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Sunday, October 19, 2014

First light for a new observatory



After a long time, a new photography! This is a first light for my new imaging setup and the observatory location. My observatory locates now at middle of the city, next to my home.


There are only 3h of H-alpha filtered light for this first light image of the Pelican Nebula. Original image size was 4096 x 4096 pixels and the image scale is 0.95 arcsecond/ pixel. Field of view is 63 x 63 arcminutes, that's little over a square degree of sky. (A full Moon has an apparent angular diameter of 30 arcminutes, that's half a degree.)

Pelican Nebula, the first light image
Click for a full size view.

This is image shows the emission of ionized hydrogen alone. Exposure time only 3h.

Image above is an uncropped frame, it's stacked from nine 20 min, exposures. Stars are absolute pinpoints from edge to edge! Seeing wasn't very good at the time, FWHM around 3,5 arcseconds. I was very surprised about the image, since the Celestron Edge HD 1100 shouldn't be able to lit this massive CCD 100%. There are some darkenings at corners but the flat frame was able to calibrate it away. Image above is uncropped, just couple of dozens pixels are cut away from sides due to some stacking artefacts.

I have now the 50mm square Astrodon narrow band filters. They are much narrower, than the Baader set I used to have. H-alpha passband is 5nm, the Baader was 7nm wide. Even large difference is with O-III and S-II filters, they both are 3nm wide, the Baader was 8,5nm for O-III and 8nm for S-II.
The narrower passband means more toleration against light pollution, more nebula details and smaller stars.

The 10-Micron mount from Italy is an absolute mechanical masterpiece! Maximum guiding error during a 20min. exposure was about 0,4 arcseconds at both axes. Pointing accuracy is stunning, any target was just middle of crosshair after a slew. 

The Apogee Alta U16 is a finest camera I have ever used! It's very heavy and the CCD is massive, 4096 x 4096, 9 micron pixels. Image below show the size difference between the KAF 8300 CCD-chip, I used before, and the KAF 16803 CCD-chip in my new camera. KAF 8300 is a great CCD but the KAF 16803 is much more suitable for large telescopes with long focal length.



Color images

I borrowed colors from my older wide field image for now. I'll shoot new color channels for this target as soon as the weather permits. I'll also shoot couple of hours more H-alpha lights for better signal to noise.

Mapped colors
Click for a large image, image is little cropped for a visual composition only.


Visual spectrum



A data from this image was used for colors 

The area of interest is marked as white rectangle.

Technical details

Processing work flow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics

Celestron Edge HD 1100 @ f7 with 0,7 focal reducer for Edge telescope

Cameras and filters

Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar
Astrodon filter, 5nm H-aplha

Exposure time

H-alpha 3h

Colorimages

Colors are taken from an older wide field image of the area.
The wide field image can be seen here:
http://astroanarchy.blogspot.fi/2011/12/cygnus-mosaic-18-panels-and-22-x-14.html






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