Archive | November 2009

Arecibo Observatory Feed Movie

While I was out the other day I made a short movie of the Arecibo feed moving. This is of course the only way the telescope “tracks” any source as the dish (being 305m in diameter) doesn’t move:

(if you can’t see the embeded video see [here])

Colraf: making colour astronomical images

Earlier this year I put together a few scripts that takes rgb FITS files and makes nice colour images. This was completed as part of development of tools for the University of Birmingham Observatory. Anyway, I meant to make this available before but I didn’t have the chance to make it friendly. Its quite simple to use but requires the user has [IRAF] installed. Examples of the images this script produces can be found on my flickr pages, but here is one for starters:
M20
Getting the scripts: [colraf.tar.gz] (version 1)
Using the scripts:
Before running anything you must ensure that you have IRAF installed correctly and that you edit your LOGIN.CL file such that it expects to use FITS files, essentially uncomment the set imtype parameter:

set imtype = “fits”

Before running the task you should make sure that the images have names of a certain format. Flats need to have FLAT, darks need to have DARK and bias images should be prefix by bias (see the wast1.cl script for more info). The colour images have to have RED, GREEN and BLUE in them. You can use to help with the organisation.
Then you need to run:

script.sh

The purpose of this is to do preliminary work on images before running IRAF. Firstly it will ask you for your reference image. Give the fits file. It will then open an editor (it uses pico but you can easily change this to use another) asking you to put in the coordinates of some reference stars that you can see in all filters (you need to give x,y pixels with a space in between – you need at least 3 positions).
This will open up and xgterm window.
Once open you need to run the first iraf script, like so:

cl < wast1.cl

Purpose: To make combined, dark / bias images and remove these along with the master flat field off images taken at the observatory.
Followed by:

dimsum
xzap (inlist=@zapin,outlist=@zapout, zboxsz =5, nsigma = 4, nrings =2, nnegsig=0, nobjsig=2, skyfilt=15, skysubs=1,deletem=yes,statsec=, cleanpl=yes, cleanim=yes,verbose=no,checkli=yes)

and then:

cl < wast2.cl

Purpose: aligns and combines the images, finally making a colour composite and deletes junk files and puts the files into “original and final”.
This post was last updated on 9/02/2010 to add some bits and pieces to the documentation that was missing.

Arecibo observing day 2

Last night was pretty cool, I got to be in control of Arecibo on my own (quite a scary and proud moment to be honest) and it all went according to plan. I get to start the observations on my own today too, so that’s going to be fun (just better make sure it all goes according to plan!). I have to say I’m quite enjoying it out here – there is something about observing that I do really enjoy (and find quite relaxing), maybe I should consider becoming a telescope controller…
Arecibo receiver
Sunrise and a rather demented (and tired!) looking me:
me at Arecibo, sunrise
I took a walk down to the dish earlier today, not all the way down (I was too tired and it was rather hot!):
Arecibo dish
under the Arecibo dish

At Arecibo

So I’m sitting down, relaxing after a stupidly long journey (Calgary -> Seattle -> New York -> San Juan in the air and then by car to Arecibo), getting ready for my first observing session with the world’s largest single dish telescope. Not bad for a Tuesday night really. Oh and if you were wondering I am Arecibo…
Arecibo Day 1

Zombies, Halloween and Skyscrapers

Over the last few weeks I’ve been pretty swamped with work, which isn’t entirely a bad thing (progress etc…), but I’ve not been able to get out and take photos or be bothered to upload the ones I took so here are a bunch of pictures taken over a few weeks in Calgary. It starts of with my encounter of the Calgary Zombie walk as I went to the shops, goes onto Halloween celebrations over the last weekend and then a nice crisp November walk along the Bow river and the downtown to take pictures of Skyscrapers.
A grim scene
Star Trekking Zombies…
Star Trek Zombies...
Owl pumpkin, Canadians seem to take Halloween pretty seriously by the number of people I saw dressed up all over the place.
Pumpkin owl
Time for some rockabilly… (was a bit like being at a ceilidh without the organisation)
KGB carn-EVIL at Dickens Pub
I hate waiting for trains… (especially when they must be a few miles long, darn freight trains!)
Freight train (BW)
Sadko!
Sadko + glass towers
Skyscrapers..
Reflections of a glass world.. skyscrapers on 4th St SW
Reflections of a glass world.. skyscrapers on 4th St SW