Observable sky

[dawson]

Is there any software which can look at the panorama of ones garden and adjacent trees and houses (for those of us unfortunate enough to have neighbours) and for it to identify what objects will and won't be viewable throughout the year? Of do I just need to work out myself how much above the horizon I can and can't see in each direction and do the "math" myself?

 

Thanks

 

James

 

P.S. I just did a panorama of the garden but it's a bit big to post!

[Tweedledee]

http://www.stellarium.org/wiki/index.php/Creating_a_Personalised_Landscape_for_Stellarium

[Guest Simes]

You can input your garden panorama to SkySafari - that will achieve what you're after.

[Tweedledee]

When you've read all that James, perhaps you could explain it to me

[dawson]

Pete! I just loaded GIMP and inserted the panorama then I started to read and gave up. haha

 

I'll try looking at SkySafari and see what that does.

 

James

[dawson]

Stuff it, it's all to complicated.

 

James

[+RonC]

I did it on paper James, just point your scope around the garden and write down the minimum angle you can see at that point. Than draw yourself a kind of graph using those angles. Clear?

Ron

[catman161]

Maybe have a read of this James

Custom Stellarium landscapes

http://www.astronomyshed.co.uk/forum/viewtopic.php?t=500#p2530

[Guest Eddy]

Looks simple enough in Felix's post, but not sure how well it would work in a back garden, especially if you have a garage right next to where I observe, I may do one at Belper next time I go and then share it with anyone who wants to use it

[dawson]

Felix, I found a similar thread on another forum. Just been doing it. Sop far I've got my garden in Stellarium but the sky is white as I've not removed it sufficiently, and the foreground is very close!

 

I'll try again. It's not as daunting as I thought. I think getting the foreground to be correct will be hardest part.

 

James

[dawson]

Well, I've done a first draft! It looks OK. I need to 'calibrate it' when the sky is clear to make sure I've got enough foreground, or not too much. I also need to do a detailed crop of the sky so it's neater.

 

My house is on the left, still with the downstairs curtains shut as I've been busy beavering at my computer upstairs all day!

 

James

 

[dawson]

Right, did a bit of tidying up of the edges, and it looks much better. The trees are an issue, but I think I could just block those out totally in black, or green so there is less white background:

 

 

[dawson]

Trees and white blocked out with green.

 

I think with a little more time this could be made to look good.

 

James

 

[dawson]

After a bit more fiddling, this is the final version. I used Ron's advice, got the telescope out at the place where I stood for the photography and measured the angle at which the sky was observable about the roof, and altered the foreground and sky to get the angles roughly the same (there will be some error as the telescope was nearer the ground than the camera was when I was holding it). I want to check the angles of other bits on the horizon at some stage; if it's not, I think it's tough. I should have mounted the camera on the mount with my my dovetail camera mounting bar and done it that way, but never thought of that first thing. Also, as the trees grow and come into leaf, I'm sure the observable sky will reduce.

 

Anyway, I'm pleased.

 

James

 

 

[catman161]

That awesome James-well done. I have been meaning to do this too. You have inspired me. I think I will have a go next weekend

[dawson]

It's not difficult, just time consuming. I'll put together some extra instructions which that link doesn't make clear. Lunch time now!

James

[+RonC]

Please do James, I have a panarama of the garden but have never got round to sorting it out for Stellarium!

 

Cheers

Ron

[dawson]

Creating your own foreground for Stellarium.

 

Make your panorama. Ideally take your 360 degree pictures at the height of your telescope, and it might be easier to mount the camera on the mount and rotate it 360 and take your frames  that way. There are various programs on the net which are free and which will stitch your frames together to make the panoramic shot; I used Microsoft’s Composite Editor, which is free.

 

I’ve used a panoramic off Google as I don’t have mine to hand now.

 

Image, Panoramic.

 

Next you need to add more foreground and more sky to your panoramic shot. I opened my panoramic image in Microsoft Paint; change the zoom (bottom right slider) so the whole shot can be seen in one go. Increase the size of the white background the image is sitting on by grabbing the little white dot at the bottom right of the image and drag it right and down.

 

Image, Panoramic1

 

Select the panoramic and drag it to the centre of the now enlarged background. To increase the foreground, I just copied and paste a horizontal strip of the grass at the bottom of the panoramic shot and kept pasting it on so the foreground builds up and looks similar. Here I’ve done it with the gravel in this shot.

 

Image, Panoramic 2

 

Image, Panoramic3

 

Then, select only the image, copy, select all, delete and paste which will insert the image to the top left. Then re-size the white background so it fits snug against the image again.

 

Image, Panoramic4

 

Now, save the image to the desktop as whatever name you want but as a PNG file.

 

Now open the Stellarium folder, mine is: computer, local disk ©, programme files, stellarium

 

Open the landscape folder. In there create a new folder and call it whatever you want, mine is “gardenâ€.

 

Go into any of the older folders in the landscape folder. Copy the configuration file called ‘landscape’ (it’s an ini file apparently). Go into your folder now and paste that file into your new folder.

 

Now, drag your panoramic PNG file into your folder too.

 

Open the landscape.ini file by double clicking it. Select all and delete. Copy and paste this in:

 

[landscape]
name = Enter your landscape name here
author = Enter your name here
description = Enter a description here
type = spherical
maptex = yourimagename.png
angle_rotatez = Enter angle

[location]
planet = Enter planet
latitude = +XXdXX'XX"
longitude = -XXdXX'XX"W
altitude = X

Click save.

Now before you close this note pad file, you need to enter some data into the above code. My data is:

[landscape]
name = garden
author = james
description = garden
type = spherical
maptex = yourimagename.png (copy the precise name of the PNG file and paste it here and it must have “.PNG†at the end of the file name]
angle_rotatez = 80

[location]
planet = earth
latitude = 52.917672
longitude = -1.154262
altitude = 27

 

 

For “angle_rotatez†you’ll need to alter this later. Essentially altering this number (0-360) will align north in Stellarium with your north of your real life foreground.

 

Click save again and close the ini file.

 

Now, open Stellarium.

On the vertical menu (left hand side), select “sky and viewing optionsâ€.

Select “landscape†option from the menu bar. Select the landscape you’ve designed, and check the “keep this as my default landscape†box. Close the boxes and look at your landscape in all its glory. There won’t be any stars at this stage, don’t worry.

 

Click on the top of your foreground, on the top of a roof or top of a tree where the foreground meets the sky, and see what Stellarium thinks the altitude at that point is (the data will appear in the top left of the screen). Compare Stellarium’s altitude with your measurement of the altitude you’ve measured using your telescope and mount from the same position you took the photos from; if the telescope is parallel with the ground at 0 degrees, at what altitude does the roof top meet the sky in real life.

 

Now you need to alter the amount of foreground in your image file to get the Stellarium angle and the real life angles the same. I did this by trial and error. Open the image again in Paint, and add or remove more bottom foreground (as done previously). Save the image again and put it back in the landscape folder you created; if you’ve changed the name of the file, update the file name in the *.ini file. Then reboot Stellarium and check the angle again. It will take many attempts to get it about right.

 

Once you’ve got the amount of foreground correct, you need to remove the sky.

 

I opened the file in Adobe Photoshop CS2. Use the lasso tool (it looks like a lasso) to draw around, and remove the sky. Best to zoom right in for this job. Lasso along the horizon between the foreground and the sky, hit delete when you’ve linked the lasso line back on itself. The chequered background will appear indicating that bit of the image will be transparent in the final image. Your task is to make all the sky transparent. It is easy to do this against the straight lines of a roof but tricky with a tree. What I did with trees was to draw in green blobs oer the outline of the trees and bushes, so this prevents the stars from being seen through them, but also hides any white light which would otherwise shine through and look odd in the final product.

 

Once all the sky is removed, save again as a PNG file and drag it back into your folder. If the file name has changed update this in the associated *.ini file.

 

Now re-run Stellarium and hey presto, it should be your desired foreground, with the correct perspective, and a translucent sky showing the stars (if you’ve got it in night mode).

 

Well done.

 

Common problems I encountered:

 

Getting the perspective and angles is tricky, but do-able.

Make sure you update the name of the image file in the *.ini file else it won’t work when you boot Stellarium. And make sure the image file name ends with “.PNG†in the *.ini file.

Blocking out trees with green blobs was a good idea.

 

Good luck.

James

 

I’ve copied the code above for the *.ini file from this website:

http://www.astronomyshed.co.uk/forum/viewtopic.php?t=500#p2530

Thanks to that author.

[dawson]

Accompanying images

[dawson]

There is a screen shot of mine a few postings above. I didn't load the gravel example into stellarium a i was being lazy. I can email anyone my panoramic file so they can run it on their own computer to see, but the file is 45MB i think. Happy to send though with instructions.

Or pat, invite me for a cuppa and i'll bring my laptop and show you

James