Hardware and software advice needed for upgrading to guided imaging

[Mick J]

I think maybe a leisure battery in a plastic box, which I would keep in the shed and bring out for each session, has to be the way to go, assuming I can get some kind of converter do that it can power the laptop.

Either that or I could try using an Android tablet, but I guess the battery wouldn't last for that either.

Not sure an Android tablet will run the software for you,  a Windows tablet may, but tablets have limited storage and usb ports,  there must be a simple diy voltage jump up whatsit to allow running off a leisure battery.  (Edit:  seen these on ebay )

What voltage will the laptop need ?  my old netbook is 12volt.

You can get Inverter's  12V DC to 240V AC but may be overkill.

You will have to keep the leisure battery charged.

These are just idea's popping into my head, I am sure others will have more knowledge regarding voltage.

great thread, good to see you progressing.

[D4N]

Dithering is very helpful with a DSLR, you will find it very difficult to process out the noise otherwise.

How you create a bad pixel map depends on what you use to stack. In Nebulosity it is in the processing menu and they are pretty much just dark frames with the noise ignored. I don't think that it is an option in DSS.

I don't use APT so no idea about the settings, just make sure it is saving as RAW at the highest resolution available.

Mains supply for the laptop would be a good idea, just make sure you protect the transformer and any connections from moisture.

I use a laptop on mains supply in a plastic box, the laptop has its lid closed.

I control the laptop over wifi using my iPad. TeamViewer and VNC both have free software to allow you to do this.

Even if you did this without the mains supply the laptops battery will last a lot longer if the screen is turned off.

/Dan

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[ianpwilliams]

I'll maybe look into dithering later on, the first step has to be to successfully guide etc (which was the stage I never reached), and get some good long subs, and some darks, and then look into dithering later.

The power thing is a big issue though. I'm not even going to try the laptop with its own battery again, because even turning the display off won't work I don't think. And I suspect you're right about there not being enough USB ports on a tablet (I currently use three, going to the mount, the guide came, and the DSLR).

I just don't think mains is going to be possible. I'm in a second floor flat, and it's a shared garden, and I'm sure the shed has no mains power. So it would be a case of hanging an extension cable out the window or down between the stairs, but of which could be hazardous, and a pain to set up every time. And depending on where the mount was (it's a big garden), the cable would have to run across the grass so it would have to be insulated somehow. Having said that, even if I used a car battery or similar I would still have to lay the cable across the grass, unless it was in a box right next to the mount I suppose. It would certainly be nice to be able to power the laptop and not worry about it packing up.

And I've never really thought about dew heaters either. That's another expense which I suppose I would have to consider.

I think I'm at a crucial make-or-break situation now when it comes to astrophotography. The fact is that guided imaging is really geared to people who have their own private gardens with their own mains power, and ideally with their own home-made observatory. So I may eventually have to accept that in a rented 2nd floor flat with a shared garden it just might not be possible. Not to mention that last night's session involved three trips down two floors and then three trips back up, although if my landlady can empty the shed then I can leave a lot of equipment in there (it's safe), and possibly a car battery or similar as well. Worst-case scenario I suppose I could do guided imaging just using a 250mm or so lens (which would be a hell of a lot easier with there being no scope etc), and produce much wider FOV images. That would certainly be better than just giving up entirely. But I haven't given up on guided imaging of DSOs just yet.

So it's crunch time really. I need to think of power options!

[D4N]

What will be easier, lugging a big battery out of the house or running a cable out? There is no point keeping the battery in the shed if there is no power there to charge it.

There are readily available outdoor cables you can use that are fine to run across the grass, just try and keep the connections dry.

/Dan

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[ianpwilliams]

The laptop appears to be 20V. It is a Lenovo Thinkpad x200s.

[salas]

Could buy a couple spare latop batteries and have them on standby, would just mean suspending everything to change the battery, or you can get jump start type battery packs with built in 3 pin plug 240v inverters. I would probably lob an extension cable out of my window but thats just me.

[ianpwilliams]

I guess I would hang a multi socket extension cable down the inside of the house between the bannisters to the back door, and then a 20v insulated cable outside to the laptop, and another insulated cable to run any dew heater that I might buy. I would still run the mount and DSLR from batteries because they always last a full session, and it would be nice to keep the cables on the lawn to a minimum.

Would I need some kind of PSU device at the point where the extension cable ended? And how would I insulate the outside cables? Could I maybe buy an extremely long 20V cable that was already insulated?

[D4N]

Domestic cables are already insulated, it is only the connections at the end that are not always waterproof.

I wouldn't run a 20V cable down the lawn, you may start to get an unacceptable amount of voltage drop if it is a big garden, I would run 220V all the way to the mount then have a plastic box with the laptop PSU in it.

You can have a 12V PSU for accessories in the box too.

You can get outdoor cables where the connectors are IP rated but the safest thing is still to have the connector protected from water.

/Dan

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[Pompey Monkey]

Make sure to use a RCD where you plug the extension lead in!!!

[ianpwilliams]

What's an RCD again? I'm useless when it comes to electrical stuff.

So I would plug the RCD into the wall, plug the extension cable into the RCD, run the extension either down between the stairs or out the window, all the way to the mount, and then have the multi socket end resting inside a plastic box?

And it sounds like I wouldn't need to have anything resting between the extension cable and the lawn, correct? It still seems wrong to me having a mains cable running along a dewy lawn.

[D4N]

Residual Current Device, it cuts the power if it detects earth leakage.

You are correct in how you would use it.

It won't hurt the cable to be in the grass, that is how electric lawn mowers work after all

/Dan

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[Thalestris24]

Hi Ian

You can get a 12v car adapter for your x200s: http://www.amazon.co.uk/Charger-Thinkpad-ORIGINAL-ELECTRONIC-EQUIPMENT/dp/B00C2CYN6G

Louise

[ianpwilliams]

Hi Ian

You can get a 12v car adapter for your x200s: http://www.amazon.co.uk/Charger-Thinkpad-ORIGINAL-ELECTRONIC-EQUIPMENT/dp/B00C2CYN6G

Louise

Which presumably would enable me to power the laptop from the Tracer battery. Although I don't know if the 22Ah Tracer would manage to power both the laptop and the mount for a full session, and I guess I would need some sort of splitter too.

The other consideration is dew on the scope. I've just been looking on FLO at their heated dew shields. They say that depending on where you live a normal non-heated dew shield might be enough (maybe £30?), but that if you're in a place which is more prone to dew then you might need a heated dew shield, and therefore dew strips and a regulator (probably more like £100?), and then you'd need power for it. How do I work out whether a normal dew shield would be enough or whether a heated dew shield would be required? Up until now I've just used a cut up piece of sleeping mat as a dew shield.

If a non-heated dew shield would be enough, and if the 22Ah Tracer battery would be capable of powering both the mount and the laptop for a full session, then maybe I could forego mains power after all.

Another option (assuming I didn't need a heated dew shield), could be to buy another Tracer battery just for the laptop. After all, if I go mains then I'll have to buy a long multi socket extension and an RCD anyway, and the total price for those might be on a par with a Tracer battery, depending on what Ah I would need to go for.

[D4N]

A non heated dew shield is effectively a cut up camping mat repackaged anyway

I built my own dew heaters, the parts are very cheap but you need to be proficient at soldering to make them.

/Dan

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[Pompey Monkey]

Residual Current Device, it cuts the power if it detects earth leakage.

You are correct in how you would use it.

It won't hurt the cable to be in the grass, that is how electric lawn mowers work after all

/Dan

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Foxes think my mains leads are snakes or something. On sunday night my RCD saved the life of one particularly destructive fox.

But not my extension cable!

[D4N]

If you didn't have an RCD you wouldn't have a fox problem anymore [emoji48]

/Dan

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[salas]

One other option to extend laptop battery life to up to 6 hours - something like this

http://www.amazon.co.uk/Powertraveller-Powergorilla-Multi-Voltage-Portable-Charger/dp/B001FQP1MK

Would save faffing about with a big cable run. Could then use your tracer battery to power the mount and dew heater if you decide to get one. DOenside is its more expense!

The 22Ah battery you have is pretty beefy and without doing any calcs I'm pretty sure if you go down that route it would easily power, the laptop, mount and dew heaters for each session.

[ianpwilliams]

In which case would it be possible for me to buy a multi splitter for the Tracer I wonder?

[ianpwilliams]

Looks like this is what I need (thanks to FLO):

http://www.maplin.co.uk/p/four-way-accessory-socket-adapter-10a-l94aw

But I would need an inverter because the laptop is 20V.

So for now I think it's a case of sticking with my camping mat dew shield, buying that splitter and an inverter, and calculating the draw of the mount and the laptop in order to make sure that I would be covered for a full session.

[ianpwilliams]

Does anyone know what I need to be searching for in order to connect the laptop PSU to one of the four ports on that Maplin adaptor (and then I would connect the mount to one of the other ports)?

[D4N]

A car power inverter should do the trick.

http://uk.rs-online.com/web/p/dc-ac-car-power-inverters/5388743/

Just make sure it is rated high enough for your laptop, that one is 100W, there are bigger ones but they cost more of course.

/Dan

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[Mick J]

Does anyone know what I need to be searching for in order to connect the laptop PSU to one of the four ports on that Maplin adaptor (and then I would connect the mount to one of the other ports)?

I think Louise has linked to a '12v to your lappy charger'  that may be better than an inverter, you can start out with both laptop batteries charged, with the charger connected you may be able to swap batteries......... you would need to check I have never done this........

Is there no mains socket on the flats stairway near the ground floor ?

[ianpwilliams]

I couldn't find any sockets in the downstairs hallway, but I'll have another look to make sure. But it's looking like

An in-car charger (probably not this one though because I've seen quite a few cheaper ones):

http://www.maplin.co...apter-10a-l94aw

Would the two above items work together, both with the mount and the laptop?

I've attached a photo of the power pack that came with the laptop. FLO reckon that the HEQ5 Pro SynScan draws about 2A when slewing and a lot less when tracking.

But the output of the laptop PSU seems to be 4.5A. So if that was a total of around 6A, doesn't that mean that I would only get about 3.5 hours from the 22A battery?

If so, I guess the laptop battery would kick in once the the PSU ran out, which would give me a couple of extra hours, which would be enough on top of the initial 3.5 hours. But I'd have to make sure that the battery was fully charged because the Lenovo website says that the battery must be charged at at least 10C.

[D4N]

It is a bit more complicated than that, the output may be 4.5A but that is at 20V, it says that the input is 1.5A at 100-240V AC, however you will be taking your 12 volt supply and inverting it to 240V AC.

90W at 20V DC is 4.5 amps, at 12V DC it is 7.5A.

That will give you a total of 9A so only 2.3 hours from your 22A battery.

However just because the AC adaptor says it is 90W doesn't mean that it will use 90W constantly.

If your battery is fully charged to start with it will only use power at the rate the laptop is using it plus any waste to heat.

Your links don't work for me so I can't see what items you are looking at.

/Dan

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[ianpwilliams]

They are the same links as above, not sure why they aren't working

http://www.maplin.co.uk/p/four-way-accessory-socket-adapter-10a-l94aw

http://www.amazon.co.uk/Charger-Thinkpad-ORIGINAL-ELECTRONIC-EQUIPMENT/dp/B00C2CYN6G"

But yes, it's looking like I may be heading back to mains power then.