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.


  • Content Count

  • Joined

  • Last visited

Community Reputation

11 Good

About cwis

Profile Information

  • Location
    High Wycombe, UK
  1. Didn't say! Just got a mail from Steve on Thursday saying it was collimated and on its way home.
  2. Hi all, Got my telescope back yesterday! There's no arguing with the below, is there? If it looks slightly out, that's my wobbly hand with my phone camera. I've tried to zoom in as far as I could digitally to show the accuracy of the collimation - It's bang on! Mirror clips all equally showing, hole in middle of doughnut etc etc... Unfortunately there also seems to have been a load of clouds in the box. Never mind - Mars hasn't got far so hopefully they will dissipate soon and I can try it out! Thank you @FLO!
  3. They will fix or replace. I hope they can fix - got quite attached to it! Either way I'll be chuffed - I was thinking that the 'scope was quite a good compromise for a complete Goto solution that weighs just over 6.5Kg (that's 'scope, mount AND tripod for 6.5Kg!) but the hints of it's true ability on Mars just blew me away.
  4. Update: With Auntie Flo's approval I loosened the screws holding on the primary cell to the tube of the OTA with a view to getting better alignment. The boltholes in the tube are slotted to assist in this, but FLO said this was the first one they had supplied that had required ANY adjustment at all - all the rest perfectly collimate when the secondary mirror is aligned correctly. The screws btw are surprisingly lightly torqued up - there are plastic threads in the mirror cell. Once I had done this there was a surprisingly large amount of adjustment - I could shift the central doughnut about 1/2 of the secondary mirror diameter by wiggling the cell about. Unfortunately this adjustment was not symmetrical about the position I first found the mirror cell in and there was not enough adjustment in the correct direction to line up the mirrors. I removed the screws completely and I could get it in the correct place, but then I couldn't get the screws back in. Rotating the cell was not possible as there is a cut out in it to accept the OTA tube seam. I reassembled the 'scope - pushing the mirror cell all the way home put the mirror back into the same place I found it according to my collimation cap, and informed FLO. It was picked up yesterday afternoon by a chap from DHL. Now I am without a 'scope I expect the weather to improve significantly....
  5. I am hugely tempted to get the screwdriver out and see what kind of adjustment I have available - it's not like I could make it much worse at the end of the day. I'd love to know whether there are springs or squidgy foam or something under those clips. I'll wait for a reply from Auntie Flo first though - there may be a "procedure".
  6. That's an amazing piece of work there - basically a different 'scope! Do the optics warrant that sort of attention or are all optics pretty good nowadays (at the entry level) and it's the engineering of the rest of the 'scope that makes up each price point? I notice that it was perfectly collimated before you took it apart. Did you expect it to be or was this a pleasant surprise?
  7. For completeness, here's what it looks like with the secondary mirror concentric to the focusser: If anyone can suggest how I get the doughnut and the c-cap to line up without using primary mirror adjusters, please pipe up now!
  8. Haha! I thought you'd remember eventually! Never mind - you've taught me how to collimate a Newtonian telescope! Many thanks! I was expecting that when I got the primary concentric on the secondary, then the doughnut would be there or thereabouts so a few tweaks and I'd be home. It looks like it's quite a way out (a good proportion of the secondary mirror's diameter) and I'd need to offset the secondary perpendicular to the primary to pick up the centre of focus - an adjustment it obviously doesn't have. Or put up with a tilted focal plane and an offset sharp spot (what I have currently). I'll contact FLO in the morning unless anyone else chimes in with any other thoughts. It could be the one that slipped though the net from the factory, or it had a right wallop during dispatch. The finish is flawless though, and the box didn't look particularly sorry for itself when it turned up, so I don't know.
  9. It makes loads of sense and thanks to you and these last few messages I feel I completely understand collimation. Just one issue: I have no primary screws! Would you agree that it looks like the primary is out of collimation? That's the conclusion I am reluctantly coming to.
  10. But that's my point: I can get the outside of the primary concentric with the secondary, OR I can get the doughnut lined up with the centre of the c-cap. I can't do both at the same time. If I could adjust the primary, I'd get the clips concentric as you say, and then work on the primary mirror to line up my doughnut. But I have no primary adjustment.
  11. Hi all, I've done a little more investigation.... I attempted collimation from first principles - using the Astro-baby guide in so far as it applies to my 'scope. I'm still scratching my head. Initially I wound the focusser down as far as it would go to close up the gap round the secondary mirror so I could centre the mirror as closely to it as I could. I put a folded plastic bag (green and white) behind the secondary, and a white bent card in between the secondary and the primary. Then I adjusted the centre screw in the secondary until it looked in the middle of the view down the focus tube (through the collimation cap) So here I am with the secondary mirror as centered as I can make it - looks like it's rotated a bit up in this photo (along the horizontal plane) Next I rotated it to get it as circular as possible - turning it around the central screw. Then, fine adjustment with the tilt adjusters on the secondary to line up my doughnut on the primary with the c-cap, with my pupil - all in a line. So - doing this I encounter a problem, or question, or something that someone can point at and go "Nope, do it like this". I've done this a few times now, and whether I have the secondary "too far out" or "too far in" so to the left or the right of the centre of the focus tube (and then line up the primary) or rotate it up, or down (and then line up the primary) it always lines up with the view like the photo, with the edge of the primary vanishing off the side of the secondary. It doesn't matter where the focusser tube is - I can't detect any tilt in that until it's nearly all the way out, but obviously the more I wind it out, the more primary mirror vanishes. This is a photo though the c-cap by the way, so central as I could make it. What am I doing wrong? My sharp spot, coincidentally, was at 45 degrees to the left of the view which lines up with this too so I'm pretty sure whatever I am doing here is the cause of that issue.
  12. Hi Steve, thanks for the reply! What I will do is more investigation on the next clear night and find out exactly what is wrong. If I still think there's an issue with the scope I'll contact you as requested. As you (very tactfully!) didn't say, the odds are it's my inexperience in something I am doing with secondary mirror alignment or similar showing rather than any issue with the scope - I totally accept that. I've asked the good people of this forum for assistance on what I saw as a collimation issue and they have given me some pointers on how to be clear what exactly the issue (if any!) could be - I'll follow their guidance to a conclusion. If we can get the sharp spot in the centre of the view (and therefore it will probably a lot bigger because it will be parallel to the focal plane) I will be very very happy with the performance of this scope. I thought it was "OK" before but the views of Mars the other night were, frankly amazing - I had no idea it could do that. Brilliant for a scope I effectively got "free" with the Az-gti and tripod!
  13. Will do - don't want to upset Auntie Flo! I'll find out next clear night as to whether it's astigmatism. I do have an artificial star flashlight thingy, but to focus on it at the end of my garden the focusing tube will be in a hugely different position to how I use the scope it's not worth doing tests with, if we suspect the focuser.
  14. All good questions. I'll see next clear night. As I recall when I received the telescope it looked like the secondary mirror had rotated. While pondering the seagull shaped stars under higher magnification during the day, I looked down the focusser and could see the mirror quite clearly was pointing in a direction!
  15. Good question! Box was fine though... I'll do more investigation next time it's clear. It was near the end of my session on Mars that I had the thought of doing a star test, so time was fairly short. Mars appears round the side of my shed above lovely cool woodland for an hour or two before hiding behind next door's house. I found the sharp bit and started waving it at Mars straight away.
  • Create New...

Important Information

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