Jump to content


Photo

SCT and Extreme Cold

  • Please log in to reply
25 replies to this topic

#1 northernontario

northernontario

    Apollo

  • *****
  • Posts: 1130
  • Joined: 01 Jul 2009
  • Loc: Porcupine, Ontario Canada

Posted 09 February 2013 - 02:02 PM

My last three sessions took place in a total combined -97 Celsius. Last night (early morning) it was -32 Celsius.

Yes, I know, I am nuts, but clear skies have been far and few between this winter. I took my SCT beyond it`s usual -20 cut off.

Some things I have learnt over the years with my SCT.

1. They do take a long time to get in tune with the temperatures.

2. A dew shield is essesntial.

3. If you are going to observe in the cold, use an AC power adapter.

4. The motors will groan and protest.

5. I don`t have one, but my next investment will be an el cheapo focuser, because when it is very cold, the mirror flop is more pronounced and tough to get focused.

6. Know your hand controller, because you are not going to see it when it`s all frozen up.

7. Keep slewing distances short. Plan your session.

8. Do not attempt to roll your wires and cords up neatly. Take them in the house in the stiff frozen state that you find them in.

9. Listen to Uncle Rod.

10. A well collimated and cooled down SCT is a thing of beauty. My best planetary views have taken place with this humble 8 inch mirror.

jake

#2 Footbag

Footbag

    Fly Me to the Moon

  • *****
  • Posts: 6249
  • Joined: 13 Apr 2009
  • Loc: Scranton, PA

Posted 09 February 2013 - 02:30 PM

You sir, are braver than I. :bow:

My record is 7F. And my mount wasn't happy, nor was my laptop.

#3 herrointment

herrointment

    Aurora

  • *****
  • Posts: 4923
  • Joined: 12 Mar 2011
  • Loc: East of Poskin

Posted 09 February 2013 - 03:02 PM

You forgot try not to breathe. Otherwise that's a fine passel of wisdom for the BTU challenged!

#4 northernontario

northernontario

    Apollo

  • *****
  • Posts: 1130
  • Joined: 01 Jul 2009
  • Loc: Porcupine, Ontario Canada

Posted 09 February 2013 - 03:45 PM

I forgot to mention Eye Pieces.

If you have 82 degree EPs, they perform really well in a cooled down SCT. Remarkable I would say. They do stay fairly true to the edge.

I should also mention, it is not wise to drink beverages from a can....... :foreheadslap:

jake

#5 DesertRat

DesertRat

    Fly Me to the Moon

  • *****
  • Posts: 5228
  • Joined: 18 Jun 2006
  • Loc: Valley of the Sun

Posted 09 February 2013 - 05:24 PM

Yes Jake, you are nuts! But I mean that in a good way! :)

Looks like you've been working beyond limits of scope and man. :waytogo: :waytogo: :waytogo:

Glenn

#6 GeneT

GeneT

    Ely Kid

  • *****
  • Posts: 12839
  • Joined: 07 Nov 2008
  • Loc: South Texas

Posted 09 February 2013 - 06:02 PM

I won't say you are nuts. :grin: However, I don't view if it is colder than 40F. Right now, at 5 p.m. in San Antonio, on Feb. 9th, it is 63F. It was a little chilly today. :lol:

#7 gfeulner

gfeulner

    Ranger 4

  • *****
  • Posts: 319
  • Joined: 23 Nov 2007
  • Loc: Bergen county, New Jersey

Posted 09 February 2013 - 06:56 PM

For some reason, having an eyeball stuck to an eyepiece doesn't do it for me! I'll stick with 25F or above thank you.

#8 rigel123

rigel123

    Voyager 1

  • *****
  • Posts: 11288
  • Joined: 29 Jun 2009
  • Loc: SW Ohio

Posted 09 February 2013 - 09:42 PM

And DO NOT stick your tongue on the CW bar!!

#9 stevew

stevew

    Now I've done it

  • -----
  • Posts: 4387
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 10 February 2013 - 02:27 AM

-32 Celsius.
Yes, I know, I am nuts
jake


Who are we to argue. :shrug:
But your also desperate........ Uh,.... I mean brave..... :waytogo:

Steve

#10 mitaccio

mitaccio

    Viking 1

  • *****
  • Posts: 514
  • Joined: 17 Mar 2009
  • Loc: Oahu, Hawaii

Posted 10 February 2013 - 03:45 AM

Right now, at 5 p.m. in San Antonio, on Feb. 9th, it is 63F. It was a little chilly today. :lol:

Rather cold for my tastes. I freeze when it DROPS to 65! :coldday:

#11 bogg

bogg

    Mariner 2

  • -----
  • Posts: 270
  • Joined: 17 Nov 2009
  • Loc: Bruce County Ontario

Posted 10 February 2013 - 10:46 AM

Last night I got out for the first time this year. -12 C the dew heater could not keep the corrector lens free of frost. I will have to try the dew shield. But that was the least of the problems. Clouds started to move in and the neibours tured on their back light for a skating party. Why did i try? For this winter I am going to bring in the C11 and work with my C8 or my refractor

#12 Pete-LH

Pete-LH

    Messenger

  • *****
  • Posts: 425
  • Joined: 25 Mar 2009
  • Loc: Wilmington, DE

Posted 10 February 2013 - 12:12 PM

Also, things contract and loosen with the cold. five years back I had diagonal loosen, flip around and drop my 32mm TV 2" Wide field lens on concrete(this is where I better understood the value of brass compression fittings although these can contract and loosen as well). Fortunately the glass was not damaged and TV checked it out and repaired the barrel(not for free of course but I must mention the people there did a nice job with great timing and communication).
Also fingers go numb during brief moment s when I need to remove the gloves for dexterity. Sometimes it is difficult to apply pressure to tighten things up. More recently I had my Orion 9x50 RACI finder fall out and the diagonal broke off ... Not too expensive a 2nd finder but very functional and expensive to replace ... I was p****d.
So I try to remenber to recheck the tension on threaded items as the temperature drops.
I find Baader Click-Lock connections are best all around and especially in the cold.

#13 Stelios

Stelios

    Surveyor 1

  • *****
  • Posts: 1978
  • Joined: 04 Oct 2003
  • Loc: West Hills, CA

Posted 10 February 2013 - 01:20 PM

Rather cold for my tastes. I freeze when it DROPS to 65! :coldday:


The coldest I've ever observed was about 42, one September night in Lockwood Valley (about 60 miles north of LA).

The coldest I've ever *experienced* was about 16 degrees, but that was on a trip to Russia, and only for long enough to get from the terminal into the taxi.

I hear of life in truly cold weather with awe, as when reading science-fiction about frosty alien worlds as a teenager...

I can't even bear to watch penguins on TV, unless it's summer. :lol:

#14 hottr6

hottr6

    Mercury-Atlas

  • *****
  • Posts: 2505
  • Joined: 28 Jun 2009
  • Loc: 7,500', Magdalena Mtns, NM

Posted 11 February 2013 - 07:51 AM

Good report. I've observed at similar temperatures (I have done zero-power observing at -65F). Single-digit (fahrenheit) observing is the norm here in the mountains, and I frequently pull out the 'scopes when the mercury goes negative.

A few extra tips for your list. I tune (clean, polish bearing surfaces and regrease) all my mounts using Molykote G4501. This is an NGLI Level #1 grease with PAO (polyalphaolefins) that is good to -60F. We use it in our equipment in the polar regions. Grease normally used in our mounts are rated to maybe 0F, and will complain a lot well above this temperature. I don't know how my new motorized focuser is going to deal with this, however.

Tip #2: I also use hand warmers slipped down the back of my gloves.

Tip #3: If you are using a battery, keep it warm in the house until needed for observing. Li-chemistry batteries do better in extreme cold than wet or gel. Regardless of battery type used, keep it warm by placing it in an insulated bag or cooler. And never place the battery directly on the cold ground or snow; place it on at least 2" thick piece of foam board or wood.

#15 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15769
  • Joined: 06 Jul 2007

Posted 11 February 2013 - 09:19 AM

My last three sessions took place in a total combined -97 Celsius. Last night (early morning) it was -32 Celsius.


I can scarcely imagine. I have experienced 20 below in Maine, but I dang sure did not try to observe. :lol:

One thing I've done to keep the HC more legible in our much more modest cold--uppper 20s, worst case--is rubberbanding chemical handwarmer packs onto it. Whether that would work in your arctic conditions, I dunno.

#16 RichD

RichD

    Surveyor 1

  • -----
  • Posts: 1986
  • Joined: 08 Nov 2007
  • Loc: Derbyshire, UK

Posted 11 February 2013 - 11:00 AM

sheesh that's cold. It pretty much never gets that cold here in England, though 2 years ago we had a bitter winter by our standards and I observed for a couple of hours at minus 14 C. I was dressed properly so no probs with comfort, but the scope got covered in frost quite quickly (it's damp in this part of England).

Here, our best nights are often those frosty winter nights. transparent and cold!

#17 Gil V

Gil V

    Viking 1

  • -----
  • Posts: 652
  • Joined: 09 Sep 2012

Posted 11 February 2013 - 09:56 PM

I've used my 8" cat on 0-5 F winter nights. You do have to watch out for frostbite on your fingertips. Dressing in layers is essential. I usually wear gloves with exposed fingertips to handle knobs and eyepieces, and keep my hands in my pockets at the eyepiece.

Ditto on the dew shield - I use one every time out anyway.

I'll remember the hand warmer idea. Plan on taking the scope out tomorrow night.

#18 DonMendoza

DonMendoza

    Sputnik

  • -----
  • Posts: 49
  • Joined: 23 Jan 2012
  • Loc: Greensboro NC

Posted 12 February 2013 - 05:39 PM

Something that happens to me, but I haven't seen mentioned often is fogging up the eyepiece with the heat from your eyeball. Long before the cold gets to me, I find myself frustrated with this repertoire: fog, wait, nudge the dob, repeat.

#19 Brian P

Brian P

    Sputnik

  • -----
  • Posts: 34
  • Joined: 07 Apr 2009
  • Loc: New England

Posted 13 February 2013 - 03:16 PM

It was -24 (Fahrenheit!) at my observing site two weekends ago. I'm fortunate enough to have the equipment set up so I can remote control it from inside, but I still didn't try...the LX200 I have seems to have conniptions below 15 F.

I've always been afraid to take it apart and re-grease it...

#20 Gil V

Gil V

    Viking 1

  • -----
  • Posts: 652
  • Joined: 09 Sep 2012

Posted 13 February 2013 - 07:52 PM

I find that my eyepieces don't fog if I keep them in the house before going out, and in my pockets when I'm outside.

#21 donnie3

donnie3

    Mercury-Atlas

  • -----
  • Posts: 2712
  • Joined: 15 Dec 2004
  • Loc: bartlesville oklahoma

Posted 15 February 2013 - 08:22 PM

i think age plays a roll in how well one can adjust to the cold. 15 years ago it wasn't too bad to observe in 15- 20 degree temp, now at 71 its becoming more and more of a pain!!! 40s and 50s not bad but i would prefer 65 and up. at my age as the old saying gos " the spirit is willing but the flesh is weak" and so gos life. donnie

#22 Pollux556

Pollux556

    Apollo

  • *****
  • Posts: 1421
  • Joined: 14 Dec 2008

Posted 16 February 2013 - 02:12 PM

... and cap your eyepieces before going indoor from -33 to +20 celcius. :foreheadslap:

Attached Files



#23 Ava

Ava

    Ranger 4

  • -----
  • Posts: 310
  • Joined: 30 Nov 2011
  • Loc: Sweden

Posted 18 February 2013 - 02:52 AM

Great tips! I regularly observe at -10 to -15 Celsius, when it actually ever gets clear here winter time it is at least that cold, often down to -20C, -25C. Some additional tips:

1) I use a thin pair of finger gloves inside bigger, really thick thumb and hand gloves. That way, when I need dexterity to adjust something small, my fingers don't immediately go numb never to recover.

2) Both dew shield and dew heater in combination are needed for extended viewing sessions with the C8Edge, at least here where it is often somewhat humid.

3) I've started closing (not latching) the eyepiece case between switching eye pieces to avoid the lenses getting covered in frost. I usually leave the caps off for more convenient switching, the eyepieces dewing up is usually not a problem but frost on the lenses is.

#24 RichD

RichD

    Surveyor 1

  • -----
  • Posts: 1986
  • Joined: 08 Nov 2007
  • Loc: Derbyshire, UK

Posted 18 February 2013 - 08:10 AM

Thermal insoles in good boots and thick wool socks.

#25 Starman27

Starman27

    Skylab

  • *****
  • Moderators
  • Posts: 4391
  • Joined: 29 Jan 2006
  • Loc: Illinois, Iowa

Posted 18 February 2013 - 08:58 AM

When my wife was working in Alaska, she had a musher suit made for me. It's wonderful. It can go to minus 40 degrees. With Sorrel boots and -30 liners I'm good to go. Except, if I fall down I can't get up. So I just lay there and look at the stars.

More often I wear multiple insulated layers and wool socks. My observatories are both on raised wood decks with rubber mat floors. It's amazing how that keeps your feet warm. On concrete or asphalt my feet are freezing in a matter of an hour. On the observatory floors it just doesn't become a problem. And that is without the Sorrels just my house shoes.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics