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Equipment Discussions >> Cats & Casses

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northernontario
Pooh-Bah
*****

Reged: 07/01/09

Loc: Porcupine, Ontario Canada
SCT and Extreme Cold new
      #5670821 - 02/09/13 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


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Footbag
Post Laureate
*****

Reged: 04/13/09

Loc: Scranton, PA
Re: SCT and Extreme Cold new [Re: northernontario]
      #5670855 - 02/09/13 02:30 PM

You sir, are braver than I.

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


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herrointment
Post Laureate
*****

Reged: 03/12/11

Loc: North of Hwy. 64
Re: SCT and Extreme Cold new [Re: Footbag]
      #5670888 - 02/09/13 03:02 PM

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

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northernontario
Pooh-Bah
*****

Reged: 07/01/09

Loc: Porcupine, Ontario Canada
Re: SCT and Extreme Cold new [Re: herrointment]
      #5670929 - 02/09/13 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.......

jake


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DesertRat
Post Laureate
*****

Reged: 06/18/06

Loc: Valley of the Sun
Re: SCT and Extreme Cold new [Re: northernontario]
      #5671071 - 02/09/13 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.

Glenn


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GeneT
Ely Kid
*****

Reged: 11/07/08

Loc: South Texas
Re: SCT and Extreme Cold new [Re: northernontario]
      #5671136 - 02/09/13 06:02 PM

I won't say you are nuts. 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.

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gfeulner
super member
*****

Reged: 11/23/07

Loc: Bergen county, New Jersey
Re: SCT and Extreme Cold new [Re: GeneT]
      #5671211 - 02/09/13 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.

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rigel123
Postmaster
*****

Reged: 06/29/09

Loc: SW Ohio
Re: SCT and Extreme Cold new [Re: gfeulner]
      #5671470 - 02/09/13 09:42 PM

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

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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: SCT and Extreme Cold new [Re: northernontario]
      #5671744 - 02/10/13 02:27 AM

Quote:


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




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

Steve


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mitaccio
professor emeritus
*****

Reged: 03/17/09

Loc: Oahu, Hawaii
Re: SCT and Extreme Cold new [Re: GeneT]
      #5671782 - 02/10/13 03:45 AM

Quote:

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



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


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bogg
super member


Reged: 11/17/09

Loc: Bruce County Ontario
Re: SCT and Extreme Cold new [Re: mitaccio]
      #5672121 - 02/10/13 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

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Pete-LH
sage
*****

Reged: 03/25/09

Loc: Wilmington, DE
Re: SCT and Extreme Cold new [Re: northernontario]
      #5672250 - 02/10/13 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.


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Stelios
Carpal Tunnel
*****

Reged: 10/04/03

Loc: West Hills, CA
Re: SCT and Extreme Cold new [Re: mitaccio]
      #5672356 - 02/10/13 01:20 PM

Quote:

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




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.


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hottr6
Carpal Tunnel
*****

Reged: 06/28/09

Loc: 7,500', Magdalena Mtns, NM
Re: SCT and Extreme Cold new [Re: northernontario]
      #5673588 - 02/11/13 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.

Edited by hottr6 (02/11/13 10:20 AM)


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: SCT and Extreme Cold new [Re: northernontario]
      #5673663 - 02/11/13 09:19 AM

Quote:

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.

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.


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RichD
Carpal Tunnel


Reged: 11/08/07

Loc: Derbyshire, UK
Re: SCT and Extreme Cold new [Re: rmollise]
      #5673826 - 02/11/13 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!


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Gil V
sage


Reged: 09/09/12

Re: SCT and Extreme Cold new [Re: RichD]
      #5674867 - 02/11/13 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.


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DonMendoza
member


Reged: 01/23/12

Loc: Union County, NJ
Re: SCT and Extreme Cold new [Re: Gil V]
      #5676345 - 02/12/13 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.

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Brian P
member


Reged: 04/07/09

Loc: New England
Re: SCT and Extreme Cold new [Re: DonMendoza]
      #5677848 - 02/13/13 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...


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Gil V
sage


Reged: 09/09/12

Re: SCT and Extreme Cold [Re: Brian P]
      #5678250 - 02/13/13 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.

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