Tips for Cold Weather Graze Expeditions

by Robert Sandy

1. Dress as if the weather is TWICE as cold as the predicted CHILL INDEX.

2. DO NOT observe through an eyepiece POINTED at the ground, since any eye tearing will "pool" directly between the observers' eye and the graze star, causing MUCH HAVOC in successfully seeing the graze star, so if possible, "slant" eyepiece NOT OVER a 45 degree angle to the ground. This may even require sitting on a stool at times, depending on the telescope design/moon altitude.

It is this writer's belief that an OBSERVING MAGNIFICATION of HIGHER THAN 150x is TOO MUCH for ANY graze (either Dark and DEFINATELY Bright-side grazes), since (A) the HIGHER the power, the MORE atmospheric turbulence is MAGNIFIED, (B) the higher magnifications "FATTEN" the star's SIZE, making it fainter-looking than it really is, And (3) the higher the magnification, the MORE times an observer WITHOUT a clockdrive, or even manual slow motion controls on his/her mounting, would have to "catch up" with the Moon/star MORE FREQUENTLY, due to the Earth's rotation on its axis.

In the process of drawing Pictorial Reductions for Graze Observers, this writer has noticed on several occasions that observer's timings have been too EARLY/LATE, in my opinion due to their using extremely high magnifications to observe with (like, for instance between 200-300x), and in some instances their SPECIAL NOTES given on the graze reports state that (quoted from an actual SPICA graze report)--"Seeing deteriorated markedly DURING observations, with much "jitter" and color and intensity fluctuations; I used a C-8 at 275x". This definately caused this "identity-confidential" observer's timings to be a good 0.10-Watt's Angle Degree EARLY/LATE when compared to several other observers on either-side of this observer;--this error could have been worse IF the Moon/star had been CLOSER to the horizon than in ACTUALITY (e.g., +18-degrees)!!

Now this writer is quite aware that several "observers" (including this writer) are NOW using video-means to TIME grazes, etc. And EVEN using my considered-SMALL 6"-f/8 at PRIME FOCUS with the video camera, my camera "SEES" at about 234x. AND on most of the FEW grazes I've videod so far, atmospheric turbulence is VERY apparent. So the only way to get the power DOWN to around 150x would be to get a so-called FOCAL REDUCER, which I may end up getting.

So PRIMARILY, I'm addressing this LOWER POWER suggestion to that LARGE NUMBER of those observers who are still observing grazes VISUALLY.

3. If possible, always place your back to any wind that might be present. In fact, it might be of great help to place observers next to the wind-breaking side of houses/barns, etc. with permission of the occupants. Of course, this means getting out on the graze sites EXTRA early!! This idea is especially good, since, during cold weather, it is best for scopes to be acclimated to the outside temperature a good hour BEFORE the graze begins. Scope acclimation is especially important IF you wish to observe each component of a close double/triple star. While on this subject; if you are an observer of a graze, instead of an Expedition Leader, PLEASE, PLEASE be respectful of the Expedition Leaders wishes, when they say to be at a designated Meeting place AND (especially) a STATED time (i.e., DON'T BE LATE) to meet; the reason for this -- the Expedition Leader is usually the LAST observer to get to their sites to get set up AND get their scopes acclimated to the cold.

4. Try to use an observing eyepiece having a large exit pupil; this is suggested so that there is less likelyhood of the observers' warm eyebrows touching a cold eyepiece, thusly/quickly "fogging" up the eyepiece, making observing very difficult. If you want to observe the graze at a higher power than what the eyepiece having the wide exit pupil will give, then combine it with a 2X high-quality Barlow, so you will end up getting twice the magnification with the same wide exit pupil.

5. Time the graze using the pocket-type tape recorders, especially during cold weather; the larger cassette recorders DEFINATELY freeze up and act VERY erratically when they are subjected to the cold, making it very difficult to "collect/analyze" the observer/s timings after the graze is observed. That is to say they usually sound like Donald Duck upon replay!! The mini/pocket-type cassettes can be started, then placed in the observer's shirt pocket, which keeps them very warm by body heat. Also, it is suggested that the pocket cassette be run at the HIGH (i.e., 2.4) speed setting; there will be plenty of tape left, when you consider that a Graze Period lasts only seven minutes MAXIMUM.

6. As always, place shortwave radio onto TV trays (I personally use a T.V. tray), or similar small table, RIGHT NEXT to the observer; this is suggested so that IF the WWV/CHU, etc. time signal reception/volume should all of a sudden get POOR, quick access to the radio controls are within arms' reach.

7. As always, make sure the batteries (definately the Alkaline or Nickel Cadmium-type; these are'nt affected as much, by the cold, compared with carbon-zink) are checked with a battery tester several hours before a planned graze expedition.


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