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Joel Shepherd

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About Joel Shepherd

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    Star Forming

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  • Interests
    DSOs, most types of history, gardening, mountaineering, bicycling, and I'm lucky enough to have an interesting day job too (principal engineer for Amazon.com's software deployment systems).
  • Location
    Seattle, WA
  1. Thanks! One of the many challenging things about astrophotography is that planetary/lunar imaging and deep space imaging (nebula, galaxies, clusters, etc.) are different ballgames. Planets are small, bright, rotate quickly and are sensitive to seeing conditions, so you need long focal length and lots of short exposures. Deep space things are big, dim, slow moving and a little less impacted by poor seeing, so you need smaller numbers of longer exposures. From that perspective, an SCT will work better on planets than a fast refractor because of its much higher focal length, if you use an appropriate camera, etc. But, if you decide to move on to deep space, the SCT will make life harder. An ED80 won't produce very good results for planetary -- it just can't get "close" enough" -- but will happily manage deep space and lunar. Solar photography is another ballgame and I don't have enough experience with it to recommend anything. I will say that the reason I went with deep space instead of planetary was because deep space stuff is always there, whereas planetary is a little more hit or miss. E.g., from here (Seattle), Jupiter and Saturn have been pretty much out of sight for a year or so, especially compared to 4-5 years ago when they were located high in the mid-evening sky. On the other hand, the Veil is reliably up high every summer night. Have fun!
  2. The AVX is a fine mount for getting started with astrophotography and I personally found that with ASPA I could get well enough aligned for 10 minute exposures. You have to be careful and a reticulated eyepiece (ie, with crosshairs) is a big help. The SCT on the other hand ... ? SCTs have long focal lengths and narrow fields of view which makes everything more challenging. Focusing, guiding, aligning, etc. : that long focal length will add substantially to the difficulty and the precision required. Consider getting the mount and separately getting a short, fast refractor, in the 60-100mm aperture range. You’ll get great pictures, learn a lot and suffer a lot less frustration (note that I didn’t say no frustration ).
  3. I’m interested in learning about EVAA for outreach, but as an astrophotographer ... it’s not as interesting to me personally. It’d be more of a thrill to see a couple gray blobs and know it’s M51’s photons impinging on my own eyeballs. Whether that thrill is worth the cost of a big Dob ... hmm.
  4. Thanks @Paz and @Piero: I appreciate the first-hand experiences. It'd be cool to have a big scope ... but I'm not it can really be justified given our sky conditions. Good food for thought.
  5. We live under Bortle 6 skies (18.6 on the SQM). With a 4-6” reflector or Newt, we can see open and globular clusters, the Ring and Dumbbell, Andromeda, etc. I’m wondering how much difference we’d see with a 14-16” Dobsonian. Would there be noticeably more detail in the clusters. Could we see some of the smaller, brighter galaxies (M51, M63 etc.) Does the aperture make that much of a difference under a fair amount of LP? Interested to hear others’ experiences. Thanks — Joel.
  6. I have an Esprit 80mm and ran it on an AVX for about two years. While I can't compare it to the Explore Scientific, I will say that the Esprit is a no-muss no-fuss scope. It works well for imaging, it produces nice stars without color aberrations, has a decent focuser on it and one which is easily motorized if you want to go that far ... it's a keeper. It actually worked just fine on the AVX. The main issue I had with the AVX -- and I think this was mount specific and not a general AVX issue -- is that periodically, typically after an hour of guiding, the mount would suddenly veer way off on the DEC axis, guiding would fail and I'd have to manually get things going again. Not the end of the world, but it meant I couldn't go to sleep. ? But otherwise, I enjoyed two good years of imaging with the Esprit 80 and AVX, and while I've since retired the mount, the little Esprit is here to stay.
  7. How bad is your LP? If you look up on a clear night, what's the magnitude of the dimmest stars you can see? I can see magnitude 3 or 4 under our skies and have never felt the need for an LP filter. My personal preference would be to not use one: it would inevitably filter out some of the light I do want as well as light that I don't.
  8. An ED80 APO will take you a long, long way (and can also be delight for visual). I've had a SkyWatcher Esprit 80ED for almost three years now and it continues to produces better and better results ... rather, my skills continue to try to catch up with its capabilities. It's true that it is not the best instrument for small galaxies and planetary nebula, but for larger nebula and medium-sized galaxies or galaxy clusters it sings.
  9. @Anne Spretty much said what I was going to stay. Use star alignment to get the mount oriented so that go-to's are fairly accurate. I'd use at least three and as many as six stars. I never understood calibration stars either: you don't need them so just ignore them. Once you've done star alignment (and assuming you set down the mount roughly polar aligned to begin with), then do the ASPA. Follow the directions on the handset closely. Now ... after you've done the ASPA, you may want to repeat the procedure because you've changed the position of the mount. I would park/home the mount, turn it off, wait 10 seconds, turn it on, redo the star alignment (because, again, during ASPA you may have moved the mount significantly), and then redo the ASPA. At that point, you should be dialed in. Also, consider getting a reticle eyepiece like this: https://www.amazon.com/Orion-8450-Illuminated-Telescope-Eyepiece/dp/B000J5OTBM/ref=sr_1_11_sspa?ie=UTF8&qid=1541394002&sr=8-11-spons&keywords=orion+eyepiece&psc=1 Yes, it's pricey; yes, there may be cheaper ones and it's fine to get a cheaper one ... but having illuminated crosshairs to help center your alignment and ASPA stars will help more than you know. Finally: don't give up. It amazes me that you were persistent enough to align a motorized CG-4 well enough to get 3 minute exposures. I had a similar set up and never did better than 15 seconds. So you have the persistence and ability. Go slow, and aim for repeatability. Master the star alignment routine and then enjoy a night of observing. After that, master star alignment and ASPA -- so you can do it without much drama night after night -- and enjoy more observing. Then do it and add a camera to the mix. Get comfy with 10-15 second exposures. Then add a guide camera to the mix. Figure out how to get it focused, get PhD calibrated, etc., and go for 30- to 60-second exposures. Etc. The goal is to get to the point where each of these things is very mechanical and predictable: where you repeat the exact same steps every night and get essentially identical results. It takes patience, but if you take a deep breathe and don't try to move too fast, with your persistence I'm sure you'll get there.
  10. I've used both and really wanted to use APT because I find its user interface much nicer but ... two things made me bite the bullet and commit to SGP instead. One was auto-focusing: it was slow in APT and relatively quick in SGP. If you have or plan to have an autofocuser, I think that's a point for SGP. The second thing was meridian flips, which was my whole goal in getting automation software. I want more lights and more sleep! ? ATP, unfortunately, does not support fully automated meridian flips. SGP does, and once you have it down it is almost magical. Start your sequence, hang out for a few exposures to make sure things are going okay, and then call it a night. Wake up in the morning to a whole new set of lights and a telescope that has flipped across the meridian and recentered all on its own (though hopefully you parked in a bird-safe position at the end of your sequence). The framing and mosaic wizard is pretty slick too (and it relates to plate-solving because SGP will use plate-solving to center you on the area you selected in the F&M wizard before starting the sequence, automagically. SGP is a little more daunting, but now that I've gotten the hang of it I won't be going back.
  11. To echo @spillage , a pretty basic laptop will serve you just fine for capturing at night. I used an old Toshiba with a wobbly clamshell hinge and 4 GB memory for quite a while, running PhD2, Nebulosity, and SGP on it, and it easily managed. Even did a fair amount of processing in PixInsight with it: other than the incessant fan noise, it was able to grind its way along. Earlier in the year the case had finally deteriorated to the point that I didn't entirely trust it, so I upgraded to a Lenovo with 8 GB memory and a small solid-state drive. Again, it has way more than enough power to handle capturing and controlling the rig.
  12. I run off household current: imaging from my back yard. One extension cord from our basement, with a GFCI so I don't accidentally electrocute myself. Much. I have a 12v DC adapter between mains and the Pegasus hub. You could run it off a battery. Without dew heaters on, but with focuser, camera, guide camera and filter wheel I use 7-8 amp-hours over 8 hours or so. Dew heaters add more but I regrettably don't recall how much. In any event, it can run off an appropriate battery w/o an adapter, or off of mains with one.
  13. I have a Pegasus Ultimate as well, though my set-up isn't as advanced as @hughgilhespie has. I have on USB cable from my laptop to the hub, a second to the mount, and otherwise everything runs off the hub including dew heaters, camera, autoguider, filter wheel and focuser. I like the design philosophy of keeping the power hub and computing equipment (laptop, stick PC or what have you) separate, so you can easily upgrade the latter without having to replace the hub itself. The Pegasus hub was smaller and sturdier than I expected and overall I've been pretty happy with its performance.
  14. This is maybe more inspirational than hard data, but it will still make you stop and think: https://skyglowproject.com/ The two photographers who've driven the project have given talks across the US ... not sure if they've done any talks elsewhere.
  15. Well, who's to say that the other image you found is "correct"? ? After all, none of us have ever seen Andromeda that close with our own eyes. That said, play with saturation. For RGB, I saturate after combining the (linear) channels, and before stretching or adding luminance. Stretching reduces saturation. so increasing saturation beforehand results in better color afterwards. Also, after combining and stretching, use an inverted range mask (so you strongly protect the high signal areas) and desaturate the background. Apply a little smoothing and fuzzing to the range mask so that the transition from desaturated to signal areas is natural. That will blacken your background and help the colors pop a little more. Overall, I'd say for your first pass at PixInsight, that's a good effort. Stick with it. I've been using it for two years now and continue to learn with every new project, and the results have gotten better as well (at least in my opinion!).
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