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patomlin76

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About patomlin76

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    Star Forming

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    York

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  1. Must be slight haze as you say, it doesn't actually affect viewing of stars and planets through the telescope, in fact it appears invisible through the eyepiece, but it definitely shows an effect on DSOs! Thanks for the help.
  2. Ok I thought the light clouds may have had something to do with the light, just need to be patient! It also doesn't help that at this time of the year m82 and the plough are sitting right above Yorks light pollution in the east. When it's more northerly (or nearer the zenith) I think I get better views...
  3. Managed to get out tonight for 20 minutes viewing between wispy cloud belts, but was wondering why some skies appear darker on certain nights. Would the wispy cloud tonight reflect a bit more light pollution back up? I had magnificent views of Orion and nebula, but the sky just appeared it as black as it can be - m82/81 in particular were disappointing, no better than my 5" scope but I felt as if I were viewing through a very faint cloud though it's hard to tell at night... one more question, to view m82 m81 and other distant galaxies am I best looking through my 25mm or 30mm 80 degree ey
  4. Yes I certainly get hung up over trying to get a perfect collimation, which isn't ever possible. Yes the op has issues with the flex that is causing the movement, but after getting collimation as close as possible last night, focuser slop meant that actually it's between spot-on and near-enough depending on how extended the focuser is. I can't control that and I'm certainly not replacing the focuser, so I'm happy that it's as close as I can get. I don't think in any other of my scopes I've actually noticed any effects of focuser-slop in any observing. Given the physics of the reflect
  5. I'd just like to add that I received a second hand scope last week, and immediately went to use it on the first clear night. I enjoyed it and thought I'd seen some pretty sharp and contrasty views, especially of some star clusters and the moon. Then a couple of days later I decided to see how collimated it actually was. The initial red dot from the laser hit the primary mirror something like 10cms off centre, and the secondary mirror wasn't centred in the focuser. On the next clear night I'm going to see what it's like properly collimated, but the point above is that if you're non the wis
  6. This collimation stuff is crazy! Last night I couldn't get anything to work, or line up, without the movement described above. Having taken your advice CraigT82, I reset the secondary mirror level, I reset the secondary mirror holder central in the OTA and started from scratch. First time, perfect alignment, primary mirror where it should be for quite a fast scope (a little off-set), then a quick adjustment of the primary back to the collimation laser eyepiece and in 10 minutes I'm sorted. Pity the skies are cloudy but I'm happy, thanks for the advice. I did notice that the red
  7. This topic can be closed as I started from scratch and successfully collimated. Thanks.
  8. Thanks. I hadn't thought of checking that, so I may well scrap it and start all over again. I'll remove the secondary and vanes, and do what you say. Would you keep the centre screw length the same, whilst making sure that all other screws are evenly distributed? After doing some research it seems that if I still can't get the thing centred properly it may be the focuser slightly out of square, but apparently if the spider vanes aren't warped then that shouldn't cause an issue. Thanks.
  9. Hi, I already have a more detailed collimation question in another part of the forum so I am not going to repeat that here, more that I would like an answer to a query that may otherwise get lost in the thread! Quite simply put: To centre the secondary mirror in the focuser, it has to be moved along the vanes by 3-4mm laterally (across the focal plane). Looking at the vanes and the OTA the secondary mirror is slightly shifted left. If I don't do this the secondary mirror always appears slightly too low in the focuser and I can never get past this stage. Can I continue with c
  10. Thanks. The image below shows what I was dealing with. Although I had checked the secondary holder was central to the vanes, it always appeared slightly too 'high' in the sight tube. So when I was trying the first couple of steps I was always getting the result on the left. To ensure all of the primary mirror was visible the secondary would have had to be rotated too much away from the focal tube. To get the result on the right I had to slightly adjust the vanes so the secondary was moved a few mms across the focal plane. Then all my adjustments resulted in what you see on the right.
  11. I understand the above was quite complicated to read so I had another go. Everything is where I want it but to get there involved moving the secondary holder slightly offset, so one spider vane is slightly longer on one axis. Having researched it seems this is normal, and I have the aligned view I want through the sight tube.
  12. Hi! Just in the middle of collimating my 'new to me' Orion XT8. I checked with my laser collimator earlier and (although viewing was quite good last night) the collimation was so far off, I couldn't believe it. The secondary didn't appear central in the sight tube and the laser red dot was at least 15cm off the centre mirror dot! So I have managed to start to correct things. Hard at first as a lot of secondary mirror movement was required, especially bringing the mirror back in - it seemed too far forward. Anyway here is my situation, I will try to describe as best as possi
  13. Thanks for replying so quickly - yes the eyepiece and diagonal are all standard. I did notice when moving the front element outwards that stars got more out of focus, so I need to move it back more than it allows at the moment. There is a locking collar as you say, I wonder whether removal means I can get the objective lens that little bit closer. Movement of the front element you look through has no effect whatsoever. Paul.
  14. Hi Wondered whether anyone can help with this curious issue. Recently I sold my old SW 130P reflector and bought an Orion XT8 dob. With it came a right angled Orion 9x50 finder scope, obviously right angled due to the dobsonian mount. However no matter how hard I try I cannot get focus at infinity. The stars are just an out of focus blob, so useful for finding bright objects in the sky but relatively useless for finding fainter stars or star-hopping. I noted on the net that instructions say to rotate the front mount (which houses the lens) until focus is achieved, but throu
  15. Thanks all, I'm away this weekend but hope for clear skies when I return. With an increase in light gathering I'm looking forward to bringing out a little more detail in DSO's. The moon looked lovely and bright and detailed last night, I'm still unsure of the maths of it all, but will my 9mm perform better on the 8in compared to the 5in, in that detail will be brighter or sharper? Thank you all!
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