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Stu

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Everything posted by Stu

  1. I do tend to think OO scopes are best bought used. Normally any issues have been sorted out by their owners then and depreciation on OO scopes is normally pretty steep so you save quite a lot. I bought a new OMC200 (8” Mak) from then and had problems collimating it. I took it back to them but was pretty much fobbed off with a tweak of the secondary. I only worked out what the problem was just before I sold it, and that was that a grub screw had dropped out so the primary was loose and tilted as a result. Once fixed it could then be collimated properly but I had to find that out myself.
  2. Excellent news Paul. Images look good! 👍
  3. I wonder if anyone has noticed that you never see Mike, Noddy or Benny from Crossroads in the same picture? I wonder why? 😉
  4. Apart from the first three, these are in no particular order. Plenty of repeats in there, and a couple of scopes I have re-bought again after selling them and regretting it. It’s an illness, clearly 🤪 Celestron C150HD Orion Optics OMC200 Astrotech 106mm f6.5 William Optics ZS SD66 Televue 76 Televue 85 Televue Genesis Televue Genesis 120ED 120ED 120ED Orion Optics VX12L Orion Optics VX12L Orion Optics VX12 f6 Orion Optics VX10L (To be honest, it may have been two 10” and two 12”, I can’t remember!) Burgess Optics 90mm Stellarvue 80ED Vixen 80mm f11.3 Vixen 80mm f11.3 Tak FS-60C Tak FC-76DC Tak Sky 90 TAL 100r TAL 100RS Sumerian Canopus 16” Sumerian Alkaid 14” TS 72mm f5.9 PST 40 Vixen 150mm f9 ST80 Carton 60mm f16.7 Tak Mewlon 210 Orion Optics 6” f11 Celestron C8 Edge Celestron C925 Zeiss Telementor Vixen FL102S Heritage 130p Heritage 150p APM LZOS 130 f6 Orion Optics OMC140 Orion Optics OMC140 Intes 7” Mak ST150 Celestron C65
  5. Yes, correct. Position the hole so it is inbetween the vanes and avoids the secondary, that will reduce any diffraction effects. As Geoff says, don’t put anything over the film such as a clear cover as this will reduce the optical quality.
  6. Providing you are using decent and safe film such as Baader AstroSolar ND5.0, and the filter is firmly held onto the scope then there is no danger to optics from using the full 12”. The issues are mainly around seeing conditions in that larger apertures for solar are often affected badly by poor seeing. Somewhere around 100mm to 120mm is often the optimum giving good resolution and cutting through poor seeing. If you can fit a 100 or 120mm aperture between your secondary support vanes that would be ideal.
  7. I think the only time I do is when using narrowband filters in smaller scopes. It just helps make sure you don't end up with a dim view whilst wondering why. Other than that it’s normally about picking the right high mag for planets or doubles etc, or at the mid/low end choosing an eyepiece which frames the object. I find exit pupil useful to explain what effects you see, but I agree it’s not something I generally use in choosing the eyepiece to use.
  8. Without volunteering his services….. could you ask @Peter Drew to have a look at it for you Paul? If still interested I’ll check the 120 and we can talk then.
  9. Gosh that’s tiny, pocket sized in fact, ideal for travel 😉
  10. I’ll answer genuinely and without being accused of going on about my scope…. I would keep my FC100DC for many of the reasons given already; airline portability, grab and go at home, great Solar, Lunar, Planetary and doubles performance, quick cooling and good widefield deep sky results too. It’s the one scope which has kept me going through periods of poor weather and busy personal/work life when there have been only brief opportunities to observe.
  11. Please stop this Paul. A question was asked and genuine answers were given. Owners of Starfield, Vixen, AP, Skywatcher, StellaMira, Celestron, Askar, TAL, APM, LZOS etc etc refractor scopes and of course any other type of scope are welcome to post. I’ve asked repeatedly not to perpetuate this brand antagonism so please let it go.
  12. I’m quite happy with what I’ve got 🤪, but I too fancy an AP at some point, possibly a 130GTX which is travel friendly, or even a Traveller but they are unobtainium now. Outside that, either a 180 or 210 Mewlon and perhaps replace my current dob with an 18” Obsession with a decent mirror in it.
  13. Nice, sure you will love them. I re bought a used pair a while back as I missed the ones I sold. They do work well with filters; I use one OIII and one UHC and it shows the North America Nebula beautifully. I also bought some screw-in solar filters which are great for a quick peek.
  14. Nice set there. Out of interest, how does the 200p compare with the 8.5”?
  15. Amusingly enough, I was reading the side effects on a medication I am taking, and one of them is listed as ‘compulsive shopping’, so I have a medical excuse for my excessive scope collection! 🤪
  16. I think you can observe quite successfully without knowing anything about exit pupil, however understanding it can just help you know why certain combinations work better than others, and why you see certain effects. For instance, observing Planets in a 100mm refractor at x200 is likely to show floaters if you have them. Understanding that they start to become prominent at an exit pupil of 1mm or less starts to explain why. In this instance it would be 0.5mm, so you options then become using binoviewers or, say, moving to a 200mm scope which would give you a 1mm exit pupil at the same mag. At the other end of the spectrum, if, say, you were using a 55mm Plossl in an 8” dob, you would notice that the background sky is washed out if observing under any form of light polluted skies, plus it feels like looking down a straw. Knowing about exit pupils and apparent fields of view might take you down an expensive path to a 21mm Ethos which gives nearly as large a field of view but with a 3.5mm exit pupil rather than 8mm. Much darker sky background and more satisfying image. If viewing through a narrowband filter, using too small an exit pupil makes the image much too dim. This help understand that you CAN use these filers in small scopes but you need to keep the magnification low to keep the exit pupil large. Similarly in unfiltered views, if you use too high a mag, you will end up with an image which is too dark; x200 on the Ring nebula gives a nice big image scale but if you exit pupil is 0.5mm you will hardly see the target. Options are again, drop the mag or increase your aperture. That’s why big dobs are used to hunt down small faint galaxies; you can use high powers whilst still maintaining sufficient image brightness to see the target. So you see it does matter what exit pupil you are using, and knowing that helps you understand what your best options are in terms of kit combinations.
  17. The trouble is, with our weather, it’s more like a scope for every clear night a year!! 😩
  18. Perhaps this should be in a different thread, but has anyone used both 180 and 210 Mewlons? Any views on the relative merits? I’m tempted at some point (when I’ve sold a few scopes and have some money 🤪) to buy another having had a 210 before. Cooling was always a challenge on the 210, not sure I ever got it right, and there is something that might make me prefer the lighter, faster cooling 180. 6 smaller diffraction spikes may be nicer too?
  19. 🤣🤣 I am well aware that it is ludicrously unjustifiable, and that I do not need them all. I do just enjoy owning them, some are fairly rare but excellent examples which would be hard to replace such as the Genesis and Vixen FL102S. The TAL Alkor is a lovely little thing. I don’t use it much but it’s not worth much either (about the price of a used Ortho!) so I keep it 👍
  20. I should probably just plead the fifth here….. Currently it sits at 16, with two additional projects yet to be completed. EDIT Forgot my Omni 120mm so that’s 17 😬 Most used are the FC-76DCU, FC100DC, FS-128, 8” f8, 16” and the two PST mods. I should really move a few on, but there are some comparisons I want to make between the ST and LT 80mm, some are kept for sentimental type reasons (Telementor and Alkor) and some like the Genesis and FL102S I just need to use more! Clouds!!! 🤬 Zeiss Telementor TAL Alkor 77mm f11.8 Hilkin ST80 LT80AZ FS-60Q FC-76DCU FC-100DC Genesis FL102S Vixen 102mm PST Mod Celestron Omni 120mm XLT FS-128 AstroSystems 150mm f6 150mm f10 PST Mod Orion Optics 8” f8 16” f4.2 Truss Dob 150mm f10 Project 12” f6 (Nichol Mirror set) Truss dob
  21. To be fair, TS have been doing it for a while but it’s good to see these sorts of features in other vendors products. I know it adds a bit to the cost, but removeable sections solve so many problems and are a benefit for travel too, so I wish more scopes had them.
  22. Back in the days when I knew nothing about anything really, including fields of view and object sizes, I tried observing M31 with my OMC200. This was an 8” f20 Mak, so had a 4000mm focal length! Even with a 31mm Nag it gave x129 and a 0.63 degree field of view, likely vignetted a fair amount. Needless to say I didn’t see much! Just the bright fuzzy glow of the core filling most of the field of view. Even M32 was out of view. Took me a while to work all this out; it was before the time I was active on here so had few sources of information. Once I got my 106mm triplet I understood!
  23. That would do it 👍 I used to have a 106mm f6.5 triplet apo which framed the Veil beautifully with a 31mm Nagler. I basically copied John’s Vixen 102 f6.5 setup after reading of his observations 👍
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