<2 hour drive to gray/black zone “Contrast is not everything. Outside of aperture, contrast is the only thing” -Carl Zambuto
-DannyMy warehouseMy Channel
Celestron 8SE Dobstuff 13.1": Swayze refigured Coulter mirror, 6 pt mirror cell (2 pt edge support) and CF focuser board made by me StarBlast 4.5 ST80/PortaMount II Zhumell 20x80/Oberwerk 15x70 on a Seronik-style tripod boom mount Hubble Optics 18 inch F/4 mirror.
Equatorial Newtonians, 20" and 14" "The purpose of life is to be defeated by ever greater things." - Rielke
10" F/4.7 Modified Skywatcher Reflector, 38mm Orion Q70, 17mm Modified Ultima LX, 10mm TeleVue Delos, 7mm Pentax XL.
Quote:I have a fan that I got with the scope that I can use, but I was also thinking of getting a larger fan with lower RPMs while maintaining the CFM rating. I have heard that he lower RPMs help with vibration. By suspending the baffle I figured that I would need something more rigid, especially if I use a larger fan.
12" Harden Optical "Bubba"
16" Meade Lightbridge "Beached Whale"
70mm ETX-AT "Peashooter"
& a slew of EPs, Baaders, Meades,a lonely Nagler ,Star party specials-GSO's and TMB's
...It is better that my wife knows the VALUE of my equipment than the PRICE of my equipment.
Quote: I just re-purposed an old plastic "For Sale" sign,
Quote:I've also used foam-core poster board. Very light and stiff and easy to cut.
Meade 16" f/4.5 Lightbridge M42 w/Paracorr & "Crossbow" EQT-200 Equatorial Platform
Meade AR-6 w/10:1 Dual Speed Crayford Focuser
Meade ETX-125 Terabeam/Wegat
Orion ST80 w/single speed Crayford Focuser
CGEM Hypertuned by Deep Space Products
Quote:Quote:I've also used foam-core poster board. Very light and stiff and easy to cut. I had thought about recommending that - it is certainly stiff and strong enough -but was concerned about its durability, especially the fact that is covered with paper which would suffer from the humidity of dew-laden air. Giving it a good coating of spray paint might give it adequate moisture resistance though.What is your experience?
Quote:but the foam in the core should be dew resistant.
Quote:Mine is made from 3mm thick PVC; rigid enough, yet lightweight. Weatherstrip on the edge seals it around the OTA. No noticeable vibration from the SilenX fan.The first photo is the baffle for an 80mm fan. The rest of the photos show the 120mm version.
Quote: ..... It seems to me that ATM is a frame of mind, rather than just doing a project.Jeff
Quote:Yes, a large (120 mm) slow fan is best.
Quote:Quote:Yes, a large (120 mm) slow fan is best.Why would this be? I think the two factors are damping, and I understand higher frequencies die quicker than low frequencies, and interaction with the surrounding materials - which would be on a case-by-case basis.