Mars photo

starfinder · Post by **starfinder** » Mon Oct 10, 2005 10:27 pm

Last month, I bought a Philips Toucam Pro II webcam with a custom-made 1.25" adaptor from the Grand Eye Scientic Company in Hong Kong (thanks to Remus for the tip), to try my hand at CCD imaging with a webcam.

It is surprisingly easy to get good results.

Here is a photo of Mars which I took on 1st Oct 2005 during moments of steady seeing. The details:

Equipment: Meade LX-90 8" f/10 SCT with Antares 3x barlow (i.e. operating at f/30); Philips Toucam Pro II webcam (without any IR filter since I don't have one). Focused on a bright star with a Hartmann-type mask.

506 frames at 640x480 resolution at 1/25 sec, 10 frames per second.

Processing: Stacked with Registax, and sharpened with Photoshop unsharp-mask feature.

Details of Mars at time of capture (taken from the Sky & Telescope website's Mars Profiler applet):
Illumination: 93%
Central meridian longitude: 25 degrees
Visual magnitude: -1.7
Angular size: 17.8 arc-seconds
No. of days to oppostion: 38.

Comments: North is up in this image. The very white but small South Polar Cap is clearly visible, which contrasts with the very bluish North Polar Hood of clouds.

A few years ago, I tried planetary imaging with a 35mm film camera. The results were poor, and couldn't compare with what was visually observed. With CCD imaging, the situation is reversed, so that the stacked and sharpened image shows a lot more detail and contrast than the visual image. Truly amazing.

Post by **Lee** » Mon Oct 10, 2005 10:37 pm

That's a great photo.
Well done.

chrisyeo · Post by **chrisyeo** » Mon Oct 10, 2005 10:54 pm

Wow. That's a very nice photo!
Can I use it for Mars Watch 2005?
Did you take it in Singapore?

kayheem · Post by **kayheem** » Mon Oct 10, 2005 11:01 pm

Great shot Gavin!

Can't wait for your shots of Saturn!

Post by **weixing** » Mon Oct 10, 2005 11:24 pm

Hi,
WOW!! Nice image!!

By the way, I wonder what is that brownish curve line on the left side of the polar cap which extend from the polar cap to the equator?? I also saw that on the same day in Mersing through my 6" newtonian... only difference is that it appear a bit whitish in my scope.

Have a nice day.

wucheeyiun · Post by **wucheeyiun** » Mon Oct 10, 2005 11:25 pm

Good job! wish my acuter imager can perform like that!

starfinder · Post by **starfinder** » Mon Oct 10, 2005 11:26 pm

Yes, Kay Heem, I too can't wait to get good shots of Saturn!

chrisyeo wrote:Wow. That's a very nice photo!
Can I use it for Mars Watch 2005?
Did you take it in Singapore?

Yup, but I am sure there are nicer Mars photos out there from S'pore amateurs!

I took it in Singapore from my room window, right in the city.

Well, it wasn't really my handi-work or skill. I would give credit to the person who wrote RegiStax, Cor Berrevoets, and whoever wrote the code for the unsharp mask feature in Adobe Photoshop. I just focused and pressed the record button for the webcam. The software did the rest. Really!

To illustrate the effects of stacking and sharpening, here are 2 images. The first is a single frame (i.e. one of the 506 frames). The second is the combined 506 frames stacked with Registax, but not yet sharpened with Photoshop's unsharp mask feature. A big difference with the end result.

starfinder · Post by **starfinder** » Mon Oct 10, 2005 11:30 pm

weixing wrote:
By the way, I wonder what is that brownish curve line on the left side of the polar cap which extend from the polar cap to the equator?? I also saw that on the same day in Mersing through my 6" newtonian... only difference is that it appear a bit whitish in my scope.

Have a nice day.

Thanks Mr. Lee, wucheeyiun, and Weixing.

Well, I think the curved brown line is an optical aberration. It runs along the edge of the globe on the left side. However, I don't know what causes it.

Post by **Airconvent** » Mon Oct 10, 2005 11:49 pm

welcome back Gavin!
I see that Matthew's LX90 imaging set up at Mersing has been very motivational for you...like Kay Heem, looking forward to your Saturn shots too as that one nearly always put up a good show...you just need to sleep early and wake up early..heh heh
great shot!

chrisyeo · Post by **chrisyeo** » Mon Oct 10, 2005 11:50 pm

The curved line appears to be present on my image of mars too. At first I thought it was just a processing artifact but if you all see it too, maybe it is caused by the atmosphere of Mars?