Multi-telescope imaging rig

[Gina]

Sometimes it works - sometimes it doesn't   But that isn't any good   This graph is a few minutes later.

[Gina]

AARRGGHH

[Gina]

Seems I still have a few things to sort out before I can guarantee a successful triple imaging run   Some of it seems to be bad connections, both power and USB.  I think I shall try running the mount from the USB hub rather than a separate port on the laptop.  Sounds counter intuitive but worth a try I think.

[hughgilhespie]

Hi Gina,

I hope the Lemsip is getting through, these long winter colds/flu/lurgys are a total pain but they do eventually end.

For your remote focus ideas, have you come across MakerPlot? This seems as if it would do everything you need. http://www.makerplot.com/

There is a free trial and if it turns out to be the dog's whatsit's it's only US$39 which isn't too horrible.

Regards, Hugh

[Gina]

Thank you Hugh   I think I'm on the mend at last - had a good night for a change and feel a bit better this morning.  Took my temperature and it's normal so don't need the paracetamol today   Still got a cough at times but not so much and it's looser, so that's a good sign.

I'm going back to looking at Python as my programming language as suggested by a friend yesterday and which I used a few years ago to produce the front end of my weather station.  A variety of graphs and gauges showing various weather trends and gauges for temperature, humidity, rainfall etc.  The graphic images were included in web pages for my weather station website (now defunct until I get my new home made hardware working).  As I recall the graphics used Image Magik but not sure now.  All this software is open source and free and is multi-platform (works in Windows, Linux, Mac OSX etc.).

I'm hoping to get back to my weather station project soon but I have been concentrating my efforts on the astro stuff.  The old station was a commercial one I bought from Maplin (Fine Offset model WH1081)  but I developed my own software to take the data and process it for human consumption.  My new automatic weather station is entirely home made with sensor data processing carried out with an Arduino Uno, plus data shield.  The shield has a real time clock and SD card control to store data.  So I shall be wanting PC software to read data from the Arduino through the USB/serial port and process it in the same way as for the WH1081.

Here are some examples of the graphics generated.

[hughgilhespie]

Thank you Hugh   I think I'm on the mend at last - had a good night for a change and feel a bit better this morning.  Took my temperature and it's normal so don't need the paracetamol today   Still got a cough at times but not so much and it's looser, so that's a good sign.

I'm going back to looking at Python as my programming language as suggested by a friend yesterday and which I used a few years ago to produce the front end of my weather station.  A variety of graphs and gauges showing various weather trends and gauges for temperature, humidity, rainfall etc.  The graphic images were included in web pages for my weather station website (now defunct until I get my new home made hardware working).  As I recall the graphics used Image Magik but not sure now.  All this software is open source and free and is multi-platform (works in Windows, Linux, Mac OSX etc.).

I'm hoping to get back to my weather station project soon but I have been concentrating my efforts on the astro stuff.  The old station was a commercial one I bought from Maplin (Fine Offset model WH1081)  but I developed my own software to take the data and process it for human consumption.  My new automatic weather station is entirely home made with sensor data processing carried out with an Arduino Uno, plus data shield.  The shield has a real time clock and SD card control to store data.  So I shall be wanting PC software to read data from the Arduino through the USB/serial port and process it in the same way as for the WH1081.

Here are some examples of the graphics generated.

Web Site Displays 03.JPGWeb Site Displays 04.JPGWeb Site Displays 05.JPGWeb Site Displays 06.JPG

'So I shall be wanting PC software to read data from the Arduino through the USB/serial port and process it in the same way as for the WH1081.'

I think this is exactly what MakerPlot does.

The weather station software you wrote looks impressive though. I have looked at Python and even downloaded JetBrains PyCharm but I am too long in the tooth for all this Object Oriented stuff. I shall stick with VB for now and plagiarise, plagiarise and plagiarise. Many years ago I wrote a graphing program in VBA for showing steam temperature in real time - don't ask - It was fun but MUCH harder than I thought it would be.

Regards, Hugh

[Gina]

I may give MakerPlot a try - could be easier to use.

[Gina]

Couldn't find any gold plated 2.1mm x 5.5mm DC power plugs so I've ordered a bunch of plugs moulded onto cables.  That should at least make the cable to plug connections safer than a plug soldered onto a piece of cable as I have at present.  The other end of the cables will be soldered onto the respective fuse holder and the 0v line and supported as the cables go through a grommet in the box side and inside the box with blobs of hot glue.

Gold plated USB leads are readily available so I can order suitable ones when I have measured the required lengths.

[comongeaff]

Hallo Gina,

I have been following your Post for quite a while now , and I,am enjoying your work..

rejoined the Forum again, after a year, too much work..

now managed to set up my equipment, with a few changes made which helped me a lot..

Regarding the problem you have with Phd, I also had the same... I noticed on your beautiful mount that your bolts between the bottom plates and the top one , they are too long.

I changed the length of mine down a bit, and that solved my problem .. At that length, they cause a lot of vibration... especially with a lot of weight on top..

Just a thought, hope the weather gets better over there, here is more or less the same..

Regards John

[Gina]

Some gold plated USB cables came today (at last) - that's the connectors that are gold plated not the cables   I hate Christmas with all the postal delays   I guess the power plugs/cables due to arrive last Tuesday might come next week if I'm lucky!!!

Mind you, I'm not in a fit state to fix the rig anyway

[Gina]

With nice sunny weather today, I ventured out to the obsy and tried to get the rig working.  But I still can't get the new 460EX working despite using one of the new USB cables with gold plated connectors    The new one was working but now it isn't   The other two 460EX cameras work fine and I aligned the images on my favourite daytime object - tree on distant hill.

I guess I really ought to forget about any idea of an imaging run until I'm better   Was just hoping to get some more data on the Pacman before it goes out of sight!

Just have the eastern wall flap open - roof is closed.  I see the camera angles are a bit off...

[Gina]

Spent a few minutes out in the obsy trying to sort out my cameras.  All three definitely work - I tested by moving working cables across from a working camera to the one that wasn't working and that one is now working.  So that proves it's cable problems.  I may venture out again and see if I can fix it.

[Gina]

Been out there again this morning and replaced all power and USB cables to cameras and fiilter wheel.  All three 4760EX cameras are now working

Now for the bad news...  The EDMOD connection to the mount has packed up   When the EQDIR device is connected to USB the laptop give the usual connection sound but the system reports a problem with the device and won't connect   If this is the EQDIR broken I'm stuffed until well into the new year as FLO are closed until 5th Jan   It was working earlier this morning though the mount went to the wrong place again and I used the manual EQMOD ASCOM controls to line it up to my usual daytime object (tree on far hill).  Adjusted the scope alignments but then noticed an error msg the EQMOD had stopped working. 

EDIT - Tried rebooting the laptop again but the EQDIR device is not there in the Ports (COM & LPT) list (Just the Arduino Mega focussing control).  I certainly looks like the EQDIR has packed up - it was quite warm to the touch though not hot - don't know if this is normal or not.

[Gina]

The good bit - a rough scope alignment.  So far this has seemed to be needed each time I set up but it may be just that I disturbed things by plugging cables into the cameras.  I'll see how it goes and if realignment is required each time I'll add remote control.  No great problem to add 4 more stepper motor controls to the Arduino Mega hardware and sketch - the drive to the adjustment controls may be a little more complicated   But it would be nice to be able to adjust the alignment from indoord

[jarl72]

Hello Gina,

Is there any chance you are drawing too much power from the USB ports? I used to work developing a... "something" that included 8 cameras. You can't imagine all the time we spent solving weird problems like the ones you mention, when the issue was the amount of power being drawn from a port, or the voltagevoltage dropping too much on a hub. We fried a camera or two, but most of the time the problems were solved playing with the topology.

[Gina]

Hello Gina,

Is there any chance you are drawing too much power from the USB ports? I used to work developing a... "something" that included 8 cameras. You can't imagine all the time we spent solving weird problems like the ones you mention, when the issue was the amount of power being drawn from a port, or the voltagevoltage dropping too much on a hub. We fried a camera or two, but most of the time the problems were solved playing with the topology.

'Fraid not - the EQDir was on it's own USB port.

[jarl72]

'Fraid not - the EQDir was on it's own USB port.

I see :/

I would try it disconnecting all the other stuff, just in case... Same goes for finding deffective cables or components. A couple of times thing just stopped working for no apparent reason, and then we found that some of the "powered hubs" are not really powered, that some ports can supply less power than others, or that two ports that were "independent" shared a common power line.

Best luck!

[Gina]

Tried it on another computer - same problem - USB Device not recognised

[Gina]

Found faster delivery on ebay so I've ordered one

[Gina]

With no telescope imaging available until the new EQDir cable arrives I'll concentrate on the all sky camera and widefield rig.  The advantage to having more than one string to my bow

[Gina]

With the bitterly cold weather I've decided to bring the triple imaging rig indoors and work on getting all the cables and connections sorted out, mount the power distribution box and powered USB hub more securely and look again at the scope alignment.  The current arrangement doesn't seem to work properly and it's very awkward to set up manually, while craning my head to see the screen while fiddling with adjustmants at arms length

Bodging things up in attempts to get things working for the next few hours of clear night sky has simply not worked and I feel I have been banging my head against a brick wall    So I've decided to get things tidied up and working properly before attempting any more imaging.  And with my present state of health I need to control things from indoors - I'm not fit enough to spend even an hour in the cold night air setting things up.

I think I have found the problem with the mount control.  Apart from a failed USB to serial adapter (now replaced) there was a power problem.  Running the EQ8 from the Maplin 13.8v PSU situated in the warm room caused problems even though the measured volt drop along the cable was insignificant.  I have since heard of problems with this model of PSU which were not cured by extra smoothing/decoupling at the pier end but which seems cured by using a backup/regulating battery at the pier.  After successful tests I will be construting a proper fusebox to mount on the pier for connecting the battery (45AH sealed lead acid car battery).

[Gina]

I think it will be worth providing remote alignment same as with focussing - I have the stepper motors and 3D printing facility for the cogs.  I shall replace the somewhat weak plastic springs with stainless steel ones at the corners providing enough force to hold the scope without clamping (I hope).

Taking the RA alignment first, with the screw adjuster, the drive could be direct from the stepper motor as that should give fine enough control.  May even be a bit slow but it wouldn't matter if it took 10 or 20 seconds to get close to alignment (one or two rotations of the screw thread).  This arrangement is shown in photo 1 below.  Alternatively, I could use spur gears as represented in photo 2, with the stepper motor on the other side of the plate.  I think the direct drive solution will be the one I shall go for - it's tidier.

[Gina]

Actually, I'm not happy with the general mounting method - I think it needs better accuracy on the pivots.  Needs more thought

[Gina]

I have designed a new alignment system using a 6mm threaded rod to provide a Dec axle and RA adjustment.  One end of this is fixed to the base with a bracket and the other has a fitting with a threaded hole running on a 5mm threaded rod driven by stepper motor to provide the RA adjustment.  I have yet to sort out the details of the Dec adjuster.  I have the 3D printed parts already printed and assembled with the threaded rods and it seems to be satisfactory.

The Dec axle bearings are plain bearings simply made of plastic.  There will be very little movement and infrequent adjustment so I deemed this adequate.  I shall use a ball bearings for the RA adjuster rod to provide rigidity and accuracy as this may be expected to turn several revolutions for the coarse alignment.  A 5mm x 16mm x 5mm rubber sealed ball bearing for one end and the stepper motor bearing at the other.

Here are a couple of SketchUp screenshots.  I have made the aluminium plate that takes the ST80 scope transparent in the first screenshot to show the parts underneath.  I have not yet modelled the stepper motor or its mounting - this will go on the right hand end of the adjuster rod.

P.S.  The ABS printed plastic is sufficiently flexible to allow a movement of the fraction of a degree that is required for alignment.  I have tested this.

[NickK]

Hmm plastic gets less flexible with lower temperatures. It may be worth trying a 'cold run'?