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Luna-tic

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Everything posted by Luna-tic

  1. I've only used a DSLR so far, don't have a dedicated AP camera yet. I'm still learning myself about pixel size, large sensor, small sensor, etc., and how they affect the image, as well as stacking and processing. Lots of things seem to trade off on each other when imaging. For instance, those two Moon pictures above had quite a bit of difference in ISO and shutter speed between them. 1st image was 1/60 sec, ISO 400. 2nd image was 1/80 sec, ISO 12800. The more "magnification" and lenses you put into the light path, the dimmer the image becomes. You then have to weigh a high ISO (more noise) against a slower shutter speed (object movement) in order to get an exposure bright enough to show contrast and detail, yet not be blurred from sidereal motion or poor tracking. The Moon isn't all that hard, it's a big, bright object. Planets become more difficult, higher magnification not only dims the image, it decreases the detail and sharpness even though the image is larger. I can't say whether or not it would be better to get a really crystal sharp image that is tiny, but has good detail and color, and then crop it to make the image larger. It would depend in great part on how high the camera's resolution is. And then there's DSO, when stuff is so dim that exposures get timed on a calendar, it seems. Then its much more than just the camera, the mount and its tracking accuracy become paramount, and stacking multiple images and processing. Still working on getting there, single image is all I've done so far, and even there, I've a long way to go. From what I understand, (to address one of your questions from the other thread), you can shoot either multiple single images or a video; the stacking software can separate the video images. You'd need to ask someone with much more expertise than I (currently I'm at 1 to the minus 10th power level) about the advantages of one over the other for processing.
  2. I didn't see anyone specifically speak about it, but EPP, or eyepiece projection photography is another way to achieve a "magnified" image over a prime projection. The extenders some have mentioned, that increase the distance to the camera's sensor, increasing the focal length, also come such that you can insert one of your telescope EP's into it, then attach your camera via the T-ring, and then insert the whole thing in the focuser of your telescope. In this manner, you can choose a wider range of image size. Whether your DSLR is a crop sensor or full sensor will also determine the image size. These are poor images, but illustrate the difference. Telescope is a Edge HD 8" SCT; first image is prime with a DSLR of the Moon. Second image is a 13mm EP and I believe I also had a 2.5x Barlow attached to the front of the camera and then into the rear cell of the telescope (or focuser if it were a refractor or Newt). Easy to see the difference in "magnification" between the two. I had a couple of issues focusing when I made these, since resolved. DSO imaging doesn't really benefit from EPP, though, just planetary or Lunar.
  3. Good description, and yes, it's more from the photographic end. A 'fast' scope allows a shorter exposure time than a 'slow' scope. A fast scope will generally have a wider field of view, too, allowing more area of the sky in an image. A fast scope is easier to learn AP on, easier to get images without movement (shorter exposure time again). You can also usually use a lower ISO for imaging with a DSLR, and that decreases 'noise' in the image.
  4. I thought that might be the case. I'm getting there, too. I'll be 70 in 2024, hope I'm not blind, or worse, by then. Maybe the old-folks' home will have an excursion so I can go see it (2024 eclipse). Maybe I can design a clamp to mount my telescope to my walker for the occasion. Patagonia that far south is so far off the beaten track you can barely see it from there. Never been there myself, but from looking at Google Earth, it's just one step removed from the Moon. My daughter has been to that part of the world (works on a cruise ship), she says that southern Chile is nice, at least the areas along the coast she's seen, but southern Argentina is pretty desolate. Certainly it would be an adventure to go there, eclipse or no. Hope you can work it out. Here's a couple more shots I made, to further whet your appetite:
  5. Are you particularly wanting to see a total eclipse in South America (once in a lifetime trip), or just wanting to see a total solar eclipse? The terrain in that part of South America east of the Andes is pretty much desert. The Argentinian coast from Viedma to about 30 miles south of Las Grutas might be the only decent area in Argentina to view. West of the Andes is a bit greener and more populated, although that's a relative term. Only three cities of note in Chile in the path of totality: Temuco, at the northern edge of the path, about 262,000 population. More in the path center are Nueva Imperial, population 29K, and Petrufquen, population 21K. My choice would be somewhere near one of those cities, or along the Chilean coast from Isla Mocha to Nueva Tolten. If you want more viewing options for a total eclipse, why not wait to 2024 and come to the States? Longer period of totality, much, much longer path to choose a site from. And English is (sort of) our first language. I was only a 2 hour drive from the path of totality back in August; I'll have to drive about a day to get to the one in 2024, but I plan to be somewhere in the path. Took these shots through a C6 back in August.
  6. Yes, but it's not that hard. Get a star chart that shows star names. The time of night you do your star alignment will determine the stars suggested by the go-to.
  7. I think what you're asking for is a Go-To mount. For ease of use and quick setup, look for something like a Celestron Nexstar 8SE, which is $1000 USD, or for a bit better optics the Evolution 8 which is $1600 USD. Both are Schmidt-Cassegrain scopes, the Evolution uses the Edge HD optics. Both have the same go-to alt-az mount. Orion and others have similar products. I'm not sure what the exchange rate is so don't know which fits your budget better. Wow, lots of answers since I started typing. Looks like we're all on the same page.
  8. Nice pics; what did you do differently in the 2nd image, the stars are quite brighter.
  9. The Celestron SCT T-ring adapter is correct length for back focus requirements. I also have an adjustable length T-tube from Orion that I reach focus in; it's designed for EPP, but can be used for prime. It screws to my T-tube, which fits directly to the rear cell in the same way the visual back does. I use them both in my C6 and Edge 8. Use Live View; depending on the object's brightness, you may have to adjust the LV screen brightness up in order to see it for focusing. I have to use max on my D3400 for stars at Mag 3-4 or dimmer, and below 6 I can't see them at all. A flip mirror diagonal may help; the camera attaches on the straight tube, and an EP on the vertical, the flip diagonal mounts to the visual back; you obtain focus in the EP, flip up the mirror and shoot a test shot to see if you are parfocal at prime with the camera. If not you adjust the EP depth in its barrel on the flip mirror until what is in focus in the EP is in focus on your test images; as long as you don't shift the diagonal in the visual back or move the EP, you'll be parfocal with both for all following shots. Vixen, Meade, and Orion all make a nice flip mirror. I have the Vixen, it requires a 2" VB. I only use my flip mirror if the object is too dim to see in the LV screen. A Bahtinov mask is still a good idea. Use a remote shutter release so you don't have to touch the camera, or you'll get blurred shots from movement. Mine uses a ML-3 infrared remote, I think yours uses a wired remote? Live view will also lock your camera's mirror up so it doesn't add vibration. You won't get perfect shots, but you can get some decent pictures of the Moon, Saturn and Jupiter, enough to see the Galilean moons and Cassini Division, maybe a bit of color. 20-25 seconds at ISO 12800 will give you M13 clearly, beyond that you'll get barrel-shaped stars. 25 sec at ISO 3200 will also give you a little of the nebula in M42 and M43, and some definition in the center. I've also gotten M36 and M103 with single exposures around 25 seconds at ISO 6400. You'll just have to play with exposure time and ISO to get a combination that limits blur from object movement, but gets enough light for an image. Also, the higher your ISO, the more noise you'll get. My times assume tracking and a good polar alignment, and I'm shooting at the native f/10; if you get a 6.3 reducer, you'll be able to trim your exposure time and maybe your ISO a bit. YMMV. Good luck, it's a ton of fun.
  10. Do you have the LV screen brightness set low? I have to turn the brightness to max on my D3400 to see anything less than around mag 3-4 stars. Sort of aggravating, because at full brightness, the exposure data on the borders is too bright and messes up my dark vision. I'll find a bright star near to the object I'm interested in shooting, focus on it, and then skew to my target.
  11. I love looking at this group. I've split A through D, and have seen E as a bulge off A, but haven't seen F. Does it split from C? I was using a 13mm EP and 2.5 Barlow in an Edge 8 to get that. The streetlights on my road have also lately been changed to LED. Although they seem better shaded than the sodium lights they replaced, the whiter light bothers me more and I have two that I can't block from view using a tree or house.
  12. It will be a while before I buy a dedicated camera for AP, the DSLR is doing okay for my purposes. I keep it (sensor) meticulously clean, never have a lens off without immediately covering the front, same as with the EP's, corrector and rear cell opening on the telescope. I think a set of flats would last a bit. The "high water" I was speaking of is all the flood of jargon in the last few posts: binning, Sigma clip, defect map, column defect, bias, etc. I'm also not really up on the CCD AP camera models, so I have no idea what to picture in my mind when one gets mentioned.
  13. I'm not at all familiar with the Flextube, but one of my clubmates has a 12" Lightbridge. I'd buy one just because it's a beautiful piece of telescope. It breaks down easily, he can assemble and collimate it in about ten minutes, and the viewing is incredible.
  14. I feel like I was standing ankle deep in the local creek and then there was a sudden flash flood and I'm being carried downstream while trying to keep from drowning. Suddenly the "water" got way over my head.
  15. Deep Sky Stacker was the one I couldn't think of; it should be sufficient for my needs, and I'll also download Registax for some planetary I plan to do. Free works for me very well. Thanks for the guidance.
  16. I tried the ASPA method last Friday night. I thought it was a bit of a PITA, and took me longer than the method I've been using. Navigating the handset is still rather time-consuming to me. I got a good alignment, but no better than I've been getting doing a good manual PA before doing s 2-star alignment with one or two calibration stars.
  17. If I had one of those, and got called "4-eyes" by all the guys in the club, I wouldn't feel insulted.
  18. Good to know, thanks much. Next question. What's the best stacking program? I see Registax recommended, and there are a couple of others I can't think of the names. I plan to use Lightroom to post-process the images. By best, I mean mainly the easiest to use. Convoluted programs confuse me, I'm not the sharpest knife in the drawer when it comes to computers.
  19. Dew is humidity and temperature directed. A shield may delay the onset (same as having the tube horizontal rather than vertical), but won't prevent it. Was the air cooler last night than it has been, or has it been more humid? Weather changes sometimes mean dew when you had none before.
  20. Wow. Ask a simple question.......LOL. Thanks for the great info. Do flats need to be current with the images and darks (meaning taken relatively within a close timeframe)? Or can I take a series of flats and just use those whenever I need them for a processing session? Same would go for darks, I suppose.
  21. Can you do without them entirely? What does it do to the processed composite if you don't make flats? If you know your optical train is clean, does it make them unnecessary?
  22. I understand the purpose of shooting dark frames, but what are 'flats' used for? Is there a general ratio of darks and/or flats to process with the collection of images when you stack them?
  23. That's good to know the strength is so good for such a small diameter screw. Great idea to exchange them for metal screws than can scratch and/or dent the EP tube.
  24. Exactly. Because it's bright, it's one of the first DSO's people try, and why I also tried it. Stacking and processing is the only way to get even lighting and a full image of it; I knew that going in, but I'm taking 'baby steps', looking at exposure times and ISO to gauge tracking accuracy without guiding (I'm using a long F/L scope). I took over a dozen images of M42 at exposures from 20-40 seconds and ISO from 1600-12800. It's easy to see in the combinations where tracking becomes an issue and noise starts becoming prominent and where lighting is enhanced or inhibited. I've also played with less-bright objects like M1, M31, M13 and some of the open clusters. Once I get a feel for this, I plan to start stacking images and playing with them in Registax and Lightroom, using filters, etc to improve coloration and visibility. Now that I've photographed a rather large-field DSO, I know what to expect with FOV and my longer F/L and a DSLR's sensor size. Hopefully, Celestron won't take the remainder of my lifespan to get their reducer availability issue worked out. Then I can open up my field a bit. Fastar and f/2 is further down the road. As for the grin, I still have it, several days later. This is FUN.
  25. If those nylon screws work for you, well and good. However, I would worry that I could not torque them tightly enough to hold my EP's without shearing them where the head reduces to the threaded portion. Those are pretty small diameter; re-drilling and tapping the holes for an M6 would give more strength to the screw. By the time I'd try that, I'd as soon just upgrade to EP holders that have a collar inside that the screw turns against.
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