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Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
Bill F
sage
Reged: 05/30/05
Posts: 202
Loc: scotland
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Hello,
At 3 o'clock this morning I woke up to see moonlight shining into the room, so I got up and went out to my dome. Daytime temperature about +10'C, temp at 3 o'clock -2'C. The scope lives in the dome, so I would think it would be down to near ambient. The Denk II and eyepieces live inside, temp about +15'C. When I started to observe, it was horrible. Totally unable to get a good focus at anything above minimum magnification (X 75 with a pair of Pan 24s). After about half an hour, things improved and I was able to get good focus at X 163 with the Nagler 11s in. This was the limit of seeing conditions. Normal for me, on the northern end of a slightly soggy island parked under the jetstream.
I am presuming that this was a cool down problem, but the scope should have been cooled down, I have always been under the impression that eyepieces didn't need cool down time, so is this the binos needing cool down time? I've had this situation before, but this was worse than usual. Anybody have similar problems?
A good couple of hours observing then followed. Needless to say, I wasn't very popular when I went back to bed half frozen at six in the morning.
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Orion Optics (UK) SPX 250 F4.8
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wargentin
member
Reged: 05/04/07
Posts: 29
Loc: France
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I had similar problems with my Baader Mark V. At the beginning I used to install the telescope 2 hours before observing to allow cooling down, and I brought out the eyepieces and binoviewer case just before observing. During the first hour, I was always bothered by a strange astigmatism in the star test, that was continuously changing. At times it disappeared, then it came back… The temperature difference never exceeded 10°C.
Later, I used to bring out the accessory case with the telescope, long before the observations. The astigmatism disappeared definitively.
So binoviewers do need cool down time.
Quote:
A good couple of hours observing then followed. Needless to say, I wasn't very popular when I went back to bed half frozen at six in the morning.
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Heavens Above
member
Reged: 01/25/09
Posts: 60
Loc: Bristol, UK
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Interesting. I've suspected the same for a while and cool down my eyepiece case as well as my scope in a un-heated conservatory before observing.
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TMB 115 F7 APO
Baader Mark V Binoviewer
AOK AYO Mount
Berlebach Model 18 Tripod
Astrophysics Barcon and Maxbright diagonal
Televue 11 Plossls's
Baader 12.5 Ortho's
Meade 5000 plossls 26mm, 20mm & 14mm
TMB 40mm Paragon
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