total NEWBIE!

[Jay Hoe]

Hi

I have never done a launch before and am looking for help and advice!  I have very quickly got lost on all the technical side with Pi, scripts etc etc.on this site

All I am looking to do is one launch, looking to go as high as possible (30k+ metres). The only data I need to gather is height, and video.  I have looked at stratoflights.uk to get me the basic kit, after which I would be looking to sell bits on probably.

1. I know I have to get approval for the launch and am about to start that

2. Is stratoflights kit very pricey? Is there a better supplier for a basic setup for a newbie's single flight!

3. I have no idea where I get the gas from :-)

4. As this is the only time I plan on doing this, is there someone experienced who is happy to hand hold me (via email) to make sure I get a viable package together! 

5... And very important for my project... I want to film without all of the barrel distortion that is so often seen. What sort of camera would be best for this?

Can any of you kind people recommend the basic equipment I will require and ideally the best supplier for it.

Oh, I'm UK.  I know there is fancy tracking that you guys use and your talking about frequencies and servers and scripts or what ever.... I would be happy with a basic tracker just so I can locate the thing afterwards!

Sorry this is all very basic level stuff, but I want to do this with my daughter as a one off and we want to try to film the curve of the Earth without any issues of distortion. possibly also placing a line or grid across the field of view to prove there is a curve and not camera distortion. I have a cheapo goPro style camera that I will probably also add just for the view (although it will distort).

So by my dumb reckoning, items requiring power are Tracker, Datalogger for altitude, camera for the view and non distorting camera.

I appreciate any and all comments, help and advice!

Cheers

J

[David Akerman]

To start with, have a read of https://www.daveakerman.com/

I'm sure there are others, but the Gitup Git2 camera comes in two variants one of which has a regular lens rather than the usual extreme wide angle lens that action cameras usually have.

The kit you mentioned comes with a simple but (in my experience anyway) unreliable tracker, so I'd avoid it.  Have a read of the above document for advice on how to choose a good tracker.

Dave

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[John Laidler]

I'm a newbie too but I'm going down the DIY route with homemade trackers using the Pi Zero design on Dave Ackerman's website. These cost around £50 each in components, the GPS module is the most expensive bit at £25.

At the risk of being slightly controversial, even from an altitude of 30 km you can't really see the curvature of the Earth. What you will see is the horizon, which will be a circle all around the balloon. Of course the horizon is only there because the Earth is curved so you can infer the curvature of the Earth from the presence of the horizon but I don't think you can actually see it unless you go far into space and can then look down at the disc of the Earth.

Cheap GoPro copies don't have a good reputation of working at the sub-zero temperatures found at altitude. You could test yours out by putting it in a poly bag in the freezer overnight but even if works at -20C that won't mean it will work at -40C.  I plan to use a Raspberry Pi camera.

BOC are the usual suppliers of gas. Helium is safest but there is a shortage of it and you may not be able to buy any. I plan to use hydrogen but getting set up isn't cheap. The regulators are about £100 and the bottle of gas around £75. You may also want to consider insurance but that is another £100.

Best wishes,

John

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[David Akerman]

Couple of things on that:

"At the risk of being slightly controversial, even from an altitude of 30 km you can't really see the curvature of the Earth. What you will see is the horizon, which will be a circle all around the balloon. Of course the horizon is only there because the Earth is curved so you can infer the curvature of the Earth from the presence of the horizon but I don't think you can actually see it unless you go far into space and can then look down at the disc of the Earth."

Indeed.

"Cheap GoPro copies don't have a good reputation of working at the sub-zero temperatures found at altitude"

Actually, I've found them to be more reliable than GoPros which have suffered from dodgy firmware or overheating.

Dave

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[John Laidler]

Thanks for that on the GoPro lookalikes - I must have misread something.

And sorry for misspelling your name!

John

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[Steve]

The main issue with non distorting cameras is weight and size. 

Cameras with short focal length lenses and wide field of view will have significant barrel distortion.   The small lightweight action cameras that we use for HAB fall into that category.  For those focal lengths can be a few mm.  We also tend to use wide fields of view are used to capture the breadth of the scene and also to stop the view wizzing rapidly past as the payload swings and rotates.

Most camera / lens combinations create either a barrel or pincushion distortion - but in many cases it's not noticeable - particularly larger cameras with large sensors where even a wide angle lens will have a much longer focal length than an action camera.   Even so, professional photo editing software (e.g. Photoshop) includes correction data and can reverse the distortion.

Recently some action cameras (e.g. Gopro Hero 5,6,7 & 8) have started to include a Linear Mode that does the correction on the fly.  My own use of these cameras tends to show the correction is not 100% but a great deal better than uncorrected.

At 30Km the visible horizon is 620Km away and just 5.5 degrees below the horizontal - if you drew a 1.24m diameter disk and viewed it from 30mm above the center then that's the view you are going to get.  Your going to see curvature - but its that of viewing a disk at an angle - (as John says) your not really proving the earth is a sphere - it could just as easily be a 1240Km diameter flat disk** - if you were to take measurements at various altitudes you might prove the point.  At 40Km the horizon is 715Km away and 6.4 degrees below the horizontal - so the measurable effect is very small.

I've used Linear Mode GoPros and non distorting DSLRs and the "curvature" is noticeable at 30Km.

GoPro: - while I know others have experienced real problems - and I've seen flaky hardware/software myself (esp GoPro 4 black) I've never had a problem with one in flight as long as the temperature is not allowed to get too high.

    Steve G8KHW

**Oh no - puts flat earther foil hat on.

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[stephen billings]

Hi Joe.  Where are you based?  As you are looking at around 30k feet, have you thought about a solar balloon?  No need for gas, and they can get over 30K.   The small ones, you could get years ago, had warnings on them, about letting them go.

And some were spotted by airline pilots above 30K.  Indeed a group on the continent, (Poland I think)  were going to use one, to lift a rocket, to take part in the original X prize competition.  In one lift test, it broke free, and was brought down after it had passed 60K feet.  So you can see it could be a possible alternative.  Also I have found that as you can get 50ft long ones on the internet, there is technically no need to get launch permission.  As you could say it wasn't tied on to the line right.  ;)   I have seen at least two of the 50ft ones launched, at different events at Santa Pod.  One of those should be enough to lift a basic camera and transmitter.  As I have lifted 125g with a homemade 30ft one.  (Wheelie bin bags and 2inch wide tape.)

Stephen Billings.

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[Jay Hoe]

Thanks Dave for the camera recommendation - it looks good and sensible price.  I am reading your site now - thank you!

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[Jay Hoe]

John

I'm afraid DIY tracker is outwith my skills - I'm looking to buy a solution (and then probably sell it on after the one flight).

Cheers

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[Jay Hoe]

Seeing any curve would be great - it would prove the earth is not flat!!  :-)

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[Jay Hoe]

Stephen,

pretty much in the middle of the UK - Banbury area. I am happy to travel to go to the best launch location.  Interesting solar balloons! Never heard of them before.However I want to more reliably get up to height.  John

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[Nick McCloud]

On Thursday, 25 June 2020 14:23:19 UTC+1, Jay Hoe wrote:

pretty much in the middle of the UK - Banbury area. I am happy to travel to go to the best launch location.  Interesting solar balloons! Never heard of them before.However I want to more reliably get up to height.  John

I have a backlog of launches, some of which aren't school ones, which you could join in with, you'd have to come 'opp north' - Peak District - or maybe make it a launch party and I can see what we could schedule down south - at present business is somewhat quiet and I'm not going to try to flog (anything or a dead horse) until Q4 so time on my hands.

[Jay Hoe]

Hi Nick - thanks for the response!

It's not going to be possible to come to the Peak District I'm afraid. I have been doing a ton of research nad am having some discussions with someone regarding helping me out.  I very much appreciate your kind offer though.

Cheers!