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jetstream

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Everything posted by jetstream

  1. Yes, time can be an issue, here its the year of clouds/snow and rain. I was 90 miles north yesterday, clear as a bell into evening and drove into a wall of cloud not too far from this place. I guess thats why they call it Rainy Lake lol!
  2. I would hold off... everything is working well for you, I would just stick some 30-32mm eyepieces in the binoviewers and observe. So far I havn't got things to work well with filters in this type of set up. Big controversy with bino prism clear apertures including mine... mine are 27mm clear at the "zero" 2.3x but the reducer or whatever is in there reduces it a bit. My humble advice? don't worry about clear aperture. "run whatcha brung"! btw 25mm plossls work well too.
  3. At f4.8 the I wanted to go lower mag than the 32mm's give. At f4.1- not tried yet- I think the 32mm range will be VG. As we know we have to deal with secondary shadow on brighter objects if the mag gets down there. You might want to consider this for your upcoming purchase.... No need for fancy, expensive eyepieces with the binoviewer IMHO, GSO plossls are VG for example. I like plossls vs orthos for this application because the plossls eye relief is tighter and not as prone to float, eventhough the 32mm TV's do float without the eyguard extender.
  4. One on my very best views of the Needle galaxy,NGC4565 was with the15", Binotron 27's/32mm TV plossls/powerswitch at 1.3x. Another stunning view is the Leo Triplet, along with M42, M57 etc... A 20" fast f4 scope should be super on these objects with the right eyepieces.
  5. @Ships and Stars From CN former mod EdZ, an important read " Exit Pupil A telescope with binoviewer produces what I would call a false exit pupil. The exit pupil is always larger than the amount of light that it delivers (as compared to exit pupil from scope without binoviewer). That is due to the fact the beam splitter delivers half the light to each exit pupil. This mathematics is all discussed above. Think about it. A 6" scope with binoviewer at 30x has a 5mm exit pupil. But the light delivered to that exit pupil in each side of the binoviewer is (150x150)/2 = 11250, then sqrt11250 = 106mm. The true exit pupil would be 106/30 = 3.5mm, or an exit pupil with one half the area of the false exit pupil. The light delivered to the exit pupil in a binoviewer is not as bright as the light in an equal sized exit pupil from either a scope or binocular. Hence, it can be described as a false exit pupil." https://www.cloudynights.com/topic/61467-binocular-vision-summation/
  6. My wife uses Baffin Impacts and as you say are excellent.
  7. When I was young, we all did this lol! All the little kids back then walking to school in -30+c. Now they shut the schools down and most all kids catch the bus.
  8. You should see the moon, along the terminator with the 15"/Binotron 27's/32mm TV plossls..... powerswitch at 2.3x The view never ceases to stop me in my tracks.
  9. The more observations and opinions on these objects the better. Some seem unique in their wants ie the filaments in the Eskimo disappear (my eyes) with a filter and yet these filters are supposed to be optically good. One of the very best views of the Eskimo was with the 15"/Docter UWA/VIP under superb transparency and seeing- a sight that will never be forgotten. I'm very interested in your reports with the 20" Mark.
  10. I've had many many boots over the years- as a kid Sorels were king and are very good and have used the excellent ones @Ships and Stars mentioned. A lot of warm boots are bulky, but some are VG for walking such as hunting/hiking boots. I just use the Baffin Titan rubber boots for everything these days and are great on the ice or if having sled issues in the cat tails (slush, water). I do have a light set of cheap Walmart "Sorel" type knockoff boots rated for -30c and are no where near that rating. I had them on the other night observing and should have worn the other ones. They are really light though. Another VG resource will be @scarp15 an accomplished trekker. I've had hypothermia onset numerous times observing and normally the feet are not the contributing factor for me- its the hands,neck and head. A hat seems to aggravate eyepiece frosting, a real issue in the cold. One rule of thumb- good boots are not cheap.
  11. I'm re visiting many objects with the larger dob and finding some nice surprises doing so. I like seeing faint objects but like viewing brighter ones with detail more. NGC 891 was really rewarding to see and the Swan nebula was incredible.
  12. Sorels are good, I like Baffin better. There are huge differences in boots that can keep you warm when stationary vs walking IMHO. https://www.baffin.com/collections/winter/products/epicm005
  13. Another quick report from the other night using the 24" dob under dark skies. M1 has always been a bit of ho hum object to observe for me, easy to see but detail lacking- until the other night. Flipping back and forth from no filter, UHC OIII revealed a startling difference- with the OIII. The UHC enhanced its "brightness" but no real structure seen. Going to the OIII I was shocked- a large "spike" of nebulosity appeared along with a shorter attached spur. There was also some intermittent finer detail in the body. I was far from optimized on this object- using 8.7mm EP- I think a hair lower mag will preserve the spikes and brighten it up so to speak. All I know is this is now a goto object for me and once the 17.3 Delos and Docter 12.5mm adapter issues are solved I think there's more to come. M1 is well worth spending time on IMHO and I cant wait to get on M97, the Owl nebula with this telescope.
  14. Without the extender available I would not own this eyepiece personally as I too dislike floating eye relief. With it though it is superb.
  15. maybe they just put it together with what they had laying around... maybe an H130 sec
  16. Is this an imaging scope? sometimes they push the focus out using shorter tubes etc. OOUK does this on their VX's unfortunately. 10.5 inches is excessive IMHO. It should be 1/2 dia of tube + focuser height +.5" roughly
  17. what is the actual measured distance from the centre of the sec to the focal plane? I ask because I've done these numbers many times same as you. One thing that the calcul;ator thankfully shows is the relationship between aperture, f ratio and central obstruction vs illumination. ie my 24" runs 19% CO at F4.1.
  18. What is the measured distance to the focal plane? I guessed 180mm.
  19. Here is a guestimate of your scope with the stock 58mm minor axis secondary Remember that illumination may drop to 70 % for visual use. Off-Axis Illum. Light Loss 0.00 mm 100.0% 0.00 mag 2.00 mm 100.0% 0.00 mag 4.00 mm 100.0% 0.00 mag 6.00 mm 100.0% 0.00 mag 8.00 mm 100.0% 0.00 mag 10.0 mm 100.0% 0.00 mag 12.0 mm 100.0% 0.00 mag 14.0 mm 99.58% 0.00 mag 16.0 mm 96.38% 0.03 mag 18.0 mm 91.96% 0.09 mag 20.0 mm 86.91% 0.15 mag 22.0 mm 81.50% 0.22 mag 24.0 mm 75.87% 0.29 mag 26.0 mm 70.12% 0.38 mag Max field for visual use with 68 deg eyepiece and 7mm exit pupil = 20.76 mm radius. offset = -2.43 mm parallel to focal plane
  20. Magnus, the primary does need a bit of room to move, all my reflectors are like this- my truss dobs can move at least 1/8" laterally in any direction. Have you checked out secondary sizing vs illumination with Bartels excellent calculator? It gives insight with respect to central obstruction size vs illumination. http://www2.arnes.si/~gljsentvid10/diagonal.htm
  21. A quick report on one of my favorite objects, the Eskimo nebula, NGC 2392. This object takes mag well and filters can enhance brightness, however the fine radial filaments tend to disappear when using them. Last night in the 24"/PCII/10Delos this exactly happened. With no filter those fantastic filaments in green appeared as well as a new to me feature- a bright green,not quite round inner ring was observed around the central star. It also had a couple of shades of green now. I need to get the 8mm Delos for more mag, 287x was just not quite enough. A great view but there is more there. The UHC/OIII killed the filaments and inner ring oddly, not sure why. This object is a showpiece, gift of the sky IMHO and well worth spending time on. Many scopes do a really great job showing it, try upping the mag and with no filter. NGC 891 showed as a bright edge on galaxy with a massive dust lane cut through it, again at 287x @ 2mm exit pupil, but I like more eye illumination, next time I'll try lower mag on it, maybe a 15mm effective fl eyepiece. So much to see out there.
  22. Yes, UHC it is! for the Flaming star anyway- I flipped back and forth on it with the filter slide- the OIII killed it for me. You can also make it out no filter. I take filter recommendation with a grain of salt these days- I try them all ie IC1318, listed as hb I think but both the OIII/UHC are go tos. The Hb is top for Barnards Loop though, to my eyes, California neb too. For me the list of Hb targets is small. I dislike the Cocoon neb lol! not really a showcase object IMHO. If you can find a good DGM NPB filter, ours is, they can be a great lower cost option. They might show stars a bit differently but the Flaming Star/HH etc are no problem in it. Cold is cold! Last night just had the long johns on over jeans but no gloves... my bad. Those Al ladders will suck the life right out of bare hands. I hope your family member is OK and you can get out to obs. BTW your scope has potentially the best mirror support for cold weather IMHO.
  23. What can be said is the excellent Televue plossls have great scatter control vs the other mentioned eyepieces. The TV plossls are my goto's for certain objects like Horse Head last night in the 24", both the 32mm TV and 25mm TV plossls are excellent for this and much more. Under the best of conditions here these eyepieces will pick out the HH with no filter. I'm glad you are now happy with these eyepieces Alan.
  24. Excellent! Great report and also images S&S! Perfect description of the HH and other targets. You are now ready for a nice little challenge seeing as you were in the M52 area... the Bubble is not hard to see, but harder to get detail out of. This however is not the challenge. In your 20" SH2-157-the Lobster Claw will be readily visible as well as a nice LBN. This is the challenge. The Wizard also has more to offer- congrats for getting it straight away! You hit a couple of favorites- the beautiful Flaming Star- are you sure an OIII is your friend here? Again congrats for a fine cold weather session, I was out myself last night observing the HH etc with temps dipping below -15c. Some of the best conditions are in this weather, particularly if there is little or no snow. Eagerly waiting reports S&S!
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