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Monday, April 4, 2016

The last imaging project of the season, PuWe1

This is my last imaging project of the Spring season 2016. We'll lose astronomical darkness day after tomorrow for about six months due to high latitude, 65N.

PuWe1 is a very large and diffused planetary nebula in constellation Lynx. I think this is the first ever three channel narrowband image of it. This planetary nebula is extremely dim, I added single twenty minutes frames at end of the post to demonstrate, how little information there really is.

The data is collected between  16. February and 3. April. Total exposure time is around 23h. To boost the sensitivity of the camera, exposures are mostly shot binned between bin 2x2 and bin 10x10.
Final data is combined so, that high signal noise components, mostly stars, are from bin 1x1 data. Low signal elements are  combined from heavily binned data.

There is a hint of  outer halo visible in this image. It's extremely dim, especially with the focal length used.  I have shot this object with much shorter focal length at Spring 2011. That was the first time I noticed the possible outer structure in this planetary nebula. I like to have this confirmed by some other imager. I will continue this imaging project at Spring season 2017.

PuWe1,  planetary nebula in Lynx
Ra 06h 19m 34s Dec +55° 36′ 42"

The photo is in mapped colors from the light emitted by an ionized elements, 
red=sulfur, green=hydrogen and blue=oxygen.

PuWe1 in visual colors
Click for a large image

Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum.


PuWe1, (Purgathofer-Weinberger 1, PNG 158.9 + 17.8, PK 158+17.1) is a large circular Planetary Nebula in the constellation of Lynx. It has an apparent diameter of 20', without an outer halo seen in the image.

Messier 27 compared to PuWe1
Click for a large image

Note. An apparent size of the full Moon is marked as a white circle atop of the image. 

Technical details

Processing work flow

Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 21 iterations, added at 25% 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 HD 1100 telescope
Canon EF 200mm f1.8 camera optics (For S-II and O-III channels)
10-micron 1000
Meade LX200 GPS 12" (For S-II and O-III channels)

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x2 and SXV-AOL
QHY9 (For S-II and O-III channels)

Astrodon filter, 5 nm H-alpha
Baader filter, 8,5 nm O-III
Baader filter, 8 nm S-II

Exposure times
H-alpha, 30 x 1200s binned 2x2 =10h
O-III, 21 x 1200s binned 2x2 = 7h
O-III, 12 x 900s binned 10x10 = 3h
S-II,  9 x 1200s binned 10x10 = 3h 
Total 23h

A single uncropped, calibrated and stretched 20 min. H-alpha frame as it comes from the camera, the data is binned 2x2

A single uncropped, calibrated and stretched 20 min. O-III frame as it comes from the camera, the data is binned 2x2

1 comment:

Sakib said...

Wow I remember your previous image from 2011, I think this halo is real! Now we need independent verification from someone else. I believe that some of these ancient evolved planetary nebulae have haloes that haven't been detected because they are too faint.