M51 with a personnal made 200mm F4.5 newtonian

[Forum_2014]

Hello ,
i'm vincent from france, i did the english to french translating for astroart,
and learned a lot from this work.
here is a test to show an image in this forum.
You put [ I M G ]the full adress of your image for example http://xmcvs.free.fr/astrosurf/m51_as1.jpg[ / I M G ]
without any space beetween the bracket , i put them to show how to do.
Astroart is a major piece of the process, as i use for L RGB assembling.
I have built the observatory with a friend, and we have a remote access.
This makes possible to catch a lot of light , for this image, we have nearly 20h of imaging ( and we discarded 63 images ! )

[Forum_2014]

A wonderful image Vincent. Amazing detail. How is the light pollution and seeing conditions where this was taken?

[Forum_2014]

Hello,
the site is reasonnably good.

There is a middle town at 25km north , that glows ( seen from naked eya) at approx 30° high, the W side has a 3000 people village at 2km , the E and S is really top, nearly nothing at 100km !

The seeing is also reasonnably good, and very important quite regular , we have the 200mm and my friend has a tec140 scope, we say :

fwhm > 4" very bad seeing => no imaging

3.5"<fwhm<4" badseeing => we keep images if we really need

3"<fwhm<3.5" good seeing => we nearly always keep images

2.5"<fwhm<3.0" top seeing => The record is at 2.40" at this moment.

The cheap coma corrector is given for 12µ star , this makes with this scope 2.22pixels and 2.67" , so i guess the scope is the limiting factor and perhaps the site is better.

This images is 100 X 10min subs, all beetween approx 2,50" and 3,50"

Thanks
Vincent