A long weekend trip to X Bar Ranch near Eldorado, Texas yielded some good results despite the wildfire smoke being pulled down from Colorado.
Eastern Veil Nebula
I intended to do a comparison of a couple of different Light Pollution filters but the weather hasn’t exactly cooperated. All I’ve got so far is 3 hours of data on M27 with a Hutech IDAS LPS-D2, my newest filter. I want to compare that as closely as possible with the older LPS-P2 to see how they differ from an imaging perspective.
3 hours (90 x 120sec) of data on a QHY168C through a Celestron EdgeHD 8″ at a focal length of 1422mm (F/7.0).
Taken from my back yard in Allen, TX. Bortle 9 skies.
I finally got another monochrome camera after years of shooting color CCDs. I’m still re-learning the ropes, particularly using narrowband filters for very specific frequencies of light associated with ionized states of hydrogen, sulfur and oxygen. I’ll probably end up doing a lot of hydrogen and overlaying red, green and blue broadband filters over that but that’s another challenge for a different day.
For now, IC 1805 also known as the Heart Nebula. Data captured over the nights of Oct 26th through the 28th. Scope was my 65mm refractor and was imaged from my very bright suburban back yard.
Seeing turbulence in the air) wasn’t great. Stars were twinkling away with the best of them which does compromise image quality fairly significantly. Still, I wanted to get M27 again since I re-calibrated the settings for my camera and learned a bit more about exactly how far is too far with a CCD. This is a quick process but sometimes those are the best.
Messier 27 is a ‘planetary’ nebula of highly energetic Hydrogen (red) and Oxygen(blue/green) in the northern constellation of Vulpecula (the Little Fox). What we see is the outer shell of a dying star of about half our Sun’s mass. This is how our star will die, in about another 5 billion years. This nebula is relatively close at 1,360 light years distance. Observations of this nebula put the expansion rate of the gas cloud at about 31km per second in a 1970 study. That puts the age of the nebula at about 9,800 years.
- 60 sub exposures of 5 minutes each
- Celestron EdgeHD800 @ F/7.0
- QHY8L CCD @ -10C
- iOptron CEM60 mount
- Orion ST-80 + ZWO ASI120MM-S for guiding
Shot through massive light pollution over staggeringly huge The Village At Fairview outdoor mall complex.
This started as an add-on session to my first attempt at narrowband imaging and turned out much better than I hoped for. Of course this would be much more grand out in the country but that’s not what this site is really about. It’s more focused on what I can accomplish from my back yard.
Messier 51 – The Whirlpool Galaxy
Depending on who did the study and when, estimates for distance vary widely from 15 million light years to 35 million light years. These two galaxies are gravitationally interacting which is a highly science nerdy way of saying “crashing into each other)”. Galactic collisions aren’t collisions at all, really. There’s so much empty space between stars in the systems that it is highly unlikely that any of the stars in either galaxy will actually collide. The law of averages says that some will but the percentage is beyond miniscule.
52 images of 5 minutes each.
Barnard 33 – The Horsehead Nebula in Orion
If you find Orion’s belt, the eastern most star is Alnitak. Just a bit South and West from that star is this region, cataloged by Edward Emerson Barnard in 1919 in his book of dark nebulae. This cloud of dust is #33 on his list so we refer to it as Barnard 33. Colloquially we know this as the Horsehead Nebula thanks to its shape reminding most people of the western world of our equine companions.
Light pollution being what it is and with LED lighting becoming more commonplace, I’m now beginning to feel that only narrowband imaging will be practical from the back yard. Narrowband images look at very specific frequencies of light. Not just Red, Green or Blue. Narrowband typically focuses on frequencies emitted by Hydrogen, Oxygen and Sulphur. The first ionization of Hydrogen (H-alpha), the third ionization of Oxygen (O-III), and the second ionization of Sulphur (S-II). Why the change in nomenclature? No idea, ask the smart guys that came up with the “standard” some time after the discovery of ionization states by Dmitri Mendeleev in 1869.
This image was taken in worst possible case scenarios. Not intentionally but I did know what I was getting into. I’m filtering at least 99% of all light by looking at a very narrow band of frequencies around 656nm wavelength +/- 3.5nm. My filter has a 7nm bandpass, thus the +/- 3.5nm metric. This frequency of light is specific to Hydrogen-Alpha (H-a) and pretty much nothing else. Exposure times for light that tightly filtered is ridiculously long. Each of the 52 frames used to composite this image are 10 minutes long. That’s 8.6 hours which had to be done over three nights. I must wait for the sun to be well and fully down and not influencing the sky so I was trying to get started at 8:00pm. That never happened, mechanical things being finicky always slows down the start up process. Barnard 33 disappeared behind our roof at about 1:00am. On the best nights I got started by 9:00pm so I could get no more than 3-4 hours per night if everything went to plan. Plans being what they are, that was never followed.
Filter: Baader Planetarium 7nm Hydrogen-Alpha
Camera: QHY8L binned down 2×2
Telescope: Celestron EdgeHD 8″ + 0.7x Focal Reducer
Guide Scope: Orion Mini Guider Deluxe
Guide Camera: ZWO ASI120MM-S
Exposure: 52 x 10 minutes