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AndresEsteban

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About AndresEsteban

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    Nebula

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    http://webspace.webring.com/people/gl/lemagicien/

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    Male
  • Interests
    Astronomy, Electronics, Languages, Trekking, Mathematics and Physics.
  • Location
    Rio de Janeiro
  1. The BCO 10mm is an amazing eyepiece! Every time I tested it over DSO fields it suprised me by showing very dim stars not visible with other eyepieces! Don't know if this is due to the low number of glass elements along the optical path, or the special Baader HT coatings. It doesn't matter though, performance is outstanding!!! I also particularly like to use the 10mm BCO with the original Baader Q 2.25x Barlow! It turns into a superb 4.44 mm eyepiece with excelent eyerelief! I prefer the views with this barlowed 10mm rather than using the 6mm BCO alone. This eyepiece is a must in any eps. collection, along with the BCO 18 mm, another amazing eyepiece very similar in performance to the 10mm BCO.
  2. The Q2.25 Barlow is a very fine one only beated by TeleVue Powermates. It also gives the flexibility of a 1.3x barlow when the lens is attached to an eyepiece without the whole lens body. Indeed one of the best barlow for its price in the market!
  3. Ok, my Meade Series 4000 32mm arrived so now I have 3 32mm plössls to compare. This is important because 32mm eps (with 50º-52º AFoV) have the maximum fieldstop diameter for a 1.25" eyepiece (about 27mm), therefore they are the eps that will give the maximum TFoV for your scope (Field stop x 57.3 / scope focal length). The plössls are: Celestron Omni 32 mm Meade Series 4000 32mm GSO Superplössl 32mm The winner is the Celestron Omni eyepiece without any doubt! Sharp an bright! The Meade came closer to the Celestron, coatings seem to have same type and coloration. Meade ep focal length seems to be longer than the Celestron and the field a little bit narrower. Anyway, looking at M44, without any doubt the Meade Series 4000 outperformed the GSO superplossl. Not only fainter stars where easy to pick up but also star colours were more vivid. These test where done with two different scopes: a 200mm (8in) f/5 reflector and a vintage 76.2mm (3in) f/16.4 refractor (this one was put side by side with a Polarex 75mm f/15 and if I should give rates, the Polarex being 100, this 3in f/16 would be 90, so yes, it's a damn good refractor). So yes, between Meade series 4000 32mm and the GSO SP, no doubts, I'd choose the Meade sereies 4000 eyepiece! REgards, Andy
  4. Technically, I agree with you John! 1) On my 200 f/5 reflector the Meade 40mm gives: 40mm/5 = 8mm exit pupil and 32mm ep gives 32/5 = 6.4mm . I'm 54 and certainly my pupils when fully dilated have not 8mm! So yes, technically it's a waste. 2) But with the 76.2mm f/16 refractor the 40mm ep gives 40/16.4 = 2.4mm and the 32mm, 32/16.4= 1.95mm. Although the field is narrower with the 40mm ep there's a gain in exit pupil than is perceptible in this slow scope (from 1.95 to 2.4mm). Well, what about the f/5 reflector and my actual pupil size when dilated? Being 54 years old I don't have 8mm for sure!!! Don't know my actual pupil diameter when fully dilated (5, 6mm?) but I know there's a small difference still perceptible for me when using the 200 f/5 and switching between the 40 and 32mm eps. That's why I still think the 40mm is worth keeping. I did all this reasoning that you did, and totally agree with you but... two nights ago looking at M44 through both telescopes and switching from 40 to 32mm, the maths proved right with the slower one but then, with the f/5 I was still convinced the 40mm gave a brighter image despite the narrow field. Subjective perception? Self-suggestion? Honestly: don't know! But the Celestron Omni 32mm was without any doubt the brighter 32mm ep of the trio! Excellent! Regards John, and again thanks for your observations! Andy
  5. Update folks! 32mm 1.25" plössls!!! I finally get my Meade Series 4000 32mm plössl. Now I have three 32mm plössls that I can compare: Meade Series 4000 32mm plössl - FMC, blackened lens edges. (Series 4000 typical body design -straight black cilinder) Celestron OMNI 32mm plössl - FMC, blackened lens edges. (Celestron and GSO share the same ep. body) GSO Superplössl 32mm - FMC, blackened lens edges. (Celestron and GSO share the same ep. body) Tested the bunch a few days ago. Object tested: Beehive Cluster, also known as Praesepe or M44. Telescopes used: a 200mm f/5 reflector (hand made with excellent mirrors) and a vintage japanese Dan Beam 76.2mm f/16.4 achromat (OKKK OEM). This achromat is comparable to a 75mm f/15 Polarex. If I'd give grades to scopes a Polarex would be 100 and the Dan Beam achromat 90. Despite the deformations at field borders when using the 200 f/5 reflector, conclussions were, from best to good: Celestron OMNI 32mm: Excelent coatings, sharp images and pinpoint stars with f/16 achro. In both telescopes excellent star colour differences. With f/5 reflector, deformation at borders but otherwise excellent images at center field. By far the brightest eyepiece of the bunch and superb colors!! Best coatings of the trio also! Celestron and Meade seem to have same type of coating, a deep dark mate green so light transmission is quite similar, but Celestron is 20% brighter. AFoV 50º. Eyepiece rating: 100 Meade Series 4000 32mm: Same as above although it seems the eyepiece has a litle bit more longer focal length (35mm?) than the Celestron Omni . Also AFoV a bit smaller than Celestron, 47º?. Otherwise excelent images, but stars on Celestron seem to have more colour. Like the Celestron, admisible correction with f/5 reflector on field borders. Ep. rating: 90 GSO Superplössl 32mm: Coatings are light brilliant green and I think is not so efficient as the Celstron and Meade. Not so bright eyepieces as the Celestron or Meade. With f/5 scope more deformation on borders. Pinpoint stars on both scopes at center. AFoV and focal distance similar to Celestron OMNI. Fainter stars that were super-easy to spot with Celestron, easy with the Meade, are not so easy with this EP. Ep. rating: 75-80 On daylight use, there's almost no difference between the three eps. Objects snap into focus easily, being easier on GSO (?). But daylight images seem more "vivid" with Celestron and Meade. At night things are completely different and Celestron OMNI clearly ourperforms the others in low light star fields. Heavy clouds prevent from comparing the three eyepieces observing the Moon. On previous tests with the Moon between GSO and Celestron OMNI results were quite similar, but strangely GSO ep was able to show more details on craters than the Celestron... No Moon tests with the Meade 32mm yet. Conclussions: The winner is Celestron Omni 32mm plössl, that's the one I'll keep. The GSO is not a bad ep. at all. As I've said Moon crater's detail seemed a little sharper on this GSO than with the Celestron, but noy by far. On low light conditions the Celestron excels, the Meade get close although as I've said it seems it has a longer focal length this fact dissapointed me because views with the Meade S4000 32mm are quite close to the ones given by the Meade Series 4000 40mm eyepiece , which I like a lot. Knowing this I'd keep the Meade Series 4000 40mm and the Celestron Omni 32mm and sell the Meade 32mm and the GSO 32mm. BTW, about 40mm plössl, although soem complain about the narrow field, about 43º - 44º and say it's better to buy instead a 32mm with wider field, these 40mm have a greater exit pupil than the 32mm. With fast scopes the difference of exit pupil between 40 and 32mm increases, so a 40mm is absolutely worth it despite the narrower field (and even if you don't have a 7mm exit pupil!) Don't know if Celestron OMNI 40mm is better than the Meade Series 4000 40mm. But a friend of mine told me Vixen NPL 40mm give better contrast and sharpness than the Meade 4000 40mm. If that's the case then perhaps the Celestron OMNI 40mm and the Vixen NPL 40mm are quite similar. It would be nice to hear others' experiences about these brands, I mean: Meade Series 4000 plössl - GSO Superplössl - Celestron Omni plössl and Vixen NPL plössl. Regards, Andy
  6. But is a trend for some manufacturers. Just checked Ricoh Imagining site for the Pentax XW series eyepieces (70º). Original Pentax MC on all air-to-air surfaces and special proprietary coating on cemented surfaces: PENTAX-Original Multi-Layer Coating for Outstanding Light Transmission Efficiency"All lens surfaces that come in contact with air are treated with the original multi-layer coating, while all laminated surfaces are treated with the innovative partial coating, to offer the light transmission efficiency of more than 90 percent (an astonishing 96 percent at 550nm) over the visible light spectrum." http://www.ricoh-imaging.co.jp/english/products/binoculars/scope/xw/ Also Vixen SSW 83º series: "Full multi-coating on all lens surfaces, in combination with special coating on the lens connecting surfaces," http://www.vixenoptics.com/Vixen-SSW-14mm-Ultra-Wide-Eyepiece-p/37125.htm But this characteristic is not in the page of SSW series @ Vixen, strange... http://www.vixen.co.jp/en/corporate/news_ssw.html Hope this info is useful for all! Regards Andy
  7. Hi John! I didn't mention air-to-air surfaces specifically. In all we have 6 interfaces in a plössl: 4 air-to-air as can be ssen in the picture you posted and 2 internals, cemented. Don't know if all individual lenses have coatings prior to cementation or if they put the coatings after it, thus leaving only air-to-air surfaces to get the coating process as common manufacture method. But, as you've mentioned I've heard some manufacturers are coatming all surfaces, but I sincerely don't know which brands are doing this and if in fact it has advantages over uncoated cemented surfaces. But for the sake of not confusing folks here, you're right: let's consider only 4 air-to-air surfaces for FMC in plössls. Regards and thanks for the remark, John!
  8. Coatings have an important role in the qualty of the image delivered, because they are responsible for optimizing light transmission through the optic sysem. As the number of optic surfaces the light path must travel increases, the qualty of the coatings turns out to be a major qualty factor. In FMC plössls we have 6 surfaces, 3 for each doublet. Celestron OMNI series and Meade S4000 have IMHO better coatings than GSO. Thus images are brighter. On the other hand we must consider the qualty of the glass used, and the manufactury process qualty variation. GSO seems to have pretty good glass in general. Two eyepieces of the same brand may not have the same qualty, nowadays mass production makes it so, unless the manufacturer takes special care in assuring a very good Qualty Control (not very common unless you paid more $$$ for that). Same happens with doublets, main reflecting mirrors and specially with newtonian secondary mirrors that should be FLAT but in the real world it's frequent ot see they are like ondulated carpets...
  9. Although we live in an OEM world with few manufacturers and several brands, some facts are clear: even with external barrel being the same, not all 32mm plössl are the same. Right now I have two and I'm waiting for a third. A Gso Super Plössl Fullu Multicoated 32mm 1.25" anbd a Celestron OMNI 32mm also FMC. Waioting for the Meade Series4000 32mm to finally choose the best from the group. So far results using my vintage OKKK 76.2mm f/16.4 refractor (39x), are: Celestron OMNI 32mm: Superb coating and brighter images than the GSO. Also seems to have a lower focal distance than the GSO, perhaps 3mm or so less. GSO Super Plössl 32mm: good coating but still darker than the Celestron, seems to have a little bit more focal length than the Celestron and just a bit more field. I think it has sharper images than the Celestron. This facts makes hard to choose one brand for only one application. In low light stellars fields (DSO) the Celestron, being brighter, is better, no apreciable difference in sharpness to GSO in stars. On the other hand, observing the Moon, bright light conditions, it seems the GSO gives sharper images than the Celestron, craters are more vivid and is easier to achieve focus. So for the Moon I'd use the GSO, and for DSO the Celestron... Let the Meade Series 4000 32mm arrive and I'd tell which one was the winner... BTW, I have a Meade Series 4000 40mm 1.25" plössl. Although it has a narrow 44º field, it's a superb eyepiece with amaziong coatings. I really love this eyepiece despite its realtivelçy narow AFoV, that's why I'd give a try to the Meade S4000 32mm. If it's as good as the 40mm, no doubt it will be the winner. Anyone with similar experience?
  10. I have this 1.25" 32mm plössl eyepiece in two brands: Celestron Omni and GSO. They are not exactly the same eyepiece although mechanically they are the same. Both have multi-layer coatings and blackened lens edges but... I think the Celestron Omni series has a really superb coating, far much better than the GSO, as a result, the Celestron seems to get fainter details and daylight images, for example, seem much brighter (20% max?). On the other hand it seems they have not exactly the same focal length. The Celestron seems to have more than 32mm and just a little less field than the GSO. Conversely, the GSO seems to have a little more field and less focal length, so images are not exactly the same. Images are crispier in the Omni (15%?). Eye relief is almost the same in both eyepieces, perhaps Celestron some milimeters longer. Getting all details together seems the 32mm Celestron Omni plössl eyepiece is slightly better than the GSO. I was looking for a Meade Series 4000 32mm plössl but it's hard to find here. I have the 1.25" 40mm model and its coating and sharpeness are astounding, even with it restricted field of 44º. Perhaps the Meade S4000 32mm eyepiece is the best of the lot (compared to Celestron-GSO), dunno. Anyone had a similar experience? I'd like to hear about it!
  11. Some videos of th Moon and planets to show the views given by Classic Refractors... The Moon http://youtu.be/oXeZvBRR_vQ?list=UUwMN3FPhdY041Y-7t_Wf8KQ http://youtu.be/pATzwlHz4M8?list=UUwMN3FPhdY041Y-7t_Wf8KQ Jupiter http://youtu.be/ZZBL6Ex1Vu8?list=UUwMN3FPhdY041Y-7t_Wf8KQ Mars http://youtu.be/su20U3-39W8?list=UUwMN3FPhdY041Y-7t_Wf8KQ http://youtu.be/OrPttYoSws8?list=UUwMN3FPhdY041Y-7t_Wf8KQ Saturn http://youtu.be/44egQ2DpO7k?list=UUwMN3FPhdY041Y-7t_Wf8KQ Castor (alfa Geminorum) http://youtu.be/YxRq9laU9XQ?list=UUwMN3FPhdY041Y-7t_Wf8KQ
  12. One important thing to get better contrast is telescope flocking. I've found that velvet glued over a cardboard sheet gives an excellent light absorbing surface. Moon and planet views show better contrast! Objective end flocking Focuser end flocking Focuser flocking
  13. Some experiments trying to take some images of double stars... Certainly this is almost impossible without a motorized EQ. However some positive results may be obtained... Castor (Alfa Geminorum)
  14. Moon viewa are excellent, with no visible CA of course. But using wide field eyepieces in afocal method may introduce some bluish line on the moon disc thta's not present in the visual mode. Also, the full moon disc centered on wide fild eyepieces brings the moon's disc over the border of the eyepice, thus being prone to produce some CA in this border zone. (Skywatcher wiled angle 66° eyepieces). Despite all these. I believe these are amaziong images for so simple settings.
  15. Mars and Saturn. Again all images are the final output of Registax program applied to 640x480 videos (30fps). Hope these pics give you an idea of how these vintage refractors perform. I don't doubt that despite of their long focus, these refractors are able to give beautiful DSO pictures (using Deep Sky Stacker for example) if a motorized EQ is available for long expsures anlomng a decent DSLR. the idea would be to put one of these OTAs on a modern EQ mount and see how performs. The same thing recording HD videos on planets with a DSLR, certainly more frames and sharpness will give better pics of Mars, Jupiter and Saturn!!!
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