"The heavens declare the glory of God; the skies proclaim the work of his hands." Psalms 19:1
C14 EdgeHD, C11 EdgeHD Zhumell 8" f/6 Newt AP1200GTO, CGEM DX, CG5-ASGT Rob Miller Tri36M tripod Canon Rebel XS, Atik 314L+, DSI pro I,II, QHY5L-II SX 7 FW with Astrodon LRGB, Ha 5nm Hutech OAG5, Rainbow Optics Grating Scorpio Observatory
Quote:kerryr, it will not travel. ive had a 12" dob before and built a cart for it and it worked out just find the only thing im concerned with is what scope would be better for dso. i have a celestron cg5 goto ( its new ) just not sure that 11" would be stable enough, a lot of real experienced people on these forums clam its really not too bad for visual. i would hate to spend $1800 then find out its too shaky for me, i already have a meade 8" sct. and like it but i wont more aperture. the 9.25 would be a nice scope but $900 more for just 1.25" of aperture i just cant see.
Money can't buy happiness, but it sure makes living with misery a lot easier!
Quote:The CG5 will be too shaky for C11 and not stable.
Scopes: 12.5" Dob w/Lightholder mirror, Astro Tech AT8RC, TPO 8" Imaging Newt, Intes MK-67 Deluxe, Tak FS-60CB, Tasco 10TE, Coronado PST
François C8 f/10, lunt 102 mm f/7 ED. SkyWatcher 12" f/5. pentax XW 40, 30,10 delos 14, 8, 6, 4.5. Vixen lvw 22 Brandon 12, 8 TV 2x barlow Closer and closer to the ideal eyepiece collection, but never reaching perfection
Uncle Rod Uncle Rod's Astroblog: http://uncle-rods.blogspot.com/
Orion xx14g Dob CPC 1100 w/Skywatcher 80ED piggybacked Coronado PST TMB 92L refractor AT Voyager mount Nexstar 6/8 mount Denk Big Easy binoviewers Oodles of eyepieces and other optical gadgets Past scopes Meade 8" reflector and 8" SCT
Whenever I have come into large sums of money in my life, I always put half of it aside to spend on fast cars and the pursuit of loose women.
I put aside the other half to spend frivolously.
Quote:Some will say that you can use a reducer in the SCT, but if you attempt to use 2" eyepeices with the reducer, the scope will work at less than even the 11" aperture.
Quote:But it's not true. Any "aperture loss" is completely insignificant
Quote:And by the way, the 12" Go-To Newt that Orion sells is f/4.9, not f/4.5The coma of the standard all-spheical SCT is in fact the same as the coma of an f/5 reflector for the same size true field.
Quote:Otherwise, your advice is spot on...except...the coma in an SCT is NOT comparable to that in a dob. A Dobsonian of the usual focal ratio for a 12-inch, which is what we are discussing, is f/4.5 and will show appreciably more coma than an SCT.
Quote:F/5 is not f/6, and field curvature is correctable with the f/6.3 r/c.
Quote:OK Jon...well, let's just agree to disagree. If we are...not really sure.
Friends call me Duane. Compustar C14, Leo Henzl's Custom C8, 6" Refractor Adv. GT mount, 6" F5 Omni XLT Newt., LXD-75 F4 Imaging SN8, Meade 8" F6 Newtonian, EX Dynamax DX6, RV-6 ETX-90 Astro, Meade 2045 4" SCT, B&L 4000 Vixen/Celestron 80mm F11 JC Penny 60mm AZ/ALT Refractor Binos 25x100
Quote:I like disagreeing with you Jon, it is the prospect of possibly AGREEING with you that I find frightening!
Keep on looking up...
Meade 60mm f/11.7 achro refractor
Vernonscope 94mm f/7 Brandon triplet APO (A-P Optics)
Orion EON 120mm f/7.5 ED APO
8" f/6 Newtonian (Mike Spooner mirror)
Meade 10" f/10 SCT
12" f/5 Meade LightBridge Dob/Newt
Many eyepieces and accessories
Always lusting after large MCT, but never buy one
Quote:Quote:I like disagreeing with you Jon, it is the prospect of possibly AGREEING with you that I find frightening! Touche... I know it would be difficult for you to agree with me... in public that is. And yet we both know you've had that 12.5 inch F/4.5 Truss Dob for years and are a big fan of the 4.5 inch F/4 Starblast, particularly when there is the possibility of using a Paracorr with it.. Jon
Rod, Jon, & I go WAY back, deep into the jungle of the SAA days...
Quote:Quote:AwRod, Jon, & I go WAY back, deep into the jungle of the SAA days... Hey! Now they KNOW how old we are. Didn't I first meet you on FIDONET ASTRONOMY?! Aperture reduction? Yeah. Believe it or not, I was mildly contemplating a 16 - 20-inch Dob not long ago. But now...I don't think so. 12-inches is just fine, I've had Old Betsy for twenty years and we know each others' quirks.
Quote:AwRod, Jon, & I go WAY back, deep into the jungle of the SAA days...
Quote:I just posted over there. Hard to say what it is...but it may be a job for good, old Mane and Tail.