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Pages: << 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | >> (show all) rwiederrich Goldfinger Reged: 11/17/05 Loc: Always Dark skies of Belfair W... Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: Stacy]       #5473717 - 10/16/12 06:00 PM Edit   Reply   Quote Quick Reply   Quote: Ah yes, image scale. I remember being curious about that when I had my f6 newt set up next to my f10 sct. Mars looked almost twice as big in the sct vs. the newt at the same magnification. It's really best to have several scopes of diferent focal ratios and diameters so you don't miss anything. Precisely why I have a 5"f/9 and a 60mmf/16 and 50mmf/5 mounted on my 10"f/15. I am making the mirror for my 17"f/8..so I can have good light grasp with good image scale. Rob Post Extras:       square_peg Postmaster Reged: 03/26/04 Loc: Maple Valley, WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: MadHungarian]       #5473854 - 10/16/12 07:19 PM Edit   Reply   Quote Quick Reply   Quote: But why is it that the SCT hasn't worked as well for you for this? I'm not an expert on SCT's but I'm not sure I've ever seen one that could keep up with the falling nighttime temperatures we have here in the NW. With the closed tube they're just always warmer than ambient. Post Extras:       square_peg Postmaster Reged: 03/26/04 Loc: Maple Valley, WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: trainsktg]       #5473856 - 10/16/12 07:19 PM Edit   Reply   Quote Quick Reply   Quote: Nice Moon shot! MSHSP Pt 6...? I can't believe this thread has gone on for so long. Keith (been gone a few years) We're a bunch of chatty Cathy's. Long time no see, Keith. I hope you and Captain Nemo are faring well. Post Extras:       zerro1 Postmaster Reged: 08/02/09 Loc: Smokey Point , 48.12°N 122.25°... Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: bluedandelion]       #5474129 - 10/16/12 10:24 PM Edit   Reply   Quote Quick Reply   Quote: So I have crossed over into APO land finally. A TMB130SS (used and in great shape) is on its way! I wasn't going to spend any astro dollars for a while, but I had some good fortune and my better half consented to the purchase as well. Second reason is that I have been most productive imaging with the small SV85s. Seeing and weather conditions never seem to favor the C925. I may just keep it for visual and planetary work and use the 130ss for imaging. It should be here Friday. Ajay Congrats of the scope! I know what you mean. I have an 8" SCT + a 6" RC. mirror scopes are tinker toy's for sure. It'd be one thing to have one setup in an observatory where you could get it dialed in and not move it, but when you do a lot of mobile imaging, or setup and break down every session it adds more complexity to an already complex process. not sayin I don't try, but it's certainly hit and miss in this region. (course since I just got my Atlas back from Ed Thomas, I'll be tryin the next chance ) Post Extras:       Stacy Star Partyer Reged: 09/15/02 Loc: 48.0153° N, 122.0625° W Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: square_peg]       #5475067 - 10/17/12 01:12 PM Edit   Reply   Quote Quick Reply   Quote: I'm not an expert on SCT's but I'm not sure I've ever seen one that could keep up with the falling nighttime temperatures we have here in the NW. With the closed tube they're just always warmer than ambient. Them's fightin werds! Seriously, a tube cooler helps, but only takes you so far. I have had similar issues with a closed tube newt, depending on the night. Post Extras:       square_peg Postmaster Reged: 03/26/04 Loc: Maple Valley, WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: Stacy]       #5476080 - 10/17/12 11:18 PM Edit   Reply   Quote Quick Reply   I've heard of active cooling systems for SCT's. The trouble is that the air has to be filtered because it's more trouble to clean the optics of a cat than it is to clean a dob. And Lymax type coolers have to be removed to do any observing so they're not actively cooling throughout the night. I recall one night up at Table where my 8" dob was throwing up better images of Jupiter than the 14" Celestron SCT set up next me. The SCT owner said is was 'bad seeing' but it was clear to me that the problem was heat (everyone with cooled dobs and refractors had good seeing). Just the same, I'll happily take all the eyepiece time I can get on your SCT. Post Extras:       bluedandelion Carpal Tunnel Reged: 08/17/07 Loc: Hazy Hollow, Western WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: square_peg]       #5476108 - 10/17/12 11:44 PM Edit   Reply   Quote Quick Reply   Quote: Quote: But why is it that the SCT hasn't worked as well for you for this? I'm not an expert on SCT's but I'm not sure I've ever seen one that could keep up with the falling nighttime temperatures we have here in the NW. With the closed tube they're just always warmer than ambient. Here's how I did it. I have thin sheets of open cell foam as a filter at each fan and vent. Can't see any dust on the mirror after a year and a half of use. The foam was dirty on the outside during a recent inspection which means they were functioning as intended. More detailed pictures of the mod are at the link in my signature. From some reading I did today cooling the lens of a 5 inch triplet APO can take more than an hour. Ajay Post Extras:       bluedandelion Carpal Tunnel Reged: 08/17/07 Loc: Hazy Hollow, Western WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: zerro1]       #5476109 - 10/17/12 11:46 PM Edit   Reply   Quote Quick Reply   Quote: Congrats of the scope! I know what you mean. I have an 8" SCT + a 6" RC. mirror scopes are tinker toy's for sure. It'd be one thing to have one setup in an observatory where you could get it dialed in and not move it, but when you do a lot of mobile imaging, or setup and break down every session it adds more complexity to an already complex process. not sayin I don't try, but it's certainly hit and miss in this region. (course since I just got my Atlas back from Ed Thomas, I'll be tryin the next chance ) Let me know how you like Ed's work. I've been thinking of getting mine redone, but after the recent splurge I will wait a bit. Ajay Post Extras:       square_peg Postmaster Reged: 03/26/04 Loc: Maple Valley, WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: bluedandelion]       #5476138 - 10/18/12 12:19 AM Edit   Reply   Quote Quick Reply   That's nice work, Ajay. How are they configured, one blowing in, one blowing out? Or two blowing in and a pressure relief? Post Extras:       trainsktg Post Laureate Reged: 08/23/05 Loc: Pacific Northwest Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: square_peg]       #5477196 - 10/18/12 03:13 PM Attachment (11 downloads) Edit   Reply   Quote Quick Reply   Quote: Quote: Nice Moon shot! MSHSP Pt 6...? I can't believe this thread has gone on for so long. Keith (been gone a few years) We're a bunch of chatty Cathy's. Long time no see, Keith. I hope you and Captain Nemo are faring well. All is well with the Nemoscope, Tom (and Mike and Rob ). Some scopes are gone now, the giant 8" f8 being one (although its in the hands of another local CNer), as well as a bunch of high end EPs and stuff that I just never use. OTOH, the 8" f26 classical cass. is now back here in Oregon with me, and a Questar 3.5 has just recently joined the stables along with a Lunt LS60 from a few years ago. Observing, until now, has been non-existant, but that's changing now that I'm back home. Work in North Dakota is on the radar though . For those that don't know what the heck a Nemoscope is, see below... Keith Post Extras:       bluedandelion Carpal Tunnel Reged: 08/17/07 Loc: Hazy Hollow, Western WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: square_peg]       #5477765 - 10/18/12 09:20 PM Edit   Reply   Quote Quick Reply   Quote: That's nice work, Ajay. How are they configured, one blowing in, one blowing out? Or two blowing in and a pressure relief? They both blow in. I have vents on the rear casing as well as on the tube near the corrector. All in all this opens up the interior of the tube quite a bit and the scope stays close to ambient once it cools. Initial cooling takes about 20-30 minutes. With a dewshield and the vents near the corrector, dewing is much reduced. See this link for pictures on where the vents are and the really sophisticated tools I used. Should give Kerry a good laugh Ajay Post Extras:       Sky Captain Metal Whisperer Reged: 11/07/04 Loc: Loc: Loc: Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: bluedandelion]       #5478146 - 10/19/12 01:37 AM Edit   Reply   Quote Quick Reply   Quote: See this link for pictures on where the vents are and the really sophisticated tools I used. Should give Kerry a good laugh Ajay No laughing here Ajay, your end result is great. I was impressed when you showed me what you had done. Post Extras:       bluedandelion Carpal Tunnel Reged: 08/17/07 Loc: Hazy Hollow, Western WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: Sky Captain]       #5478611 - 10/19/12 11:12 AM Edit   Reply   Quote Quick Reply   Thank you Kerry. I personally think the drill is worth a laugh nonetheless. Ajay Post Extras:       Stacy Star Partyer Reged: 09/15/02 Loc: 48.0153° N, 122.0625° W Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: bluedandelion]       #5478782 - 10/19/12 12:51 PM Edit   Reply   Quote Quick Reply   Quote: They both blow in. I have vents on the rear casing as well as on the tube near the corrector. All in all this opens up the interior of the tube quite a bit and the scope stays close to ambient once it cools. Initial cooling takes about 20-30 minutes. With a dewshield and the vents near the corrector, dewing is much reduced. See this link for pictures on where the vents are and the really sophisticated tools I used. Should give Kerry a good laugh Ajay Fantastic work Ajay! What about filtering? My Lymax uses a replaceable filter to keep the inside of the cat clean. It looks like you could easily add external filters to your system? Anyway, I think I might attempt something similar on my own, that is if I can't recruit you to help me with it? Post Extras:       bluedandelion Carpal Tunnel Reged: 08/17/07 Loc: Hazy Hollow, Western WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: Stacy]       #5479770 - 10/20/12 12:26 AM Edit   Reply   Quote Quick Reply   Stacy, Thanks. I have all the work documented on this CN thread. A lot of the inspiration and help came from our own Tanveer Gani's work. The above link has a reference to his effort as well. Let me know when you are ready for the surgery. We could meet up or chat via phone. Ajay Post Extras:       bluedandelion Carpal Tunnel Reged: 08/17/07 Loc: Hazy Hollow, Western WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: bluedandelion]       #5479772 - 10/20/12 12:29 AM Edit   Reply   Quote Quick Reply   The TMB arrived today. I was a little surprised by its size but it is a little easier to manage than the 9.25 SCT I think. Seems to be in excellent shape, but haven't had a chance to play with it much. Ajay Post Extras:       Stacy Star Partyer Reged: 09/15/02 Loc: 48.0153° N, 122.0625° W Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: bluedandelion]       #5479865 - 10/20/12 02:49 AM Edit   Reply   Quote Quick Reply   Quote: The TMB arrived today. I was a little surprised by its size but it is a little easier to manage than the 9.25 SCT I think. Seems to be in excellent shape, but haven't had a chance to play with it much. Ajay Woot! New scope That may explain SOME of this rain lol. Post Extras:       bluedandelion Carpal Tunnel Reged: 08/17/07 Loc: Hazy Hollow, Western WA Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: Stacy]       #5480744 - 10/20/12 05:41 PM Edit   Reply   Quote Quick Reply   Quote: Woot! New scope That may explain SOME of this rain lol. Explains all of it. I bought this last Sunday. You can see the scale of the scope from the fact that it is riding an Atlas. I peered though it at a distant tower with some antennas on it. The sharp edge of a gray antenna against a brighter white sky showed no color along its edge. Of course I don't know how long I will have to wait to try it on some stars. The 3.5 inch Starlight focuser is smooth. The entire scope is really well built and rather substantial. For a change I have a front heavy scope. Things should balance nicely with the addition of imaging equipment. Ajay Post Extras:       Stacy Star Partyer Reged: 09/15/02 Loc: 48.0153° N, 122.0625° W Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: square_peg]       #5481223 - 10/21/12 12:13 AM Edit   Reply   Quote Quick Reply   Quote: I've heard of active cooling systems for SCT's. The trouble is that the air has to be filtered because it's more trouble to clean the optics of a cat than it is to clean a dob. And Lymax type coolers have to be removed to do any observing so they're not actively cooling throughout the night. I recall one night up at Table where my 8" dob was throwing up better images of Jupiter than the 14" Celestron SCT set up next me. The SCT owner said is was 'bad seeing' but it was clear to me that the problem was heat (everyone with cooled dobs and refractors had good seeing). Just the same, I'll happily take all the eyepiece time I can get on your SCT. That's really the deal. When the seeing is good, my scope rawks. Cool down or no, it throws up some ubertackolous sights. The subtle dust lanes in the sombrero, the core of m13, the multifacited rings of Saturn, really awe inspiring poopedoo. Did I say that? You get the idea. When the seeing is bad, well, I jjust join the pack. Remember Sunrise last fall? We were all scratching our heads for awhile lol. Add my CF tube and that just exacerbates the issue, great for imaging stability, cool down not so much. But really, if things start looking murky, a quick check of my observing mates with dobs and refractors reveals the real issue.... YMMV Post Extras:       trainsktg Post Laureate Reged: 08/23/05 Loc: Pacific Northwest Re: Pacific NW Mt St Helens EternaThread Pt 6 [Re: Stacy]       #5481279 - 10/21/12 01:05 AM Edit   Reply   Quote Quick Reply   I just learned some new words tonight . Keith Post Extras:       Pages: << 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | >> (show all)

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