C14 XLT, CGE NexSTAR 11 GPS + 120ST APM/TMB 130/780, AT111EDT SW EQ5P (2" Tripod/20" Pier) XW's 3.5mm - 20mm, 28mm RG, TVZ 2-4 ES14mm/20mm 100° UWAN 28mm,Paragon 40mm, TV55, Meade 2X 2" TeleXtender TMB SMC 4mm-16mm, Pentax 0-18, CZJ 0-25 EarthWin PFS-DBSE, WO DuraBright, AP MaxBright TV Bino's Bino Sets X 2: UO H.D's ~ 5mm-18mm, TV Pl.(NJ's)7.4mm - 40mm 16T5's, 24mm Pans Canon 18X50 IS Pentax 7X35 (9.3°
Quote:My current Dew Strap position is closer to the lens cell, but has to travel through the Kruppax Dew Shield which never makes direct contact with the lens cell Itself. My guess is that the minimal heat transferred to the inside of the Dew Shield is sufficient to keep the Dew away.
Quote:Placing the shorter Dew Strap directly behind the Dew Shield is more commonly recommended, but I'm wondering If this is time effective?
http://www.astrobin.com/users/orion69/ TS 150 mm APO Triplet, Feather Touch 3.5" focuser, Micro Touch Focusing System CGEM on custom made platform Atik 383L+ mono, Atik filter wheel, Baader LRGBC + narrowband filters SX Lodestar + TSOAG9 Dew-Not heater
Mike Lynch Frankfort KY USA
Quote: Can you post a link where is that recommended? IMHO placing Dew straps between lenses could lead to deteriorating image quality because it could compromise scope's thermal equilibrium.
Quote:One short discussion on CN here:http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3587309/Main...
Quote: Knez, All the diagrams I've seen have an SCT as an example and the Dew Strap is placed behind the Corrector. Also, the Manufacturers measurements and specs insinuate that the OTA and not Dew Shield is the proper placement.i.e. in the Specification Table (D) they state that a DN006 is "best for" a 5" Scope. That would barely fit my APM 130/780 OTA let alone the Dew Shield. Also in "B. Selecting a Dew-Not Dew Heater" They state "measure the circumference of your telescope tube (then X by 3.14). You have me confused as placing the Dew Strap behind the Dew Shield isn't necessarily between the lenses?
Quote:IMHO placing Dew straps between lenses could lead to deteriorating image quality
Quote:Quote:IMHO placing Dew straps between lenses could lead to deteriorating image quality
I have asked about this statement and what it means before and did not receive an answer.
"between lenses" what?.... does this mean between objective lens and eyepiece lens?
Quote: If you put dew straps anywhere between front and rear lens then it's .... between lenses.
Quote:Wrapping the heater around the cell, or 'between the lenses', as it were, has no adverse effect. Again, around the dew cap, around the cell, or around the tube just behind the objective/corrector, is all much the same thing.The amount of heat (nominally) being applied is merely compensating for that lost to the cold heat sink of the clear sky, keeping the optic temperature not much different from the ambient air temperature. It's not like you're pumping such a flux of heat into the scope that thermals or optic warping can result.