There is a faint arc of ionised hydrogen gas glowing in HII light around Orion. This is Barnard’s Loop. Its not really visible by eye or backyard telescope.
Tried to image this last night with mixed results.
As this is such a large object, I used a wide-angle Canon 50mm f1.4 lens with the Canon 60Da DSLR set at f2 and ISO 800.
I used FWHM focusing which seemed good but the final image (26 x 30 second sub-exposures) seemed to have a lot of poorly focused field stars. I guess I should take a few test images first in future – especially for low f-stop, wide angle images. (Ive also read since that the 50mm f1.4 is said to be best for astrophotography at f4).
Also the lower 20% of the image was overwhelmed with light pollution despite waiting until Orion was at its zenith (around 2330 GMT) and using a CLS filter.
Must try harder!
Sh2-276 emission nebula in Orion. Barnard’s Loop.
Barnard’s Loop in Orion (Sharpless catelog – Sh2-276). An arc of high temperature ionised hydrogen gas around Orion – probably the remnant of an old supernova explosion. It forms the backbone of a “G-shape” with the burning bush and horsehead nebulae at the crossbar. Orion nebula is bottom right
Two beautiful nebulae in Orion. They lie beside the left-hand star in Orion’s belt. Ive always wanted to see the Horsehead but it is too dim for my telescope.
This image was taken with a Canon 60Da with 200mm f2.8 L lens set at ISO 800 and at f3.5. 16 x 30 second sub-exposures were stacked together to make the final image (processed in PixInsight and Photoshop).
The “rays” coming from the brighter stars are a diffraction artefact caused by the 8 blades of the iris in the lens. After some research, I found out that this can possibly be avoided by using “step down” rings attached to the end of the lens – these are used to attach smaller diameter accessories to a lens but have the effect of “stopping down” the lens. A 72mm – 65mm ring is the equivalent of stopping the lens down to f3.2 and a 72-55mm ring gives f3.6 for this particular lens.
Barnard 33, Dark nebula, Orion. Horsehead Nebula.
NGC 2023, Reflection Nebula, Orion.
IC 434, Emission nebula, Orion.
IC 431, Reflection nebula, Orion.
The bright star in the centre is Alnitak. The left-hand star in Orion’s Belt. Just to the left is the Burning Bush nebula(NGC 2024). Below is the Horsehead nebula (Barnard 33) outlined by the glow of Hydrogen alpha light (IC 434).
I knew it was too windy but couldn’t resist trying to run an imaging session with a Canon 60Da and 200mm f2.8 lens tonight. I just ended up with some slightly blurred 1 minute exposures showing Alnitak in Orion’s Belt with the adjacent Flame nebula (emission nebula) NGC 2024 and the reflection nebula IC 432. Nothing I would want to post here, but it was interesting to see them relatively clearly on a long exposure compared with their invisibility through an eyepiece.
Swopped over to a 80mm refractor and enjoyed looking at M42 and M45 through 27mm Panoptic and 10mm Delos eyepieces.
NGC 2024 emission nebula, Orion. Flame or Burning Bush nebula.
IC 432 reflection nebula, Orion.
Orion Nebula M42 with M43 [with above NGC 1977 (Running Man nebula) and top left, open cluster NGC 1981]
After a few false starts with cloud tonight, I set up about 11pm with my new Canon 60Da DSLR camera. The 60Da is modified to pass through more Hydrogen alpha (red) light than a standard camera and I have also fitted it with an in-camera Astronomik CLS filter to supress urban light pollution.
I slaved the camera to my laptop and used the Backyard EOS program to obtain sharp focus through a Canon 200mm f2.8 L prime lens set at f3.5. I then set up a series of 30 and 60 second exposures at ISO 800 via the laptop.
Some of the exposures showed blurring due to poor tracking (I only have a Alt-Azimuth mount) but many were good.
I was able to stack 5 x 30 second exposures in PixInsight (using darks, flats and bias frames for calibration) then edit in Photoshop to produce this image.
Overall, I am impressed with the 60Da.