Sunday, 24 January 2010

Cold enough for astrophoto gear?

22th January 2010, Mikkeli, Finland. 10 PM. Temperature -26C. Sky: no clouds. Adequate seeing and temperature for astrophoto gear test!

Cold enough?

Barely, but yes! I don't know what most people really think about this low temperature, so let's cool down and not get into details about weather. I wanted to test my equipment in case I really need to use them in very low temperatures.


- Canon EOS D60- Canon EF 50mm 1.8 II- EQ-1 equatorial mount with EQ-1 Simple Type motor and EQ-1 foto adaptor- Tronic portable battery (12V/7Ah) with 9V output modified as regulated 8V
- YongNuo MC-36b timer (on the PCB there is a text "MC-36C")- Panora 10x50 binoculars- small astronomical lens telescope (D=60 mm, F=415 mm)- some home-made DC cables- headlight, or how do you call it, a fore-head light with red LED

The test

The one purpose of the test was to find out whether the EQ-1 motor runs below -25C or not. EQ-1 runs on a 9V battery, except when the battery loses the power. Previously I had seen that rechargeable 9V block is not enough in -15C. Now I have eliminated the power supply factor by using a bigger battery. Rucksack at my back, smaller camera rucksack in the front, binoculars hanging there somewhere as well and the EQ-1 + telescope in my left hand I walked to the lake. It's just a half a kilometer walk. At the target, on ice, I tried to carry out the normal procedure required when taking astronomical photos on a random location. Just one exception: I really cannot take my gloves off for no longer than, say, 10 seconds at a time. Cold hands are always worse than warm hands with gloves.

Let's fast forward to the test. I was able to fix the camera to the mount, connect the cables etc. with my gloves on. Actually, at first I tried to align the mount by using the telescope with 20x magnification, but I just wasted time. Let's not waste time now by explaining all that stuff. I will eventually cover the EQ mount alignment in another post. Anyway, I replaced the telescope with the camera. Note that not all the equipment and cables had cooled down to ambient temperature during my walk, just close to it. The DC cable was pretty curly when I connected it to the battery. I decided to use the BP-511 battery and not the adaptor for Canon, as I wasn't going to take very many photos.

The EQ-1 motor runs on 8V regulated power supply! Good news. Only changing the direction (swithing to "S" as for "Southern hemisphere") caused bad noise, probably on the motor axle. I switched the direction immediately back to "Northern". Luckily, there was no extra noise with clockwise operation. The electronics did some "curve" at one point, making the motor run noticeably faster for some time. I don't have a good explanation for this. Let's just say the speed control circuit does not always function correctly ;) I eventually had everything set for the actual photography.

Frozen observations

A number of things were different than in warm environment.

1. The declination axle of EQ-1 had some extra friction, but not serious.

2. The declination setting circle that was supposed to be fixed and calibrated at the factory, started to partially move along with the declination axis.

3. The mechanism overall had reduced feel, so I wasn't sure how much force to use when tightening the locking screws. For the first time I had the idea that the wings can be broken by excessive force. They have to be tightened so that neither axis can turn by themselves, and on the other hand, the right ascension will turn by the motor.

4. Breathing. Exhaling to any glassware makes it practically opaque. Be careful.

5. Canon D60. Works very well. The LCD display on the top didn't slow down, and the same goes for the colour display. All the buttons and dials operated like in warm environment.

6. Canon EF 50mm 1.8 II. Works extremely well! I am talking about the auto-focus. I didn't notice a difference in operation between room temperature and serious frost. Very good news for astrophotographer :) Or hobbyist, like me, when talking about gear like this :P

7. Plastic fantastic! Need I say more? The cables can cause problems. Even if you can unpack them, make sure you have plenty of room for them when you are packing! It's almost like dried up spaghetti.

8. The timer obviously had a "southern" type of LCD. I knew about this by previous experience. Although the operational temperature range begins at -20C, at that temperature the cable begins to get stiffer and the display is really slow. You may need to wait for a few seconds to verify what you have entered. However, that was not a big problem, I could still make the changes I needed. The buttons seem to work just fine.

9. When you get back home, don't just run inside with your gear! Moisture will be developed if you do this. I did the easiest thing possible to avoid this: I left the packed rucksacks on the floor of the entrance, close to the front door, away from the radiator. I took the gear to the normal room temperature on the next morning, but still didn't unpack until afternoon.


11.50 PM. Temperature -28C. The test was successful! A bunch of paper tissues needed (next time: remember to pack them!), a mug of warm water and check out the photos later. Good night!