Mars 13th Jan 2014

[Sebbie (Sebastian)]

Had another go at Mars yesterday morning, here's a combination of 1200 frames from the best f40 capture taken between 4:57 and 5:00 am AEDT.

Seeing stabilised just before the break of dawn.. red planet is noticeably larger now and growing fast!

Cheers,
Seb

[Troy]

Good image and nice colour

[Sebbie (Sebastian)]

Originally Posted by Troy

Good image and nice colour

Thanks Troy. With the heatwave hitting us now it was a very warm morning but still not easy to be outside due to mosquitos

[Stefan Buda]

Terrific resolution!

[Sebbie (Sebastian)]

Originally Posted by Stefan Buda

Terrific resolution!

Thanks Stefan. I found that running wavelets on the resized drizzle stack image tends to yield the best results, certainly from noise reduction point of view. Again had to Photoshop the edge artefact out, is there a way of minimising bright limb ringing at capture time?

[astronobob (Bob)]

Thats a mighty fine mars Sebastian, can make out the Valles Marineris I reackon
Do you use auttostackert or Registax for your Planets & where does the Annotated Mars image come from, if I may ask, thats coool ! !

[Sebbie (Sebastian)]

Raw stack image with the artefact highlighted. Darker arc is more of a concern than the bright one away from the planet. I've come across this thread on Cloudy Nights discussing this issue.. it seems to me that no clear consensus has been reached yet as to what the main cause is.

http://www.cloudynights.com/ubbthrea.../o/all/fpart/1

[Sebbie (Sebastian)]

Originally Posted by astronobob

Thats a mighty fine mars Sebastian, can make out the Valles Marineris I reackon
Do you use auttostackert or Registax for your Planets & where does the Annotated Mars image come from, if I may ask, thats coool ! !

Thank Bob, I usually go with auttostackert for stacking and Registax / Astra Image for the wavelets.

Reference map is from Starry Night Pro.

[John K]

Had not seen this photo - excellent!

The good Mars images from Australian amateurs so early on in this apparition continue!

[astronobob (Bob)]

Cheers for that mate, all the best with the artifact issue, way out of my league sorry , ,

[Sebbie (Sebastian)]

Originally Posted by John K

Had not seen this photo - excellent!

The good Mars images from Australian amateurs so early on in this apparition continue!

Thanks John, something to compensate for the loss of Jupiter this time round

[Stefan Buda]

Originally Posted by Sebbie

Thanks Stefan. I found that running wavelets on the resized drizzle stack image tends to yield the best results, certainly from noise reduction point of view. Again had to Photoshop the edge artefact out, is there a way of minimising bright limb ringing at capture time?

I'm quite convinced that it is a diffraction effect and it is affected by seeing and spherical aberration caused by thermal gradients in the primary.
I don't think there's much one can do other than minimizing tube currents and getting the mirror to ambient temperature.
If your scope has coma then a bit of miscollimation in the right direction could reduce the effect, but it is not a very practical thing to do.

[Sebbie (Sebastian)]

Originally Posted by Stefan Buda

I'm quite convinced that it is a diffraction effect and it is affected by seeing and spherical aberration caused by thermal gradients in the primary.

Thanks, the scope was out all night but temperature tends to go down quickly in the last three morning hours here in Canberra.. I guess the air inside the tube does not have the time to adjust and I don't have a fan to speed up the process.

Given current heatwave conditions the drop rate wasn't great this time round, it was still 15 degrees at 5am.