Date
1 - 12 of 12
It's a cold one tonight
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Roland Christen
Hello fellow Astronuts,
First really clear night in a month and that always means two things: Moon is full and it's bitter cold. The lack of clouds and haze means that the daytime air temperature will rapidly cool off to well below freezing. Temperature started off well below freezing and is now standing at -25C (-12F). It will drop further and is supposed to bottom out at -30C after midnight.
I'm shooting some images with my 12" F12.5 Mak-Cass operating at F10 with our 27TVPH compressor. Seeing is rated as very poor on Clear Sky Clock, but stars in 10 minute exposures are coming in at 2 arc sec FWHM. What's interesting to me is the complete lack of focus change over a 20C temperature drop. The scope uses Sital mirrors and carbon fiber tube. I love the fact that no refocusing has been needed for the last 5 hours. Perhaps if the seeing was better it might require a slight refocus to get the very best resolution.
One of my other aims is to take advantage of our Midwest temperature extremes to cold test all 3 mounts:
The Mach2 with 130GTX and 110GTX piggyback, the 1100 with the 12" carbon fiber Mak, and the 1600 with my 17" F8 Quartz Astrograph.
And also to cold test the corresponding scopes to make sure we don't have any problems with temperature (pinched optics, etc).
In these temperatures I can work outside for about 10 minutes at a time before my fingers become numb and I begin shivering uncontrollably. Then it's back inside for 20 minutes to warm up. At this point I'm extremely pleased with the performance of all this equipment. The 3 mounts don't seem to care about the cold, unlike me. They are all slewing and guiding happily along as if it was summer. My little 110 GTX is showing a great image of the Orion nebula, giving its bigger brother, the 130 a run for the money. All good fun!
Rolando
-- Roland Christen Astro-Physics |
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Woo hoo! Send some of those clear skies please (but keep the cold)! Stuart Heggie
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Roland Christen
Here's what she looks like right now: https://www.cleardarksky.com/c/AstrPhyILkey.html
Rolando
-----Original Message-----
From: Stuart <stuart.j.heggie@...> To: main@ap-gto.groups.io Sent: Mon, Jan 30, 2023 10:21 pm Subject: Re: [ap-gto] It's a cold one tonight Woo hoo! Send some of those clear skies please (but keep the cold)!
Stuart Heggie
-- Roland Christen Astro-Physics |
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Nice! I have some chance of clearing Wed night. Frostbitten fingers crossed! Stuart Heggie
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dvjbaja
Crystal clear and cold here in the SF Bay area tonight. Mars scooted by the north pole of the moon by a few arc minutes. Another stunning telescopic view. Sent via the Samsung Galaxy Note9, an AT&T 5G Evolution capable smartphone |
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R Botero
Excellent Rolando! Looking forward to one of those 110GTX to keep me warm!
Roberto |
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midmoastro
Awesome! Thank you for all you do here Roland. Love reading reports like these.
Did any of the mounts have the lower temp encoders? Just curious if these were standard temp? Sounds like no pinched optic concerns? Sure looking forward to more news regarding the 110GTX. Todd |
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thefamily90 Phillips
Great report! Please be careful with those temps. Hypothermia is real and very dangerous ( says the guy from SC. 😂).
All the Best,
JimP
From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of midmoastro <teche70@...>
Sent: Tuesday, January 31, 2023 8:22:02 AM To: main@ap-gto.groups.io <main@ap-gto.groups.io> Subject: Re: [ap-gto] It's a cold one tonight Awesome! Thank you for all you do here Roland. Love reading reports like these.
Did any of the mounts have the lower temp encoders? Just curious if these were standard temp? Sounds like no pinched optic concerns? Sure looking forward to more news regarding the 110GTX. Todd |
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Roland Christen
I have standard encoders on these mounts. It got down to -25C (-14F) and everything worked great. No pinched optics.
Rolando
-----Original Message-----
From: midmoastro <teche70@...> To: main@ap-gto.groups.io Sent: Tue, Jan 31, 2023 7:22 am Subject: Re: [ap-gto] It's a cold one tonight Awesome! Thank you for all you do here Roland. Love reading reports like these.
Did any of the mounts have the lower temp encoders? Just curious if these were standard temp? Sounds like no pinched optic concerns? Sure looking forward to more news regarding the 110GTX. Todd -- Roland Christen Astro-Physics |
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I was wondering about the encoders. I am probably going to transport one of my mounts to my house in Montana to set up another observatory and am trying to decide if I need the extended low temperature ones. I have a question. Would they get damaged if exposed to temperatures in the -25 range or do they just don't work at those temperatures? I think our low (I was not there) a couple of nights ago was about -29 degrees at an altitude of 6872 ft above sea level. I think my practical limit for imaging is -10 or so and that would cover most nights. That is somewhat arbitrary, since I have never really imaged there yet, but I am wondering about this.
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Roland Christen
There's no damage to the encoders in cold temps. It's just that the internal laser source runs out of poop at some low temp and the encoder stops reading the code ring. Then when it warms up a bit the laser comes back on. I don't know what Renishaw does for the extended temp readheads, maybe use a different laser source?
Rolando
-----Original Message-----
From: Emilio J. Robau, P.E. <ejr@...> To: main@ap-gto.groups.io Sent: Tue, Jan 31, 2023 10:54 am Subject: Re: [ap-gto] It's a cold one tonight I was wondering about the encoders. I am probably going to transport one of my mounts to my house in Montana to set up another observatory and am trying to decide if I need the extended low temperature ones. I have a question. Would they get damaged if exposed to temperatures in the -25 range or do they just don't work at those temperatures? I think our low (I was not there) a couple of nights ago was about -29 degrees at an altitude of 6872 ft above sea level. I think my practical limit for imaging is -10 or so and that would cover most nights. That is somewhat arbitrary, since I have never really imaged there yet, but I am wondering about this.
-- Roland Christen Astro-Physics |
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On Mon, Jan 30, 2023 at 08:01 PM, Roland Christen wrote:
First really clear night in a month and that always means two things: Moon is full and it's bitter cold. The lack of clouds and haze means that the daytime air temperature will rapidly cool off to well below freezing. Temperature started off well below freezing and is now standing at -25C (-12F). It will drop further and is supposed to bottom out at -30C after midnight.That reminds me of my time in Minneapolis... brrrr. I have many fond memories of waiting for the bus in the morning,,, standing in a snowbank on the side of the road... in the dark... and its -20C out. It is very inspirational to see you out there, sacrificing yourself, doing product testing. I can report that my Mach2 does just fine at -8C out here in the San Diego County desert. -- Dean Jacobsen Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/ |
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