Orion ED80 - AT Voyager with TNT,pier ext.,Vixon steel tray and Manny's mod.
Omni 120 cg4 with Orion pier ext. and RA drive, Binotron-27 (25mm & 17mm Sterlings)
Orion XT10(Original F/5) SkyStopper Equatorial Platform
Jason Constellation Model 311(Modified with 1.25"Crawford Machine focuser & rings)
Quote:Then the DGM filter - drum roll please - and the filaments were barely seen at all - dang! So my twenty year old Lumicon OIII is the clear winner on the Crab, but then I had the sudden and wild notion to stack the filters to see how they worked together...To my surprise, the view through the stacked filters was superior to the Lumicon OIII by itself. The Crab showed the main two filaments well along with a faint but distinctly lacy background overlain on a soft nebulous background glow. The view was not perceptively darker than with a single filter, which at first surprised me, but with a moments thought made sense - the transmission lines of both filters must line up pretty well, but with just enough difference to enhance the Crab's filaments. Pretty cool!
Meade 12.5" F/6 Research Grade
1971 Criterion RV-6
Orion Observer 70mm Refractor
Homemade 4" f/12 reflector (being rebuilt)
10" f5.6 Bartels Dob Celestron NexStar 8SE Orion ST120 Sky-Watcher Pro 100ED Celestron 102GT Edmund 4 1/4" Palomar Jr. (Thanks, Dad. I'll never forget) Twilight I & Oberwerks Tall Agena 38mm SWA Konig II 32mm 2", GR Konig 6.7mm ES 24mm 68*, 11mm 82* Meade 20mm RG WA Baader Hyperion 17mm, 13mm, 8mm Meade 7mm RG Ortho SkySafari Pro w/SkyFi
Quote:It's virtually guaranteed that the bandpasses of the two filters differ. And so the combination of the two will result in a narrower resultant bandpass which the two share in common.
Quote:Interesting. Presumably all interference filters are different and stacking them is averaging; like a bunch of musicians playing the same tune sound cleaner than each one ever could. I had never thought of this though. If I ever get to observe again with this weather, I may stack my 2 and 1.25" Orions - surely they are not identical either.Howard, any idea why the sky was brighter than usual?
10" F/4.7 Modified Skywatcher Reflector, 38mm Orion Q70, 17mm Modified Ultima LX, 10mm TeleVue Delos, 7mm Pentax XL.
Quote:Lets not forget that the DGM O-III has a WIDE band pass and compares to the Orion Ultrablock very close in performance.
Remember that comparison we did Eric?, (Beatlejuice).
22" and 14" Dobs on EQ platforms and Deep Sky Observing