Speed Posted March 13 Share Posted March 13 Hi I have read conflicting reports about how to bring a refractor inside from the cold Some say uncapped others say capped and inside a case or a bag to prevent dewing up Advice would be appreciated Speed Link to comment Share on other sites More sharing options...
Nightspore Posted March 13 Share Posted March 13 I take mine back indoors capped in a bag/case. Although, if after a particularly dewey session, I uncap the objective and let them dry naturally. Otherwise I let them dry capped in the in their respective bags/cases. I've only known my 80ED (above) still to be dewed over the following night. I'd left it in its case and capped. As a consequence I observed the comet NEOWISE with my 72 ED. +Bino-viewer 1 Link to comment Share on other sites More sharing options...
+Stu Posted March 13 Share Posted March 13 I've taken some advice from some other members and bring it in with the cap off and a desiccant cap in the focuser if I've been using it for visual. If I've been imagining it's cap off and imaging gear left attached until the next morning. Nightspore and +Bino-viewer 2 Link to comment Share on other sites More sharing options...
+Bino-viewer Posted March 14 Share Posted March 14 As @Nightspore says. Exactly that. What you don't want is to store a 'wet scope' in a warmer environment (indoors) as this can lead to big problems like mould / fungal ingress within the optics. Not good. Let it dry out and gradually reacclimatise. But be careful not to 'thermal shock it' - ie subjecting it to a 25ºc temperature change, from outdoors to indoors, and vice versa, particularly if you have delicate optics, such as Fluorite for example. Nightspore 1 Link to comment Share on other sites More sharing options...
Speed Posted March 14 Author Share Posted March 14 Hi Thanks for the info there seems to be two trains of thought here 1 caps off 2 caps on I contacted Takahashi Europe and this is what they said After use, when you bring your FC-100DZ into the house, do not replace the front caps on the objective side and the rear caps on the eyepiece side. Leave your FC-100DZ dry all day to evacuate internal humidity. Preferably on a table, optical tube horizontal, to avoid the entry of dust. Moisture should never be confined within the optical tube. I was a little concerned about the objective misting up when bringing it in and again this is the reply Hi Remi Does it matter that the objective lens will dew up on the outside when I bring the telescope inside without the cap on The reply It does not matter. The important thing is to dry the tube well externally and internally. The enemy of optics being confined condensation. Best regards, Rémi Link to comment Share on other sites More sharing options...
+Bino-viewer Posted March 14 Share Posted March 14 With the FC-100's i'd keep it in its cold case when you bring it indoors (have the case outside while you observe) for 30-60 mins or so with the lid ajar / unzipped a bit just to let it slowly acclimatise. A good idea is to keep lots of silica gel sachets in the case to keep moisture levels down. Then once its slowly warmed up take it out and let any leftover moisture / condensation evaporate. This way you won't be thermally shocking the optic. This scope is a Fluorite doublet (the 2 elements are very close together indeed) and the more sensitive Fluorite element is BEHIND its mating element (not facing outwards) so this gives the fluorite some protection. This is called a Steinheil design. Other fluorite designs do it the other way around so the fluorite is facing forwards : a Fraunhofer design, and a little more care is needed. One thing you don't want to do with Fluorite is thermally shock it, for example use a warm hair dryer on it to help evaporate dew etc. This may shatter the lens. My own scope has a Fluorite element, although its an oiled triplet design, with the fluorite nicely protected and effectively 'sandwiched' in the middle. But i'm still very careful with it, and try not to get complacent or anything. But its good practice to take great care with these expensive optics, the last thing we want to hear about is a big mishap and damaged optics. Lots of silica gel sachets in the case around the optics and tube and focuser are a good plan going forward. HTH, Rob 🙂 +Streetbob 1 Link to comment Share on other sites More sharing options...
Speed Posted March 14 Author Share Posted March 14 Hi bringing it inside in the case seems like a very good idea as is silica gel I also have a Desiccant Cap that I use as well +Bino-viewer 1 Link to comment Share on other sites More sharing options...
+Streetbob Posted March 14 Share Posted March 14 Very informative thread. I have now purchased a desiccant cap.👍 Link to comment Share on other sites More sharing options...
Nightspore Posted March 15 Share Posted March 15 I've got to worry about fungus? WTF? Thanks guys! lol Link to comment Share on other sites More sharing options...
+Bino-viewer Posted March 15 Share Posted March 15 >I've got to worry about fungus? WTF? Thanks guys! lol< In this climate..........most definitely !! 😀 Link to comment Share on other sites More sharing options...
philjay Posted March 15 Share Posted March 15 Bring it indoors uncapped and leave the dew to dissipate naturally. If you take the case out and leave it open, that will get wet with dew also, so putting the scope in a wet case at the end of your session will only make matters worse. Same with eyepiece cases. By all means take them outside and leave them open but when you bring it all back indoors open the case remove and uncsp all eyepieces and let the case and eps all dry naturally. +Streetbob 1 Link to comment Share on other sites More sharing options...
+Streetbob Posted March 15 Share Posted March 15 New Des Cap arrived and fitted. Nightspore and +Stu 2 Link to comment Share on other sites More sharing options...
Speed Posted March 15 Author Share Posted March 15 Same as the one I have from FLO 👍 Link to comment Share on other sites More sharing options...
+Bino-viewer Posted March 15 Share Posted March 15 5 hours ago, philjay said: Bring it indoors uncapped and leave the dew to dissipate naturally. If you take the case out and leave it open, that will get wet with dew also, so putting the scope in a wet case at the end of your session will only make matters worse. Same with eyepiece cases. By all means take them outside and leave them open but when you bring it all back indoors open the case remove and uncsp all eyepieces and let the case and eps all dry naturally. If its a Fluorite element refractor scope and you do that, you will risk thermally shocking it with a big change in temperature. With respect, this is not a good idea. I would urge caution. If its a non fluorite scope however, the risk is mitigated somewhat. Regarding the case, yes, once the scope is out of there and mounted, close and lockup the case. It only dews up on the outside of it then, but the inside will be nice and cold, and dry as its full of silica gel sachets. Link to comment Share on other sites More sharing options...
Speed Posted March 15 Author Share Posted March 15 Just ordered some silica gel bags 👍 Link to comment Share on other sites More sharing options...
Nightspore Posted March 15 Share Posted March 15 8 hours ago, Bino-viewer said: >I've got to worry about fungus? WTF? Thanks guys! lol< In this climate..........most definitely !! 😀 Most of my refractors are 80mm or under anyway (biggest is 102mm). I usually give them a decent airing after use if the session has been a damp one. I'm tempted to get a desiccant cap for the 102mm Altair. I actually have one for my SCT. IIRC they need desiccant refills though. The only place I know that sells these is FLO and I won't buy from them on principle. I don't think fungus is a problem on any of my fracs at the moment. It's going to give me nightmares though lol. I'll have to distract myself from the mold event horizon by watching Surfrajettes videos. Link to comment Share on other sites More sharing options...
+Streetbob Posted March 15 Share Posted March 15 4 hours ago, Speed said: Same as the one I have from FLO 👍 That’s the one. It had to be ’cause it matches the scope. Link to comment Share on other sites More sharing options...
+Streetbob Posted March 15 Share Posted March 15 2 hours ago, Nightspore said: The only place I know that sells these is FLO Rother Valley Optics do a good one but unfortunately only in blue. Nightspore 1 Link to comment Share on other sites More sharing options...
Nightspore Posted March 16 Share Posted March 16 3 hours ago, Streetbob said: Rother Valley Optics do a good one but unfortunately only in blue. Blue's cool. +Streetbob 1 Link to comment Share on other sites More sharing options...
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