windjammer

Hi all So, on a dreary Sunday I settled down to get my brain around arcsinh stretching and have a play to see what its all about. I'm using Affinity Photo and got a blank - it doesn't do it. So here is a close (?) work around for arcsinh and a preset setup for a live filter layer tool that does the business. I've got a headache now but wanted to put this out before the urge passes. Comments welcome Simon Arcsinh stretching is used to stretch the image histogram while preserving the colour in the image. Generally the idea is to define a function f(x) so that: x' = f(Z*x) where x' and x are the new and old pixel values for R,G, B and L, luminance, and Z is a parameter to control the strength of the effect (a larger Z gives a bigger effect). The function f(x) in the Affinity world has a value in the range 0,1, as do all the R,G,B and L values across the image. The colour preserving bit of the arcsinh recipe comes from swapping R,G,B for L in the argument to f(x), so that: R' = (R/L)*f(Z*L), G' = (G/L)*f(Z*L) and B' = (B/L)*f(Z*L), and in the arcsinh method, f(Z*L) = arcsinh(Z*L)/arcsinh(Z), with Z in range 1 to 1000s. The first pic shows the family of curves f(Z*L) for a range of Z values, 2 to 500. Now, the arcsinh function, asinh(x) = ln(x+sqrt(x*x+1)), where ln is the natural log function. Unfortunately Affinity Photo's version of pixelmaths does not supply a ln function so it cannot be computed in AP. So, are there any curves that are similar in shape to the arcsinh family that could be used instead? The second pic shows the family of curves for x^p, where p is in range 0.17 to 0.8, which have similar shapes to arcsinh with Z in range 2 to 500. So we can supply a new f(x): f(L) = L^p, and R' = (R/L)*L^p, G'=(G/L)*L^p and B'=(B/L)*L^p 1. To add this into AP, open an image in AP. Click Layer->Live filter layer->Colours->Procedural Texture. 2. Click on the '+' symbol on the left hand side, half way down the Procedural Texture (PT) window. 3. Paste the following string into the equation window, making sure the R channel box is selected: var lum=clamp(0.2126*R + 0.7152*G + 0.0722*B-b, 0, 1);(R-b)*pow(lum,a)/lum 4. Click on the '+' symbol again to create a new equation window, with the G channel box selected. Paste in the same string with G substituted for R: var lum=clamp(0.2126*R + 0.7152*G + 0.0722*B-b, 0, 1);(G-b)*pow(lum,a)/lum 5. And '+' again to create the Blue channel equation: var lum=clamp(0.2126*R + 0.7152*G + 0.0722*B-b, 0, 1);(B-b)*pow(lum,a)/lum 6. Now create user control variable a: At the bottom left of the PT window, click on the 0,1 symbol. A symbol 'a' appears and a title box to the right. Type in a useful name such as 'power to raise Lum'. 7.Now create user control variable b: Click on the 0,1 symbol again. A symbol 'b' appears and a title box to the right. Type in a useful name such as 'black point subtract'. 8. Go to the top right of the PT window and click on the small pull down menu to the left of the Preset name window. Select 'create preset' and type in useful name, eg 'arcsinh'. The now created preset macro can be used again and in the future to do arcsinh-like stretching. If the Procedural Texture window does not behave as expected, the chances are there is an error in the equation strings, so check the syntax carefully. 9. Dismiss the PT window. To invoke, select the layer you want to process. Layer->Live filter layer->Colours->Procedural Texture. Click on the Preset pulldown, and select the arcsinh preset, (or whatever you called it). 10. To use the preset, first move the 'a' control to the far right. This sets 'a', the power to raise L, to value of 1: L is thus unchanged. Next move the control 'b' from the left (b=0) to the right so as to set a black point - watch the histogram window to locate the histogram near the left hand side of the graph. From the family of curves you can see that very strong stretching occurs at the smallest values of luminance, so setting the black point enables you to decide how much of the crud at the bottom you are going to stretch. After that, move control 'a' left (p ->0) or right (p->1) to get desired stretching. Smaller values of p give greater stretching. Values between 0.4 and 0.8 estimated from the bar slider seem most useful. What do the equations do: var lum=clamp(0.2126*R + 0.7152*G + 0.0722*B-b, 0, 1);(R-b)*pow(lum,a)/lum 1. var lum=clamp(0.2126*R + 0.7152*G + 0.0722*B-b, 0, 1); This computes the luminance value at a pixel from the R,G,B values, according to a recipe off the internet. The value of 'b' set by the slider subracts the black value, so luminance is zero at the chosen black value. The clamp function just constrains the value of lum between 0 and 1. 2. (R-b)*pow(lum,a)/lum This computes the black corrected R,G,B value to luminance ratio, before multiplying with luminance to the power set by 'a'. So we get for each channel R' = (R/L)*L^p, G'=(G/L)*L^p and B'=(B/L)*L^p as discussed earlier. ends

Inside Pixinsight 2nd ed by Warren Keller is a v good - thorough and a bit of a slog, but complete. It is a few years old (2018) and PI is evolving, but worth a few quid. His most valuable piece of advice IMHO: learn to use the tools separately before using the scripts. Also, Harry's Astroshed Tutorials (also a few years old but still good) https://www.harrysastroshed.com/pixinsight/pixinsight video html/Pixinsighthome.html Personally, I hate the damn thing! Simon

>> https://www.astroshop.eu/instruments/fujinon-binoculars-lb-25x150-mt-sx/p,23647 What cracked me up was 'CUSTOMERS WHO BOUGHT THIS PRODUCT ALSO BOUGHT...' I think the bijou eyepiece tray is the winner. Simon

Yes, a lot to be said for the achro doublets. Cheap and cheerful but good fun - and capable imagers as well, but not OSC. Here is my ST150 short tube F5 ... Simon

Its worthwhile playing with eyepiece projection as well, with or without a barlow. You will probably have to dip deep into the junk box, ep projection needs lots of extension rings to finagle something together. Also a collection of eyepieces to experiment with to find the sweet spot. On image size, try and get the planet disk as big as possible, compatible with keeping it in the frame as it bounces around, and bright enough so that short exposure times (video rates if you can manage it, 1/25or 1/50 s) give a good signal to noise. I always think something like Registax can pull amazing detail out of a few thousands subs, and the more pixels it has to work with the better. Sub rayleigh resolution detail is possible. Getting a planetary camera is good advice - it doesn't have to be cooled or have a huge sensor, so not too expensive. My 2 bits. Simon

Thats a cracker! Beautiful I was wondering if /when we would see any time lapse sequences from Jupiter or Mars this year. They add so much to the still pics - even if a sysyphean labour to make! Simon

Hi Here is M101, the Pinwheel Galaxy, Messier 101, NGC 5457. Mono RGBs and Ha composite. I took the exposures in March this year but wasn't able to make much of them until now. Affinity Photo, Topaz DeNoise AI and GradXpert arrived on my computer. Stars still aren't right - StarNet2 took quite a lot of the galaxy detail with it on star extraction, so processed with stars in place. Probably the wrong choice - I might have another go if the rain keeps up! The exposures were done 3x3 binning, the target so faint, so I think a lot of the stars in the galaxy arms get absorbed into the general low resolution glow or are a bit blocky. I think 2x2 or even 1x1 binning might be possible to resolve more stars with longer exposures in the 15-20 minute range. It would be a marathon tho'. Simon Details: Pinwheel Galaxy, brightest member of the M101 Group of galaxies, part of the Virgo Supercluster and our Local Supercluster. Photograph taken in Astronomik RGB broadband filters, Ha narrow band filter. Total exposure time 12.2 hrs. R 3x3 bin - 18x300s (West side) = 1.5hrs, 18-19 March 2022 G 3x3 bin - 13x300s (West side) = 1.1 hrs, 24 March 2022 G 3x3 bin - 33x300s (West side) = 2.75 hrs, 26-27 March 2022 B 3x3 bin - 13x300s (West side) = 1.1 hrs, 25 March 2022 B 3x3 bin - 33x300s (West side) = 2.75 hrs, 27-28 March 2022 Ha 3x3 bin - 18x600s (West side) = 3.0 hrs, 25-26 March 2022 Rig: Imaging scope: SW Startravel 150mm F5 Refractor, 2.5x Celetron Luminos 2inch imaging barlow, Atik 460EX mono Guide scope: SW Evostar 90mm F10, with guiding XY stage, ZWO 120MM camera Guiding: 2 stage PHD: high frequency guide scope (mount tracking) and low frequency OAG image train guiding (guidescope flex) Mount: Home made German Equatorial pillow block mount, permanently rooftop mounted. Spring loaded DEC axis gearing. Other gadgets: ST4 based anti vibration shutter, ST4 based PEC Processing: PixInsight: Lights, Darks, Flats, Biases, Align Calibration, StarNet2 star removal/star layer GradXpert: Gradient removal Topaz DeNoise AI: Noise removal Affinity Photo: 32 bit image processing (curves, high pass masking, selective colour)

I have found these panel mounted sockets to be very reliable, unlike the skinny ones. Unfortunately they need a 11.5-12mm oval panel hole to fit, larger than the 8mm (crap) ones. So retrofitting to existing projects a pain. https://www.rapidonline.com/truconnect-2-1mm-single-hole-chassis-skt-20-0980 Simon

Vlaiv is right about the 50mm finder. There is almost no backfocus and CA is atrocious. Here is a pic of one in video finder mode with helical focusser and ZWO120MM. It only works because the ZWO120MM has its sensor at the end of a long snout that reaches a long way forward. Even then you have to remove the objective lock ring and screw the objective cell right the way in. If the helical focusser is M42 then you will need to also get an M42 adapter that replaces the eyepiece plate and screws into the OTA tube. They are available (can't remember where I got mine!), but added to the cost of the helical focusser it all adds up. Its quite acceptable as a finder but probably not what you are after - why not a pair of observation binos ? Simon

The rolling sentry box (good description) is interesting. I like the idea of it leaving the scope area totally free and accessible. Rather than rolling away (my space too constrained for that), I wonder if a stackable design would be possible - somehow build up and clip wall sections together and put a roof on top, maybe just a flexible top cover strapped to the walls. From the man handling point of view, maximum height would probably only be to shoulder height or so. If that were a 10 minute job I could go for it. I take the point of wind loading and possibility of fly away v. seriously. It could mangle the scope on the way out - does not bear thinking about! (... and thanks all for the kind words about my diy GEM) Simon

Hi Since you ask....and here is probably more than you wanted to know ! Attached is a pic of latest incarnation. Its called Kevin. It lives on a small flat roof about 1m wide, facing south. An umbilical runs from the roof to an office just below for power and remote operation. You can put two plastic curtains up (made from those cut up garden funiture covers I mentioned) to make a hide and block out neighbours' lights. One of them is shown erected running from chimney to stink pipe, the other rolled up waiting to be unfurled for deployment(!). Its a home made GEM carrying a 150mm F5 refractor (in white) and a 90mm F10 guidescope (in blue). There are three finders of progressively narrower fields of view carrying USB cams. The shafts are scoffolding pipe (steel 48.4mm by 4 mm wall) riding in 50mm pillow block bearings. The counterweights you see in the pic are around 18kg. Each axis is identical, just DEC plate bolted to the end of the RA shaft. The gearing is straight cut spur gears, 4:1 on the final ratio, with a pick off gear on the opposite side for the angle sensor. The gear train can be uncoupled from the final gears by loosening the chuck, so each axis can be swung by hand if needed. Each axis has a floating brake clamp on the shaft riding on leather linings and tightened to just hold the scope in its most unbalanced position. There are stops either side of the brake on the RA axis that prevent any slop between gear teeth while tracking. On the DEC axis the brake stops are spring loaded, so that as the drive motor reverses into the backlash void, the springs push back to move the scope. You get movement of a couple of fields of view in DEC before the springs run out. So on PHD guiding, you get a perfect star cross pattern. Driving the final gears is a 1300:1 gearbox made up of the epicyclic gears from cheap or broken cordless drills off ebay, mounted inside a short bit of scaffold tube. There are 4 chambers, each giving about 6:1 ratio. Cordless drills usually have 2 chambers, are very robust, if crude, and you have to try quite hard to damage the gearboxes. Each axis has two motors, a DC slew motor and a stepper, salvaged from my dead printer collection. I could not drive a stepper fast enough for slewing, so two motors. A little model aircraft standard servo moves an idler gear to engage the slew motor or the stepper to the gear train. The steppers are 7.5o bipolar, giving 4*1300*48*16 = 4million steps/rev for tracking at full microstep setting. I used the StepStik stepper driver chips for the stepper controllers. PHD RA+ and RA- commands are used to give pulses of lower and higher speeds for tracking. There is also an automatic PEC motor speed controller that monitors the ST4 RA signal lines and adjusts the base stepper speed up or down by increments so that PHD RA+ and RA- commands become equally balanced - the PHD dartboard display pattern is nicely circular. A whole bunch of electronics boxes hang off the pier, RA and DEC stepper and DC drives, motorised focussers for G/S and main OTA etc. The 100W heater is mounted in the wedge space. Also an 8 channel video switch - cheap analogue cams are great if you want to monitor what is happening remotely: so there are cams on the bahtinov mask, filter wheel, anti-vibration shutter, pier collision monitor. A spare video channel is used to relay the downstairs computer monitor to a roof top display. All the electronics can be controlled at the pier or from down below, depending on where you are at - normally remote. The image train has an anti-vibration shutter, basically a filter wheel that moves a black filter back and forth, depending on the activity on the ST4 DEC and RA signal lines. When PHD guiding gets too active, the shutter closes until the mount quietens down again, when it opens. I live near a main railway line and busy road so anti vibration measures are needed for exposures past 300 seconds. After that is a barlow, motorised filter wheel and Atik 460EX cam. Guide scope rings attach the cam via a strut to a clamp on the OTA finder shoe slot - you can adjust the whole train for collimation and filter flare using the flat lamp and aiming for a centred and circular vignetting shadow. There is also an off-axis guider in the imaging train - this takes long exposures in the 5-10 second range, and inputs to a second instance of PHD guiding. The ST4 commands from the OAG are used to move the guidescope cam on an XY stage tiny amounts in the guide FoV. These adjustments of the XY stage enable flexing of the image and guidescope to be guided out: the guidescope is fooled into thinking it is off target and moves in such as way as to come back on target and compensate for the flex. The guidescope is normal except for the coarse and fine XY stages. The coarse XY stage is used to align with the main OTA, or search for a guide star, and the fine XY stage adjusts for flex. The guidescope cam inputs into the first instance of PHD running and controls the RA and DEC stepper drives. The mount performs best (sub arcsec rms guiding) with a guide update at 100ms interval, and g/scope exposures of 10ms to 50ms, so guide stars have to quite bright - mag 7 or so. You never have this outcome with a fixed OAG in the image train, so this is why there is two stage guiding. It stays outdoors under covers so setup time and tear down is quick - around an hour, depending on the gremlin population. The whole thing is a bit off-piste I know, but happy to answer questions. If only I could fix the image processing malarkey! Simon

Hi I use garden furniture covers like this https://www.amazon.co.uk/Woodside-Outdoor-Garden-Furniture-3-25ft/dp/B00CQ4DOK6/ref=sr_1_15?crid=B6JGHHNNA21O&keywords=woodside+garden+furniture+covers+waterproof&qid=1668347114&sprefix=woodside+garden+covers+waterproof%2Caps%2C115&sr=8-15 They come in small, medium, and large sizes. They are basically open ended cylinders that will drape nicely over an up pointing scope. You can use gorilla tape to stick extra sections on if you need an intermediate size. I use three of them one inside the other. Outer will degrade in 12-18mths due to sunlight, but inner two will last. I found the three layers is 100% weatherproof. You should consider a small heater under the covers to drive off condensation and a remote greenhouse temp and humidity sensor to keep track of dew point . A 100W bulb will do, or a 12V supply driving resistors. My scope stays fully mounted with cam and electronics on an exposed rooftop, and it has been there for 5 years. See attached pic

Hi Here is M63, Sunflower Galaxy, NGC 5055 - mono RGBs and Ha. The exposures were taken over 18mths ago, but this is the first time in many attempts to process the data into something that doesn't look like a cartoon. It was such a struggle that I am almost astonished that features in the image are real and match up with high quality images from much larger instruments! It still isn't quite right - there are still very faint features left in the murk that I haven't pulled out and which got lost somewhere in the pipeline. Colour of the main galaxy is not quite right and a bit dull, and the core is burnt. And the stars are a bit off, defringing and debloating have left artifacts - who knew, processing the star layer is just as tricky as the rest of it...But its OK for now! On the plus side, I was able to convert Harry's Astroshed PixInsight pixelmaths recipe for combining Ha with RGB into Affinity Photo's 'Apply Image' function. I think it works quite well. Simon Details: Sunflower Galaxy, Messier 63, NGC 5055, M51 Group of galaxies. RGB and Ha composite. Photograph taken in Astronomik RGB broadband filters, Ha narrowband filter. Total exposures15.8 hrs. R 2x2 bin - 8x300s = 0.7hrs, 23-24 March 2021 R 2x2 bin- 11x300s (East side) + 14x300s (West side) = 2.1hrs, 30-31 March 2021 G 2x2 bin - 6x600s (East side) = 1hr, 1 June 2021 G 2x2 bin - 16x600s (East side) = 2.7hrs, 2 June 2021 B 2x2 bin - 14x600s (East side) = 2.3hrs, 6 June 2021 B 2x2 bin - 20x300s (East side) = 1 hr, 12-13 June 2021 B 2x2 bin - 18x600s (East side) = 3hrs, 13-14 June 2021 Ha 2x2 bin - 12x900s (East side) = 3 hrs, 9 June 2021 Rig: Imaging scope: SW Startravel 150mm F5, 2.5x Celetron Luminos 2inch imaging barlow, Atik 460EX mono Guide scope: SW Evostar 90mm F10, with guiding XY stage, ZWO 120MM camera Guiding: 2 stage PHD: high frequency guide scope (mount tracking) and low frequency OAG image train guiding (guidescope flex) Mount: Home made German Equatorial pillow block mount, permanently rooftop mounted. Spring loaded DEC axis gearing. Other gadgets: ST4 based anti vibration shutter, ST4 based PEC. Processing: PixInsight: Lights, Darks, Flats, Biases, Align Calibration, StarNet2 star removal/star layer GradXpert: Gradient removal Topaz DeNoise AI: Noise removal Affinity Photo: 32 bit image processing (curves, high pass masking)

Narrowband image of NGC 7635, Bubble Nebula Ha 2x2 bin - 16x600s (East side) + 600sx5 (West side) = 3.5hrs, 8-9 October 2022 SII 2x2 bin - 11x600s = 1.8hrs, 10-11 October 2022 OIII 2x2 bin - 20x600s = 3.3 hrs, 17-18 October 2022 Rig: Imaging scope: SW Startravel 150mm F5, 2.5x Celetron Luminos 2inch imaging barlow, Atik 460EX mono Guide scope: SW Evostar 90mm F10, with guiding XY stage, ZWO 120MM camera Guiding: 2 stage PHD: high frequency guide scope (mount tracking) and low frequency OAG image train guiding (guidescope flex) Mount: Home made German Equatorial pillow block mount, permanently rooftop mounted. Spring loaded DEC axis gearing. Other gadgets: ST4 based anti vibration shutter, ST4 based PEC Processing: PixInsight: Lights, Darks, Flats, Biases, Align Calibration, StarNet2 star removal/star layer GradXpert: Gradient removal Topaz DeNoise AI: Noise removal Affinity Photo: 32 bit image processing (curves, high pass masking, selective colour) Simon

Yes, that is about right. I presume the normal mode if no button pressed is to run at the sidereal rate. I have been round a similar loop as this. I would be very wary about attaching bits of kit to each other - eg are there any voltages you don't know about on the Vixen switches when you tap onto them. I think the ST4 from something like a ZWO cam is just open collector that conducts to the ST4 common but I have no idea what the current limits are. Which bit of kit do you power up first etc etc. So a small risk that expensive bits of kit could get fritzed! I built this ST4 fanout box for just this issue - some pics and a (rather scrappy) circuit diagram attached. The ST4 signals are buffered and used to switch simple reed relays that can be safely tapped onto other bits of kit with complete electrical isolation. One other point - you might find the Stop and X2 modes a bit brutal for speed adjustments. PHD only updates at the end of every guide exposure which could be several seconds apart, so you could end up hunting in RA swinging one side to the other. If so, you could always synthesise an RA+ and RA- speed. A simple variable mark/space oscillator switching the mount (for example) x2 to sidereal would enable you create an RA+ just a bit faster than sidereal, and similar a slightly slow RA-. By varying the mark/space you can fine tune the RA+ and RA- that the ST4 sees. Simon ST4 fan out box.PDF

I forgot to upload this - shutter mounted on scope !

Hi Here are plans for an automatic anti-glitch and vibration camera shutter. I live near a railway line and a busy road, and vibrations from trains and buses etc often give PHD guiding heavy weather for staying on track. Passing clouds dimming the guide star also send PHD off target. The chances of completing a 300sec exposure without a glitch are pretty low, and a 600sec shot pretty much impossible. Looking at the PHD log and a bit of excel work showed that a shutter closing to occlude the camera during tracking excursions would be effective in dodging 90% of the > +/- 2arcsec excursions for a penalty of 20% of the exposure time. Which seemed an OK trade if it could be done. As PHD loses its grip, the RA/Dec corrections get larger before getting back on track - and these pulses are available at the ST4 interface coming off the guide cam (a ZWO 120MM). Basically the four RA+/- and DEC +/- pins pulse low when a correction is requested - the greater the correction needed, the longer the pulse. This repeats for every new incoming exposure of the guide cam. The idea was to get hold of a filter wheel, motorise it, put it in the image train, and have it shuttle between two filter positions - one position with a 0% transmission filter in it, and the other completely open. The ST4 pulses - in separate RA and DEC channels - are used to discharge an RC network, which then recharges when the pulse terminates. The voltage across the capacitor rises and falls. The charge and discharge resistors are separate, so the attack and relax time constants can be adjusted independently. When adjusted correctly the RC voltage hovers in normal operation just above a trigger voltage, and when the excursions become extreme the voltage falls below the trigger point, before rising back above the trigger when on-track guiding resumes. The passage through the trigger points are used to signal the motor to rotate the filter wheel closed and then reverse back to open. A pulse is also generated at each close/open to start/stop a clock so that the amount of exposure time closed can be monitored. Here is a pic of the final assembly mounted on the scope (Skywatcher short tube 6inch F5 refractor, the filter wheel shutter, Celestron 2.5x barlow, 9 position 11/4in filter wheel and Atik 460 cam). The first video is a Pix Insight blink video from a run of 33 exposures at 300 seconds without the shutter. Target was M63 Sunflower Galaxy, red filter. I have cut out the worst frames, but the general vibration issue is clear. Next video is a run of 17 exposures at 600 seconds. M63 again, green filter. The vids are of the un-calibrated frames so the images are pretty CCD so-so, but overall I think it works. Attached are the circuit diagrams and also some pics of assembling the strip board and the finished control unit. The shutter filter wheel was motorised with a Hitec 485 servo modified for continuous rotation. The servo is fitted with a 48 tooth plastic Mod0.5 gear on the servo arm. This engages with the thumb wheel of the filter wheel. Matching gear teeth are fabricated on the thumb wheel with a needle file - the thumb wheel rim has little grippy indents in it at half the pitch of the gear, so filing the teeth into the wheel is easy, and you only need enough teeth to drive two filter positions and not the whole thing. The internal click stop spring of the filter wheel is removed, so the filter holder rotates very easily inside the wheel. Packing washers are needed over the axle to stop the filter holder wobbling on its mount. Attached are some pics of the modifications to the filter wheel. Stops are mounted on the inside of the wheel to obstruct and stop the black filter at either ends of its motion open and closed. Little bits of the furry velcro from hook and loop tape are stuck onto the stops to act as shock absorbers. Attached are some pics of the filter wheel modifications. The servo turns the wheel quite slowly - it takes about 3 seconds to open or close. So the circuit has to drive the motor for that amount of time, (it is adjustable). There is very little torque required to turn the wheel and direct connection of the motor to the shaft would be possible if a much faster response is needed. The current arrangement doesn't upset the imaging train with vibrations, which could be an issue with a snappier response. Here are some pics of the continuous rotation mod to the servo. The 485 is quite a torquey beast and a lower spec one would do. (NB: The circuit does not provide a servo driver - all it does it switch the forward and reverse servo control signal from another unit. Servo driver circuits are ten a penny on the net. A single 4538 dual monostable will do the trick and provide forward and reverse). Now to fix that pesky guide scope flex that no amount of ironmongery has sorted (yet) ! Simon attachments: Pix Insight mp4 - M63 before video Pix Insight mp4 - M63 after video Circuit diagrams Strip board assembly pics Filter wheel modification pics Servo continuous rotation mod pics 300sx33_T1s_3c_dv8.mp4 vid_5c_T1s_dv8.mp4 Shutter controller ct diag final_upd_210603.PDF aaa_pics_Shutter ct board asm_2.pdf aaa_pics_Shutter FWheel modify_2.pdf aaa_pics_485 servo CR modify_2.pdf

Thanks for the info - downloaded PHD2. Connect Equipment tab, ZWO 120MM connected, On Camera mount connected - and off we go. The manual guide tab lights up the LEDs on my ST4 breakout box, and guide mode blinks the RA led (until it decides the 'scope' isn't moving) - so I think this is working fine. I don't know what is wrong with MetaGuide. Perhaps the zwo asi st4 ascom driver has not installed itself properly on my PC (the PHD2 zwo support is native, not an ascom driver AFAIK). I was looking at MG for high frequency guiding, so I might have to come back to that and have another go at some point. Meanwhile here is a circuit diagram for my ST4 diagnostic box - perhaps others might find it useful as well... it would be good for driving relays too, the ULA2004 can sink a fair bit of current. Simon

Thanks for this - In metaguide the setup dialog does not offer an 'on camera' mount - it only opens an ascom chooser with the options I stated above. So, is the mount dialog you describe an option in PHD ? I have the camera connected as you say. Simon

Hi I have a similar problem and thought to resurrect this thread. Basically an ASI120MM mini camera w. ST4 port. I want to use the ST4 interface on the cam to drive my ST4 scope. I cannot find the ASI ST4 Telescope Driver (ASCOM) - I don't think the ZWO ST4 camera driver exists anymore. Certainly the link given earlier in this thread is no longer there (404 error). The cam works fine with sharpcap. Ascom platform 6.5 installed, asi camera ascom driver 1.0.4.3 installed, directshow asi driver installed. I wanted to use metaguide, rather than phd, so installed M/G 5.4.4. So - M/G finds the 120MM, displays video. Under Video Properties, there is a zwo window with an ST4 test tab. I have made an ST4 breakout box that plugs into the cam ST4 port with LEDs that come on when the RA/DEC +/- pins go low. The ZWO ST4 test tab turns the LEDs on and off as you would expect. So that works. When you try and go the ASCOM Telescope Chooser under setup, the only scopes listed are Device Hub Telescope, Simulator and Telescope Simulator for .NET. Nothing about an ASI ST4 Telescope Driver, so I think that is the issue. Metaguide info is bit thin on the ground - maybe I should install phd and get that going first ? Has anyone got (recently) phd+ZWO ST4 working ? Thanks for any help - Simon

Hi I am confused about setting up metaguide and the zwo120mm for guiding with my dumb mount. So the mount has just the hacked handpad that can speed up/slow down in RA, and twitch up and down and stop in DEC. The idea was to use the ST4 connection from the ZWO120 to drive it. So, I have ZWO drivers, directshow, ascom platform, zwo ascom driver installed. Metaguide installed and getting video from the cam. MG wants to 'connect to my mount'. Obviously this isn't going to happen being a dumb mount. Looking at the cam control options in MG, the zwo offers ST4 test pulses. So am I correct in thinking that 'connecting to my mount' can be ignored, and MG will send guide info to the ZWO cam and it will output ST4 stuff all by itself ? Thanks for info on this Simon

I agree, fabulous image

Scott - background is physics and software but I've always liked the workshop... Barkis Good question - what do all those cables do (go wrong mostly). I don't know how people keep their scopes so tidy: this is what is going on with all the ribbons 1. RA and DEC fast slew DC motor drives 2. RA stepper controller 3. DEC stepper controller 4. RA/DEC transfer gearbox servo controls 5. Autoguider controller 6. 8 channel video feeds and switch 7. 4x SCB2000 daisy chain control cable 8. Bahtinov mask motor drive and camera 9. Filter wheel motor drive and camera 10. OTA focus 11. Guidescope focus 12. Guidescope XY stage controller 13. Narrow FoV finder focus 14. Setting circle encoder RA/DEC head ends 15. 1004x planetary camera control Simon

Thanks all for your kind words on .... the FRANKEN scope :) Re moving to the roof, just being out of the mud and bugs, and above the trees has made a huge difference to my hobby. So I would heartily recommend it. As far as planning permission goes, it is not a permanent installation and is no different really from putting up a satellite dish. No-one has ever come back on it. I think if you tried to put a dome or roro shed up there, then someone might object. Kevin lives under green garden furniture covers so few realise it is even crouching up there. Being a remote imaging rig, even in use there is no noise, lights or human activity to get people upset. A couple of caveats: the eyepiece end of the scope is usually out over the roof space, so you can't look through it. Not great if you do visual stuff. That depends on how much flat roof you have handy of course - my space is only about 1m by 3m. For the same reason manual adjustments on bits that are out of reach are a hassle, so everything you want to fiddle with has to be motorised and remote controlled. Secondly, up on top it is v. exposed in winter so operating remotely from a warm room below makes life a lot easier. So much so, the next thing after the roof move for hobby improvement is being able to sit down and watch the computer screens and monitors in comfort. Much easier to concentrate. Simon

Thanks for the info on PSFs. You achieved a very good improvement on the M27 pic. A good motivation to experiment. I have just started to use PI and was vaguely aware of processes with PSF in their names! I am still l climbing the learning curve on PI and expect to be on that trek for a fair while, but this would be a good excuse to have a play with some of this stuff. I definitely have guide scope flex - over the space of a few hours the target will drift a bit over the frame - star ellipses have their major axis aligned on the drift direction, and successive exposure ellipses join where the previous exposure left off. And guide algo hunting - I can see that happening in real time. I agree sorting the mechanics is best for flex, and adding brackets and draw tube locks to my rig has improved it immensely. Still a little way to go on that. My hunting issue comes from a poor g/scope star image, and incorrect settings which given a decent run of weather (!) I might actually solve. Simon