pads which were close by the selector pads? I marked the common pads on your sketch with a green dot and marked proposed connections in red:

Excellent, thanks very much! I've looked over it and it doesn't look much different from what I have from my sensor.

Thanks Mark. It does look worse than I am used to. Here's a 10min dark i took before I started attacking the camera. The thermal noise looks a lot lower even accounting for the different ISO setting. https://www.dropbox.com/s/4b68i9cocvddvj0/D_2013-07-27_04-27-50_4637_ISO100_600s__29C.CR2 Maybe somebody would be so kind as to take a 20min dark at ISO400 from an 1100D and post the RAW file for comparison?

Here's 3 raw files from last night: 2min sub with IDAS LPS filterhttps://www.dropbox.com/s/hr855pvajqu5hq7/IDAS_ISO1600_120s__15C.CR210min sub with Baader 7nm Ha filter https://www.dropbox.com/s/g4a4zle5vczla14/7nm_Ha_ISO400_600s__16C.CR2 20min sub with Baader 7nm Ha filter https://www.dropbox.com/s/oro22i7800mcul4/7nm_Ha_ISO400_1200s__15C.CR2

Random noise. On a stretched image it looks like a lot of white pixels. I can post an image this evening.

I was trying the sensor out last night under the stars but I was getting quite a lot of noise. I took some shortcuts when putting the camera back together (i.e. not connecting all the cables or using all the screws) but I didn't think that would have caused any issues. So, I'm wondering if anyone that's been debayering sensors has noticed any excessive noise and if there was a simple fix?