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.

Search the Community

Showing results for tags 'collimation'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • Welcome
    • Welcome
  • Beginners
    • Getting Started General Help and Advice
    • Getting Started Equipment Help and Advice
    • Getting Started With Observing
    • Getting Started With Imaging
  • Community
    • Official SGL Announcements and Events
    • StarGaZine
    • SGL Challenges and Competitions
    • SGL Star Parties
    • Star Parties & Astro Events
    • Celestial Events Heads Up
    • The Astro Lounge
  • Retailers
    • Sponsor Announcements and Offers
    • FLO Clearance Offers
    • IKI Observatory
    • Supplier Reviews
  • Astro Classifieds
    • For Sale / Swap
    • Wanted
  • Equipment
  • Observing
  • EEVA (Electronically Enhanced Visual Astronomy)
  • Imaging
  • Science
  • WADAS's WADAS Discussion Forum
  • Beaufort Club's Topics
  • Swindon Stargazers Club's Topics
  • East Midlands Stargazers''s Topics
  • Central Scotland Astro's Topics
  • SGL Cumbrian Skies's Topics
  • Herts, Beds and Bucks Group's Topics
  • SGL East Anglian Group's Topics
  • South Leicester Observers's Topics
  • South Wales Group's Topics
  • SGL Surrey Observers's Topics
  • South Yorkshire Stargazers's Topics
  • Yorkshire Astronomers's Topics
  • Devon and Cornwall's Topics
  • West Midlands's Topics
  • Essex Cloud Dodgers's Topics
  • Essex Cloud Dodgers's New equipment
  • NLO and Planetarium's Topics
  • Astronomical Society of Edinburgh's Discussion
  • Dorset Stargazers's Topics
  • Hairy Stars Club (Comets)'s Tutorials and Guides
  • Hairy Stars Club (Comets)'s General Discussion
  • Hairy Stars Club (Comets)'s Observing Campaigns
  • Hairy Stars Club (Comets)'s Analysis results
  • Hairy Stars Club (Comets)'s Useful Links
  • Pixinsight Users Club's Pixinsight Discussion Forum


  • Astro TV
  • Celestial Events
  • SGL Calendar
  • Astro Society Events
  • Star Parties
  • WADAS's Events
  • Beaufort Club's Events
  • Astronomical Society of Edinburgh's Events
  • Dorset Stargazers's Events


There are no results to display.

There are no results to display.

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start





Website URL







Found 65 results

  1. I'm aiming for the best possible field illumination for my Explore Scientific PN208 f/3.9 imaging newtonian. The scope is 5 years old now and while doing maintenance I wanted to do something about the design flaws as well. With the current secondary holder design it's impossible to center the mirror beneath the focuser. My question is: is this really an issue when the entire primary is visible? I read about optimal field illumination when the secondary is centered, but this isn't achievable with this telescope. I attached an image showing the (very bad aligned and already degrading) secondary at the moment. This is as far down as I can go, I would need to replace the holder screws with longer threads to go further but I don't know if it would make any difference for field illumination? Thanks in advance, Michael
  2. Hi, I have just recieved the last item which was on back order for a couple of months from USA. I already had the Infinity Eyepiece but was waiting for the BlackCat. Everything was ordered from FLO and i was very happy with their service. Instead of writing an essay, i made a video of how I use the tools and how they look, but in short - Theese tools are FAR superior to the Howie glatter, even with the Tublug. /Daniel
  3. Hi there, I've recently jumped fully into the DSO side of astrophotography and have been having trouble with stars that aren't quite round. My last two imaging sessions have produced stars seemingly pointing in different directions across the field of the image. After the first image we collimated the scope and the problem has continued but we think our collimation may still be off. I use a SkyWatcher 130PDS with a Canon 6D Mark II and the Baader MPCC Coma Corrector. The problem persists regardless of whether or not the coma corrector is in the imaging train. It also persisted regardless of the exposure time. I have uploaded processed images which show the problem, but if unprocessed files would be more helpful I can upload them also. The processed images have been cropped slightly. If anyone has suggestions as to what the problem could be I'd really appreciate it. Kind Regards, Ryan
  4. 150mm F/5 Newt, as received new, view down eyecap collimator (no adjustments attempted by me): I've read a couple of intro guides, so I'm led to believe that the off centre image of the secondary in the primary is normal for a fast reflector. The whole image of the primary in the secondary seems to be reasonably central too. My concern is obviously that the black dot from the collimation cap is not within the "doughnut" centre marking from the primary. I've tried here to superimpose a circle with centre lines, but I'm not sure if I've got the circle itself correctly positioned (I'm not sure what I should be lining it up against): Now, the interesting thing is that it's one of those jobbies with a sealed, non-collimatable primary. But I believe the secondary has all the usual degrees of movement. Does it look likely to be far out? I can try a star test tonight (first time for that too).
  5. So, I have been testing three different kind of lasers, each one is supposed to be the "best" in each category or what you want to call it, the hotech and HG is almost the same, but whit the difference in how you lock it down. The Catseye is very different in how it works. I made a Youtube video of my thoughts https://youtu.be/ERF33hNVieQ What do you think? which one do you use? Regards, Daniel
  6. Hi, I am trying to collimate my astrpgraph, a TS N-AG10 with a Hotech 2" self centering laser and I am having some questions of the clamping procedure. Each time i am trying to tighten the collar so that the laser would tighten up in the focuser, the laser dot is quite far off the earlier spot the laser hit. I have sience bought a Howie Glatter 2" laser, when i adjust the secondary so that the laser dot hit exactly in the center of the primary dot and change laser to the hotech, the laser dot is about 4-5mm off, if I release the Hotech laser and re-tighten it, the dot will hit somewhere else. I can not just trust the hotech laser - has anyone else experienced the same thing? *Both of the lasers is collimated itself at 5 meters distance with the dots not moving at all. /Daniel
  7. I'll begin this post by saying, I've searched every forum. I've tried every tip. And I'm hoping you beautiful people can provide some suggestions based on my specific issue. Because, as my title states, I'm just about ready to give up. Here's a bit of background before I list the many ways I've tried to resolve the issue. I own a Celestron NextStar 8SE and a Canon Rebel T6. After many nights of trying, I cannot get a clear image of planets, or even the moon. I've given it plenty of time to reach thermal equilibrium each night (1-2 hours). When viewing through the eyepiece, the image is an absolute blur. When viewing from the camera, I get no image at all. Here are the things I've tried on the telescope itself: Focusing the telescope via the "Focus Knob" Collimating the mirror via the 3 screws Using a Duncan Mask to make collimation easier. Focusing the telescope on an object much closer, getting a clear, sharp image through the eyepiece and the DSLR, then attempting to view a star. Waiting for, and viewing during, a near-perfect clear night with very little atmospheric turbulence. I live on the westcoast of the US. So, the only objects I'm able to see clearly (with the naked eye) are the moon and Venus. I cannot describe the level of disappointment and frustration I feel when I can't clearly view them from the scope. Venus is as bright as ever, and I'm getting a blur. I tried using the DSLR and the planet doesn't show up at all. Just black skies. My DSLR settings are as follows: Manual Focus Shutter Speed: Bulb ISO: 1600 What am I missing? I feel like I've tried everything and I just want to throw up my hands in defeat.
  8. Guys , i am so frustrated .I can't collimate my newt. I m here with my chesire eyepiece trying to adjust the secondary but when i turn the centre screw, the mirror moves a lot and then shifts back to where it was. And turning the little screws arouns it ddnt so much either. I don't have much time before my session (2 hrs) pls help VID_20190324_202528.mp4
  9. Hello everyone, As a farely new member and astronomer, I've decided to seek help for collimation. The task seems pretty daunting at first but I think I got the basics down. Unfortunately I cannot find any answers for the questions I have, so here it is: Is it 'normal' to see the focuser's end? As you can see in the attached picture (poor quality, let me know if I should do another) we can see a rectangle at the left, the focuser. I don't think I should be seeing this and I don't know what causes the problem since the secondary 'seems' to be aligned and the doughnut is dead center. I'm using a XT10 and the focuser is all the way in. Thanks for your precious time, Antoine
  10. I have encountered a unique problem last night while trying to image using my GSO RC6. The scope is well collimated using a long Cheshire as well as a Howie Glatter single beam laser for verification. CCD inspector also gives me good results when checking with an artificial star. However, when I check using a collimation cap the innermost shadow looks offcentered as well as when I pointed the scope on a real star yesterday (Alp Libra) as well as Spica, it showed a crescent shaped star. This I found to be really weird. Anyone have any idea whats happening here? I live in Bangalore, India, so there's virtually no cool down time required. The temperature gradient between outside and inside is very little if any.
  11. I knew from the start, that my Mak (which is new) was a bit out of collimation, I also knew that alhough they hold collimation very well, they can be a pain to collimate. With this in mind I scoured the net for articles and videos before attempting it rather than ending up having a major wobbler when messing it up lol. The key was to understand the push/pull system by which the spider is moved, and very small turns of the screws while adjusting them in sequence with each other. I am happy to say that after 30 minutes, and thanks to Arcturus and a high power eyepiece, I have come as close to perfect as I will get and I am more than happy with that. I took a cell phone shot, I wish it was as sharp and defined as the rings were visually but regardless, it was rewarding. Both inside and outside focus was the same which is great, after snuggling up the locking screws, I won’t be messing with them anymore unless I drop it.
  12. Hello all! today i had a very brief moment outside with my 150 Mak before the clouds rolled in, between the time i put it out under clear skies and the two hours i gave it to equalize the clouds had rolled in but with some breaks here and there. so during a short break in clouds i picked the brightest star and quickly checked collimation with my 14mm eyepiece, my question is if i should bother to adjust collimation because while im getting a beautifully symmetrical disc with sharp rings on one end of focus, on the other end im getting a disc thats not so symmetrical with a bit of doppler effect going on where concentric rings are compressed a bit more on one end, dealt with this before on my big dob but not sure to what degree it will affect performance in my mak. I remember some saying here that Mak's don't ever need collimation and hold collimation short of a hammer blow to the tube, should bother opening the pandora's box that collimating can be in worst cases? (star was dead centre in FOV of course) Thanks everyone!!
  13. Whilst carrying out a star test I have noticed with a friends C8 that one side of focus appears to be collimated and the other side of focus its off, is this a common problem? Is his best option to collimate as an average so its slightly off either side?
  14. Hi Can anyone help with a collimation problem. I have a 200pds Skywatcher and I am trying to collimate the scope but I am having problems centering the secondary under the focusser. The secondary looks to be circular and positioned correctly to the optical axis but I do not understand how to align it in the axis 90 degrees to this - see photo The mirror is central to the tube on the spider, so the only thing I can think of is that the focusser is not pointing directly at the centre of the tube, so the focusser mounting itself needs adjusting - Is this correct or am I missing something. I have taken a few photos and an example is attached ISO 800 30 seconds. Any help would be greatly appreciated. Pete
  15. Hello all Im just started in imaging and I have to say I'm pleased with the first result BUT on closer inspection I see I have slightly oblong stars. So people know what I've got and done here it is http://www.astrobin.com/full/271950/0/?nc=user I have a baader coma corrector that I'm using set to 55mm from canon sensor and I have tried short exposures and I notice that it's still there in short exposures. Could it be collimation? It's the only thing I didn't do that evening. I would appreciate your input! Thanks Gerry
  16. For Sale: Hotech Advanced CT Laser Collimator for 2" Focuser The HoTech Advanced CT Laser Collimator (patented) is a breakthrough in Cassegrain Telescope collimation! Collimate Your Cassegrain Telescope: Without using a star Indoor or outdoor - day or night Focus stays at final view setting Within focal distance from your telescope One-man operation Portable and simple to setup and use Works on CT, SCT, SN Mak, & RC Collimator is in excellent condition having been used on both my SCT scopes. Includes all original parts. Now sold.
  17. Hey guysIm really struggling with an issue. Recently purchased an Orion ST80. At 20x to 44x using stock 20mm/9mm eyepieces stars look pretty good. But if I test it at 175x using 2.3mm eyepiece and point to bright star I get the pattern like in the images below.Will unscrewing the ring and tapping on the side of the tube resettle the lenses? Or is this an alignment/collimation issue that isnt fixed easily? Defocused, the center circle isn't too off the centre..but focused in, it looks like a cone. Really annoying. If I send this back, no guarantees that the next one will be any better. Or is this typical for type of scopeThanks in advance!
  18. Hi. As a response to ebeygin in the whole-scopes section, here's how I insert shims in refractor cells. I stick 6 strips of adhesive tape at 60° from each other. If that's not enough, I add a layer of narrower strips. I forgot to photograph the job I did in the cells, so I'm showing it with a cap. If the layers become too thick I remove those barely visible strips this way: I lift the corner of a strip with the tip of a thin blade, and remove it with tweezers. Its edge remained visible because this strip is narrower than the previous one. 3 strips at 120° don't hold the lens as well, the large empty space between them still allows the lens to play. Plus, 3 strips have to be thicker, to the point the lens drags against them when you want to insert or remove it. 4 strips at 90° don't work too well either. Because of tolerances/inequalities in the lenses edges and (plastic) cell, 6 strips hold better with less pressure. All this is known by frustration experimentation, so trust it. In other shim jobs, I've noticed that 5x72° works well, but only with small circumferences. Worries: - a friend asked if the glue could seep onto the lenses; no, the "glue" on transparent adhesive tape is a solid, like gum, not a liquid, and it doesn't melt at daytime temperatures. I've kept rolls of tranparent tape in a drawer for years, the glue never seeped out. However, don't use electric tape because its glue does flow out with time (also something I know through frustration experience), and it's too thick for accurate centering, anyway. - too much shimming? The inside focus pattern will seem ok, but outside focus the pattern will be an hexagon with rounded edges, the clue that the 6 strips pinch the lens; another thing I learned through shameful blunder experience. Tips: - making the strips narrower has the same effect as removing one or two broad strips, because the friction area is reduced, the lens will enter the cell more smoothly, with less binding. - blacken the lens edges before you shim the cell, because the layer of ink is thick enough to cause binding (another piece of wisdom got from aggravation experience) - the two 80mm scopes I worked on required two layers, and then the removal of one or two strips. It makes the contour a little uneven but you don't care because the lenses have to be centered relative to each other, not relative to the cell. - the first strips have to be about 25mm-30mm long, the next about 10mm shorter Personally I shim only the rear lens, and add centering screws at the front, but locking the rear lens with shims, and tapping the front makes the process less random. Don't forget the alignment marks on the lens edges. Yeaaahh! I finally found how to write between pics!!!
  19. Hi all, New Skywatcher skyliner 200P, straight out of the box. I thought I would have a go at checking the collimation for the first time. This is a photo taken through the hole in a diy collimation cap. Everything looks ok to me, what do the experts think? The spider vanes look to be crossing smack in the center of the donut on the mirror. Ignore the sparkly thing, it's not a star cluster, 'tis nought but a lamshade :-) Does everything look aligned? Neil.
  20. I have just got a second hand Astromaster 130EQ. I want to say that i have collimated scopes before without the use of a laser but in this case i have 2 questions as this is so far out i cant see what i am looking at half the time. So hopefully you can help, thank you. Info about the first problem: The secondary mirror fixing screw that hold the mirror and the collimation allen key bolts were so loose the secondary mirror had rolled facing the bottom of the OTE. In every other case the holding screw never needed touching and all i had to do were make small adjustments with an allen key, no screwdriver was needed. So this case is a whole different scale then any other collimation i have ever needed to do. You probably all know that i need to get the center of the eyepiece in line with the center of the mirror before can move on with this step. Question 1 What is the best way to do this, shall i just eye it for now? (i have seen people measuring to the center of the eyepiece and then do the same with mirror but then i still dont know if the mirror is facing me directly.) Info about the second problem Every other time i have collimated a scope the mirror and scope were very low quality and just used for practice basically. The old scopes were used to see if i wanted to go further into this hobby which i definitely do. Any how the old scopes had a flat mirror and i could find the center by placing the mirror on paper and tracing a circle template. The thing is this mirror is concaved so any template iswill have to be pushed into the vurve (i think). Question 2 So how can i center the mirror without placing it face down on a piece of paper which cant be a good thing? Thank you. I hope i have not gone on to much, thank you for your patience in reading a long winded post.
  21. My 10" DOB (f4.7) gave me stunning views of the Orion nebula on a night last week of good seeing. Today I decided to check the collimation The Hotech Lazer collimator showed it to be a fraction off so a little tweak was given.....then I popped the collimation cap on and it looked a bit off.....which is right? Star test when I get to see some on Saturday. Wonder what a big frac would cost.....only joking. Clear skies
  22. I just got my Glatter (RIP Howie) tublug/laser and holy cow does this thing work! and it makes primary collimation so easy espc for my truss dob. In comparison to the Catseye cheshire it is very close, if not the same. My Catseye triangles seem made for the tublug. I think I'll change the triangles to hotspots down the road though as I heard us collimation fanatics can get a bit more accurate with them. ATM I run all red triangles. Of course I could always pull out the AC
  23. I recently posted about my first successful collimation experience (an SCT). I'm sure we all have our stories, of those moments when we perceived optical clarity. Come on everyone tell us of those collimation 'eureka' moments and your experience of your first observing session immediately following. Paul.
  24. Hi all! I bought a set of Bob's Knobs for my Celestron NexStar C8 based upon many recommendations I had read. They have shown up, and the threads on the Bob's Knobs seem to be wider than the threads on the original collimation screws. They don't really want to screw into the scope easily, and I certainly don't want to force anything. Does anybody have experience with this? Should these work for my telescope? The set I bought had the following description: Bob's Knobs Celestron 8" SCT f/10 Collimation Knobs fit Celestron 8" (20cm) f/10 post-1980 SCT with factory silver or Allen Phillips collimation screws, with or without Fastar secondary with silver collimation screws (NexStar 8, Ultima 2000, C8 black, or gray, etc). Please note that this includes post-2000 orange tube but does not fit pre-1980 orange tube or majority of scopes with black Phillips factory collimation screws. Has anybody else had trouble with these? Thanks for any help!
  25. Hi all I have recently acquired a Newtonian reflector 150/750 and I am having a few issues with it. First of all I have read numerous pages on collimation but I don't know what is wrong with this scope. First off I align the secondary with the focuser by eye and using a collimation cap make sure that I can see the 3 primary retaining clips. Then using a Cheshire eyepiece I align everything up as it should be. When I place a good collimated laser in the eyepiece the laser is way off centre on the primary and in actual use stars and planets wont focus and the flare is awful. If I then use the laser to collimate then objects look better but still not great and in this position the secondary holder is leaning away from the focuser and not aligned with the tube. The Cheshire then shows the centre of the primary way off alignment from the circular secondary mirror. Any ideas? Should a laser and a Cheshire agree that a scope is aligned? I will try to load some images tomorrow but its difficult to get what I can see on camera.
  • Create New...

Important Information

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