Last months we worked hard on developing a prototype EL flatfield panel for the Takahashi. Using CCD's makes this kind of panel mandatory. Here are some pictures of the prototype:
Since we use an A3 EL panel (with shortest side 29.7cm) and the Takahashi's main mirror is 300mm, is is a few millimeters too small. We tried to compensate this by using diffusers made with transparant perspex plates.
Here's a pic of the Takahashi with my Artemis 4021 mono installed on its huge helical focuser:
The first thing I did was testing the prototype EL panel on the Takahashi: this gave good results: nice histogram with 15sec exposures, that seems well reproduceable. What was special is that I got a strange reflection of the secondary mirror/spidervane construction on it (I also saw it in the astrophoto's). See the test-flatfield 15sec exposure:
Okay, I aligned the Takahashi's CP-180 mount on Pollux using the FS2 control. After that I goto-ed to NGC2419 "The Intergalactic Wanderer".
NGC2419 (discovered on 31st December 1788 by William Herschel) is a very remote globular cluster,standing 300.000 lightyears from the center of the Milky Way.
Most globular clusters (like Omega Centauri and M31) lie within 65.000 of our galaxy center. See the drawing (source: Burnhams celestial handbooks) for an indication of the distance.
Most clusters are hovering close by, NGC2419 is way left. It is not called "The Intergalactic Wanderer" for nothing.
This object is very remote, but it is a magnitude 9 object, so it can be seen under clear dark skies using a telescope of 102mm aperture.
And here it is! The astrophoto is a combination of 5 20min exposures (no filters) shot with my Artemis 4021 mono in prime focus of the Takahashi E-300 300mmF3.8 Astrograph at Halley observatory. Check it carefully. It contains small faint galaxies of magnitude 18+!
I also included an extra enlarged version:
And a printout from the field of view (Cartes du Ciel) to show how many galaxies are on this picture:
The autoguiding was very stable. At first there were many people in the observatory, but after 2200hrs it became quiet, you see that in the datalogging, the average tracking error (rmsPE=0.34arcsecs) is well below the resolution of the camera (1.34 arcsec/pixel):
Finally, after 1 year of work, it can be concluded that the Takahashi of Halley is fully operational for CCD astrophotography work.
A fellow amateur astronomer Andre van der Hoeven analysed the exposure with Unimap. It discovered a larege amount of very faint galaxies on the astrophoto. Here is the Unimap result:
This is a fine result. What a joy to work with this beautiful astrophotography instrument!
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