LtE in CMO #272

From Eric NG

© . . . . . . . Also I have upload my first Mars image for this apparition in the image too.


Kind Regards,

             (25 April 2003 email)


© . . . . . . .Sent: April 27, 2003 9:30 PM 

Subject: Re: CMO #270 updated


Dear Masami, That is my pleasure to contribute my images to CMO group. I will keep sending you the Mars shots in coming few months. Kind Regards,


© . . . . . . .Sent: April 28, 2003 8:31 AM 

Subject: 20030427 Mars this morning


Woke up a bit earlier this morning for Mars. Seeing was bad and I had to manual select the 135 out of 800 frames for stacking. I am quite satisfied for the result under such turbulent seeing. I tried 1/25 sec, 0% gain but all details washed out so I switched to use 1/33 sec, 30% gain which gave better raw detail.


© . . . . . . .Date: Wed, 30 Apr 2003 11:55:56 +0800


Dear Minami and KC, Have you recieved my April 27 Mars as I did not see it in CMO homepage. KC just forwarded the email you mentioned about the issue of poor sensitivity of B channel in ToUcam…..

  In recent years, the atmospheric transparency is very low in Hong Kong. We are affected by strong water vapour in spring/summer and also the misty polluted air blew from mainland china. That aborb the blue channel very much. Mars is still low at the sky while we took the image that may be another reason.・・・

 One of our friend Mr. Chan Tin Ping kindly modified the cooled version of ToUcam for us. From my experience in Jupiter imaging, it dramatically reduce the noise level of B frame. I believe this can definitely increase the S/N of B frame that gives better details on it.

 Although we have some experience in Jupiter imaging with ToUcam, I believe for Mars that is another story. We shall keep testing and experiencing, I am better results can be obtained. Cheers

      (30 April 2003 email)


© . . . . . . .Subject: Transit of Mercury - Internet webcast by HKAS


 The Hong Kong Astronomical Society will arrange the internet webcast for the event of Mecury Transit on 7 May, 2003 at:

(5 May 2003 email)


© . . . . . . .Date: Wed, 14 May 2003 21:39:05 +0800


Dear Minami, Thank you for your mail. Yes. I also discussed with Weileong for the issue of B tail into G that contaminates the B frame, which leading the surface detail appear on a "real" B frame. Seems the magenta filter would be good to cut out the G to get the corrected "B". However, the noise would be another consideration ... And also what we get would be the R(G)B shot.

 To me ... B frame is the most interesting layer as the atmospheric details on it are more dynamic. In fact, Weileong and I will do some test for it. If finally the B frame by ToUcam Pro still not good, I may go for the ST-5C and guarantee to have good B by extending the exposure of it. Of course LRGB would be my approach.

 Hope the sky can be clear and we can do some research on it.

 Minami, I decided to move to my rural observing site in August for 1.5 month and hopefully I can get some better shot with my coming 12.5" and the 25" dobsonian.


© . . . . . . .Date: Fri, 23 May 2003 10:14:04 +0800

Subject: Re: Syria Planum following Solis L


Dear Minami, We will certainly keep track with mars if the sky is clear. I am attaching the Mars I took in this morning. The seeing was ok and some atmospheric dispersion on the image. I am pretty pleased with the surface detail for this shot. I don’t think there is any visible dust storm from my image but I do some cloud detail near the Tharsis.  Please kindly comment,


© . . . . . . .Date: Sun, 25 May 2003 17:39:13 +0800


Dear Minami, The sky is cloudy recently and it will be clear on Tuesday, hope I still can keep track with the dust storm. I am reprocessed the 20030222 Mars and it looks better and less artifacts. Please kindly comment.

Kind Regards,


Eric NG (Hong Kong)

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