Dew on the Primary???

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helicon United States of America
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Dew on the Primary???

#1

Post by helicon »


I had a good view of the Andromeda galaxy which I shared my sister and my nephew who were over for dinner last night. I set up the scope at 5:00 and by 5:30 the views were pretty good - not entirely dark but M32 could clearly be seen. In the state of partial light M31 appeared like a comet.

I decided to leave the scope out over night and get up at 4:20 for a morning session. Ursa Major was well placed for observation but as I slewed towards M81/M82 I noticed the stars had rings around and them and were faint. The culprit was dew on the primary, which for me has been a very infrequent experience. Over night the humidity increased from 30% to 75% - I guess that was the problem. Should have used the fan I guess...
-Michael
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
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Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
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Re: Dew on the Primary???

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Post by notFritzArgelander »


I swear by the hairdryer. :)
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Dew on the Primary???

#3

Post by turboscrew »


notFritzArgelander wrote: Thu Dec 02, 2021 5:15 pm I swear by the hairdryer. :)
Not at? :lol:
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helicon United States of America
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Re: Dew on the Primary???

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Post by helicon »


Since my hair is thinning on top I don't need a hairdryer anymore....
-Michael
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
Binoculars: Celestron SkyMaster 15x70, Bushnell 10x50
Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
Camera: ZWO ASI 120
Naked Eye: Two Eyeballs
Latitude: 48.7229° N
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Re: Dew on the Primary???

#5

Post by KathyNS »


Yes, the fan will delay dew formation. I run mine all the time. After the fact, a hair dryer is the best tool for de-dewing.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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Re: Dew on the Primary???

#6

Post by notFritzArgelander »


turboscrew wrote: Thu Dec 02, 2021 5:54 pm
notFritzArgelander wrote: Thu Dec 02, 2021 5:15 pm I swear by the hairdryer. :)
Not at? :lol:
Never at. It's too good a friend. ;)
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Dew on the Primary???

#7

Post by notFritzArgelander »


helicon wrote: Thu Dec 02, 2021 6:00 pm Since my hair is thinning on top I don't need a hairdryer anymore....
Neither do I. What hair I have I keep close cropped. My hair drier is battery powered and a dedicated astronomy accessory. :)
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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