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sockatume

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About sockatume

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    Nebula
  1. Thanks everyone, I really appreciate you taking the time to set my mind at ease! I tend to get anxious about big purchases (which this was for me). Understanding how much dust it can really deal with has, I think, helped me stop babying the telescope and encouraged me to drag it out and just use the darn thing. It's a tool after all!
  2. Sorry, just to confirm, you think the haze is normal? It's not dust or anything that's landed on the surface as far as I can tell. The telescope's only been used a couple of times so far.
  3. This is probably a common new telescope owner question but I’d been having some trouble finding an answer by searching. Basically, my secondary mirror seems to be quite hazy in bright light. My second or third night out, I thought I might have got some dust on my improvised telescope shroud (Heritage 130p) and hence on to the secondary. After I packed everything up I pointed a torch at the secondary to check and gave it a few puffs with a rocket blower, one of the ones that’s not got any bristles. (I’m sticking with the general rule of not ever touching any of the surfaces until the day comes that they’re completely filthy.) I noticed that the mirror looks irregularly hazy when lit this brightly. An image is below, along with the dust that’s too small or too sticky to blow off. (My main observing site is next to a tree that has now gone in to bloom, I figure some of this is pollen.) Is the haze just the inevitable light scattering you get with the surface coating? It’s not really hazy looking in daylight, just under a lot of contrast like the LED below. I figure any light actually hitting the mirror is both fainter and moving through the coating at a steeper angle than this, so it’ll scatter far less. Looking through the ‘scope seems fine but I thought I’d ask anyway. Thanks in advance!
  4. Thanks all, I think I'll get the 21st Century... and the laminated field map to get me started. It looks like there's another Sky and Telescope map, "Sky And Telescope's Moon Map", rather than "Sky and Telescope's Field Map of the Moon" pictured above, but from the dimensions I figure that's probably a single square map folded in half rather than four big quadrants.
  5. I’ve been enjoying the moon sections of Turn Left at Orion, especially as it’s an object that doesn’t depend on particularly pristine dark skies. The book’s little tours are fun but I’ve now got a hankering for a good set of reference maps I can use when I spot an interesting feature. I do own a Philips map but it’s more suitable for a wall than next to a telescope. Is there a good reference book for this? Something ring bound or spiral bound would be ideal for using next to my telescope but that’s not mandatory. Thanks in advance!
  6. I had exactly what you are describing, I think it’s normal for certain designs of secondary mirror holders. I don’t have the thread handy right now but perhaps you can see it through my profile. It made the process a bit less intuitive than with the primary but I haven’t touched it since. I have a Skywatcher Heritage 130p and I imagine the mirror holder design is reasonably similar across their range. Edit:
  7. Thanks again everyone. I finally got first light tonight in the form of some staggeringly crisp views of the moon, a bit of the Plaiedes, and splitting Mizar. Nothing too exciting but Orion was behind a street light (seriously) and Andromeda behind a house. Still very satisfying to see the upgrade from my previous “hobsonian” telescope and evidence that I had got it reasonably well collimated. Can’t wait for better conditions, and I’m already snooping about the second hand adverts for plossls...
  8. Thanks all. I’m still figuring out how my secondary support is put together but this has been very helpful in how much I really need to bother with it.
  9. Kind of jamming my smartphone camera against the collimation cap, an arrangement I have a bit of trouble lining up. The camera is focusing on the secondary there, which makes the offset less obvious - there is definitely an offset like yours. This is nearly-collimated:
  10. I’m treating it like a computer project rather than woodwork in that regard. Tight enough to hold the part in place but not so much that it has to hold up a bookshelf. I think I’ve about right now, however the exact mechanism works. It’s a circle, it’s almost centered (I’m second guessing myself what correction it would need, if any) and I can see the whole primary mirror. And hopefully I can just leave it like that for a good while before it needs tweaking.
  11. It’s been really useful, thanks. I’ve also been reading Gary Seronik’s one which has helped me angst less about getting the secondary right!
  12. A whole week has passed since I bought my Heritage 130p without getting a single day of good-enough weather, so I've naturally been spending that time messing with all of the dials and getting the hang of collimation. (I feel like buying a Newtonian is as much of a route to becoming a collimation enthusiast as an astronomy enthusiast...) The primary is easy to align but the secondary seems kind of fussy, so I'm wondering how the mechanism on this telescope works to give me a better feel for it. Whatever mechanism the primary mirror has, turning a screw in either direction raises and lowers that edge of the mirror. That's pretty intuitive. The little secondary mirror in my baby Cometron 76mm seemed to work the same way, if you slackened off a screw it would naturally tilt away from that direction, and if you tightened that screw it would tilt towards it. I'm not so sure about my Heritage. It seems like if you slacken a screw, the secondary mirror only moves if it's sitting on that screw due to gravity. The screw that's furthest away from the ground when the telescope is on its side doesn't really do much of anything - either it's screwed all the way in and won't go any further, or you unscrew it and a gap opens up between the end of the screw and the secondary support, without the mirror actually moving. So, basically, the mechanism seems to be that it's on a little tripod of three collimation screws, and the centre screw seems to act as an end stop. There is a spring in between the two parts of the secondary mirror support (which you can see above) but I'm not sure what it does? It doesn't seem like it would generate enough leverage to control the tilt of something as heavy as the secondary mirror. I'm not sure what it's doing exactly. The way I've been working is that I slacken all three collimation screws a bit to give me something to work with, at which point it tilts off downwards and rests on two of the screws. I turn it if necessary so it's face-on to the eyepiece, and I adjust the two screws it's resting on, ideally without causing it to rotate too much, until I can see the primary nice and concentric. Then I gently tighten up the third screw to take up its remaining slack and snug up all three a little at a time to keep the primary mirror centred. At this point I'm basically back exactly where I started, so at least I'm being consistent as I play around with it. That seems to work OK? (See below.)
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