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Everything posted by Luna-tic

  1. Luna-tic


    No argument taken, maybe it's just my old, tired eyes . Jupiter's almost too small for me to see in or out of focus there, and I even have some focus issues when looking through my own EP's. Yours is a cracker of an image, hope I can get as good with my WO scope. You and I seem to have a bit of similarity in our equipment when reading your sig. How are you liking your Starsense? I used mine first time a couple of nights ago, seems to be all it was hyped to be. How do you attach it to your Zenithstar? I may send a PM to keep this thread on topic.
  2. The WO website shows it as "in stock" in gold. I've read a couple of good reports on it; they impressed me enough that I can't wait for an opportunity to see how well my GT81 will do with and without the reducer with a DSLR. I've only had the chance to use it for visual a couple of times since I got it after Christmas, and the clarity was stunning.
  3. There are lots of places on Stellarium like that; some aren't noticeable unless you're zoomed in a lot. I suppose it's due to how the sky is "assembled" in the software sources. It may also be the particular version you have. I ignore it, it's still pretty accurate.
  4. Rome wasn't built in a day, and the sky wasn't learned in a night. You're doing it about like everyone else; reading and looking, and eventually memory will put it together. I'm like Luke, I don't believe in astrology, but knowing the order of the zodiac helps me with where the constellations are relative to each other and which ones you see at a particular date or time of night. Stellarium is a great help for me as well, especially learning the individual stars. I know many by their traditional Arabic or Latin names, but I'm trying to learn the new Bayer designations, too. Wikipedia is a good source but you have to approach it by specifying what you want to know about. Beyond reading and studying, the repetition of looking every chance I get helps cement them in my mind.
  5. Luna-tic


    Looks great. Hard to get a bright object and a dim one together without overexposing the bright one or losing the dim one. Focus is okay or Jupiter would be a fuzzy ball. I would try bracketing exposures, vary the shutter speed and/or ISO over a series of shots.
  6. I don't buy into that; pointing a laser is like aiming a gun, be sure of your target before pressing the trigger. I've yet to see a star or nebula with a green and red wingtip light or flashing strobe. The US FAA is not very forgiving of "accidents" when it comes to pointing a laser at an aircraft, so it's best to take a look around at outreach or other stargazing events and make sure there's nothing around before using a laser pointer. I agree with Photogav that educating the public about them is important . Our observatory is directly below a pattern entry point at the edge of Class B airspace for a major international airport, so for us at outreach events (every other Friday night), it's a constant thing for us to watch out for. The pointer I use is an Orion Skyline Deluxe. It's 5 mW, takes two AAA alkaline batteries. Comes in a nice padded metal case and has a pocket clip. Green is most visible to the eye and shows up well against a dark sky. It's $50 USD on their website.
  7. Same basic principles as land photography, with one major exception. The difference is that aperture no longer determines depth of field, which is unimportant in AP (it's all at infinity), but now becomes part of your exposure calculations along with Shutter speed and ISO. Focal length will determine your field of view and image scale, as usual. So, determine how large an area you want in an image, choose your focal length accordingly and get the largest aperture lens you can afford. A 300mm f/5.6 lens will allow shorter exposure times than a 300mm f/8, etc. with shutter speed and ISO the same. Unlike land photography, you now have to contend with Earth's rotation, so longer exposure means the stars will move and you have to accurately track them, so shorter is better with exposure to keep the stars round. Stacking allows a series of short exposures to be processed to give the detail of a long exposure without the problems of movement. The longer the focal length, the more that movement becomes an issue.
  8. I picked up an older CG-5 mount and tripod the other day for $50. It's in good shape, just a bit dirty. The Dec axis moves freely with the clutch loosened, and drives very smoothly with the clutch tight. The RA axis drives very smoothly with the clutch tightened (bear in mind this is a totally manual mount), but is stiff to move with the clutch loosened, and has a couple of spots where it is very slightly "notchy" when it is turned. How can I loosen this up, to make hand-skewing to a target easier? It has no polar scope, no big deal, and has provisions to add tracking motors, but I doubt I'll do that. I bought it to have a simple, grab-and-go mount to throw the frac or C6 on to look at the moon, etc. It's usable as-is, it tracks nicely with the worm drive, but I'd like to get it back to its "former nights of glory" condition. I think it may be as simple as re-greasing the bearings, but I'm not sure what I need to do to take it apart. There is a collar that has two small holes for a tool like a circlip plier, located underneath the RA setting circle ring (at the bottom, where you'd insert a polar scope), looks like that has to come out to break the RA bearings apart.
  9. You got me curious; if you have two 9.25 Edge's, one with and one without a Feathertouch, why would you want to swap focusers? Unless the one with the focuser is broke beyond repair..... I got notification today that the Feathertouch focuser for my Edge 8" is on the way. Can't wait to install it.
  10. That lens hasn't even started to get dirty. If you feel the need to remove the dust, try blowing it off first. I found a flat-tipped, fine camel hair paint brush about an inch wide (artist's brush, not a house painter's) that I use to flick dust and lint off the correctors of my SCT's and the objective of my frac. Works great, won't damage the glass or coatings. Hold out as long as possible when it comes to cleaning a lens with anything that is wet or that you have to rub with. The less you mess with the lens the better off you'll be. Keep covers on them at all times when not in use to help keep them clean.
  11. I think the current operative theory on the Moon's creation is that a smaller planetary-sized body impacted a primordial Earth and blasted material into orbit that eventually accreted into the Moon. It is true, though, that the distance is increasing between the two, as a result of tidal forces that are also decreasing the rotational velocity of Earth.
  12. Saw this on weather.com. The premise is, "what if the Moon orbited at the same distance from Earth as the ISS?". Physics and orbital dynamics aside, the graphics are pretty nice. The video is Moonrise to Moonset, accelerated, with the Moon only 250 miles out. https://weather.com/science/space/video/what-if-moon-orbited-at-same-height-as-iss
  13. Gorgeous setup. Send it to me, the latitude is properly set for my area, that way you won't need to change it. One question. What is the rubber band that is stretched over the 11:1 knob on your focuser and connected to something lower on the mount? Is that an electronic/autofocus setup, and if so, how does it work?
  14. I have a 13mm Ultima Duo EP and love it. I didn't realize that Celestron doesn't make them any more, that's a shame. I also have a 8mm Baader Hyperion EP that has the threads for a T-ring, same as the Duo. The Hyperions also have replaceable lower barrels to change the focal length of the EP, and are about the same price as the Ultimas are (were). The Hyperions also have a 68* apparent FOV, same as the Ultima Duo.
  15. Try a different EP in the tube, one with shorter f/l (such as a 20 or 25mm). You may not have enough back focus available with that EP adapter. An alternative to using that adapter tube is to use an EP that has a threaded collar for a T-ring already on it (such as a Celestron Ultima Duo, or Baader Hyperion)
  16. Me likee. My Nikon doesn't have the articulating rear screen and it's a real PITA when trying to focus on an overhead object. I'll use a diagonal to make it easier, but it sometimes makes the light path too long. I have an HDMI cord for my camera so I could use a computer as a monitor, but this would be so much easier, I can just Velcro this screen to my tripod. At 800x480 screen resolution, I wonder if the resolution is good enough for a sharp focus?
  17. TLI is designed to establish a trajectory to the Moon that provides for a free return trajectory (with minor course corrections enroute) should the SPS [service propulsion system] engine fail to fire at LOI [lunar orbit insertion]. The LOI burn created a 3000 fps Delta-V to achieve lunar orbit from the free return trajectory. Since the SPS was not functional on Apollo 13 due to the O2 tank explosion, the throttle-able LEM descent engine was used for course corrections, both on the way out and the way back. This is an interesting read; seems that we were at the very edge of technology of the day to land and take off again from the Moon: https://history.nasa.gov/afj/loiessay.html
  18. Add to that the stronger magnetic field of Jupiter, can influence a travelling body much further out from its surface, and most meteoric masses travelling inside the solar system are being influenced by solar gravity (they are travelling roughly towards the Sun) and their velocity out at Jupiter's orbit is less than it would be at Earth's orbit due to the acceleration constant of the Solar gravity well. Pete mentioned above that he'd like to "witness one live". So would I, as long as I was outside the blast radius.
  19. Well, the AVX is plenty for either/both scopes for visual, and probably sufficient for imaging with either scope. Mainly want it for a more solid base for imaging.
  20. I'm considering a second mount; not sure if I'll keep the AVX or sell it later, but looking at something a bit heavier, so I can mount two scopes. Budget is a serious consideration, and the two I've narrowed down to that I can reasonably afford are the Celestron CGEM II, and the Skywatcher EQ6R-Pro. Same money, very similar features. What's the consensus on which one is better, and why? Please don't bring other dogs to the fight, it's just between these two. Right now, the SW has a slight edge; 4 more lb. of capacity (but the CGEM has as much as I need). SW is belt drive, couldn't readily find what the CGEM uses (stepper motors??) SW is a couple of pounds lighter for the mount and the tripod, which makes moving it a tiny bit easier. Both can handle Vixen or Losmandy dovetails, both have illuminated polar scopes, both can use SkySync and StarSense. I like black better than white for color, but it certainly wouldn't be very high on the decision tree..
  21. Next clear night I'll give it a try, thanks for the suggestion.
  22. Between the C6 and C8, based on what you said above, definitely the C6, and a small alt-az mount. You might also want to consider a doublet refractor around f/7 and 100mm or so aperture. The Explore Scientific 102 DAR102065-1 would be a good choice. It's longer than the C6, but is the same weight(and less expensive), and has a wider field of view than the C6. You mentioned the reducer for the C6; it changes the f/10 focal ratio to an effective f/6.3, and flattens the field so stars at the edge are in focus. To give an example of the difference in image size, at native f/10, the full Moon will completely fill the FOV at prime focus (no eyepiece, what a camera would "see". With the reducer in place, the full Moon will take up about 80% of the FOV. Certainly when looking at deep sky objects the FOV with a given EP will be wider with the reducer, but it's really not a substitute for having a wide-field telescope. You'd only appreciate the wider field at the lowest EP magnification. The reason I mention a refractor is that it would be more durable with frequent travel. A SCT will need periodic collimation if bumped around much, where a refractor won't. Your views might not be quite as bright due to smaller aperture, but a small achromatic refractor is a very nice travel scope.
  23. This is the first time I've seen them in my scopes. Seeing was much better than usual around here, but there was still a lot of "shimmer" in the atmosphere. I tried imaging the Moon with both the frac and SCT, but low power in the frac was all that would give me acceptable images. Everything else looked out of focus from the atmospheric movement, even when it was sharply in focus through the EP. I can generally split most of the more common doubles, Castor is usually my 'barometer' of how good the sky is; if I can get a clean split I know it's a good night.
  24. First, I'd like to say that I'm in wet diapers as far as imaging goes, just making a few baby steps. Tonight was clear and not as freezing cold as has been recently, so I took the kit into the barnyard where I have a fairly decent sky. I just added Bob's Knobs to my Edge HD 8", and had done an indoor collimation; I wanted to fine tune it outside as one goal of observing tonight. Another goal was trying out my new WO GT81 on the Moon, I haven't had the opportunity to use it for lunar because of recent weather.....and no Moon. So, one of the last things tonight was to swing over to M42 after the Moon got too low to observe. I used the frac to observe wide-field for a while, then put the Edge on the mount; to check collimation I swung over to Castor, and clearly split it with a 25mm Plossl. Then I went to Capella, defocused so I could get the 'donut', and it was so perfect as I closed it down while focusing I left the collimation as it was. Skewing over to M42, I started with a 25mm Plossl in a 2" diagonal and worked my way up, ending with my 2" 2.5x Luminos barlow and a 13mm Ultima EP, giving me 385X. Visually, I could split 'E' and 'F' in the Trapezium, so I thought I'd see if I could get an image through the EP with my DSLR, since the Ultima is threaded for a T-ring. This is a single image, 2.5 seconds at ISO 6400. Less exposure did not bring out 'E' any better, and 'F' is showing as a bulge in its companion. More exposure hid both as the Trapezium stars were too bright.
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