Bortal 8+ Imaging from West London

[susan-parker]

Here is the latest version of the Orion Nebula in a big stack of over 1200 frames with all seven filter's frames from two seperate sessions on the nights of the 20th and 27th, plus the previous 921 Optolong monochrome frames taken on the 1st as additional luminosity.

So basically a combination of three sessions, with different orientations, gains and filters; stacked with Astro Pixel Processor.

The SpaceCat telescope has really good geometry, so these images have stacked together without bluring.

Slightly more detail in the wispier parts, although pragmatically I am up against the background light pollution levels and exposure times which is curently at magnitude 16.

[susan-parker]

The Horsehead and Flame nebulae using the Hydrogen-alpha narrowband (7nm) filter only.

Stack of 175 frames, processed to show nebula detail, with stars down into magnitude 14.

Atik Horizon monochrome camera, William Optics "SpaceCat" with Atik NB Hydrogen-alpha filter, Gain @ 30, with 30 seconds per exposure, sensor at -15C.

[susan-parker]

This is a "random" bit of sky, just under the head of Hydra.

The central bright star is HIP44030 at magnitude 6.65, and stars are down into magnitude 15.

Image is 33% scale, taken with Atik RGB filters, with 100 frames per colour of 8 seconds each (no luminance), and Dusk setting Hi Gain (30).

Given the sensitivity of the camera sensor to different wavelengths, is there a standard RGB ratio to compensate to get better accuracy for the colours of the stars, or does one tend to leave them "as shot"?

BTW Vince, the EFW2.2 filter wheel now seems to be working properly in Dusk; thanks.

[vince]

Hi Susan,

You can use a G2V star to calibrate you filters to work out the offset for each filter, there are many articles online if you search for 'rgb calibration star' or similar.

Good to hear the wheel is behaving.

Nice images BTW

Vince

[susan-parker]

An enhanced colour version of the Horsehead and Flame nebulae with Atik Hydrogen-alpha, Sulpher II and Oxygen III narrow-band filters for RGB, plus Optolong UHC filter for luminance.

This mosaic is a combination of all the sets taken of this area using the SpaceCat telescope and Horizon camera, including the previous Orion's Belt set.

The superb geometry of the SpaceCat allows the stacking with great star registration even when putting corners of one set into the centre of another.

This was a massive stacking sequence with the Astro Pixel Processor software that took most of the day to process on my 2nd gen i7 computer.

Stars are down into magnitude 16 in the original (for the 600KB limit I have had to go down to JPEG guality 7 in PhotoShop).

I have not tried to hide the stacking set edges in the mosaic.

[susan-parker]

For comparison with my recent Orion images I have restacked four sets I took at the beginning of 2019 with my D800 and Nikkor 105mm f/2.5 lens at f/2.8, static mounted (i.e. no tracking), with the Astro Pixel Processor software (took a full day to process).

This is a crop and 25% scale from the new overall stack which came out of APP as a 9222 x 5492 pixel, 32bit depth RGB, 600MB image!!!

The faint redish blur to the top left is emission from the background wisps, not lens flare (although perhaps not very visible once crunched by the JPEG settings needed to get the image in under 600K).

Stack of 1556 frames of 2 seconds each (51 minutes and 45 seconds total exposure time) mostly at ISO800, with stars down to magnitude 15(ish) discernable in the original.

BTW I started with 5 sets of 2256 frames in total, but didn't have enough space on my empty 1TB SSD for the integration phase so had to dump one set.

[susan-parker]

Beehive open cluster, from the 16th March.

33% scale of RGB filters image. Stars down to magnitude 16.

12 seconds per exposure - 100 frames per RGB.

SpaceCat, EFW2.2 with Atik filters, Horizon mono. Processed with Astro Pixel Processor and Photoshop.

[susan-parker]

Close-up of the BeeHive, at a one-to-one pixel crop from the previous full frame.

[Noah4x4]

Great stuff Susan.

Sorry to hear that your second generation i7 takes so long to process the stacks. Have you tried increasing RAM as a cheap fix?

I have adopted an end to end 4K UHD wireless system using Windows Remote Desktop and observe from indoors. I found that my seventh generation i5 quite often choked with 4Gb RAM and still struggled with 8 Gb. I now employ an eighth generation i7 with 16 Gb and it now processes stacks from my Atik Horizon in near real time. 

I suspect others might be frustrated by processing that might take hours, and I thought it might be helpful to indicate what processing power and RAM might be desirable for faster performance. Admittedly, 1080p HD might work fine with lesser computing power, but to use the Horizon's full 16 megapixel resolution with short stacked exposures potential needs a fair bit of ooomph.

[susan-parker]

Great stuff Susan.

Sorry to hear that your second generation i7 takes so long to process the stacks. Have you tried increasing RAM as a cheap fix?

Hi Noah,

Thanks for your post

I had undated from 16 to 32GB of RAM last year, plus a SSD for the OS and another SSD one for working temp files, and updated to Windows 10. Overall ran better but still ran slowly for stacking and I continued to get the occasional "Blue Screens"... which wasn't reassuring.

I built the i7 machine 9 years ago, upgrading from a Pentium 4 keeping the case, and discs but with a new power supply.

I decided to update my computer (keeping the case, discs, and power supply so not really a new computer, honest) after the multi-session stacking of the Horsehead and Flame Nebulae; which was painful.

Now have an AMD 12 processor 24 core Threadripper and 64GB memory, plus the other bits to go with that. It is at a minimum 5 times faster!!!

At present my observations are out of the bedroom window, I am slowing moving to have something portable so I can try some "real" astrophotography

[vince]

Hello Susan,

Another nice image, this was the first DSO that I tried imaging with an SC1 modified webcam many years ago!

I can see a few weird colours on my monitor which could be the colour saturation has been pushed slightly high?

Stay safe

Vince

[susan-parker]

Over the course of the last three nights the sky has been good enough to get in a few frames of the area centred on Procyon (one of the few stars I can actually see!); 2000 in all.

Pic is 33% scale of original, stars down into magnitude 15. Processed with Astro Pixel Processor.

Stack of 1500 colour frames (500 each RGB), 8 seconds per frame, high gain (30) with Dusk. SpaceCat, EFW, Horizon as before.

Vince: the odd colours probably come from the amount of pushing the image to bring out the low level details - plus the "Increase Star Colour" in Astronomy Tools. My images are quite noisy because of the background light pollution and poor seeing conditions.

[susan-parker]

... and this is a 1 to 1 pixel crop of the previous image.

[susan-parker]

First section of my mosaic from last night - shot as luminance / monochrome only, and each frame is static.

Cropped the edges, so about 800 frames worth from the first 999 frames, 1.0 seconds per frame (Horizon CMOS sensor + USB3 made this possible), high gain (30).

The centreline of the equatorial grid is at about +5.5°. The crop Field of View is about 10° wide.

The two brighter vertical stars to the right are 63 and 66 Orion, and the brightest star towards the lower-left is 8 / Epsilon Monoceros A.

Despite the short exposure time, stars in the original are visible down into magnitude 15. I have had to scale this version down to 16.5% to make it under the 600KB maximum.

I have another 9000 frames to process !!!

[susan-parker]

... and a crop at 33% scale with Epsilon Monoceros A towards the lower-left.