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jetstream

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Everything posted by jetstream

  1. A high transmission low scatter widefield around 12mm would be a great addition for the 12" dob IMHO. The Morpheus comes to mind eventhough I've not used one (yet). Less than 82 deg AFOV EPs seem (in general) to offer less scatter and higher contrast IMHO.
  2. Over time I've found that orthos or Delos class eyepieces fit the bill for me starting around 12mm as these designs offer less scatter and enhanced sharpness if conditions allow the difference to be seen. The large hyperwides are a challenge in the fracs- the 20mm APMs substantially less weight help here. You mention filters... the right choice is crucial for success IMHO...
  3. I own TV Ethos, Delos and the 20mm APM. With the Paracorr II in my f4.1/f4.8 dobs the APM 20mm shows slight astig when unmasked from coma, whereas the 21E does not. The thing is I use the 20mm APM more- it equals or betters the 21E on my favorite objects- nebula. Each one shows things a bit differently but I can say that the 20mm APM is excellent and for the price difference I can't say I would buy a 21E again... The highest contrast hyperwide I have owned was a 10mm Ethos, sold only because in this fl I have other personal considerations or preferences if you will. I use my equipment a lot weather permitting but I don't sit and examine slight edge performance differences, I'm too busy observing objects for this.
  4. Awesome! Eagerly waiting reports!
  5. Did you order this Steve? Very nice telescope!
  6. When dealing with these top optics I'm not so sure some of the specs will be a deal breaker. What will show for sure is a difference in cooling ability and a friend here had an Intes and while a great scope prefers his Mewlon... Excellent considering the driven mount - the AZ EQ5 should be more manageable than my AZ EQ6, a real beast. I can put a planet in the FOV and comeback way later with it still in there. This mount has upped my observing ability. Eagerly waiting info on your choice!
  7. Used Circle T orthos are good eyepieces as well that can be bought for a reasonable price.
  8. What type of scope is the 127?
  9. Someday I'll have a Mewlon, one is on the top of my list actually. The only thing is the gymnastic ability required to use one, exacerbated by a manual non goto mount. A dobsonian is much easier to use for me over my AZ EQ6 and TSA120. The TSA 120 appears technically perfect to my semi educated eyes but my 10 VX shows so much more... IMHO you will love every bit of the 180mm Mewlon, including the optics. @Stu might be able to add to the conversation.
  10. I would seriously consider one of these- f 6 is a great place to be and the 200mm should be easier to transport.
  11. Yes, for sure Steve. I tried the Baader Neo from my former town location, about mag 20- it didn't help...
  12. Sadly enough any filter cannot increase contrast on galaxies, the bright sky reduces one of the 2 main components of actual contrast. Observing from extremely light polluted skies are the realm of NV IMHO, their primary use- again IMHO.
  13. Great report! I have push to DSC on my dobs and love it, very accurate if I do my part.
  14. Fun is the name of the game! Yes the obstruction does that and strangely enough increases contrast in the higher frequencies and keeps the frequency range intact for the aperture. I would guess, if the mirrors are 1/4 wave total that this scope would give the Telementor a run on the moon detail wise. I would definitely flock it, and paint the sec edge and holder with flat black paint with the smoke in it. The drawtube and area would also get attention. It would be nice to check reflectance before getting re coated- don't know how maybe someone here does? Roland Christen tested mass SCT's before the "Starbright" coatings era and some of those were extremely low in light transmission, as were some eyepieces. The SCT had the 88%x2 x mirrors and about the same for the corrector...about 68% transmission and without counting the CO reduction in aperture. With high reflectance mirrors, all flocked up etc I would be surprised if the TAL didn't offer similar DSO views. To its + side it is already APO chromatic. With the most modern equipment available and from an optician that is VG -Terry O - my 97% nominal mirrors are about 93% true reflectance avg, which is top tier. There just might be a bit of hocus pocus with the mass produced reflectance numbers...but I think a lot are 90% or so.
  15. I would think that a couple of things might be at play here- the possibility of stray light reducing contrast- the u tube video shows much reflections with a light shone down the tube. Another thing is mirror reflectivity- even the best are quoted as "nominal" and also vary in reflectance across its surface. A typical 96% high quality mirror will produce in the low 90's -92%-93% ( a top coater told me this). So, if the TAL has 88% reflectance X2 for the secondary were down to 77% , add the eyepiece at 97% and were at about 75% system throughput. This does not take into account the reduction in aperture from the secondary. The Zeiss will have top coatings and polish around 97% so were comparing a top 63mm (60mm effective with EP) to a scope operating around <48mm effective that has stray light issues (possibly). The obstruction will make the TAL easier to split stars for sure IMHO- airy disk stuff. The CO might be a goodly number on this scope. Glad you had fun Stu!
  16. How big do you figure it is? obstruction can do weird things IMHO
  17. Great report Stu! It sounds like the TAL has well figured lenses and the Zeiss has excellent coatings and a fine polish that allows better views of the galaxies.
  18. AFOV... I find that 100 deg eyepieces give me better results on large diffuse nebula that smaller AFOV eyepieces, regardless of TFOV. Some say that the larger, full engagement of the eye, with no visible field stop can provide better views on certain things and in my experience this holds true. Please note I usually observe these objects at an exit pupil smaller than my 7mmish pupil dilation. Dilation measure by the "drill bit" method. There is a sweet spot mag wise for every object in each telescope IMHO. It might be possible that photon concentration as dictated by the exit pupil (field stop) plays a role. I get better views around 4.5mm-5.5mm that at say 6.25mm, still below the 7mm dilation. Ive been testing this for years.
  19. what are you going to look at primarily? the article said the contrast booster removes most all CA but reduces transmission and adds a yellow cast. It would be good for planets IMHO but my natural no experience guess would be to use the semi APO
  20. How many teflon glides are in this focuser? from me: The adjustment is now done and the Tak focuser is now buttery smooth. I loosened the 3 glide set screws until I had backlash and drawtube side play. The set screws were then slowly snugged up until both the backlash and side play were "just" gone. For me there is no need (yet anyway) to delve into the bottom plate area as there is a nice relationship between the glides and the rack & pinion backlash. As a test a hvy Baader/Zeiss prism diag and 30mm Es 82 were put vertical in the scope- no problem holding it at all. Tonight we'll see how the Binotron 27's make out."
  21. Mine too- the TSA 120 adjusted up nicely, smooth as butter and no play.
  22. M13 is a bright object and might show as a smallish fuzzy ball at low power in your 100mm and upping the mag will resolve more stars. The propeller feature can be tough and personally find that there can be a smallish sweet spot mag wise. Highly recommend playing with magnification on this one.
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