SteveBz

Hi Guys,

Here are two calibrated single shots of IC5146 (Cyg) or NGC 6946 (Cen).  IC5146 (Cyg) is the Cocoon Nebula and NGC 6946 (Cen) is a galaxy.  If I amplify the images I can just make something out, but they seem amazingly dim.  Processing is as follows:

200 mm Newtonian (f/5) with PHD2 guiding and Nikon DSLR D5000.

1 NGC 6946) or 2 (IC 5146) light frames of 240 secs @ISO 1600.

61 x BIAS (ISO1600).

37 x FLAT (ISO1600).

No darks.

Then Noise subtraction and white balance using gimp.

But at no point can I see a nebula or a galaxy, unless I really ramp up the signal amplification, when everything is noise.

What's gone wrong?  Is there just too much light pollution in West Sussex?  The signal was sooo... faint, I spent a long time just working out if I'd even got the right location, it was just plate-solving against the wonderful Henry Draper catalogue that convinced me.

Let me know what you think.

Regards,

Steve.

On 22/09/2019 at 07:47, jbriare said:

Hi Steve

How do you operate the Bosma  TCE-200?  I threw one into a cart when buying some other junk online and it came with no manual or no software.  Trouble is, I can't find either online.  Did yours come with any documentation or direction to how to download software or anything?  I'm glad i bought cheap but would like to at least know that I gave it a try.  thanks for any advice/comments.

 

JIM

Are you on Windows or Linux? On linux, it's just treated as a webcam as in /dev/video0 etc. On windows I don't know, but I guess it's the same. It was probably made for a microscope and converted for a telescope. It's not terribly sensitive, but you can use it for a guidescope on brighter stars. You can also get planetary images, although they're not great.

I upgraded to a QHY5 which is much much better. You can also use a zwo asi120mm for 100 odd quid off alibaba express.

Good luck,

Steve.

Just found a Celestron manual with 9 settings.  Maybe I just need to test it.

9 hours ago, Dr_Ju_ju said:

Why not lose the handset & drive the mount directly ?? 

Have you done this? 

You've got quite a lot of Newtonians.  Is there much difference between them?  I have a 114 mm and 200 mm and the difference is so huge I only use the smaller one for outreach and testing.

Steve.

9 hours ago, JamesF said:

What do the rest of the slew command parameters do?  Tell it how much to move?  If so then presumably having 0 for "stop" is meaningless?  Or is it "slew until I tell you to stop"?

James

As I read it, it's slew until I tell you to stop. 

I've attached the full protocol, but as I understand it, the first three parameters are "fixed rate slew", "positive or negative" and "RA/DEC", not necessarily in that order.  Then you give it a rate.  Like this:

The text says:

For fixed rates, simply use a value from 1-9 (or 0 to stop) to mimic the equivalent hand control rates.
Note: in most configurations, issuing the slew commands will override (or conflict with) the tracking mode of the
mount. Hence it is always best to disable tracking first using the Tracking Commands, issue the slew command,
and then re-enable tracking. The main exception to this is when tracking equatorially - the fixed rate slews at 1 or 2
will not override tracking. This can be useful to simulate auto-guiding.

But the rates are:

So there seems to be a tension between the two definitions over what happens for zero.

I may just test it, but it's hard to measure rates like .5x and 1x, without a vernier calliper.

Regards

Steve

synscanserialcommunicationprotocol_version33.pdf

8 hours ago, Dr_Ju_ju said:

Why not lose the handset & drive the mount directly ?? 

Hi Dr Juju,

You said that before, and I'd love to. It just a long process. I think you saw my previous attempt, but it's on pause until I can get something working to look upwards. Then I'll have some spare time.

Regards,

Steve

Hi Guys,

I'm trying to automate my scope and I've upgraded from a Skywatcher Enhanced handset controlled by an Arduino to a goto Synscan controlled by a Raspberry Pi with Python. I have control of the handset now, but I'm having difficulty interpreting the manual. It says send the slew command (eg 'P' +chr(2)+chr(16)+chr(36)+chr(rate))or something like that. Rate is supposed to be 1-9 or zero for stop, but there are 10 rates with 0 =. 5x. How does that work? Does it mean 0.5x is not available? I'm a bit thrown.

Regards,

Steve.

2 minutes ago, StarDodger said:

Ubuntu mate 18.04 works pretty well on my rpi...as Stellarmate is now based on 18.04..

Excellent!  I could never get Mate 16.04 to work.

5 minutes ago, stash_old said:

Perhaps you should read this https://www.element14.com/community/docs/DOC-92642/l/benchmarking-the-raspberry-pi-4-model-b?_ga=2.91698202.1256246369.1561375659-1063832030.1561375659&_gac=1.152376651.1561375659.Cj0KCQjw6cHoBRDdARIsADiTTzb6WWPmx0WeFOVZkgtKYjs_gedi8gNbmwQ2vPxLv_PlA_WwxW2-LroaAhP6EALw_wcB

It looks about the same with more ports and memory.  Is that what you see?  The CPU doesn't look any different.

I have the RPi 3b+ and struggle to put it under stress.  I have been thinking of moving plate-solving to it, as it would speed things up.  Maybe that's what the RPi 4 is for.

3 minutes ago, stash_old said:

If you look on this site under DIY you will find a simple method using ESP8225 which converts to the correct TTL level (it can handle 3.3v to 5v so no logic converter) - uses Wifi or Bluetooth I believe and behaves as a serial bridge. In built Web server so long as you get a "real one" - mines wasn't and didn't work but OLD-TIMER ? has it working I believe.

If you use the Synscan AP software you can simple talk direct to a mount via the above or ESP8266/ESP32 via UDP - UDP simple fast comms but with no error correction - not needed really in today's electronics IMO.

But as Julian always says Wifi is really Wiffy especially the Arduino sized boards - which is true as most are limited to 50mb(ESP are 2.4ghz only last time I looked 🙂 ) as opposed to wired Ethernet (1gb) and little latency via say a RPI3b instead of ESP chips - then thats another story

So lots of options already done 🙂

Nice. OK. After a lot of building work my pc ended up on the wrong side of the house, so I installed a RPi on the scope-shed side and I talk to that with a python program. Everything in the scope-shed is driven by an Arduino. The RPi really just acts as a WiFi relay.

Now the eq5 with Handset is being replaced with eq5 goto, the Arduino needs updating, but I could run a usb from the RPi to the Synscan.

S

So the one I'm doing, because it seems to be the least additional work, is using the handset as a relay. It seems to use a simple st4 type connection with three wires. Tx, Rx and Gnd. I just want Synscan's definition of these to be the same as Arduino's

S

38 minutes ago, stash_old said:

 

Personally cant see the point of doing it but if you want to - great best of luck - sincerely

Are you saying you can't see the point of directly driving the motors, or connecting the Arduino to the handset.

The former I probably agree, and the latter I could be pursuaded of, but it's the latter I'm doing.

31 minutes ago, stash_old said:

See attached - so that should be all he needs to drive a set of motors  in one form or another - i.e. no hand set (EQMOD type direct motor control) or via Synscan App (another protocol)  or via the Handset as a relay (yet another protocol) but they are all described some more complicated than others. Unless I missed the point - more than likely.   🙂  The more complicated one is the mounts motors direct and you have to work out all the timings,positioning and maths etc  to control the steppers which normally have encoders- not just do Goto XYZ etc. The latter is not explained very well in SW docs IMO.

e.g. https://skywatcher.com/download/manual/application-development/

There is a simple diagram some where on Skywatcher site that gives a pretty picture of the required methods and protocol involved - just cant find it at the moment. 

He could of course look at the Indi code for Skywatcher/skyatcher Synscan etc.

The main problem is that talking to the motors direct involves talking at the correct TTL level(3.3v or 5v depends on kit) - e.g. cable from hand set to mount  but  some mounts use only 1 connection as the TX and RX lines are connected together  on the motherboard and you have to pull up/down the line to become the "Master".   Others use separate Tx and Rx lines and are pretty standard and will work with most Arduino boards (subject to 5v/3.3v voltage levels - i.e. you might need a logic level converter. The cable that ran from the handset to a PC is std RS232c and deals with higher voltages (12v plus) and of course had 2 functions - handset firmware update or if the hand set was in "PC Mode" acted as a relay for CDC ,Stellarium etc.

Personally cant see the point of doing it but if you want to - great best of luck - sincerely 🙂

But as I say I most likely have got the wrong end of the stick 🙂 

   

skywatcher_motor_controller_command_set (4).pdf 787.72 kB · 1 download

This is the one I have.

synscanserialcommunicationprotocol_version33(2).pdf

The commands look quite simple as long as I don't blow it up with the wrong voltage to the wrong pins.

S

47 minutes ago, Dr_Ju_ju said:

You've got the electronics there to drive the mount motors, if you've not seen it, have read through Tom Carpenters site https://www.astroeq.co.uk/about.php  where he has done what you are trying to do....  and it works well as it's what I use to drive my EQ5 system.

If you could integrate the handset into the Arduino driver module, all you'd be getting is a control system, which in AstroEQ terms, is some form of PC.

Also, Skywatcher haven't been fully open in their protocol, used in the handset\mount, understandably, as they are a business, therefore trying to get all info is difficult....

Yes, that what I started to do, now I'm going to ignore the a4988s and go straight to Synscan. The box I've built has the Bluetooth hc-05 which means I can run it without cables. Plus it has all the i2c stuff like sky temperature monitors and so forth. So it's quite useful in its own right. I could however bypass it with a USB cable with a MAX232 to 6p6c cable and that would give me the same thing, just an extra cable. And who'd notice with the jungle of cables we all have!

I'll post the Synscan docs I have.

S

1 hour ago, Dr_Ju_ju said:

What are you trying to achieve ??  From the bottom picture it looks like an Arduino Uno on a CNC shield ?? driving the mount motors ??  Most configurations would simply put the handset into a draw, and forget about it.....

Hi Dr J,

Well it started that way when my Starwatcher handset blew up, but then I was offered the chance to use a Synscan Goto, and I wanted to modify the Arduino project for the synscan. If it was easier to put the handset I a drawer I would. I guess then I'd need an eight pin ethernet cable and ports. Would it otherwise be easier?

What do you think?

Regards

Steve.

Hi Guys,

Trying to connect an Arduino to the 6-pin serial port of the Synscan handset.

If I look at the various connecting cables from a pc to a Synscan h/set they come with two variations, those with a MAX232 (or similar) chip and those without. A usb needs a MAX232, the db9 doesn't. As far as I understand it, the uart connector to an Arduino is equivalent to a MAX232. If I then connect to a second rx/tx pair I don't need a further MAX232. Its already the right protocol (TTL? ). Is that correct? So I can just use a 6p6c to 6p6c 6-core cable direct from tx/rx Arduino to Synscan with no extra encoding or decoding.

What do you think?

Regards,

Steve

Mine is a 200mm Newtonian on an eq5 mount. I'm very happy with it. If I upgraded, it wouldn't be by much, maybe 259mm rc on an eq6.
I'm sure that bigger scopes give magnificent views, but they're too heavy for one person to handle.

Good luck.

Steve.

15 minutes ago, George Gearless said:

1. Ugh...I figured. I couldn't quite wrap my head around how the camera would do both at the same time. Not unsurprising, since it can't. 

2. I do want to keep my options open. So thanks for that little tip. It would however need to be quite the bit superior to that of my DSLR to justify the extra cost of a colour one.

3. Indeed. I was just wondering how big a problem this is. If at all. I suppose the problem varies according to what scope you are using it with.

4. Power wise I should be ok with the USB-hub. The question was/is if there is a minimum requirement system wise and CPU wise. But if I understand you correctly it is just more convencient to work with a 'real' laptop.

The colour cameras, for reasons I don't understand, are usually cheaper than the monochrome, eg zwo 120mc-s vs 120mm-s. But the monochrome is several times more sensitive (about 3 or 4 times) because for every red pixel the colour cam throws away a blue and 2 greens etc. Whereas for the monohrome they are all um, monochrome.

Good luck

Regards

Steve.

On 19/03/2019 at 23:46, Alan64 said:

What an amazing amount of work you have done. And the final product looks great. But you still have the plastic wing nuts! Mine split as soon as I tightened them.

Very good luck,

Steve

Hi guys,

Has anyone used an mpu-9150 or mpu-6050 to support tracking or goto?

https://www.google.com/search?q=mpu-9150+astronomy&client=firefox-b-m&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjNjNv23rviAhVqTxUIHSNMCNkQ_AUIBygC&biw=360&bih=412#mhpiv=9&spf=1558961188046

I'm thinking about it, but I think it maybe a lot of effort to do what plate-solving does better.

Regards

Steve
 

Ok, this is what I have so far.  It's not tested yet.  The output is turns of the Alt/Az screws on an hours scale (that is hours turn of the Alt/Az adjustment screws) and it is not dependent on orientation of scope.  There is no photo, because you don't know the angle of the camera and it would be misleading.  I haven't adjusted the picture of Polaris for the error yet (I plan to).  I also haven't accounted for the time it takes to slew from photo A to photo B, so presumably I'll need to do the clutch release trick, rather than actually slew.  Also the time I've taken is the time of the jpeg, when better times would be the time of the raw photo, or even the time of the button press.

The test data is the two photos I posted earlier in the thread.

5 hours ago, themos said:

I should add that the method I used in PPA also appears in SharpCap http://www.sharpcap.co.uk/sharpcap/features/polar-alignment so if you like the extra bells and whistles you might like to give that a try.

Even down to your screen layout!  (Plus apostrophes and ncp ).

2 minutes ago, themos said:

I think it would be great for someone to add this, but I wouldn't be using it myself. Given that hardly anybody has a mount with motorised elevation/azimuth controls of the polar axis, the PPA process will always involve a human being iterating moves and closing in on the error. People with observatories can take their time and people that set up every night can use a piggy-back camera (even a compact camera will produce good enough stars in 10 seconds or so).

Nice,  well I shall probably create it as a piece of standalone code that I'll strap onto the output of the PPA calculation.  I have a shed-type observatory with a lift off roof and a concrete floor, but I still have a tripod and not a pier, so occasionally it gets bumped and I have to re-align it.  I want to put an automatic nightly check into my observing check list.

Like Gonzo, I'm Linux throughout with Arduino controllers, but I do a lot of little projects to tighten up elements of observing, like PA, focus, collimation, guding etc.  I was half-way through an HFD auto-focus computerisation when you wrote to me, so I stopped to do this.  When it works, I'm back on HFD.

Regards

Steve.

17 hours ago, Gonzo said:

If you download helvO08.pil and helvO08.pbm (Google it) and udpate the code, it looks slightly better.

 

OK, I tried this and the apostrophe on my setup doesn't show, so I reverted to HelvR10.  However using the smaller font for everything - I agree it looks better.