malc-c

Like I mentioned I'm no expert, and a lot of what Vlaiv mentioned went over my head, but from what I do know is that I think you are faced with a couple of fundamental issues. There is a relationship between focal length and exposures. It's probably no linear but at a guess for a given ISO and same aperture you need to expose twice as long for a scope of twice the focal ratio. But the problem with long exposures is that you need to guide (unless you have such a high end mount that has fantastic tracking and minimal PEC. Now an ALT AZ mount has two issues where imaging is concerned which compound the problem. The first is that guiding becomes difficult as the drift tends to be on two axis rather than one when comparing an ALT/AZ mount to an EQ, which is related to the second issue of field rotation. If left unguided a long exposure will result in field rotation, which is approx 45 degrees in a three hour period. This can then lead to stacking issues because each sub is rotated a few degrees. So I guess to improve things you either need to consider a focal reducer or fit some form or wedge so the scope can be used in an EQ format and then possibly consider guiding so that more data can be gathered.

Hi Stuart, I'm no expert, but 46 x 30sec is only 23 minutes worth of data which isn't a lot IMO. Granted you have a high ISO, which can result in a more grainy image, but even when I was imaging at 800 ISO I would still gather at least an hour on bright galaxies such as M31 and M81. M51 is quite a faint target by comparison. Also that's with a 200P so like your SCT an 8" but at half the focal length as the 200P is f5. Do you have the LX on a wedge or is it in an ALT/AZ format, and are you guiding ?

LOL - You can include me in that camp.... I find it very frustrating when you gather hours worth of data, stack them and then get disappointing results especially when you know there is more details in the result, even after hours of fiddling with stretching and colour matching etc. My friend who is (IMO) at the top of the game when it comes to imaging (his main camera cost more than my 8yr old Volvo V70 !!) and has had many an image featured in Astronomy Now to my subs and performed some magic on it and got the result above ! - Would love to know what his secret is

Chris, Possibly the reason Synta (or Chinese manufacturing in general) manage this is due to cheap materials and up until recently, cheap labor. For years the quality of chinese motorcycles has been questioned, with screws so soft they need replacing as the first time they are undone the heads are chewed up. Not saying that Synta products are of the same standard, but I bet the steel and ali used is not as high a quality of something that used to be produced in Sheffield. On a slightly different tangent, I like designing and building electronics projects. The first time I needed a PCB made I contacted a local company that is a large producer in the UK. The quote that came back for the tooling, let alone the single board was over £500. I then discovered companies like PCBWay and JLBPCB in China, and had five boards made to the same standard for less than £50 delivered via DHL. Not sure what part of that £500 were for materials and the rest for "time" of the various technicians or managers, but it certainly makes UK companies uncompetitive. If Synta can make finished mirrors for less than you can buy a glass blank here, even at "trade" prices, then how could any UK company compete, especially as whilst Synta scopes are not perfect, they do perform well at their intended market level. But even when you look at the high end, made to order "connosure" market, companies like SuperScopes that were based in Bedford didn't last long. The costs of buying or making parts, either in their own workshop or subcontracted made these scopes so expensive there was no market for them, and their reputation was such that they couldn't buy cheap optics from China as they only used the best David Hinds optics. I think you are correct. Synta have cornered the market, especially if you work things back. I know retailers portray a poor sob story about margins being so small, but I would hedge a bet that the net material cost to Synta for say a 200P is around 30% the retail cost in the UK. The rest is Synta's profit margin, distribution costs, sole agent wholesalers profit, and then the retailers markup, with various taxes and duties added in.

There's a listing in the classifieds Here

Olly, I was going to add that to the equation, but thought it may complicate things. Most of us use EQMOD to handle the mount control, with guiding handled by PHD2. However the OP has a celestron mount which is not supported by EQMOD, and even if it did, wouldn't function as the clue is in the name, EQmod... for EQ telescopes. Personally, given that guiding is an aid to taking long exposures, the field rotation (15 degrees an hour) will be in issue, especially when trying to stack three or more hours worth as the software will most likely complain

OK I'm going to state the obvious here... you are using an ALT/AZ mount which will suffer the same issue of all ALT/AZ mounts and that is field rotation. Now if you guide on a star for long periods, I would have thought that may also be a problem due to the field rotation?? As for guidescope, I've used ST80 and now the stock Skywatcher 9 x 50 finder and found that both worked well. Given the weight saving the 9x 50 would be the cheapest option. You will need an adapter to suit the camera so you can connect the two (best speak with RVO or FLO). The 9 x 50 SW finder is £54, and should slot right in the shoe where the current 6 x 30 finder is. However, I would seriously suggest you consider looking at upgrading the mount to an EQ (ideally an Skywatcher so you can use EQMOD with an EQDIR cable) to really get the benefit of guiging for longer exposures. An EQ mount will also help with stacking and post processing the results as you won't have to deal with the field rotation issue.

Just received this PM from the "customer" It really pleases me when I read through this thread to know that I've been able to help five SGL members get their scopes back up and running. But I'm gobsmacked to see this all started almost a year ago ! - where does the time go !!

If you run the tool box (C:\Program Files (x86)\EQMOD and run EQMOD_Toolbox.exe) and then under the set up select "driver setup" a configuration window appears Top right is a box - Mount options - Change it from auto to custom by clicking on the dropdown list arrow. - Then click the spanner Leave the entry in the RA and DEC dropdown boxes blank. For both axis In the total steps enter 4608000. In the worm steps enter 25600 - leave tracking offset as 0 Click OK and Ok

Thanks for letting us know which mount you are using. There is no EQ35, so I'm presuming its an EQM-35 Pro. The confusion with the HEQ5/6 reference in the screen captures above may be down to how EQMOD works. It reads the RA/DEC values direct from the motor control board, but then may just display HEQ5/6 as originally these were the two mounts that EQMOD was written for. It's worth registering with the EQMOD user group to confirm (I can't test as I don't have an EQM-35 Pro, I have an HEQ5). If for any reason this isn't the case then there is an option to set the values from the prerequisites page for each mount into EQMOD as a custom setting http://eq-mod.sourceforge.net/prerequisites.html ST4 guiding was the original protocol. From a quick google it seems that a guide camera is connected to the PC via USB, and an ST4 cable is connected between the camera and the mount. There is no other connections between the mount and PC. PHD (and later PHD2) is set to "on camera" for the mount settings. In this set up, the drift of the star is detected by the camera, it sends the drift to PHD2 via the USB cable from the camera to the PC. PHD2 then works out the correction and sends the correction back to the camera via the USB cable. The correction is then fed through from the camera to the mount via the ST4 cable. A better way is to remove the ST4 cable, connect the mount via an EQDIR cable and use ASCOM drivers to control the mount. In this setup you change the "on camera" mount setting to ASCOM. Now PHD2 does all the work. It monitors the drift, calculates the correction and sends it direct to the mount. If you have PHD2 set to "on camera" and the mount set to ASCOM then guiding won't work unless the ST4 cable is connected between the camera and the mount, but then you may be confusing things as PHD may well also try and send guiding commands via EQMOD. Personally I think you need to research setting up the EQM-35 with EQMOD and confirm that it moves the mount when the slew instruction is sent. Then when that's confirmed connect the camera via USB to the PC, and set up PHD2 for ASCOM mount control. Then on the next clear night, pick a star, and try guiding having run a calibration session and see how you get on

Here's my result - taken Monday evening when the Moon was at 98%, so the sky was quite challenging. 12 x 360s exposure @ ISO400 and 20 x 360s @400ISO darks. Stacked in DSS and then I had the Wizard Mr David Davies process them as I was struggling with stretching the data. My monitors acting strange as from one angle it may look dark, the other it's stretched too far and all the dust bunnies are visible - so on your screen it might look anywhere between ! Camera is a modified 400D - no IR filters .

If you google Powerseeker 50AZ the scope is as basic as it comes.... The use of software as a control platform is pointless on this occasion. I have a copy of the basic Starry Night program form around 1999 that came free on a cover disk of a computer magazine, which was just a standalone planetarium program without any mount control (with an upgrade path to this if required). Naturally as this scope has no motorised drive then if the OP wants to learn the night sky by using a PC base planetarium application then there are plenty of free options. Cartes du Ciel being the most common, Kstars, Stellarium and SkytechX to name a few will be excellent alternatives

It was the background of the star field. I'm no expert when it comes to imaging, but I just had a hunch that something was "missing". Most people seem to miss out the flats or bias images, tending to use lights and darks only. You may find you get a lot more contrast by adding the darks... It's a nice image and some nice round pinpoint stars so tracking was good too...

Is this just stacked lights? - Did you take any darks or flats ?

Sorry, but you still haven't answered Martins question regarding the main scope and mount, or confirm the small guide scope is connected via the finder shoe. Can you also confirm that you are using an EQDIRECT cable between the computer and the mount or is the mount one of the new generation with a direct USB connection.

The confusion I'm having is the mention of ST4 cables but reference EQMOD and pulse guiding. I've always used USB for the camera connection, a USB EQDIR cable and EQMOD to control the mount, and have PHD2 set to "HEQ5/5 ASCOM" for mount settings. With EQMOD set up as per the link above (other than my QHY5 selected as the camera rather than simulator". I've used an ST80 and now the 9 x 50 Skywatcher finderscope as guidescopes and whilst my guiding graphs are not as perfect as some with modern small pixel cameras, the tracking has always worked and the resulting images have had nice round stars.

Just read through the manual, and watched the 0978 video again. As no alignment was done, does the scope have any idea where it is. Whilst the default home position is pointing the scope North whilst the tube is horizontal and on the presumption it resets its co-ordinates to 0000000 then you would have thought it would have worked out where it is, unless that glitch means something ?

With the shops reopening it might be worth locating your nearest retailer (There is one in Tring) that could have a look at the scope first. let them try and reflash the firmware (although I don't think the motor board needs it, but the handset may have been flashed with the wrong firmware, but I doubt it as its a standard firmware that is used for most mounts and dual purpose - EQ or ALT/AZ). The fact that it's sending commands to the mount, the mount moves suggests that the basics such as communication between the handset and motor board is established, and that the commands are being responded to, yet it fails to stop or have any idea where the actual tube is pointing is baffling. I wouldn't want you to shell out £100 on a new board and still have the same issue as the encoders are at fault... Which is why I would have a shop look at it, or send it off to OVL for an estimate first

In 0982.MOV - at the end you rotated the mount through quite a few degrees (my guess at least 15) but the handset only showed the movement a single arcsecond from 06 to 07 - My guess is that IF the handset is expecting feedback and not getting it then it just continues to drive the mount. If they are disabled then it will display its calculated position... which in theory I would expect the mount to stop. For example if something had an altitude of 40 degrees then the scope should raise itself 40 degrees as "calculated" by the handset and then stop, even with encoders off. Why it's trying to drive the ALT way passed 90 degrees I have no idea You don't need this - all that does is echo a test "hello" sent out from the handsets TX pin back to its RX pin It doesn't actually test anything else other than confirm the handset is sending commands - as the motorboard is responding to the pressing of the NSEW buttons communications is established.

0978.mov - To my untrained eye it looked as if it was trying to rotate passed the vertical point (thanks for showing us that, but it won't do the motors any good trying to drive passed the stop that restricts the movement further) Now according to the jumpers JP1 needs shorting to place the motor board into goto mode so maybe by removing that jumper it also removes the option to read the encoders which is why it's trying to drive through the 90 degree point, but when shorted the scope moves in "reverse" which isn't a help either. Now from what I understand these mounts used DC Servo motors and physical encoders to feed back their angular position, which is why you can manually push them to a target and it can keep track of its location. The encoder data is pre-processed by the smaller 14pin ICs before being passed to the relevant PIC, so there could be a possibility that these have been damaged by the previous owner when he shoved 12v up the handset port. Again, and not trying to be judgemental, this is assuming the encoders are plugged in ? Also at around 20 seconds in to the video there is a noticeable but short pause / stutter as if both motors stop and restart. 0979.mov - At the beginning the motors don't sound right, they sound as if they are binding on something, or that the power supply to the mount isn't rated enough current to cope. a 12v supply that can deliver 2.5 - 3 amps is required , can you confirm the specs of the power supply being used. The fact that the scope is stuck but you can hear the clicking as you try and move it would suggest that instructions are been sent and processed by the motor board, but either there is not enough current to get passed the stalled position, or there is something physically preventing the mount from moving. Other than that I'm at a loss. The fact that the scope will move in both directions on instruction from the handset confirms the repair to replacement the two reprogrammed PIC micros worked, but the scope itself has other issues which would appear unrelated that repair. I'm guessing that if you took the scope back to a repair agent they would flush you a lot of cash for a complete set of replacement motors, control boards and a new handset, plus any parts like gear sets that may be faulty. I would take a look at the motors, and if there is a way to adjust any meshing see if that improves things. If you have access to another power supply that has enough current rating try using that. If none of that resolves the issue, but the scope still tracks at sidereal rate, then the choice is yours to use the scope manually, purchase a complete new goto kit and have the scope serviced, or cut your losses, flog some of the parts or sell the scope as faulty, and look at getting a replacement. Sorry, but I have nothing else to offer - any diagnosis of the motor board is beyond my level of expertise, and even then given how damaged the board was around where the capacitor was fitted it's impossible to say if any shorts or breaks have occured on the inner layers (the boards have four layers of copper traces.). I hope you can resolve this issue, and hopefully other forum members can chime in here and comment on the videos and possibly come up with a possible solution. (Geoff just posted as I was typing - which would suggest that the encoders might be the first thing to look at, along with the meshing of the drive)

I posed the question about the jumpers to OVL - This was the response I've asked for better clarification as to why if JP1 is short the scope would move in the opposite directions, and what is meant by Dob tracking and Dob goto when the MC003 is fitted to all goto mounts - and what the hex reference is (0x90 0x91) related to. As you can see, trying to get detailed information that is easy to understand is often not as straightforward as it may seem. Hopefully OVL will come back with more details

Geoff, I don't believe it's possible to control the mount from both handset and software with the Synscan handset as it needs to be set into PC-Direct mode, which as mentioned simply acts as a relay to pass on commands from the PC. It's been a long time since I used Stellarium (it needed a 3rd party plug in to work with synta mounts at the time ! - I'm betting now that the relevant telescope drivers are built in), so can't really comment on that. EQMOD can be used for visual observers who have permanent set ups in observatories etc. But has advantages in control when it is used with an imaging set up. I can't really see any advantage of using a PC and planetarium software just to move the mount for visual observing when the handset does the same, and with less complexity. By the time you've connected the handset, booted the laptop, waited for windows to load, launched the software, hopefully connected to the mount without any trouble spots, and then selected the first target you could have been observing the target if just the handset was used.

The guys have asked for more details. Can you provide info on the mount you are using, details of the guidescope and camera used. It would be helpful if you could provide screen captures of the configuration settings so it can be confirmed if you have set the values correct in PHD so it can calibrate correctly. Notes on setting EQMOD up for PHD2 guiding can be found here

The ironic thing is that given how flakey Prolific drivers are under windows 10 (which as mentioned is very well documented), as every windows update renders the prolific drivers inoperative, Skywatcher opted to use this chipset in all their devices (handsets/mounts) that use a USB cable. Driver here In essence what they have done is taken an EQDIRECT cable and placed it internally in the devices so a standard USB cable can be used. The problem is that they should have used FTDI chipsets rather than PL2303. Unless this was "chipset" standard built into the ARM processor assuming the ARM processor has direct USB connectivity. If the mount has an USB port then use a standard USB cable, otherwise I would still suggest using the tried and tested EQDIR cable. Regardless of the method, Geoffs comment about dispensing with the handset is irrelevant as it plays no part in controlling the mount when EQMOD and a PC is used. Even with the handset placed in PC-Direct mode it's only acting as an EQDIRECT cable to pass commands from the PC through to the mount, but using the handset in this way does indeed save the £34 on a commercial EQDIRECT cable as Geoff suggests

Daz, you do realise the last post was two years ago... I would have thought the issue would have been resolved by now 😉