19 February 2019 at 6:24 pm #574257
I have just finsished a project to enable remote control (from inside the house at least!) of my scope and lhires lamps. It runs over my LAN with a wifi point outside. Its detailed (with pics) as an entry on my ‘comminity page‘. I hope to be able to sit in the warm and select targets, and acquire flats and calibration frames.. I had a quick field test last night before clouds rolled in… we’ll see how goes with protracted testing.
Kevin20 February 2019 at 5:32 pm #580724
I have remote control options on my mount, it has its own WIFI address as well as using the LAN. I have found using WIFI to be risky because if the link breaks down you may not be pointing the scope in the right direction.something I have encountered. I am considering using ethernet with a dedicated cable which would be far more reliable.
Nick21 February 2019 at 11:59 pm #580730
I have a dedicated outdoor wifi point which gives a pretty strong signal… but in general, I agree, I like wires too. I am currently running a session – I’ll let you know if it goes pear shaped!
Kevin25 February 2019 at 11:01 am #580753Mr Jack MartinParticipant
I hard wired an Ethernet cable from obo to upstairs very reliable, works better than wifi.
Essex UK28 February 2019 at 6:19 pm #580769Mr Jack MartinParticipant
I have looked at your kit on your ‘comminity page’ very impressive.
How do you switch the calib and flat lamps on and off.
Shelyak have a gadget for this.
It is possible to operate robitically I only heard of one instance of this in spectro.
PRISM and ACP software have robotic functions, which will enable you to create an observing plan.
Essex UK28 February 2019 at 6:40 pm #580770
When I started down the road to spectroscopy automation I had and still have the main controlling PC in the observatory and a keyboard and mouse extender over an cat 5 cable to a room in the house. While the main PC ran a script I could interact directly if need be. This worked well when doing a search for possible Be stars looking at one every few minutes.
I also have a cat 5 cable onto my LAN hub and could link via wi fi to any PC in the house using Radmin.
I now have fully automated the finding and capture process and do longer exposures without the need to inspect in real time. So I run a Python script that does all the work while I do other things. I keep a weather eye on it via a laptop via wi fi but I do find it drops out once a night on average.
Lamp switching is via a USB relay controlled by Python. All else is via two instances of The Sky X.
I think the video of the talk I gave on this at the joint BAA/AAVSO meeting is still available on this site.
Regards Andrew1 March 2019 at 4:22 pm #580773Grant PrivettParticipant
Theres at least one USB relay on Amazon that can be run via a simple serial port command (but which plugs into USB). If not done in Python its only a few lines in VB6 to create an executable that opened or closed the relay. It even has a small LED on it so you can see the relay status.4 March 2019 at 12:43 pm #580791
Everything is controlled at the business end by relays which mimic switches. Note, you can turn the lamps on and off with switches using the lamp control port on the Lhires. There is a wiring diagram in the ‘add on kit’ documentation I believe (back in teh day when it was an add on…). You just have to switch in 12V for the required lamp.
I think Shelyak’s gadget does the same thing.
I have used Prism’s automated method for imaging (as its handy to do filter changes, refocus etc on the fly) but I just use the camera sequnce panel for spectroscopy.
Kevin4 March 2019 at 12:47 pm #580792
Sounds a few steps beyond mine! I just use TeamViewer to see my obsy-based laptop indoors, and the bit of hardware I descibed here to control the scope. How do you position a star on the slit? I would have though this is hard without manual fine control? I’ll look for the video..
Kevin4 March 2019 at 3:38 pm #580794
Just watched Andrew’s video (joint BAA/AAVSO)… Incredible rig, and I think I can see the differences with mine..
(i) Use of on axis guiding (ONAG) to help locate star
(ii) accurate pointing model
(iii) A guiding algorithm that ‘pulls in’ the star onto a *hole* – not a slit
I don’t bother with a pointing model – I sync to one star and then ‘star-hop’ using a guidescope with ZWO camera. I take my scope down periodically (if we are going to be away for more than a few days), so I figured getting a good pointing model would be a waste of time…
I dont have ONAG.
I use slit guiding with the target star (23mu or 34mu slit). I haven’t tested this to the limit to see how good it is as ‘pulling’ something in that isnt actually on the slit, but it does lose DEC sometimes and can oscillate in RA if not parameterised well, so I am not confident it would do this.
On the other hand I have written a script for attempting to position the star, once its in the guide cam image. It gets pretty close, but relies on human interaction to position cross hairs on the star in the first place. I am happy with remote control just now without the full robotic thing but – one day, one day 🙂
Kevin4 March 2019 at 7:08 pm #580797
Kevin, there is no magic in pulling the target onto the slit or hole. I just use the standard The Sky X autoguider. I set the center of the hole as the guide star position. Then once the star is placed close to the “hole” by the finding process the autoguide is set going. It assumes the closest object is the guide star and guides it on to the hole.
I am looking at “bright” stars so they are always the only bright object in the guide field. I have to take very short exposures so set the guide settings very “loose” so as not to chase the seeing.
Regards Andrew5 March 2019 at 11:11 am #580800
“I just use the standard The Sky X autoguider.” I use Prism… (I used to use PhD2 for guiding). But, in any case, I think main difference is that, if you are using a slit, then the star is double lobed, which can cause problems with normal (unimodal spread function) guiding; hence use of slit guiding. You use a fibre which presents a hole so you can use regular guiding.
” have to take very short exposures….so as not to chase the seeing.” Surely other way round? (longer exposures stabilise against seeing)? I use between 4 and 9 secs…
Kevin5 March 2019 at 1:35 pm #580801
” Surely other way round? (longer exposures stabilise against seeing)? I use between 4 and 9 secs…” indeed but…
… to clarify I have to take short exposures to stop the guide camera saturating. I then use a low gain to prevent chasing the seeing.
By setting the guider aggression quite low it essentially needs to integrate up several exposures corrections before a sizable move is built up. Thus random excursions due to seeing get averaged out by only causing a series of small insignificant corrections. All the guider is doing is correcting for the slow drifts as the Paramount ME II with Protract does a good job on its own.
I agree a slit with it’s bipolar lobes is more difficult a guide challenge than the “hole” presented by a fibre. One reason I never felt happy with a Lhres III on a Barlowed Newtonian.
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