Welcome traveller

This blog is very much written for my benefit. I've previously tried writing a blog, but I got bored as I had nothing particularly interesting to say. In this blog I will be mostly documenting my progress when it comes to astrophotography. There are many resources on the web for astrophotography, but crucial and useful details are often overlooked. This is a my astro-journal.

21 February 2012

Processing Jupiter with Registax and Gimp

In this post I'm having a proper crack at Jupiter in Registax and Gimp, and documenting the process.  The post is for process steps only - play with any and all parameters until you get the image you like!  Below are all images of Jupiter produced from the same .avi capture.  Which is your favourite?

I)

II)

III)

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Processing steps

1) I took ~1800 (3 minutes) frames of Jupiter on Sunday 19th February 2012.  The capture parameters are shown below.  I used my Celestron 6SE with a Tele Vue 2.5x and my Orion Starshoot IV webcam.  The video was captured with SharpCap.

[D-PEN]
Frame Divisor=1
Resolution=1280x1024
Frame Rate (fps)=10.00
Colour Space / Compression=RGB24


The gain was set very low - just enough to show a little detail.  The image below is a single frame and demonstrates how the image appeared on my laptop.  Still playing with the contrast/brightness etc, but set parameters that make the image look reasonable.









2) Open the video in Registax 6.


3) Align the image and hit limit.

4) Stack, set the wavelets and align RGB.  Also play with the brightness and contrast..

5) Might also help to play with the histogram..

6) Autobalance for giggles?

7) Final Registax image - save as a .png somewhere


8) Open Gimp and load the image.  Adjust the levels

9) Adjust brightness and contrast

10) Despeckle the image (in filters)

11) Unsharpen mask (in fliters)

12) Adjust the colour balance

13) Adjust hue and saturation

20 February 2012

Astro image processing with Virtualdub

Yesterday, Sunday 19th February, I recorded a few .avi files of Jupiter.  One can process the .avi directly, but sometimes it helps to split the .avi into a series of jpegs for greater control over the frames used for stacking.

I will post about last night's observations at some point, but this post deals with the Virtualdub processing.

Virtualdub is a free video processing utility and can split a single .avi into a series of jpegs.

1) Open Virtualdub and open the video capture .avi
2) Export .avi as image sequence

3) Select export settings and hit 'OK'.  Note that the file extension should be .jpg rather than .jpeg for Registax to notice.













4) Go to the directory location of the images and do as you wish with them.

17 February 2012

Jupiter - a first crack

For my first post I thought I’d have a crack at Jupiter. I might put together a better tutorial on Registax 6 at some point, but here’s a first go to test the format of posting a "journal" of my steps.

I used my Orion webcam at the prime focus of my telescope – at some point I might cover the tips and hints to get a good focus /alignment and all that jazz.  The webcam captured the image of Jupiter over a period of about 3(ish) minutes or approximately 1800 frames.  The details of the capture are given below:
Resolution=800x600
Frame Rate (fps)=10.00
Colour Space / Compression=RGB24
Exposure=13
Brightness=31
Contrast=136
Hue=139
Saturation=129
Sharpness=119
Gamma=67 

Below is an example of an 'untreated' Jupiter frame:

I then used Avidemux (I think) to convert the captured video file in .avi format to a series of jpegs – I’ll cover the capture and up-front processing another day.
In Registax 6, I used the following settings:
Align: 
Alignment parameters: Min distance 5: min distance from edge 20            
Intensity: 3x3 area; low 5; high 230 – 27 alignment points (APS) used.
Best frames: 1000
Stack:
Normalisation of frame intensity
Correct geometry
Stretch histogram after stacking
Wavelet:
Use interlinked wavelets
Parameters below:

The final image of Jupiter, with brightness levels tweaked in Gimp - will also cover this someday.

An improvement? - yeah, I think so but plenty more tweaking and learning to be done.

UPDATE: Used the same data and played around a little more with the Wavelets and number of frames.  Key difference in the below image is that I only used 1000 frames to begin with to avoid planet rotation screwing up the detail.

15 February 2012

Astronomy software

Getting one's ass outside to set up the telescope and actually take the images is only the first part of the process. Arguably the most time consuming aspect of astrophotography is the processing that takes place afterwards. Although, it's during that stage that the images come to life. In this post i'm going to list the various programmes I use or have come across that might be of some use. This list isn't definitive and will be updated as I find other useful programmes. As I'm generally cheap, I'm avoiding paid software and focusing Open Source programmes wherever possible... :)

Planetarium software:
Stellarium
SkyX First Light Edition (came with telescope)

Capture software (webcam)
SharpCap
Orion AmpCap
D-PEN AMCap
wxAstroCapture

Stacking software
Registax (planets)
Avistack (planets)
DeepSkyStacker (deep sky)

Other useful tools to convert avi captures to jpgs or extract segments of video
Avidemux
RAD Video Tools
Avisynth

Image editing
Gimp
Photoshop

Other
Panda Batch File Renamer (rename a large batch of files e.g. jpgs)

Watch this place for updates....

My equipment

Before we get down to serious astro-business, it's probably best I say something about the equipment I’m using.  Note however, this blog is going to be very pragmatic, so in this post there is no discussion or explanations.  I will explain how and why I do things when the time comes. I want this blog to be useful, and not a theoretical exercise.

My telescope is a Celestron 6SE. A bunch of specs can be found here, but the key stuff is that it’s a 6” (150 mm) Schmidt-Cassegrain with a focal length of 1500mm.   

Celestron 6 SE


The aperture makes it very good for moon and planetary viewing, and the computerised Alt-Az mount is excellent for an intermediate viewing scope.  

The scope is not ideal for deep-sky astrophotography due to the mount setup.  In particular, as the mount is not equatorial the star-field in deep-sky observations will rotate – making long exposure images near impossible, and that’s not to mention the quality of extended tracking!  Note, however, the tracking is fine for visual observation.  I might have a bash at combating these hurdles in the future with a Wedge, but for the time being any deep-sky stuff will be done by stacking short exposure images, which avoid the tracking and field rotation problem.  The mount is not the only problem for deep-sky imaging – the scope is very slow for deep-sky i.e. much long exposures are needed.  I’ve alleviated this a little by attaching a Celestron focal reducer corrector f/6.3 – makes the scope ‘faster’ and the exposures required much shorter by ~3.  We’ll explore this in due time.

One day I might buy a complementary scope for deep sky astrophotography, but for the time being I’ll make the Celestron work.  This is one of the issues with astrophotography – there is no one-size fits all solution.  It depends what you want to do, and my telescope does planets, solar and Moon stuff very well.  Note however, NEVER EVER look at the sun through a telescope unless you have the appropriate equipment – not only would it break the optics, but it WILL blind you instantly.

In terms of other bits, I have:
9mm Meade Possl
25mm Celestron Plossl
Tele Vue Powermates 2.5x and 5x (1,25”)

For the taking of photos, I use:
Orion StarShoot Solar System Color Imager IV webcam (Good for Moon and planets)

Orion StarShoot Solar System Color Imager IV


Canon EOS 550D DSLR (deep-sky / other stuff) 

Canon EOS 550D

AND, don’t forget a Power Tank to power the telescope.  Batteries run down fast and ruin tracking!  Needless to say, a computer is needed to capture images from the webcam and process a night's observations, but I will get to software shortly.

Watch this space – my equipment list might get an update at some point ;)

13 February 2012

And so it begins - the astrophotography adventure

My first new post.  Awesome.

Over the, hopefully, long-term I will be documenting my progress when it comes to astrophotography.  In particular, I will post my experiences with my equipment – from taking the actual observations through to the digital processing that invariably occurs once the image is on my computer.

I hope to use this blog to keep track of the things I’ve done and hopefully build up a resource for me to come back to in the future when I’m stuck or if I need rediscover those awesome ‘wavelet’ parameters.
To any guests that stumble upon my blog I would appreciate any comments or observations regarding my posts and images.  I’m not doing this for science but to produce aesthetically pleasing images, where your input is valuable.  

Maybe one day others will use these posts to enhance their astrophotography experience….well maybe..

Cheers,
Rama