Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

B4silio

Members
  • Content Count

    38
  • Joined

  • Last visited

Community Reputation

71 Excellent

About B4silio

  • Rank
    Nebula

Profile Information

  • Gender
    Male
  • Location
    Zurich, Switzerland
  1. A quick and dirty trick for a rough polar alignment if you don't see Polaris and you have set up a perfect "home position" as in the video Jiggy 64 linked to: Put the mount in home position, be as precise as possibleturn it on and don't calibrate anything Slew to a known star (if you're NOT polar aligned it will get nowhere near that star :D) Use the Alt+Az adjustments to align manually the scope to that star Repeat for another star somewhere at 90° from the first one You should now be roughly polar aligned
  2. A bit late to the party, but just to give a bit more detail: Park Position: Position of the mount with weights all the way down, scope pointing straight up (toward the pole if it's perfectly polar aligned) Home Position: Where the mount thinks [DEC: +90°0'0" & RA: 0h0m0s] is. In an ideal case this is exactly at the Park Position which and it means you never have to star align anything Star alignment: The procedure to tell your mount where the origin of the sky [90°0'0" x 0h0m0s] is, or how "off" the Home Position is from the Park Position Current Position: Where the mount think it is pointing in the sky, it uses the motors to know that, which means every time you unclutch your mount, it loses the match between it think it is pointing and where it actually is The best way to NOT have to star align is to always put it back to Park Position at the end of a session or every time you've unclutched it for any reason (e.g. whenever you're changing equipment on it, re-balancing). If you have a reasonably well marked Park Position this becomes very quick.
  3. After working on collimation of my RC for a week, all under an ever stronger moon that started out just in front of it, I think I'm at the limit of what I have learned to do so far. So here is NGC 2174/5, the Monkey Head Nebula in Narrowband TS RC 8" + 0.67x reducer + ZWO ASI1600MM-Pro & Astronomik filters 11h for Hydrogen Alpha, 7h for Oxygen III and 3h for Sulphur II
  4. That is one gorgeous image Gina! I love how well the broad nebulosity contrasts with the tiny details (for example the Crescent and the fainter veils on the bottom part of the image). Sadr is so well controlled that it almost disappears in the middle of the composition (rather than burning everything to smithereens, which is more my experience :D). Also: incredible image for a supermoon night!
  5. Wow! Glorious colors and the amount of details is simply stunning! I love the moon one day before or after full, as it has so much more depth, and you've captured that beautifully!
  6. A simple comparison of yesterday's moon with a smaller version of itself from last year. (I was actually a day late last year so it's not exactly full)
  7. Thank you David! I just had one of those epiphany moments where you tell yourself "So THAT's how that works!". Very clear images and it totally makes sense! Also indeed, it seems like they've made those screws with the exact purpose of digging in through the metal (the black ring next to the spring in your first image seems to be a witness to that ). So basically the "lock" screws are mainly staying flush with where the silver screw are so that they dont move back, and in the other direction the spring is making it keep its distance. If I might think aloud here, that means that if you simply push it will act on the springs but still move a bit on the inside. So when you attach your imaging train, it will always push a bit on the bottom springs and lighten the load on the ones above. For the ones above the lock screw should keep the mirror from tilting, but there's nothing (besides the springs) keeping the mirror from getting pushed in at the bottom. So that's why it's better to have them "as screwed in as possible" while still retaining collimation. (Today I Learned!) Thanks for the images and the explanations!
  8. Looks indeed like a balance issue or a gear skip problem in the mount: if the weight is not well balanced (or TOO well balanced) the mount might skip one gear tooth from time to time, which gives you the tiny line to the side you see. Depending on how big/small the issue is it could only pop up every couple of minutes or so.
  9. Hehe I totally understand and I think we're indeed speaking at incredibly different levels of expertise. I think that what you say is even more true for the "cheap" RCs compared to similarly priced scopes, where with enough time spent on them they can outperform the quality of refractors or newts, but at the risk of not getting to that point before abandoning ship. What David showed us is indeed how you get another step forward, but I also think that at that level there are other questions that come into play as well (from guiding, to processing and everything in between).
  10. Hey Tom! First of all, what a monster of a scope! Following a tip from David on the other thread on RC collimation (seems to be a popular sport these days!): To skip the back and forth between secondary and primary you can take out the secondary entirely (mark the position of the screw so you can get back to the right spot, and do a rough count of the turns you do when unscrewing) and aim the laser to the center of the screw hole where the secondary would be (the real center of the mirror, not where the small ring happens to be right now). This means that once that is done you won't have to go back to changing the primary and can focus entirely on the secondary Attach the secondary back on and realign the screw to its marker With the laser on, adjust the secondary so that the pointer is reflected back to the Howie Glatter (you'll notice the beam become a lot brighter when the two are superposed). The advantage of the truss design is that you can stick your head inside to have a better look at the pointer getting projected back to the source Put the camera in and either get an artificial star or a real star and re-adjust the secondary, as the optical axis and mechanical axis might not be identical (less likely on such a high quality scope) A tip to test how good it is: you'll need a crappy filter that does huge halos, when your primary is well collimated, the halo will be centered on the star when it's in the center of the image, when the secondary is well collimated, the ring will be evenly thick all around. You need a bright star to do that! (here it's actually venus right over the pleiades!)
  11. Hi Luke (and Malcolm!) I think it would be a shame if the take home message of this thread were "Collimation of RC is a PITA, better forget about it". As a complete newbie, I have actually tremendously benefitted from reading a few pointers here (@david thanks a lot!) and am coming out with the feeling that it's actually easier than I would have thought before. I sat down twice to try to improve things, and each time I was understanding things better and the results have been improving enough that I wont be trying to adjust it anymore. If this thread motivated me to revisit collimation I hope it will get you to do the same!
  12. BTW, both APT and CCDCiel have focus aids that give you a read on FWHM so that can help you out as well. Good luck with collimation, as you've seen I've been playing (and banging my head against a wall) with it, but I'm feeling reverse frustration ("Why on earth did I not do this 1 month ago!"). Clear skies! Basilio
  13. A very quick trick I found for collimating the secondary mirror and get a very good result ridiculously fast (2-3 minutes). I'll assume two things: You have a laptop/tablet/electronic viewfinder or anything that you can turn around and see when you're in front of the scope You can see a bright star Now do the following: Point to a bright star, get out of focus and put the ring at the center of the image, it should be deformed Get close to the screen so you can see well and slew around so that the ring changes shape If you slew in the direction of the THIN side of the ring, the thin side should get fatter and the ring should become more even When you have a perfectly even ring leave the star where it is (probably nowhere near the center) Now turn the screen toward the scope so you can see it when in front of it Adjust the screws on the secondary to move the star to the center of the screen Your secondary is now perfectly collimated The main idea is: By slewing around until you have a perfect ring, the image of the star is being projected in the correct way, and you adjust the mirror afterward to point that "correct image" right back at the camera The whole thing takes ~3 minutes and the only issue is whether I can find a star that is bright enough to see well how even is the ring. The Primary, however, is still a pain in the bum!
  14. Hey Andy Moon looks gorgeous! Even from a phone picture of a screengrab of a preview the details on the craters look like it's absolutely well focused, I suspect any difference in focussing would have less impact than the distortions due to viewing.
  15. Thanks a lot Vlaiv, that makes a lot of sense! From what I see happening I'd say that the black ones are indeed simply locking things in place (i.e. turning them doesn't really have an impact unless I tighten too much), while the larger silver ones actually turn the mirror, so unless I'm doing something bad I'll just stick to that assumption!
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.