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alan potts

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Everything posted by alan potts

  1. Derek, Nice collection there, I rather like the T4's from Televue though I only have one, the 12mm and that may well go soon. There is not much between the 13mm T6 and the 12mm in cost but with the 12mm you feel you are getting your money's worth. Now all we need to do is spend some more of your money to fill the holes, 3 of them you say? Alan
  2. Tinker, Yes one of the other Moderators told me about this as with larger scopes it makes it easier, with mine my arms need to be a few inches longer but I have done it so many times now I could almost do it in my sleep. Know what you mean about clear skies though. Alan
  3. John, The WO goes to 11. One of the all time great films, I love it. :grin: Alan
  4. Aaron, I have never seen most of the Pentax range but I would not make the mistake of buying one if I were you it could end up costing a pile of money. The 30mm and 40mm I believe have been discontinued but the others are still available I think, I always fancied the 40mm for the LX but could never get one, I have the 41mm Panoptic but I am not over the Moon with it, in fact now I regret selling the 40mm Meade SWA at F10 it is a great piece of glass in every sense of the word. Alan.
  5. Collimation of a SCT. The collimation or alignment of a telescope is very important if you are going to get the best from your equipment, at first it may well look very difficult and many can be worried about touching anything which is normally no bad thing. Basically all SC telescopes have three screw adjusters located on the outer surface of the secondary mirror which sits on the other side of a housing in the middle of the collector plate. Some people fit a system known as Bob’s Knobs which is just an extension replacement screw system that makes the job easier. Most adjustment is done with the use of an Allen key and some with Philips type screw heads, if this is the case great care must be taken when performing the task. The good thing about this type of scope is that they hold their collimation very well indeed so this will only need to be done occasionally. It is a good idea to perform this with the use of a torch until such time you are comfortable with the job, night vision is not important to carry this out and it is always better to be safe than sorry. Choice of star. I always select a star that is not too high up in the sky, select something of at least 2nd magnitude that is about 45 degrees above the horizon, this will make it easier to view the star and to easily adjust the screws. On larger scopes you will always find your arms are just a few inches too short making it essential to make journeys to the front of the scope. First steps. You have selected a star and placed it in the center of the field of view, on driven scopes there is no problem of the motors holding this position. I do not know of an un-driven SC telescope but if there is one out there then select Polaris as all stars appear to revolve around it. I use an eyepiece giving a power of between X80-X100, a bit little more or less will not matter. I also collimate without the diagonal fitted but some people do it with it in place, the choice is yours Once the star in the centre then de-focus it so that you see a large starlight circle with a blacker circle somewhere within, this is the shadow of the secondary mirror assembly, if it appears in the centre then the scope is fine. I always go for a fairly large star circle as I find it easier. Let’s say the scope needs adjustment. Whilst looking at the defocused star take note of where the shadow is offset within the light circle, now place your finger on one of the screws at the front if you can and see where the shadow falls, be careful not to touch the glass collector plate, you will see you fingers shadow on the light circle. You need to locate the screw that needs to be adjusted first, move the finger around until you see the shadow at the thinnest part of the off centered circle, once you have located this you know the first screw to adjust. Using the drive motors at a very slow slewing speed move the de-focused star to the edge of the field, this needs to be in the same direction that the darker shadow of the mirror is off-set within the brighter star circle. Careful place your Allen key or screwdriver in the selected screw head and turn it a little, then check the image, if it has disappeared from view you have moved it the screw the wrong way, so turn it back the opposite direction . Correct action at this point will bring the star back to the centre and will have moved the shadow of the secondary to a point nearer the middle. Never turn the screw more than one full turn, it will never be required to turn this far for normal alignment. If you can do this whilst looking through the scope it is so much easier, however on larger scope it is a process of elimination to find the correct screw at first. In most cases the screws will only require a quarter of a turn or less. It must be noted that on some occasions small movements of two of the screws will be required to achieve this. Once you are getting the shadow closer to the centre of the starlight disc you may find you need to adjust other screws, the same applies very small movements until you have the star as close to the middle as you can see. If it is near or in the middle you will start to see a number of small thin concentric rings of light around the shadow at the centre. Increase of power. I normally increase the power using an eyepiece to give X150-X200, then repeat the process using very small adjustments of 1/10 of a turn or less, until the shadow looks exactly in the centre of the light from the de-focused star. Check the image after every action and if a mistake has been made undo that action. Look for the concentric light rings again. I often repeat the process using an even higher power of over X300 but this is not always necessary, if you are happy with what you have done focus the star and have a look at the diffraction rings, the scope should now be in good collimation and ready for use. A good final check is select a star of around 4th magnitude and check for a clean point of light, this is known as the Ariy disc and offen has concentric diffrations rings around it on brigher stars. Any adjustments made at this stage will need only the very tiniest of screw movements, be careful not to undo the work you have done. This seems very worrying and difficult at first but once you have done this a few times you really will wonder what all the fuss was about. The scope should now be in good collimation for a night of astronomy. Clear skies to all, Alan.
  6. I will try and borrow the 14mm as well as something else, I had the lions share of the set as my first eyepiecs so they are not new to me, it was only the 40mm that I didn't bother with. I remember the first target with these eyepieces, Mercury with the 14mm and the 12 inch, out the window of the apartment in town, I was still building the house at the time. I have never seen Mercury since, there is always a tree in the way, or treed out as the Great Man would have said. Alan
  7. I have got to go to see Dani in Sofia at the end of the month as he had a couple of Televues I was selling and the buyer has let me and him down, I was thinking of doing the 14mm S Plossl against the 14mm Delos and maybe the 26mm against the Panoptic 24mm, I will see what he will lend me, he is a bit red faced, he don't like to upset his best customer. Alan
  8. Well that is a very nice offer, the only thing being here, many a time I want to help people and just can't. I am even running out of eyepieces to test but I have some Meade 60 degree S Plossl's form the Series 5000 range that I can do, 5.5mm, 9mm, 14mm, 20mm, 26mm, 32mm and 40mm I don't think I will do all of them but a couple could help people, I used to have all but the 40mm, they are not bad eyepieces. I think the 4mm ortho may be a bridge too far though, I have long lashes, the girls at school always wanted to put that black stuff on them, that I am not even going to try to spell. I sometimes find the 6mm BGO a bit difficult for long periods but think I could just manage the 5mm. Alan
  9. Dave, If you dropped it on you foot it would become attached to you, great eyepiece though isn't it? Must try and use it more. Alan
  10. Mark, I did a review where I was using an Ethos and a BGO and I gave up because of the difference in field. I feel the transmission is not far short of the BGO and Hutechs but I believe that field plays tricks on the eye as there is so much more infomation for the eye to take in where as on the ortho you are much more focused on the object. Even if you are using 6mm or both types, it sure doesn't look like it for the first few seconds of viewing. I have done this on Jupiter a fair amount and you would swear blind they were different magnifcations. Alan
  11. Mark, Last night was superb before this mornings early call for all, only trouble was I concreted in front of where all my scopes are and could get them out. Michael made a point of it in his first post about the amount of difference in focus there is between these two, it really can be a pain to mix them, which I have with the 5mm in between 6mm D and 4.5mm D. I have one of the Hutech orthos (12.5mm) that I got from FLO, who were very kind and put one aside for me as they knew I was coming from afar, I would like to get a 5mm for those top draw nights and I would love a 4mm as well but maybe that is too short on ER, it's one to try before buy. The 10mm is a gem and I would love another, sold mine to Stu as i had got the 10mm Ethos, I find the massive field a bit too much sometimes for planetary on the LX where 10mm is giving X304, a good Mars power. Alan.
  12. Avtar, There is a review of the 6mm Delos and a 6mm BGO amd I believe 6mm setting on the Nagler zoom on site by me from last year.. Alan
  13. Shaun, I wrote a longish review only about two weeks back on a TBM 2.5mm and Radian 3mm, I think you must have missed it. I am working on one at the moment with 12mm Nagler and 12mm Delos as many ask which is best, I am going to try and help answer that question, the problem is the weather. As I write this it's just past 6 in the morning and we have a thunderstorm, it terrible, with the best will in the world I can't write reviews without observations. Alan
  14. Well that seems to have got people talking. The 3.5mm Xw is not only up there with the best it also has a 70 degree FOV and 20mm of eye-relief. Taking John's point about the Supermono, I am sure that what he says is absolutely bang on but what good it an eyepiece like that if you have to wear glasses as quite a few on site seem to, this is why I do the reading glasses test to try and help them. I fully believe no matter what you choose XW or Delos , it is not going to be a bad choice and I am sure anyone will be delighted with either but those last two lines hurt me a bit. I've done 5mm XW and 4.5mm Delos and liked the Pentax more and now this, I am beginning to wonder why I didn't listern to John in the first place, he told me they were this good about 18 months ago. A bad case of black and green fever. I am going to do 6mm Ethos Delos. Alan
  15. Pentax XW 3.5mm TeleVue Delos 3.5mm. Well here we go again having just wiped 2000 words from Word by pressing a wrong button. Pentax 3.5mm XW This eyepiece is the shortest of the Pentax XW line up and like its fellow combatant is about the tallest of the range. The eyepiece comes in a rather nice screw fit bullet case and that fits neatly into a well made and padded box, no surprises there from what is a quality company marketing near to the top of the price scale. The 3.5mm tips the scales at a modest 365 grams according to my Argos specials in the kitchen, though this is of course subject to a tolerance of plus or minus half a kilogram. The eye-relief on all the models from the range is 20mm though the eye-lens is a little recessed but presents no problems for me when I put on my glasses and tried it out, this is something that I do not need to do normally.The field of view is a nice 70 degrees and one would expect it to be sharp. As a part of the same system there is a twist up eye-guard that can be deployed to help get the eye in the correct place for viewing, this is something that I took advantage of as although I can use Delos without the system raised I could not on the Pentax, this is due to the fact I am used to one and not the other and black-out or kidney-beaning is something we can do without. TeleVue 3.5mm Delos. This eyepiece has been on the market for about 18 months now and is one of the shortest from TeleVue, because of that it will not appeal to everyone as the magnification is going to be very high on all but the very shortest focal length scopes. However it is an eyepiece I can use on very good nights on a small selection of targets, mainly the Moon and Planets. Older TeleVue eyepiece just used to come in a study box with a thick plastic bag inside holding the goods along with some instruction and a little chrome and black sticker. Now the box seems to have been upgraded a little with a type of poly foam liner holding the eyepiece wrapped inside a plastic bag with the other bits as well. I have noticed this on all my Delos and Ethos eyepieces but others seem to be as they always were. The Delos is again about the largest in the line and weighs in at 460 grams, so it is a fair bit heavier than the Pentax but I do not believe is likely to trouble any Dobsonian uses, it must be the extra 2 degrees of field the Delos offers. Eye-relief is the same 20mm with a newer design lift up and twist lock eye-guard, of the two here my preferred choice and a massive improvement over the T4 Nagler and Radian systems. Look no beans. Scopes Because of the focal length I am only going to use my shorter scopes. Total scope time for the test was 15 hours 20 minutes over a very long period due to inclement weather. 115mm APO, which is F7 and gives a magnification of X230. 190mm Maksutov/Newtonian from Sky-Watcher, this is F 5.26 and give a power of X 286 70mm ED refractor which is F 6 and gives a lower X120, this is still close to its maximum though. Targets. Moon Saturn Jupiter Mars Comet Panstarrs. Apo 115mm, well cooled, power X230 used driven and undriven The Moon. I viewed the Moon with this scope on two nights when seeing was good but not the best ever, nonetheless it was allowing me to use X230. The Moon was 5 days old and later in the week just about exactly first quarter on the second night. On the first night I was studying the craters Kant, Tacitus, Pitiscus and Hommel switching eyepieces at about 4 minute regularity, being very careful with focus. I was trying to see if there was any detail what so ever I could see in one that was not there in the other, it was a good job I was not holding my breath on the result. I changed location to craters Burg, Plana and Plana ‘C’ witch lie north of the Mare Serenitatis but the result was as far I could determine the same. The next time the Moon had moved on a couple of days, it was now in about my favourite position half illuminated, up to this point I find the Moon an interesting object but much passed three-quarter phase leaves me a bit cold and no doubt annoys our astro-photography members no end. I was scrutinizing the area of Werner and Nonius ‘F’ and later taking in the area of Mons Hadley, part of the Apennins Mountains where Apollo 15 landed and made base. It is difficult to comprehend that men walked and bounced near or where I was looking and may even have played some golf, my they left it in a mess. I spent a long time on the Moon with both eyepieces and at no point could I see one was any better than the other, though there was a small amount of chromatic aberration from the very edge of the Pentax when you got the Moon in the right place that was not visible in the Delos, I struggle to believe it would be an issue with anyone though. One thing I did notice was that whatever eyepiece I was using when I changed them over, thought that the next eyepiece had better contrast as the black looked, well blacker. I can only think this is something to do with the eye relaxing as it is taken away from the views of the bright surface into the darker conditions around me. Then the eye dilates again as it’s reintroduced to the surface of the Moon which must be may times bright than my surrounds. Mars. Mars has never been one of my favourite planets and I believe this is much to do with the power that you need to use to see it at any size, doing this we are fighting a battle with the seeing Gods, one we seem to loose most of the time. First night on Mars was April 9th so it was very close to the opposition which we only see ever two years or so. I was seeing some detail on the surface that was triangular in shape and checking SGL the following day told me it was Syrtis major which to me looked a bit like Africa in the wrong place. There was also the white of the polar cap to be seen when seeing permitted which is never enough. Both eyepieces perform excellent on the first night and on this scope I again could not really drive a wedge between them. I would say that there was very slightly more peachy orange about the Delos rendition, the Pentax seemed paler but only just. I was getting a little flare from the XW from time to time that was there one moment then gone, I didn’t see the same with the Delos. Second and third nights on the planet with this scope were a month apart and results were much the same though one of the nights I could see a bright area to the south of the disc which I am lead to understand is an area known as Hellas. The last night I could see Mars was not a bright as I could remember it was the month before though there was still a good deal of detail that could be weeded out from the view. Saturn. This planet takes magnification very well and the rings are wide open making a spectacular view, though unfortunately it is not best placed this year as it is low down in the sky for me and must be worse from England. I was rather astonished that I could see as much as I could as it was wobbling around in the turbulent air but Cassini was there and I could also make out a little of the polar region being darker than other parts of the disc. This was something to leave for a few weeks as I did not want to stay up all night. When I final got back to it the other night conditions were excellent and the air was nice and still for once, with the scope being one of three I was using in a scope juggling ( very dangerous art taught to me by a circus performer) routine, the X230 the APO delivered was close to optimum for the planet. Again Cassini was there but this time clear and shouting ‘look at me’, the polar shading was clear with a definite line there to be seen and I could make out what I think was 4 of the moons. I believe it was John that said to me there could be a situation where one eyepiece would better the other on a target specific basis, for me this was true I did just prefer the Pentax on Saturn as the view seemed a bit more polished where as with a gun to my head I would have picked the Delos for Mars, now we have to have two eyepieces of same focal length costing a fair wedge just for planets, it sort of left me wondering if it varied for different scopes as well. Jupiter. The largest of the solar systems members is past its best now but it is still high in the sky for the first part of the night, though it will not be long before the twilight claims it. Always a joy to look at though any scope and for many X230 is prime power, though in my opinion it is a little too much, for me less is more and I prefer to view around the X170 mark regardless of telescope aperture. Of the two nights I viewed this target oddly the moons were all on one side but the belts were clear to see through both eyepieces and again I would not say one was better than the other. There was no detail as such that I could see in the equatorial belts though of course they stood out clearly and as usual the Great Red Spot was on its holidays, I was unable to see little in the way of clear polar region shading that was there with a lower power which always makes me wonder why people seem to over egg the pudding. 70mm ED refractor, let us not forget with Carbon fiber tube. Power X120. Jupiter This was viewed only the once with this scope as a part of the juggling act and I am always amazed just how much you can see with a small scope when X120 is getting close to its theoretical limit. All moons were clear to see albeit a bit unbalanced and the two equatorial belts stood out nicely. The chromatic aberration on the Pentax XW seemed a little worse with this scope and there was some visible using the Delos as well so the scope was having a hand in matters, it is fair to say it is not in the same class as the other one. There was no light scatter that I could see and both views were very alike but there was something that was telling me the Pentax was just a tad cleaner, it was just a feeling with no hard evidence. Comet Panstarrs. This little scope has a massive field of view with the right eyepiece and I used it to track down Comet Panstarrs which is just below Ursa Major or the Plough at the moment. I don’t know who gave the name of the Great Bear to this collection of stars but I would suggest they were into some strong narcotics at the time, the Plough I can see and live with. I fully understood this was going to be a difficult object in so smaller scope but I was able to locate it with a finder eyepiece and work up with other eyepieces until the 3.5mm’s were selected for the breach. I will not lie, it didn’t look a great deal like a comet to me, more of a dim blob, I am sure without sky like mine it would have remained invisible. The thing though I did notice was the Pentax seemed to make a better job of point star sources in the area of the blob, again though I am being hyper-critical here and either one would out perform most it not all on the market. It has to be said that the night of this observation was my best sky so far this year, it was truly exceptional. Sky-Watch 190mm Mac/Newt. F 5.26, cooled and collimation checked. Saturn. I viewed Saturn the other night in excellent condition and the extra aperture of this scope, which I think is under-rated as a visual instrument by some way, it always seemed to get labeled an astrograph, but extra size was there and telling. There is nothing like top conditions to bring out the best in a scope and make me look tired out all the next day but with the weather of late you have to make hay while the sun shines. This telescope was giving a rather large X286 and boy Saturn didn’t seem to mine one bit. Everything was there that was there before with the smaller scope and then some. With both oculars I was able to see not only a bold Cassini Division and polar belt but I could see a difference in colour between the A and B ring but no sign of the other elusive Encke gap, I think something much larger is called for. I believe I could see 5 moons as well but could not check as my outdoor laptop has finally given up the ghost. I spent over an hour on Saturn alone and this time I just feel the 3.5mm Delos was top of the class but Pentax was pulling the shirt tails rather hard. With the right scope and conditions these two are really sharp There is of course another explanation as well, that it is all in ones head and these two really are as good as each other. In some respects it is a shame that I cannot lay my hands on a Vixen LVW 3.5mm as then we would have just about every top line 3.5mm eyepiece I know offering such eye-relief albeit with a slightly smaller field of view. The Moon, Without going over the same ground I used the exact same craters on the same nights with the Mak/Newtonian and I have to say on this target even at a large magnification of X286 there was nothing in it what so ever, just sharp and contrasty views. It must be said that even on something short of top quality seeing the views these two eyepieces give of the Moon are worth the price tag alone, they are truthfully jaw-dropping. My Son Daniel wanted to look and rightly made the comment, “our house wouldn’t last long there look at all the meteorite damage,” since seeing the program on the Russian Meteor everything is meteorites and dinosaurs. The optical illusion, for want of a better way of putting it, that I saw on the 115mm Apo was still in evidence here with regards to the perceived contrast difference, I would love to hear any thoughts from site as to what this is and has anyone else noticed. Mars. The good thing about this scope is quality of image and with the eyepieces both 3.5mm in focal length the power is right up there in the Mars power band at X286, with the right conditions the telescope is large enough and can handle this. Firstly the disc was much larger but focusing between the two completely different focus points of first the Pentax and then the Delos was tedious, the tiniest bit out and all detail is gone. Again I was seeing a slightly more orange Mars with the Delos but it was so hard to pick up it could have been me. Details seemed a little more up front with the TeleVue and sort of looked like the glue lines you see on a tennis ball when looked at the right way, as well there was a complete lack of any aberration that I could see from one side of the field to the other. The Pentax was again showing this slight flare from time to time, nothing serious but it was there and the detail, whilst the same was just a touch more subtle. Just as I was ready and willing to believe the flare I was seeing periodically in the Pentax was a fault in the XW, I saw the exact same thing with the Delos just for a fleeting moment, this just goes to prove that an eyepiece test needs to be done over a few nights as this was clearly variation in seeing conditions and nothing to do with the eyepieces. Conclusion. I think whilst I was doing the observations for this report on what must be two of the very best 3.5mm eyepieces that are currently on the market, I have been wondering what to say at this point, not that I am usually lost for words. After 15 hours and 20 minutes I think both are outstanding eyepieces from two of the finest producers. They are both sharp, full of contrast with little or no scatter. I always wonder what Pentax could have done if they had set out to design an astronomical eyepiece as opposed to a range for a finder scope. My one criticism is I feel there could have been more in the range, I feel the jump of 10mm, 7mm, 5mm and then the one we have here is a little lacking, however this is just my opinion. TeleVue’s Delos on the other hand has more in the range and were designed with the night sky in mind and I believe some of the range are the best on the market. I own the Delos and it is a superb eyepiece, I borrowed the Pentax from my friend in Sofia, Dani, and I thank him for that. There were plus points on each side all the way through the test and very little I could say that was negative. However I think if spent my money again I believe I would buy the Pentax XW, 3.5mm as it really comes so close to orthoscopic quality no matter what you point it at and it will also be on it’s game in the daylight as well. I hope you enjoyed reading it. Alan
  16. Avtar, My oh my those Sky-watcher super wide 3.5mm are a size, nice selection of gear there. Alan.
  17. It is a very nice start Dan, don't forget some people would love to own just one of them. Alan
  18. Faulksy, Did it come from Stu, if so that's two that have my finger prints on. I want it back, BTW nice collection coming along there. Alan
  19. Arron, Two cases, I don't thing so, a chest of draws more like! Alan.
  20. Stu, The other point I can undersatnd about the eyepiece selection. I had as you know thw 21mm E and the 20mm Nagler, I bearly used the Ethos, so I had to sell the Nagler. The same is true of the 35mm Pan and the 31mm Nagler, I just keep using the 35mm Panoptic even though it may well be not as good in some repects I may just sell the 31mm. It is only when I get down to the shorter end I give them all a fair airing, horses for course seems to matter more at higher power. Alan.
  21. Stu, That reminds me I need more Orthoscopics. I really want the the 5mm and want someone to tell me the 4mm Hutech Ortho is not impossible, which I think it could be. Alan.
  22. John, So that is is 3 Nagler zooms now? If so I think that means you don't like it for some reason. Alan
  23. Reeny, That makes the postage look hellish expensive, nice little case. I am not friends with the post my sons Birthday present has gone missing and they make it sound like its my fault for ordering it. Alan.
  24. Faulksy, I have a space in one of my cases now and nothing seems to fit it. A very nice collection of glass there if I may say so. Alan
  25. Very well done it sounded a really good evening, wish I could have been with you all. Alan.
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