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SiriusB

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Everything posted by SiriusB

  1. 2" 40mm 60 AFOV ~ approx 1.6 deg, TFOV vignetting very apparent but useable~for me at least, as it's easier to find stuff on an undriven alt az. 2" 32mm 60 AFOV~ approx 1.4 deg TFOV vignetting mildly noticable. 1.25" 32mm 52 deg~ approx 1.1 deg TFOV no vignetting apparent, but it's still there on paper at least. Certainly Defies the laws of Physics,if not plain old common sense, but works for me. Bigger problem to me is 2" diag & ep make the wee mak rather bottom end heavy. Also in such a scenario you may find eyepieces blackout more readily than in a scope with no restriction. If you already have 2" accessories give it a go, probably better sticking with 1.25" otherwise. Interestingly, once object found, i find the mak will take a higher power more readily on any given object/night than my st120.
  2. I think you can be justifyably proud of the result. Excellent work!
  3. Know nothing about guiders, but find most movement of my finder comes from not having dovetail thumbscrew tight enough, i'd look at improving that arrangement first. A slightly bigger cross sectional o ring at front end might also help reduce unwanted movements?,think installed one is 2mm thick. Finally,Locking nuts on existing thumbscrews maybe?
  4. Commonly found astro gear thread details: 2" filter m48x 0.75mm pitch 1.25" filter m28.5 x 0.6mm pitch T thread m42x 0.75mm pitch SCT thread 2" x 24 TPI Skywatcher focuser tube thread~ i think there are two versions kicking around, mine's external M56 x 1.0mm pitch, i think theres also an M54 internal thread x ?? pitch on some focusers. Hope thats useful.
  5. Another dfference to consider is the weight, 120 refractor is (suprisingly) significantly heavier than 100mm, if you want easy grab & go then maybe 100mm better? I use my st102 more often than my st120 for just this reason.
  6. All seen with st120 or st102, skymax despite larger nominal aperture falls somewhere between the two on D.S. I wouldn't say LP low,edge of town location, transparency was just excellent~ m74 normally a struggle to see, never mind the veil. A good night, everyone needs one of those once in a while.
  7. It's been a cracking night here, best one i've had in 2yrs or more. I knew i was onto a winner when i picked up the veil nebula, pretty much mission impossible 364nights a yr with my gear & location. Seemed pretty much anything i pointed the scope at popped into view,shame i'm a bit rusty. seen, in no particular order m103,52,56,57,92,13,15,36,37,38,35,1,74,77,45,33,31,32,110,81,82,27,76,78,42,43. Just couldn't get over the clarity tonight, even m74 a piece of cake! More please
  8. Thanks guys, good to know there's one or two fans of old ep's out there. Still a bit saddened no one makes these ergonomicly shaped ep's any more but well, that;s progress. I guess all the optical designs have long been supassed, except maybe the Orthos?
  9. Just my slightly overdue tribute to the now extinct (NLA new) Japanese volcano top eyepiece. Now the circle T manufacturer has unfortunately retired. ...I start therapy Mon morning for err.... overcollecting
  10. my once owned 12" f7 had a 2" flat. you could see all the primary as per umadogs post, fov ulimately limited by 11/4" focuser. Assuming it's for visual use only I think a well placed smaller flat would arguably be better than a larger badly placed one. By that i mean the closer you can get the ep to the flat the larger the fully illuminated field you'll end up with. So with some careful forethought you could use a smaller flat than if the ep comes to focus say 7" past the outside of the tube. Some careful measuring etc before you fix the primary to secondary distance~ you want all your ep's to come to focus, & design accordingly, hope thats of some use.
  11. From the back yard,rule of thumb normally 3- 1.5mm,I find larger exit pupils don't work so well unless you have a dark site.This being for galaxys/nebula, star clusters more tolerant as regards exit pupil. Experiment & see what works best in your locale.
  12. Cheers for the link, sounds like modern glass is ok then.
  13. Something in the depths of my brain recalls Lanthanum glass being mildly radiactive & long term stabilitly of the glass questionable. If so, not sure i'd want prolonged close proximity to my eyes. Can anyone confirm/ refute this?
  14. Lol. Well in the interests of re~burying the post I've found you one http://www.telescope...epiece_2__.html Same eyepiece, different badge~honest! Me, I love Konigs, but in fairness there's undoubtedly better for your money out there these days.
  15. Assuming similar quality & that we're talking reflectors i'd be suprised if there was much to choose in the views between the 114mm & 130mm. The 130mm f5 will have a larger %~wise secondary lowering contrast somewhat c/w the 114mm offsetting it's marginally greater resolving power. One thing to consider is the ease of focus, i've found acheiving crtical focus particularly important on the planets. Ease of focusing varies inversely with the square of the focal ratio so the 114 f8 will be over twice as "easy" to focus as the 130 f5 without resorting to fancy focusers. FWIW. i'd be tempted to save up a bit longer & go for a 4" f10 refractor or a 6" f8 reflector if it's the moon & planets you're chasing.
  16. FWIW: 2" diag gains you about 0.2~0.3 useable field of view( the Physics of this is highly argueable,but somehow it works) With a 2" ep & diag the little Mak's a bit bottom end heavy. Don't tend to use a 2" ep in it much, but the sct diagonal's staying for all sorts of reasons. Stops me banging my head against the finder for starters.
  17. I remember the Sky & Telescope review on that Orion off axis reflector. They said it performed pretty well. but also pointed out when compared to a same brand 6"f8 newt you could see more L&P details in the newt & obviously D.S. is a no brainer. Also a similar sized package as tube has to accomodate the off axis flat, but the newt was actually cheaper if i recall correctly. Back to the old SGL maxim of "aperture is king" i guess.
  18. Treat yourself to an Orion Optics hilux coated one, they're not that expensive, well, compared to a refractor diag anyway;) & you'll be getting a few extra photons into your eyeball as a bonus.
  19. Seems to be a hammerite type paint, hammerite white is definitely a whiter shade of pale though. TBH i think you may be struggling to match, short of a can from OVL or repainting the lot i'd be tempted to let things lie. Couple of drops of yellow paint in with the hammerite maybe?
  20. Actually it Looks like a gpdx to me if anyones interested~going by my observers guide to astronomical equipment A closeup pic would confirm, gp & gpdx look mighty similar.
  21. & me! At least it takes your mind off the wayward weather.
  22. http://stargazerslounge.com/showthread.php?t=185952 Might be worth playing with a cheap webcam first?
  23. Thanks to OP for the heads up. Just cycled down asda & bought one, well two actually as it was £2.93 on shelf label & £1.47 on till. Never saw myself as an imager but for three quid i'll give it a go. I'm Sure i can attatch a 11/4" somehow... But, just for dummies like moi~ do i want the lens on or off,? I've got an old version of registax somewhere:icon_scratch: does this control the camera for imaging or do i need something else to do that? Sorry for the dumb questions, but last time camera & telescope met in this house it used film:eek: so i'm pretty clueless.
  24. Just a few musings for you to ponder: 1) How wide do you want? my 35mm 1.25" celestron ultima gives a fairly well corrected 3.3deg+ true field in the st102, & a power which is a little low for most purposes. 2) 2" diag plus 2" ep makes the st102 somewhat back end heavy. 3) The st102 @f5 eats lesser WA ep's for breakfast,dinner and Tea 4) You'll get vignetting with a 2" ep in the st102,you may or may not notice it, but according to my calcs there's only about 20mm linear field @100% illumination. JMO. hope it helps
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