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spaceboy

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Everything posted by spaceboy

  1. An advantage you would find with the solar Max III 70mm is that it has an externally mounted etalon so it is possible to remove this out of the equation along with the blocking filter (replace with star diagonal) and use the scope as a traditional refractor. Great for a grab and go or travel solar / astro scope but not really as an upgrade from your LS60.
  2. A member did send me a paper on this years ago as I always argued a central obstruction would surely reduce aperture but it isn't the case. I can't remember what the "adverse" effects were of a central obstruction other than the ones we commonly complain about, diffraction and loss of contrast, but light grasp was not one of them. The academic side of astronomy was never my strong point so I shall try to find the original thread as it will better explain it than I can. Either way I agree completely that the views through a well corrected refractor are hard to beat and far more aesthetically pleasing than other scope designs. I don't know what it is but I also enjoy using refractors over other scopes.
  3. No need to be sorry Dave. You know your scopes and have had a bad experience with a MAK (although I know a few who didn't favour the 180 MAK over others in the line). We all have our own preferences. My thinking was just that you could end up spending a lot of money on the scope to only find out it is what it is and the money could have gone towards something else. As you said you've already checked collimation which your happy with. I did though forgot to mention...... have you checked there isn't a filter in the optical path. Stupid question to ask I know but I remember a thread on SGL a while back where someone had totally forgot they had put a filter in the diagonal when looking at the moon then when they next went out observing wondered why they couldn't see the same detail they had previously seen when looking at DSO's. I admit to doing it myself one time so assume it is a more common occurrence than some may think. You know.......end of a long night observing and all you want to do is quickly pack up, get inside and go to bed. By the time the skies are clear again you've long forgotten you left a filter in the diagonal or on the end of an eyepiece.
  4. Please don't take this the wrong way but your going to be looking at a few quid for anyone worth ones salt to look at it. Personally I feel you would be better off putting your money towards a 90mm Mak https://www.firstlightoptics.com/maksutov/skywatcher-skymax-90-ota.html They come up used now and again for around £50-£65 which is more than likely going to be a drop in the ocean compared to what it is going to cost for someone to look at your Towa. The performance in the mak should far exceed the Towa. Just my 2p
  5. I've only owned one 6" f/8 achromat the Evostar 150 with collimateable cell. I really enjoyed owning one although mounting it was often challenging due to the size and weight. I am one of those who can observe through an achromat refractor with little distraction from adverse effects of CA but admit that the use of a semi apo filter is almost a given to tidy up the views on brighter objects (roughly a 20-25% reduction). CA will still be dominant when using a filter and often a yellowish hue to the overall views will be evident as a result.
  6. I was a little slow with my post and you replied before I had a chance to finish. Great to hear its all sorted and your having good results now.
  7. As above. + It is also worth noting how much experience you have with telescopes? You clearly understand the need to cool your optics but the longer a scope is out the more chance it will be susceptible to dew. It can be a balancing act some nights between cooling optics and avoiding dew with the only way around it being dew bands, then other nights you can be out all night and there is nothing. Again it all depends on the size and type of scope. Seeing conditions also play their part to how much magnification can be used on a given night. Poor collimation again can have an effect. Even picking an object to observe can limit use able magnification with low objects suffering and higher zenith objects seemingly unaffected by seeing. Quality of the scope and eyepieces needless to say play a huge part.
  8. I have had 6", 8", 10" & 12" Newtonians and out of them all I still have the 8". In my opinion there is no beating the scope for ease of use while still providing enough light grasp to keep you interested. The problem is scopes get large very fast. You may only think 2" aperture increase but in truth the whole scope grows by a substantial amount. In the UK scopes sit dormant far more than they do used so storage can become an issue with larger scopes. Then there is moving big dobs about which isn't for everyone. Just my 2p worth.
  9. That's a great setup you have there now Shane but I have to ask what made you go for the equinox when you already had the ED120? I was lead to believe they both possess the same glass and it was the fit and finish of the equinox that demanded the higher price tag? Knowing how stubby my ED120 was I'm guessing those equinox pack down nice and compact with the extendable dew shield retracted? I think is sure is safe to safe you've well and truly caught the refractor bug mate I have to say I'm liking the whole white / black theme going on. I know scopes are for looking through and not at but I don't think it's a bad thing to have a set up that looks as good as it performs.
  10. In reply to your PM Paul...... I'm far from an expert so I wouldn't want to give bad advice and figured it best to post here so others can add comment if I overlooked something. "I would like to know which models can work best, that is, if with an acromatic refractor, or with an ED or APO, and also with what aperture I could observe well the sunspots with their different shades and shadows, pores, plages, and solar granulation .. In this case, is the focal length of the telescope important? An achromatic refractor with short focal length can give sharp and sharp images, or will it give "colored" images?" I have found that an ED refractor offers the best results in WL but as you are observing in a specific wavelength and often using either a continuum filter (makes the image green until your eyes adapt) or polarizing filter (to dim the image so it is more visually bearable), an achromatic refractor can do just as good a job as false colour is not a significant issue. Where the ED / APO shows improvement is the overall sharpness good quality optics bring not so much the CA control. As for focal length a longer FL refractor is always going to be better corrected towards the edge but a short tube refractor is more manageable and easier to drag in and out between cloud. As for what you will see, pretty much everything you would want to. As with anything astronomy the bigger you go the more you will see. But as with anything astronomy in the UK what you see is also governed by the pee poor seeing we so often suffer. As you say you no longer have the ED80 your next option is either an ED120 (hugely expensive beyond this aperture) or various achromatic refractors up to 120mm with the 1.25" wedge or 150mm with the 2". HTH
  11. I will have to remove the one focuser end when shortening the OTA anyway as I'm led to believe the etalon protrudes some way on lunt's, but my estimates are that the 90mm ~ 85mm ERF should sit nicely behind the middle baffle. Although the middle baffle isn't quite middle of the ota I don't think ??
  12. It was not so much having the largest one that was causing me the concern but having one that gets the energy back out of the OTA the quickest. I do get rather involved in solar observing and when I had the https://www.firstlightoptics.com/telegizmos-telescope-covers/telegizmos-solar-observing-hood.html an Hr can pass by in a blink of an eye. All that UV energy has to go somewhere and I'd rather it back out of the scope than building up inside it. I honestly cannot see there being enough room for the 110mm. I drew out a couple circles to give an idea of how a 110mm erf would sit inside the tight 113mm OTA and there really isn't as much wiggle room as you might think. The 90mm is now my only option but comfortably with in budget and while it leaves me with faffing trying to find a cell I'd rather go with this than the 75mm which may end up 65-68mm when in a cell. With the OTA being shortened to achieve focus my guess is a 68mm filter will end up far closer to the etalon than the objective.
  13. I'd already looked in to Delrin as it would be easier to work with, have some shock absorption, be lighter and already be black but oddly the cost is more than that of aluminium.
  14. I had thought about it's nature to swell due to going in and out the flat with different temperatures and air moisture but would this still happen with kiln dried timber?
  15. I agree I need to tread careful when thinning my kit. I'm not the biggest fan of Newtonians if I'm honest and this is why I purchased the ED120 but the truth at the end of the day is the 8" 200P is always going to show me more than the 4.75" frak. I'd have liked to keep both but it drives me bonkers having excessive kit gathering dust especially when I have other projects on the back burner waiting on funds. As for choosing between my mounts it will be a far more difficult decision.
  16. OK so as long as people agree there would be no real and significant advantage in having the larger 110mm D-ERF I shall be taking Peter's knowledge in good measure and going with the 90mm filter now I have funds in place. My next query is would an internal cell mount be ok in wood and what wood type would be best. I can get one made in ally when having the OTA / lunt adapter made but my thinking is wood can easily be painted matt black, it's softer material so more shock absorbing if the unthinkable might happen . My thought is that wood has a degree of friction too it so could (if within tolerances) in my mind at least be push fit with no need to fix it in place with a bolt. I had looked in to black Delrin as an alternative but this is stupidly expensive. On another note. OTA have to be shorten for the solar scope to achieve the correct focal distance. Does this mean baffles have to be adjusted to suit ? I know the focuser end will likely need to be removed but what about the middle one or would you just remove that altogether and just use the celled ERF in it's place??
  17. Great job Fozzie. Finishing post in sight and can't wait to see the end result.
  18. Thanks for the comments guys. It is just me whingeing but astronomy is such a frustrating hobby I need to vent off from time to time. I already solar observe mate and TBH I prefer it over the night sky. With the sale of my ED120 hopefully I shall have all the funds I need to get my lunt mod up and running in time for next summer.
  19. And ready to throw in the towel. At least that is standing out in the late night dark getting freezing cold and damp looking at the same dozen night sky objects because 20' high LED St lights have killed the chance of ever getting dark adapted and finding anything other than the brightest of messier items. I'm well aware of my frustrations come partly from not participating in the hobby over summer and again now due to determined cloud cover or full moons but I'm also aware it has been a long time coming. My skies have become worse over the past 3 years. May be coincidence with LED lights being installed or the fact even Seemingly clear nights have a high murky cloud washing out views but I much prefer sitting out in the warm day sun solar observing than I do trying to separate a distant white smudge from a pale grey sky. I enjoy star parties and the dark skies they 'sometimes' offer so while I'm going to thin out my kit, (I do have probably more than I need anyway) I do plan to keep a scope that will show me something more than a tiny blob. In doing this I also have something to hand should the UK ever experience a power cut and I can see what my back garden really could offer. Other than this I'm sticking to solar which while cloud can still create much frustration I much prefer chilling out on a warm summers day than I do shivering on a wet stool watching bats fly over head. I guess the purpose of this post amongst venting my frustrations is to convince myself I can still keep my hand in the hobby. Another reason is to get peoples advice on what they would whittle their kit down to? I currently have an EQ and AZ mount. I'd like to if I could reduce this to one but EQ have their uses for solar /double stars but the AZ has the convenience of grab and go and fuss free observing albeit nudging constantly. Another is I currently have my much loved ED120 up for sale. This is a reluctant move but I have a 200p which I'm guessing would be the better choice to keep? At least I keep telling myself that! I do have an ST120 to keep my foot in the refractor door. Not in the same league as ED glass but by far my most used scope as its perfect for solar wedge WL solar and grab and go between clouds (which we have a lot of). I had considered just having this as my only scope for night and solar or do you think I'd be best keeping my 200p in case?? Mounting will not be an issue either way. If you had one affordable scope and mount which would be? Only criteria is it would have to be as at home solar observing as it was night sky which in all fairness doesn't leave much to pick from?
  20. I'm only planning on doing it once though Pete so saving the bit extra towards the larger ERF is ok as long as there are gains to be had...... and IT FITS that is?? I think the cells and adapters are my biggest gripe as far as potential cost goes as if my lathe was a tad bit bigger I could have done the majority of it myself, making any necessary changes along the way. Instead now I need to be better prepared and make sure everything is correct before I commit someone else time to it I appreciate a smaller filter will do the job but I also figured the larger 110mm will have everything back out the objective before any possibility of thermals or otherwise gathering and with it so close to the objective I shouldn't have any concerns of the lens getting any warmer than it need to do sitting in the midday sun. It is my understanding the difference in views between an external filter over an internal one is an obvious one and my logic was, if internal was the only choice, the closer I get to the objective the better the views should hopefully be for it?? Unless I am missing something that is ???
  21. I think getting the filter in is easy enough. Simply hold the filter with white gloves and get someone to lower the ota over my hand until it reaches the baffle then flip the ota over. I think the best thing to do is try to find some cardboard the right thickness and cut out a 110mm circle and see how it fits the OTA. This will highlight any deviations in the OTA width along with giving me a more practical representation of how things will or won't work. What ever the case I think it is safe to say the general consensus is to go with the Baader D-ERF no matter what size I go with, so that's that box ticked Now it's a case of figuring what size will work and if I can find an afford way to have an adapter made for the lunt to attach to the XLT
  22. You can't complain for £20. I once bagged myself a still boxed Helios 90mm evostar with EQ3 off ebay for £20. There are deals out there to be had that's for sure.
  23. I had one and can't say I was all that impressed TBH but many sing high praise of them. It is worth noting that the newer ones use up more back focus than the earlier thumb screw ones so something to consider if you don't have much inward focus travel. I believe there were 3 different versions in total with the one with white lettering and thumbscrew to be the best of the bunch.
  24. Short summer nights, early morning commitments and the usual poor weather often means plenty of down time for all that expensive astronomy kit so is anyone else guilty of just setting their kit up in the middle of the living room and playing with it pretending there actually is some distant nebula in the eyepiece ??
  25. The trouble is a 110mm filter in a 113mm OTA gives me less than a 1mm gap around the circumference of the filter which I have to allow a little for expansion / play. When you add to this the tilt my guess is the filter is going to end up wedged in the OTA at some point. At the money these things are I have to make sure I get it right.
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