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Monday, October 27, 2014

A start of the new project, the Tulip Nebula

At night of 23.10 I managed to shoot 3h 20min H-alpha lights for the Tulip Nebula in constellation Cygnus.
It looks like we going to have a clear nigh ahead, I'll shoot more lights for the emission of Hydrogen and if possible, some data for other two emission lines, O-III and S-II.

I need some more signal to show better the area of Cygnus X-1, a black hole candidate. It's a strong source of X-ray emission and there are some interesting but kind of dim shock fronts around the X-1.  This microquasar is a brighter of two stars above the Tulip Nebula, just middle right at one o'clock position.

The Tulip Nebula
Click for a large image

The Tulip Nebula at H-alpha light only, 10 x 1200s.

Some optical analysis

I'm amazed about the optical quality of the Celestron Edge HD 1100 with a 0.7 reducer for the Edge scope.
The massive reducer seems to do some magic, since the whole image area of the massive CCD in Apogee Alta U16 camera (36,8 x36,8mm) gets filled with a pinpoint stars from corner to corner.  That shouldn't be possible, since the CCD is somehow larger, than the light path in Edge scope. See the image bellow.

As seen in the schematics, there should be some unusable areas at corners of the image. 

A single uncropped, calibrated and stretched 20 min. H-alpha frame

Image above is an uncropped, calibrated and stretched, frame directly from the camera. Even the very corners are filled with a pinpoint stars.

Analysis of the image field
With the CCDInspector software

There is some very minor tweaking needed for the perfect collimation. Otherwise the image field is nearly perfectly flat. One pixel is about one arcseconds in this analysis. 

Image corners as a closeup
Note. Images are from a single unprocessed, calibrated and stretched 20 min. H-alpha frame

Some very minor distortion can be seen, especially at image 2. That's due to some slight miss collimation. So large sensor is very picky about a correct distance (146,5mm), collimation and tilt.

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