Astrophotography by Tomi Virtanen, nebulas, NGC6888

Nebulas, NGC6888

nebulas index
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Updates:

19.9.2004 - created this page

Image list:

16.9.2004

Images:

Target: NGC6888, bright nebula.
Also known as the Crescent nebula Date: 16.9.2004

Time: -

Location: Vantaa, Finland

Conditions: -

Telescope: N150 f5 (GSO) Mount: GEM w RA stepper motor (Sky-View)

Camera: SC2 webcam (PCVC840K).
Raw color mode Filters: Baader #2459207 UV/IR-cut

Exposure: Mosaic of 4 images.
80 x 15s on each of the 4 (out of 684 total), dark frame and synthetic flat field. Unguided.

Processing: Stacked in K3CCDTools. Adjusted in Photoshop.

Images:
small version displayed, click on the image for full resolution version

Notes: Clearly the exposure time was too short to capture this nebula well. I also had problems building this mosaic since the partial pictures tended to have different background levels and faint details did suffer when trying to process the background even. The variations were caused by stray light entering the telescope tube, and as the RA axis turns slowly during and between exposures the amount varies. I think it can be remedied by using an additional stray-light shield in front of the telescope in future.

email: tomi.virtanen@yahoo.de

Target:	NGC6888, bright nebula. Also known as the Crescent nebula	Date:	16.9.2004
		Time:	-
		Location:	Vantaa, Finland
Conditions:	-
Telescope:	N150 f5 (GSO)	Mount:	GEM w RA stepper motor (Sky-View)
Camera:	SC2 webcam (PCVC840K). Raw color mode	Filters:	Baader #2459207 UV/IR-cut
Exposure:	Mosaic of 4 images. 80 x 15s on each of the 4 (out of 684 total), dark frame and synthetic flat field. Unguided.
Processing:	Stacked in K3CCDTools. Adjusted in Photoshop.
Images:	small version displayed, click on the image for full resolution version
Notes:	Clearly the exposure time was too short to capture this nebula well. I also had problems building this mosaic since the partial pictures tended to have different background levels and faint details did suffer when trying to process the background even. The variations were caused by stray light entering the telescope tube, and as the RA axis turns slowly during and between exposures the amount varies. I think it can be remedied by using an additional stray-light shield in front of the telescope in future.