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Having retired as a professional astronomer and moved to a rural (Bortle Class 3) site in New Zealand, I decided to take up the hobby of astrophotography six months ago. I started with a good knowledge of astronomy, CCD processing, but no kit apart from a DSLR. I thought I would put down a few of my lessons learned – and still to learn – over the a very enjoyable start to the hobby. 1) It is highly addictive. Early on, I produced a number of Milky Way time-lapses with just my DSLR and a fixed tripod. But like any 2) Do not try to do too much per observing session. Early on, I tried to do any many objects as I could squeeze in during a night. Sometimes even swapping lenses/telescopes. But finger trouble increases exponentially during the night, and I learned to focus (both literally and metaphorically) on one object per night. Keep the set-up and observing as simple as possible while still stretching (a little) your comfort zone in order to improve. 3) SNR, SNR, SNR. An extension of lesson two. Nothing beats SNR per resolution element. Modern detectors have really low read noise and dark current, so you will mostly be battling sky noise in broadband exposures. No need for the 5min sub in these cases. In fact, tracking errors, dynamic range drive towards almost as short a sub as your file storage, CPU and your patience can take. As an aside, I am intrigued by all the talk around “fast telescopes”. Almost like a “fast car”. But owning a fast telescope comes with almost as many tuning issues as a fast car. [See point 2 above]. And indeed, it is not the speed of the telescope (or beam) that counts – but rather what you do with it. I can turn my RC8 f8 into an f4 simply by resampling at x 2, with a small additional cost in noise. 4) Post-processing is critical. Coming from the professional side of things, I had an ingrained reluctance to go “non-linear” with processing. But coupled with noise reduction algorithms, this is where most of the “Wow!” factor comes from in DSO imaging. I know I should probably complement it with other software tools, but PixInsight does the job for me from go to whoa. 5) Broadband imaging is just the start… Even during my professional career, I marvelled at the images created by "amateur" astronomers. That sense of awe and wonder in even greater today I look at many of the images on Astrobin. They inspire me to do more and improve all the time. This extends beyond my current focus on DSO imaging to the planetary and narrow-band images. Like magic, they inspire in me the question “How did they do that?”. After the purchase of two mounts, two telescopes, one humungous CMOS colour camera, one ASIAir, autoguider, electronic focuser, software package and the construction of one roll-off roof observatory, perhaps I need to heed lesson 1. 6) Invariably great and friendly advice from Astrobin. The lessons above were in almost equal measure from experience and Astrobin. Thanks everyone, this is my feeble attempt to give a little back. |
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Brian, Thanks for your post. As retired optical engineer with an advanced degree in optics, I've often mentioned to colleges that I ultimately learned more about digital sensors, imaging, radiometry, and image processing from my deep sky imaging hobby than I ever did in graduate school. I have a close relationship with the Wyant College of Optical Sciences at the University of Arizona and we've discussed the idea of presenting a joint Department of Astronomy and College of Optical Sciences class in "low-light astronomical" imaging. When I talked with the head of the astronomy department about the idea, I could tell that he really had no idea of the depth of the subject when he suggested that it might be perhaps suitable for a 1 credit undergraduate course. He is a very smart guy who is a very accomplished astrophysicist, but it's easy to under-appreciate all that goes into deep sky imaging in both a practical and a theoretical sense. Also thanks for your comments about focal ratio. Constant angular sampling in image space eliminates the effects of focal ratio on irradiance in the focal plane. I like your point that you can achieve the effect of a different focal ratio simply by changing the sampling in image space. There is no such thing of what amateurs call "The focal ratio myth." That "myth" is simply a misunderstanding about how irradiance and sensor size combine to to produce signal. Fast optical systems are really just about field of view. John |
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Great points, John. Even as a professional I found the term “fast” confusing. I much prefer the adjective “wide” when it comes to f-ratio. A hang-over from film/glass plate photography. |
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I am also sorry to hear of your struggles. There are alway a small number in any profession who are reluctant to seek advice/input from outside their profession. Astronomy is, I suspect, no better and no worse than any other. As A PhD student in the early 80s, I benefitted greatly from profession’s eagerness to adopt CCD imaging technology developed outside the field by some very smart engineers. Indeed, throughout my career, I continued to rely on clever engineers to build the instrumentation that would allow astronomers to exploit new areas of parameter space on existing.telescopes - and sometimes build new telescopes entirely. As a colleague one said “Astronomers dream dreams, engineers make then happen” |
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Hi Brian, Welcome to join this hobby. As you have realized, it's addictive. I am a professional astronomer, but started astrophotography when I was a high school student. So I still do both. I visited New Zealand last October with my wife. We both love it. We were lucky that the only clear night we got during the 9 days of visit occurred when we were at Tekapo. The sky there was amazing. It's great that you do astrophotography after retirement. Looking forward to see more pictures from you. Cheers, Wei-Hao |
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Brian Boyle: ...or another, "Without engineering, physics is just philosophy." As a former grad student in physics, I crossed over to the "dark side" when I realized that the thing that I most enjoyed about astronomy was the gear and I had sure had a lot of fun designing and building optical equipment over the years. I was in New Zealand a month after Wei-Hao where I spent 8 days based in Wanaka flying a little airplane all over the South Island to get my NZ pilot license. I fell in love with the place but the weather on the South Island seemed a bit too sketchy for astronomy. Where are you based and how are the weather conditions? I got my first views of the southern sky on a few clear nights on the North Island. I look forward to seeing your images. Just realize that as a retired astronomer, the pressure is on for some good write-ups on the objects that you image!  )))John |
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Hi John, I can't beat Wikipedia for write-ups on the images I take. Besides my expertise was in observing quasars (lot of them) which don't make for thrilling DSO targets. Having said that there are a few good AGN out there: CenA, NGC1068. I am lucky enough to live about 20km from Queenstown, in a rural setting 3km from beautiful Arrowtown. It is wall off the main through roads into and out of Queenstown. The skies here are remarkably clear, we are again lucky enough to live in a bit of rain shadow from the Southern Alps. I have fifty archive folders on my disk from each nights observing over the last 180 days - so that's a 30% success rate. Not back when factoring in the moon. The winter here was really good (but quite cold), but the spring was poor. Summer is supposed to be good, but the nights are short. The seeing is not great - haven't got any better than around 4arcsec - but I would only have been able to tell that latterly when I graduated to longer focal lengths. And I am still not sure how much of my own instrumental set-up contributes to the poor seeing. Perhaps I should get an EAF.... [Lesson 1] |
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Hi Brian, Welcome, from a retired executive - instrument maker, physics guy..Like John making telescopes in my home shop full time now and fielding them at my remote observatory in the southern California Sierra Nevada mountains, very dark skies and dry Chaparral environment.... Do you have any special astro projects in mind? I too look forward to your images and write-ups. Best regards, Dave |
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Hi Brian, Welcome to AB and thank you for your post, its a really good read and something any new AP'er should read for overall guidance. Being only 6-7 months in myself this would have been useful guidance for me. Your points are all great points and yes, I think this has to be one of the most addictive hobbies I have done and it really does hurt the pocket as you are always craving more. 7 months in and I am just completing my home observatory lol. My wife, although very accommodating, thinks I am a little crazy! Looking forward to seeing more of your images and some great scientific insights too. CS Brad |
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Hi Dave, An instrument and telescope maker in the Sierra Madre mountains? Wow, and I thought I had the ideal retirement. In my professional life, I led the establishment of the Murchison Radioastronomy Observatory in Western Australia (one of the SKA sites) and the build of the Australia SKA Pathfinder telescope on the site. Different scale (and cost) but this shed on Speargrass Flat Road nestled between Coronet Peak and the Remarkables has given me just as much pleasure. |
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Hi Brad, If there isn't a Forum topic already perhaps we need to start a "Home Observatory" topic where we all get to exchanges images on lessons learned of our various observatory builds. Like you building a home observatory was initially met with skepticism by my partner and friends. But I have one everyone around by paying attention to form and function in the design. I have posted a pic on Astrobin of the now nearly completed observatory. Would love to see a pic of your observatory. |
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Hi Wei-Hao, Thanks for the kind words. Combining professional astronomy with astrophotography must be very time consuming. I would not have had the energy to do both simultaneously. Good on you! Brian |
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| Thank you for this. |
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Thank you very much for sharing your experience! I always believed that amateurs astronomers can give a great contribution to scientific community. Reading your words make me full of hope. Galileo was a good astrodyer!!!  |
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Nice post with good insights! I think most of us have learned it the hardway.. which in most cases is, in my eyes, the best way. Another quote along the way of astrophotography i like is: Adversity is the best thing to happen to someone. Thanks for taking the time to write this. Regards, redbeard |
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Hi Brian, I saw that you are working on a field very similar to mine (galaxies and AGNs in radio and other wavelengths). It's amazing. We don't have that many clear nights in Taiwan. So astrophotography didn't actually occupy that much of my time. If I don't do astrophotography at all, I might have some more time for research, or not, because I may not be that motivated on astronomy. Cheers, Wei-Hao |
