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Saturday, January 25, 2020

A deep view to the California Nebula in mapped colors

I have been shooting few nights with my "new" wide field instrument. Undersampling is a great thing if you want to capture very dim and diffused gas structures with a minimal exposure time. The Tokina AT-x 300mm f2.8 optics combined to CCD with 9 micron pixels (Apogee Alta U16 4096x4096 9 micron pixels) gives me a spatial resolution of 6 arcseconds/pixel. The problem with one pixel stars is actually not a problem. I'm using dither when imaging and when lights are stacked, it delivers
beautifully rounded stars.

The very same optics with a camera, that has a very small pixels, will give a resolution of around one arcsecond / pixel. With same optical configuration, 300mm f2.8, system that has spatial resolution of 1 arcsecond / pixel is 36 times slover, than same optics with large pixels and spatial resolution of 6 arcseconds / pixel.


California Nebula, a deep view to the NGC 1499
Please, click for a full size image

Image is in mapped colors,  H-alpha = Green, S-II = red and O-III = Blue. 
This is a very deep image, I haven't seen those extended shapes at upper right and  around the brighter nebula before. I have published the same image in visual color palette, it can be seen here, https://astroanarchy.blogspot.com/2020/01/deep-view-to-california-nebula-ngc-1499.html


A closeup
Please, click for a full size image

A very good resolution for the 300mm camera lens



An experimental starless version
Please, click for a full size image

Various shapes in nebula are easier to see when stars are removed.


INFO

The California Nebula is an emission area located in constellation Perseus. It appears to resemble outlines of State of California on long exposure photographs, like this one. It has a very low surface brightness and it's very difficult to observe visually. Distance from my hometown Oulu, Finland, is about 1000 light years.

this image spans around five degrees horizontally. The Wikipedia article states, that the angular size is about 2,5 degrees (Five full Moons side by side) but as can be seen in this image, the actual size, with a dim outer parts, is much large.



H-alpha exposure alone
Please, click for a full size image

H-alpha image contains seven 20 min sub exposures stacked together. Exposure time is 2h 20 min..



Technical details

Processing workflow
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
Tokina AT-x 300mm f2.8 camera lens

Mount
10-micron 1000

Cameras, filters and guiding
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x 2 and an old spotting scope of Meade LX200
Astrodon filters,
5nm H-alpha 3nm S-II and 3nm O-III

Total exposure time

H-alpha, 7 x 1200 s, binned 1x1 = 2 h 20 min.
O-III, 2x 1200 s, binned 2x2 = 40 min.
S-II, 2x1200 s binned 2x2 = 40 min.



The apparent scale in a sky
Please, click for a full size image

This is a large object
NOTE, the apparent size of the full moon is marked in all of the images above.
The angular dimension of the moon is 30 arcminutes, that's 0,5 degrees.




Thursday, January 23, 2020

A deep view to the California Nebula, NGC 1499

I have been shooting few nights with my "new" wide field instrument. Undersampling is a great thing if you want to capture very dim and diffused gas structures with a minimal exposure time. The Tokina AT-x 300mm f2.8 optics combined to CCD with 9 micron pixels (Apogee Alta U16 4096x4096 9 micron pixels) gives me a spatial resolution of 6 arcseconds/pixel. The problem with one pixel stars is actually not a problem. I'm using dither when imaging and when lights are stacked, it delivers
beautifully rounded stars..

California Nebula, NGC 1499
Please, click for a full size image

Image is in natural colors combined from the narrowband channels. H-alpha = Red, O-III = Green and O-III + 20% H-alpha = Blue. This is a very deep image, I haven't seen those extended shapes at upper right and  around the brighter nebula.


INFO

The California Nebula is an emission area located in constellation Perseus. It appears to resemble outlines of State of California on long exposure photographs, like this one. It has a very low surface brightness and it's very difficult to observe visually. Distance from my hometown Oulu, Finland, is about 1000 light years.
this image spans around five degrees horizontally. The Wikipedia article states, that the angular size is about 2,5 degrees (Five full Moons side by side) but as can be seen in this image, the actual size, with a dim outer parts, is much large.

H-alpha exposure alone
Please, click for a full size image

H-alpha  image contains seven 20 min sub exposures stacked together. Exposure time is 2h 20 min..






Technical details
Processing workflow
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
Tokina AT-x 300mm f2.8 camera lens

Mount
10-micron 1000

Cameras, filters and guiding
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x 2 and an old spotting scope of Meade LX200
Astrodon filters,
5nm H-alpha 3nm S-II and 3nm O-III

Total exposure time
H-alpha, 7 x 1200 s, binned 1x1 = 2 h 20 min.
O-III, 2x 1200 s, binned 2x2 = 40 min.



On older image of California nebula in mapped colors
The apparent scale in a sky
Please, click for a full size image


This is a large object, note, the size of the Moon is marked, as a scale, in all of the images above.


Sunday, January 19, 2020

An animated Heart Nebula, IC1805 with and without stars

I have originally published this deep image of IC1805 at January 14 2020. This time I made a starless version of  the image. I'm usin the starless version of photo in my processing routine and sometimes they look kind of interesting. The actual nebula stands out very nicely without stars.

My "new" imaging system combines a Tokina AT-x 300mm f2.8 lens to a large CCD of Apogee Alta U16 astro camera with 4096x4096 9 micron pixels. This combination has a resolution of about 5 arc seconds/pixels. Undersampling imaging system is a great tool to bring out very dim and diffused nebulae very fast. This photo of Heart Nebula has only 2h of H-alpha light and just 30 min O-III light.

IC 1805 without stars
Please, click for a full size image

It's easier to see the actual nebula when stars are removed. Human brains has a tendency to form quasi logical shapes and forms from a random cloud of dots. Famous example of this phenomena is Percival Lowell and canals of Mars.


An animated image, IC 1805 with and without stars
Please, click for a full size image




Technical details

Processing workflow
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
Tokina AT-x 300mm f2.8 camera lens

Mount
10-micron 1000

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x 2 and an old spotting scope of Meade LX200

Astrodon filters,
5nm H-alpha 3nm S-II and 3nm O-III

Total exposure time
H-alpha, 12 x 600 s, binned 1x1 = 2 h
O-III, 3x 600 s, binned 1x1 = 30 min..




From Bubble to Cave Nebula in visual colors

At January 10. I shot few lights for this busy area in Cassiopeia from the Bubble Nebula to Cave nebula. The Tokina 300mm AT-x f2.8 camera lens combined to Apogee Alta U16 camera is a very good to capturing photons. The combination of fast f2.8 optics and 9 micron pixels, (4096 x 4096 pixels) goes very deep very fast. (First light photo here, https://astroanarchy.blogspot.com/2020/01/first-light-for-winter-season-2019-20.html)


From Bubble to Cave Nebula
Please, click for a large image!


Image is in visual palette combined from emissions of  ionized elements. Red=H-alpha + S-II, Green= O-III and Blue=O-III + 25%H-alpha to compensate missing H-beta emission.
Same data in mapped colors can be seen here, https://astroanarchy.blogspot.com/2020/01/second-light-for-my-wide-field-imaging.html


Orientation
Please, click for a large image!

The area of the new photo is marked as a white rectangle. Info about this image here, https://astroanarchy.blogspot.com/2014/01/a-grande-finale-of-cepheus-project.html


Technical details

Processing workflow

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
Tokina AT-x f2.8 camera lens

Mount
10-micron 1000

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x 2 and an old spotting scope of Meade LX200


Astrodon filters,
5nm H-alpha 3nm S-II and 3nm O-III

Total exposure time

H-alpha, 18 x 600 s, binned 1x1 = 2,5 h
O-III, 6x 600 s, binned 1x1 = 1 h.
S-II, 2 x 600 s. binned 1x1 = 20 min.