LtE in CMO #283

From Konrad DENNERL

. . . . . . .Date: Tue, 11 Nov 2003 18:11:02 +0100

Subject: X-ray observation of Mars on November 20-21


Dear Masatsugu,


first of all I would like to congratulate you to the CMO Gallery, which is currently one of my most favorite Web addresses. It is always a pleasure for me to have a look into this nice collection of stunning amateur images from all around the world.


I have now finally got time for observing Mars in X-rays. This time not with the US satellite Chandra, but with the European satellite XMM-Newton. Unfortunately, XMM-Newton can only observe objects which have a solar elongation between 70 and 110 degrees, and so it was not possible to observe Mars during its very close approach to Earth.


XMM-Newton will observe Mars soon after its solar elongation will have decreased to 110 degrees (this happens on Nov 16), during the following period: *** from Nov 20, 00:07 - Nov 21, 05:04 UT ***


This is a particularly long observation, which will cover more than a full Mars rotation. Compared to the previous observation of Mars with Chandra, the upcoming observation with XMM-Newton will collect more X-ray photons and will have better spectral resolution, but less spatial resolution. Mars will also be considerable smaller in angular diameter (12 arcsec compared to 20 arcsec before), so that its disk will probably not be well resolved. The scientific investigation will more concentrate on the X-ray halo which was indicated in the Chandra data.


Despite these limitations, it might nevertheless be good to have some simultaneous optical coverage. Although there is a good chance that such images will be taken anyway by amateurs around the world (according to the beautiful CMO Gallery, which contains practically for every day stunning amateur images), I think that it might be good to inform amateurs in advance that November 20-21 will be a particularly rewarding time for taking images of Mars.


I myself will also try to take optical images, although I have only a 112 mm Newton telescope at home (more than 30 years old). During several Mars oppositions in the past I had used it for taking images on photographic film. During this opposition I have used a WebCam for the first time, and I was impressed how easy this is to handle and how much detail this technique reveals, even when used with such a small telescope. I have attached one such example, which, however, cannot compete with the incredible quality which can be reached with larger amateur telescopes.


Coming back to the X-ray observations, we are now in a period of enhanced solar activity. This is, on the one hand, a very interesting situation for X-ray studies of Mars, but, on the other hand, also a real threat: last week practically all X-ray observations with XMM-Newton had to be cancelled because of the high radiation. I hope that this will not happen on November 20-21; I will keep you informed.


Best wishes,


. . . . . . Date: Fri, 21 Nov 2003 11:30:01 +0100

Subject: X-ray observation of Mars on November 20-21


Dear Masatsugu,


the Mars observation with XMM-Newton is now over. I have just received the information that it was possible to perform the observation. This was not so obvious before, because the Sun did indeed become quite active. Last night I could see an auroral display, which is a very unusual event for Southern Germany (it was the second aurora which I have seen in my life; just three weeks ago I had seen my first one).


I enjoyed the beauty of the aurora, but was at the same time very worried about the fate of the Mars X-ray observation.


In fact, the XMM-Newton observation immediately after Mars had to be stopped because of high radiation.


I do not know yet how much the data quality is affected by the solar activity, but it seems that an X-ray signal from Mars was successfully detected.


Best wishes,

. . . . . . Date: Sun, 23 Nov 2003 11:57:13 +0100

Subject: Re: X-ray observation of Mars on November 20


Dear Masatsugu,


thank you for this information. It is a pity that the Japanese islands were all covered by clouds - the meteorological satellite image looks very impressive! Also large parts of Europe seem to have suffered from bad weather, although more from fog than from clouds, and it seems that there will not be much simultaneous optical coverage available. In fact, the image taken by van der VELDEN is the only simultaneous Mars image which I am aware of (except for those images which I had taken though my small telescope). I think that under these conditions it might be justified to use Mars images which were taken a few days before or after the XMM-Newton observation to illustrate the optical appearance of Mars - unless you have evidence that there are currently major changes going on.


Best wishes,


On Friday 21 November 2003 20:34, you wrote:

> Dear Konrad,


> Congratulations! on the success of the XMM Newton in your project on

> 20 November in spite of the dangerous Solar activity. I suppose the

> results will prove to be much more interesting than expected because

> of the thrilling situation.


> Unfortunately we are sorry to inform you that there is no hope to

> provide you with the ground-based observations from the Japanese

> side. As shown in a meteorological satellite image attached, the

> Japanese islands were all covered by thick clouds on the evening of

> the 20th day. The clouds over the southern Okinawa islands looked

> barely to be thin, but I heard from Isao MIYAZAKI, Okinawa, at

> midnight that, though he prepared, the planet Mars did not appeared,

> (while it was extraordinarily humid with 28 degrees C!).


> Just up until now we received an image from Van Der VELDEN,

> Australia as was already uploaded in our Gallery.


> Thank you again for your kind information, and we hope we shall look

> forward to hearing from you about the results of the XMM Newton

> observation soon,

> With best wishes,


> Masatsugu

Konrad DENNERL (Mnchen, Deutchland)

Max-Planck-Institut fr Extraterrestrische Physik,


An previous email from Konrad


 Back to the LtE Home Page

 Jump to the LtE Archives


 Back to the CMO Home Page