LtE in CMO #273

FromChristophe PELLIER


. . . . . Subject: Mars may 26, 2003

 

Hi all,

here is a Mars image from this morning. Despite my unfavourable latitude I find that the observing conditions are really improving and I didn't expect to see so "much" on these images... The "Lowell band" is impressive. Finally I can work with the W38A filter to make a blue image but it lets IR pass (a faint IR Mars was barely visible on the screen, several arcseconds shifted from the blue wavelengths) so I need to wait for a new equipment. For the mars observers group, I have uploaded the image in the recent images folder (it's in the second page of that folder now), but you can also follow this link:

 

http://astrosurf.com/pellier/2003-05-26-CPE.jpg

 

Best wishes

(25 May 2003 14:57:52 -0000)

 

. . . . . .Subject: Mars may 27, 2003

 

Hi Mars observers.

 

This morning the seeing was a bit poorer than yesterday but the major dark regions are seen. The blue image couldn't be totally processed because I didn't have enough frames to do so. Image uploaded in the "new images" folder.

Best regards

(26 May 2003 15:24:24 -0000)

. . . . . .Subject: Mars may 28, 2003

 

Hello everyone

 

This morning the seeing was better than on the two previous days. I made two series of blue, red and LRGB images showing CM 150-160 on Mars. A white cloud is noted over Tharsis, very well seen in the blue images. It has been uploaded with the other recent images.

Best regards

(27 May 2003 15:45:57 -0000)

 

. . . . . .Subject: Mars may 29 2003

 

Dear Mars observers,

 

this morning seeing was fairly good (above all at 20-23 high), but transparency was a bit fair and this has lowered the quality of the blue images. Note some possible details inside the SPC itself. Images uploaded in the photo sections.

Regards,

PS note that I have changed my image format from "CPE" to "CPI", to match the CMO code.

(28 May 2003 17:39:31 -0000)

 

. . . . . . Subject: Mars may 31 2003

 

Hi all,

Mars this morning in good seeing but poor to fair transparency. This is the first time I use a good Astronomik filter for the blue image, and despite the hazy/cloudy sky the image is yet better than the previous ones with the wratten filter. Again the same shadowy areas are noticed in the SPC. Clouds over Tharsis, and in the first image Solis Lacus comes into view.

Best wishes,

(30 May 2003 15:59:26 -0000, 31 May 2003 18:12 JST received)

 

 

. . . . . .Subject: Mars June 5 2003

 

Hello all. The atmosphere was quite turbulent this morning, but the Solis Lacus area is well visible on these images. They are however far from being as good as Paolo's yesterday images of the same region ! Note that I have added a RG610 red filter to my equipment, but I still need to rely on the exotic RR(G)B composite for the color image, which is there more for illustration purpose indeed. The blue image seems to show some clouds over Xanthe.

 

Note for the Mars Observers group: I have uploaded the image in the files, but there is also a link :

 

http://astrosurf.com/pellier/2003-06-05-CPI.jpg

 

Regards

(4 June 2003 15:51:13 -0000)

. . . . . .Subject: Mars June 6 2003

 

Hi all

Seeing was just a bit better this morning but the images still have a moderately pleasing aspect, not to say more, however the "canals" around Solis Lacus are well visible. A question to all : in the first red image there is a very thin rift inside the SPC. Is it real, and if so could it be the Rima Angusta ?

 

http://astrosurf.com/pellier/2003-06-06-CPI.jpg

 

Regards

(5 June 2003 20:26:01 -0000)

 

. . . . . .Subject: Mars june 9, 2003

 

Hello everyone, this is an image of Mars taken with a C14. Unfortunately seeing was poor and there was a mistake in the setting of the webcam. Sorry for the low quality, I will improve the images in the times to come.

 

http://astrosurf.com/pellier/2003-06-09-CPI

 

Best wishes

(9 June 2003 00:18:09 -0000)

 

. . . . . .Subject: Mars june 16, 2003

 

Hello : this morning the seeing was the better I had so far on Mars, amazing at the 22-26 altitude. This really give a change to the images, I hope I'll have more mornings like this one ! I see no change in the Sinus Meridiani - Syrtis Major area since the previous images taken from other places in the world.

 

http://astrosurf.com/pellier/2003-06-16-CPI

 

Regards,

(16 June 2003 11:12:50 -0000)

 

. . . . . .Subject: CMO 271

 

Dear Masatsugu:

it's two weeks now since the CMO 271 issue has been uploaded to the CMO homepage; but this time I did not received any paper copy of it. Was there any problem ? If so please openly tell me !

Best regards,

(16 June 2003 12:11:09 -0000)

 

 

. . . . . .Dear Masatsugu and all ;

 

Thanks for your long e-mail. I was only a little bit surprised to have no news from CMO, but I guess how you can be very busy and how this CMO work can be very demanding...

 

I have closely followed the discussions about the problems with the color chip of the ToUcam. Originally I started to filter my images because the planet is too low here to make a correct unfiltered color image (even with an IR blocking filter). But at last I think that it turned to be also a good solution for the blue image. Yes my blue filter is an Astronomik of type II, which reject IR wavelengths with no need of an additional IRB filter. Although my images with this filter haven't been outstanding (if the transparency is less than good the final image will be very noisy), they barely show the white clouds of the planet and so far I don't think that they have ever revealed any hint of the dark markings. The Astronomik filters of type II seem to have almost the same characteristics of the IDAS ones - I have attached the filtering curves for your interest. About the Wratten blue filters, they produce images that are strongly polluted by the IR. If you take a look at these images I have also attached you will see this. The W38A has always a ghost IR Mars at the background ; one way to solve this until I received the Astronomik filter was to separate the image taken in color mode into R, G, B, and then the greatest part of the IR was kept in the "Red" component. Of course in my mind it was just a way to secure a blue image that could be useful at a minimum. But the greatest surprise came from the W47 filter. You are correct if you think that this filter may give an incorrect blue image. As you can see on the images, used without an IRB filter the W47 produces a very bright image of Mars in IR (and maybe a bit of R also). Even visually there may be a problem: if I take a look with naked eye through it after sunset at the bright thin clouds that sometimes can be seen in the darkening sky, these clouds appear of a beautiful deep purple tint. But if I use it with an IR-Block filter stacked, this color totally disappear; unless my W47 is an unusual bad one, it is clear that it leaks a good part of the red spectrum...

 

The good news about this topic is that I will soon have a new CCD sensor: Paolo Lazzarotti, who has a little firm of astronomical accessories, is going to send me this week a modified ToUcam with an ICX098BL Sony black and white sensor : it will gather much more light and will solve for ever the wavelength problems of the color chip !

Thanks also for your thoughts about the use of the green filter. This was really a question for me. I'm going to consider buying the rest of the Astronomik RGB set. I also prefer RGB composites to LRGB ones ; indeed, the color images I have produced so far where there only for illustrative purposes. The point is that my 180 mm newtonian is hard to master in a mechanical point of view: the fine RA movement doesn't work and I have no filter wheel so it will take me a lot of time to change the filter, refocusing the instrument, trying to keep Mars inside the field... So it will maybe be hard for me to secure three images in a limited range of time to build a RGB image.

About my images from this morning 16 june, the bright western part of Hellas is certainly a floor-feature, as it is seen also on almost every image of the region taken recently (for example, Don Parker may 20 image or Tan Wei Leong may 5 image). I'm surprised however that you say the bright streak in Hellas on 11 june 2001 was not a dust streak, this was also clear for me, as the MGS images on that day (taken a bit later if I'm not wrong than the images secured in the USA by Parker, Grafton and Bates for example) really seem to show a dust cloud in south-western Hellas. About Edom, I don't know if it's a brightening or not; on others images I see a similar phenomenon (see for example Ed Grafton image on 19 may), could it be only the result of a lighter-toned region ?

The weather here is usually variable. During summer my region can have periods or two or even three weeks of cloudy weather, and this can't be predicted in advance. Right now France is concerned since a week or more by thunderstorms coming from Spain (I can hear thunder right now!), and it may going to continue.

I wish you much luck for your observations. On my side I hope to catch the important Syrtis Major/Hellas area on the following days.

Kind regards,

(16 June 2003 20:34:43 -0000)

 

. . . . . .Dear Masatsugu :

Many thanks for sending me the CMO issues, and the e-mail.

 

At the end of the week I'll be equipped with the B/W ToUcam and the complete RGB filters set of Astronomik, and I think I should go for that method. I'll keep using the RG610 for a single high-resolution B/W image, alone.

My best regards,

(18 June 2003 15:58:31 +0200)

 

. . . . . .Subject: Mars June 21, 2003

 

Hi all : this morning the seeing was good and the transparency excellent. I've been able to make three series of images ; and for the first time I've managed to get a correct image with a "normal" color avi file of the ToUcam, despite the low altitude of the planet. Note that the three blue images all show clearly the dark markings of the planet.

 

http://astrosurf.com/pellier/2003-06-21-CPI

 

Regards

(21 June 2003 20:17:09 -0000)

 

. . . . . .Subject: Mars June 24 2003

 

Hi all:

Good seeing and transparency this morning. This time all color images have been realized with the ToUcam in color mode (with an UV/IR blocking filter). I find that the aspect of the planet is much more realistically rendered than with my previous RRGB composites; like the very fine creamy color of Hellas, beautiful in visual. The NPH looks prominent.

 

http://astrosurf.com/pellier/2003-06-24-CPI

 

Regards

(24 June 2003 22:23:00 -0000)


Christophe PELLIER (Bruz, Ille-et-Vilaine, France)

chrispellier@tiscali.fr


Back to the LtE Home Page

Jump to the LtE Archives

 

To the CMO Home Page