RedZoneOS Posted August 22, 2016 Share Posted August 22, 2016 Hello all, Long story Short - I cannot get anything in the sky to focus at all. I tried to look at the moon with a 32mm zhumell eyepiece, and a 25mm meade eyepiece, same result. a really bright white blurry blob. there is no detail at all, its like staring at a fluorescent light bulb from 2 inches away! I can see the focuser "wanting" to focus, but no matter what, I see nothing worth seeing. just joined and am desperately seeking assistance so I can get up and running and start looking up at the heavens and check out other parts of the forum that will help me develop this hobby! I purchased a used 10" skywatcher collapsible dobsonian along with a number of accessories, and I have been struggling to get it to work. condition looks fine. externally its in excellent condition, practically brand new. optically there is some dust, but no visible scratches, cleaning marks, etc. I know nothing of telescopes, but I don't "think" there is anything physically wrong with it. problems (please help with whatever you can!): 1. Collimation - I have never properly collimated a telescope except the very first time I bought a Meade DS-2114ATS way back around 2001. This scope came with a laser collimator so I popped it in. The optics were BADLY out of alignment. the laser beam wasn't even hitting the secondary on the return trip and it was a good 3 inches off center from the primary. I ended up unscrewing the secondary and hand adjusting the mirror. then I unscrewed all of the adjustment screws on the primary until I couldn't anymore before I began even attempting to collimate (maybe this caused my current problems??). I have it now to where I think it is "close enough". The laser beam hits the primary directly on the left edge of the center circle (not dead center). It also hits the center of the collimator on the return trip, however I can see a bit of a red edge on the lower left portion of the black center. This is the best I've managed in 3 weeks so I really do hope its "close enough" haha. 2. spotting scope doesn't align with telescope - there is only one fixed way of attaching the spotting scope, but no matter how much I try to wiggle it around, loosen the adjustment knobs etc, I cannot match it up with the telescope. its not even close. If I point to the moon with my scope (blurry blob), I don't even see the moon in my spotting scope, and vice versa. I tried to follow the manual I found online for this scope, took off the spotting scope completely and set it up from scratch, to no avail, still not even close. I have no idea how to (or if its even possible) to fix this issue. 3. focuser, adapters, and eyepieces - I got a number of eyepieces, filters, and adapters included with the scope. I have no idea what is an additional item, and what came "factory" with the scope. I'll be more specific tomorrow when I get a chance to have my scope right in front of me, but taking a guess for now - the focuser assembly is attached. Then there is some sort of adapter on top of that which I assume is the 2-1.25 eyepiece adapter. and then my eye piece on top of that. I feel like there is 1 additional piece also attached but I can't recall right now... mentioning all this, in case it can be the source of my problems. I know for sure that there are at least 2 separate sets of tightening screws, in addition to one that is below the focuser which allows for finer adjustments (I think) 4. truss tubes - I think I am supposed to pull the tubes out as far as they will go, which is how i have it setup. thought i'd mention it in case I have the tube pulled out "too far" which may be creating my problem? Side note - I have a Meade DS 2114 from 2001. I stopped using that scope after the tracking motor crapped out some time in 2004. This scope has been through hell. trunk of my car with no padding on a road trip from california to illinois. basements, garages, dropped a few times, completely uncovered and unprotected optics for well over 10 years. I pulled it out the other day and literally cleaned off dirt, crust, spider webs, with soap and water, rubbing alcohol, and paper towels. LOL. clearly I don't care at all for this scope.... I am mentioning all this because after ALL THAT, I can still see the moon reasonably well!! This is what has me really really stumped about my new scope!! please help! Link to comment Share on other sites More sharing options...
DRT Posted August 22, 2016 Share Posted August 22, 2016 7 minutes ago, RedZoneOS said: 3. focuser, adapters, and eyepieces - I got a number of eyepieces, filters, and adapters included with the scope. I have no idea what is an additional item, and what came "factory" with the scope. I'll be more specific tomorrow when I get a chance to have my scope right in front of me, but taking a guess for now - the focuser assembly is attached. Then there is some sort of adapter on top of that which I assume is the 2-1.25 eyepiece adapter. and then my eye piece on top of that. I feel like there is 1 additional piece also attached but I can't recall right now... mentioning all this, in case it can be the source of my problems. I know for sure that there are at least 2 separate sets of tightening screws, in addition to one that is below the focuser which allows for finer adjustments (I think) This is the problem. These scopes come with two extension tubes that fit into the focuser. One is a 2" diameter tube, the other is a 2" to 1'25" adapter. You must only fit one of these to the focus tube. Do not stack them one on top of the other otherwise you will not reach focus. Hope that helps. Link to comment Share on other sites More sharing options...
rockystar Posted August 22, 2016 Share Posted August 22, 2016 The number one reason for this, is nearly always either too many or not enough extension tubes in the focuser. There is a sweet spot where your eyepiece will come into focus, you need to find this make make sure you have the correct extension tubes in place to reach this point (and DRT just beat me to it). Also make sure that the thumb screw on the bottom of the focuser is loose, this locks it in place, but the wheel will still spin just won't move the focuser in and out. Link to comment Share on other sites More sharing options...
Bonnylad Posted August 22, 2016 Share Posted August 22, 2016 Welcome, Red. Lots of advice here. If your problem can be solved, it will be. Link to comment Share on other sites More sharing options...
rockystar Posted August 22, 2016 Share Posted August 22, 2016 (edited) As for collimation: don't know how badly it needs to be out before it becomes unusable, but the first time I tried collimation, I made it much, much worse and it was still usable (far from ideal, but usable) - this did mean that the mirror wasn't pointing straight out of the tube, and I couldn't align the finder scope. If you sort collimation out, then the finder should align (I suggest you seek assistance the first time, see if there is a local astro club - as much as the help here is fantastic on this subject, and as many articles and videos I watched, it wasn't until I had some real life help before I got it). Edited August 22, 2016 by rockystar 1 Link to comment Share on other sites More sharing options...
Alan64 Posted August 22, 2016 Share Posted August 22, 2016 (edited) I wouldn't trust a laser collimator that just so happened to come with the telescope. Laser collimators, unless it's a Howie Glatter, often arrive, brand-new, in need of collimation themselves, and before they can be used to collimate a Newtonian. I strongly recommend these two items instead of the laser collimator that came with the telescope... https://www.astrosystems.biz/coltlsm1.htm ...and either the 1.25" or 2" Lightpipe/SightTube tool. If you choose the 2", choose the longer one(f/4+) for your specific Newtonian. You will need the cross-hairs of that tool in order to center the secondary mirror directly under the focusser, like this... The second item... http://agenaastro.com/rigel-systems-aline-telescope-alignment-eyepiece.html With a collimation-cap, you can view the entire scene of your optical system, like this... ...with that being the scene of a well-collimated 6" f/5 Newtonian. Yours should appear very similar once collimated properly. Instructions for collimating your telescope... http://www.astro-baby.com/collimation/astro babys collimation guide.htm http://garyseronik.com/a-beginners-guide-to-collimation/ http://www.skyandtelescope.com/astronomy-resources/how-to-align-your-newtonian-reflector-telescope/ http://www.schlatter.org/Dad/Astronomy/collimate.htm If you have any further questions, please feel free to ask. Edited August 22, 2016 by Alan64 Link to comment Share on other sites More sharing options...
Stu Posted August 22, 2016 Share Posted August 22, 2016 Good advice already given. I think one key thing to say is that if your scope won't focus, and by focus I mean go through a point of minimum star size and start to increase again, then collimation is not your primary problem. A mis-collimated scope will give poor images, but you will at least go through this point, and you will be able to discern some detail on the moon. Sort this problem out first and then think about collimation. As has been said, the most likely problem is using both adaptors together when you should either use one or the other, not both. Another concern I have is that you said you have backed all the primary adjustment screws off to their limits. If I understand what you've done correctly, this is probably not a good idea. The main issue with doing this is that the collimation springs will be at their loosest and you may find the collimation doesn't hold. Many people do the opposite i.e. Compress the springs as far as they will comfortably go, then back off a few turns and collimate from there. The extra compression helps keep the collimation. A possible, but less likely side effect is that you may either over fill the secondary (losing light) or more likely just be using mirror surface closer towards the edges which may show errors not seen in the central area. Hope you get sorted soon. Link to comment Share on other sites More sharing options...
Singlin Posted August 22, 2016 Share Posted August 22, 2016 Either too many extension tubes or none at all. 1 extensio. Tube might have a thread on the end and the other a flange. The threaded one is for attaching a coma corrector which then slides into your focuser. The other with only the flange or lip on the end goes directly into your focuser and is the one to use if you do not want to use a coma corrector.l Link to comment Share on other sites More sharing options...
Moonshane Posted August 22, 2016 Share Posted August 22, 2016 I think your problem is adapters. Usually you will need just one - the 2" for 2" eyepieces and the 1.25" for the rest. To cover all bases, check your focuser draw tube is moving when you turn the wheels as sometimes it's locked off with a thumb or grub screw 1 Link to comment Share on other sites More sharing options...
ronin Posted August 22, 2016 Share Posted August 22, 2016 Skywatcher have this amusing habit of putting the 2" eyepiece adaptor in the focuser, then putting the 1.25" eyepiece adaptor in the 2" one. There should be only one in the focuser, in effect the 1.25" one is held too far out and so the focuser gets close to an image as it is wound inwards but never quite makes it. If there is a big dark "patch" appearing as the focuser is would out this is usually the secondary staring to become apparent. Examine the focuser, and gently tug on the "bit" that the normal, 1.25", eyepieces slide into, then gently try to pull out the "bit" that the first "bit" went into. If/when that comes out you can put the 1.25" eyepiece bit back in all on it's own. Store the 2" item somewhere safe. Leave collimation for now until you can see something, collimation will not prevent you from seeing something just it will not be as good. Have to ask this: Have you collimated the collimator ? Finder alignment. Unfortunately it sounds like you need a small shim. This is not uncommon. No idea which end it needs to go on and also no idea how thick it needs to be but this problem appears fairly regular. The finder is not dedicated to the scope, they are a generic bought in bulk item and they are put on whatever scope at the time. You may be able to purchase another foot/base, however you are still stuck with getting the right one. Cannot help on 3 but use just the 2 eyepieces for now, better start with the wide (long) one first, do not go mad on the idea of magnification for a while. Yes the truss tubes need to go all the way out. Concerning collimation again, you will need to get used to it since truss tube newtonians tend to vary in accuracy of the alignment more. Still suggest that this comes a little later. Link to comment Share on other sites More sharing options...
RedZoneOS Posted August 22, 2016 Author Share Posted August 22, 2016 Thank you all so very much for the quick advice! I'm not at home to test it out now, but I did glance at it before heading to work. I definitely think at least one of my issues is too many adapters. There were two separate pieces attached to my focuser before the eye piece. I took the larger attachments off and I was still able to replace the smaller one and attach the 1.25 eyepieces. I'll try it out with this setup after work and see if it solves my problems. I will say though that I am super annoyed at how easy this was if it works and I wasted 3 weeks!! Should have joined here before I even attempted this lol. @Stu - I didn't describe it well but I think I did it right according to your description. I turned the primary adjustment knobs as much as I could to pull the mirror as close it's housing as I could...e.g., tightened the springs and compressed them. Then I went about my collimating. I'll give you guys an update this evening when I'm back home and try it out without the extra adapter. Hopefully that solves all of my problems and then I can pick your brains about other matters 3 Link to comment Share on other sites More sharing options...
Stu Posted August 22, 2016 Share Posted August 22, 2016 @RedZoneOS, that sounds like you did it correctly Sure you will be sorted with using just the 1.25" Adaptor. Link to comment Share on other sites More sharing options...
RedZoneOS Posted September 4, 2016 Author Share Posted September 4, 2016 it worked!! I feel incredibly stupid that i wasted so much time (and all of yours, while writing a novel on here), but thank you everyone for helping get this sorted out! now to learn to find the good stuff... 6 Link to comment Share on other sites More sharing options...
knobby Posted September 4, 2016 Share Posted September 4, 2016 Happens all the time thats how we all new the answer ... Happy viewing . Link to comment Share on other sites More sharing options...
barkis Posted September 4, 2016 Share Posted September 4, 2016 Never a waste of time on SGL when someone needs help or advice. There are experts in the many areas of Astronomy on the forum, in most of the sciences that makes up Astronomy. The contributors to your thread are just as pleased as you that the problem was quickly diagnosed and sorted. Never be shy about posing questions here the folks thrive on them. Enjoy your new acquisition, and please share your observing sessions and thoughts as you please. Best Wishes. 3 Link to comment Share on other sites More sharing options...
ronin Posted September 5, 2016 Share Posted September 5, 2016 I am sure Sjywatcher do it deliberately. Next time a post of "Cannot get my Skywatcher Dobsonian to focus", you can get in there with the answer. And believe me the next occurance of this will not be long. As said I am sure that Skywatcher do it deliberately. 2 Link to comment Share on other sites More sharing options...
DRT Posted September 5, 2016 Share Posted September 5, 2016 9 hours ago, barkis said: Never a waste of time on SGL when someone needs help or advice. There are experts in the many areas of Astronomy on the forum, in most of the sciences that makes up Astronomy. The contributors to your thread are just as pleased as you that the problem was quickly diagnosed and sorted. Never be shy about posing questions here the folks thrive on them. Enjoy your new acquisition, and please share your observing sessions and thoughts as you please. Best Wishes. ^^^^^ very well said, @barkis 1 Link to comment Share on other sites More sharing options...
barkis Posted September 5, 2016 Share Posted September 5, 2016 55 minutes ago, DRT said: ^^^^^ very well said, @barkis Thanks Derek, I've been here a long time, and merely expressed what I know to be true . This is a very rewarding place to be a part of. 1 Link to comment Share on other sites More sharing options...
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