Posts Made By: Anthony Wesley

Guess what - another mars image!

This one was taken this morning at 3:17am local time. Seeing conditions were pretty good, considering mars was at an altitude of about 45 degrees.

Equipment:

10" f/6 newtonian
5x powermate + TruTek filter wheel
Astronomik RGB filters
PGR Dragonfly Express camera
Captured using Coriander for Linux
Processed under Windows with Registax, Neat Image,
Astra Image and the GIMP.

Stacked best 1000 frames out of 3000 in each colour

regards, Anthony

All my mars images have a hard, bright edge on the sunlit side. I tried a lot of different things yesterday but I'm ^%$#&^ if I can stop it from forming.

It shows up in the stack, and even very gentle wavelets in registax make it start to appear, and it's all downhill from there - every processing step seems to make it more evident.

Does anyone have the secret about stopping or removing this?

regards, Anthony

Trying different processing steps to minimise the "hard edge" that seems to appear around the sunlit side of Mars.

Seems like it's a real phenomenon, maybe dust or refraction in the martian atmosphere, but many processing steps really enhance it too far.

I'm now experimenting with a modified processing sequence consisting of mostly filtering + smoothing and leaving out the Lucy-Richardson deconvolution that I found so effective on Jupiter.

Another trick I'm trying is to set the high numbered wavelets in registax to -1 or lower. This has the effect of subtracting detail that is large in scale and has a distinct edge - on Mars this is mostly the bright edge.

Here's the red-light image. The bright edge is much reduced.

This is a stack of 2000 frames taken at a focal length of 10,000mm through a PGR Dragonfly Express camera. Expsures for each frame were around 20ms.

The scope is a 10" f/6 newtonian.

regards, Anthony

I've been trying for the last day or so to find a way of processing mars that doesn't exaggerate the "hard edge" that we all seem to get, and I've made some progress.

Have a look at the attached image, again it's one from sept 24 but I don't have any new ones to try - it's been raining the last couple of days :-(

The edge is now a thin blue line, I think that's probably close to correct since there is an atmosphere and dust etc, we should see something around the sunlit side.

Now something else has shown up that's very interesting - look near the south pole and you'll see that the haze there is green, not blue. I hadn't seen this before, I think the true colour was lost in the overbright edge.

Overall I think the colour is better - Olympus Mons is now distinctly visible and it's a different shade of red to the surrounding plain.

Here's what I did, please try it and see if it helps your images:

- In registax wavelets, be gentle. You don't have to do all the sharpening in that one step, we can apply unsharp masks etc later on. Set layers 5 and 6 to -1 or maybe even less, this should help reduce the edge by subtracting off large, bright bits of the image.

- Next, save the image and load it into your favourite photoshop-like program. I use Astra Image, but I guess photoshop or similar would do as well.

- If you have a high-pass filter, try applying that. It will increase the contrast in the image without enhancing the edge.

- Apply an unsharp mask with a reasonably large radius, but only gently.

- Now smooth the image with something like an "alpha-trimmed mean" or "3x3 gaussian mean", whatever you've got. There will be artifacts introduced by the previous sharpening stages to get rid of, and this smoothing will help do that.

- Now apply another unsharp mask with a smaller radius to highlight the remaining features.

This is what works for me, but please remember that your mileage will vary, depending on your raw data.

I'd love to hear if this sort of approach can give you good images without exaggerating the hard edge.

regards, Anthony

This has taken me a couple of days to process due to the less than good seeing conditions when I grabbed the data. I've probably done 2x as much image processing on this one as on any other image.

Mars was at an altitude of around 30 degrees, and the seeing was very unsteady due to jetstream conditions that we suffer from time to time.

Images captured using my PGR Dragonfly Express on a laptop running Coriander and Linux. 10" newtonian @ F42 (approximately), Astronomik RGB filters.

Captured 3000 frames of red and green @ 50 fps, and 1800 frames of blue @ 30fps. Stacked the best 1000 of each.

Try as I might I can't get rid of the bright edge, the raw data is just too poor.

regards, Anthony

After much more processing I've improved the results from my imaging run on the 4th of this month.

There are still edge artifacts present which I'm working on, but overall I'm much happier with this version.

10" newtonian @ f/42
PGR Dragonfly Express

regards, Anthony

Hi everyone - I've been away to my first ever star camp, it was in Ballarat which is about 6 hours drive from home. First 3 days were a washout but then on the last night of the camp we got virtually 10/10 conditions, out of nowhere.

Here's a mars image from that night, imaged when Mars was only about 31 degrees above the horizon and 2 hours past transit. The air was incredibly still and transparent.

Equipment:

10" f/6 newtonian w/ 5x powermate and extension tube
Dragonfly Express camera + RGB filters and filter wheel.
Stacked approx 1500 frames in each colour

regards, Anthony

Here's another image from my trip to Ballarat last weekend. (about 6 hours drive from home). This was from the same night of magical seeing as the previous post.

Mars was only about 31 degrees above the horizon and 2 hours past transit. The air was incredibly still and transparent.

Equipment:

10" f/6 newtonian w/ 5x powermate and extension tube
for effective 8x (f/48)

Dragonfly Express camera + RGB filters and filter wheel.
Stacked approx 1500 frames in each colour

Images resampled to 150% for processing

regards, Anthony

Taken this morning just before dawn. Conditions were good but I left my imaging a bit too late and so only got one run before the seeing started to deteriorate.

I'm using my Lumenera LU075M at the moment, got the linux drivers to work and I'm using a modified version of the sample Linux capture program that came from Lumenera. I'm a lot happier with this camera now that I can use it under Linux and avoid streampix :-)

My firewire camera had to go back to the manufacturer, not sure if it died or if I inadvertently damaged it, but I hope to have it repaired/replaced and back in a few weeks.

10" f/6 newtonian @ f/48
Astronomik RGB filters
Lumenera LU075M @ 15fps
60 seconds each or red,green and blue

regards, Anthony

Nice image Robert.

Anthony