Friday, June 06, 2008

Planning for the solar eclipse trip

For the solar eclipse, I will use the following:-

Mount: Nothing but the TG-SP II, latitude adjustment will be using a Manfrotto 410 head, polar alignment will be done with a third party polar scope attached to the 410 head, tripod will be a Gitzo G106 or maybe a bigger one, still thinking

Power of the mount will be from the USB port, or a 4AA rechargeable battery pack.

Video and Photography:-

1. Video: I'll use a Konica Minolta Z5 with a 2G SD card, that would allow more than one hour of continuous recording at 640x480x15, I will use a white light filter before and after the eclipse. It will be used at maximum zoom.

This camera will be left untouched during the process, just as a record of the whole event, as well as, to capture the voice response of different people.

2. H-alpha: I'll use a Borg 45ED II, Solarmax 40 + BF10. Camera will be a DMK 21AU04 (with reducer) or maybe a DMK 31AF03 (without reducer), I plan to take a few shots from the very beginning of the partial eclipse, and then somewhere in the middle, etc.

I am wondering if the USB bandwidth (and also power) is enough for both the DMK and the external hard disk which I'm going to buy, got to test before the trip.

The solar disc is bigger in H-alpha especially when we have prominences. Therefore, it would be nice to capture the eclipse in H-alpha, and it should be slightly earlier than in white light, so it would be nice to record this time. It would also be nice to capture, if there's any, when the moon covers some prominences. It's better to do at higher power, and at the same time, I will need to check the orientation where the moon cuts in. Partially covered active regions could be nice, too.

All these events will be in early phase of the totality, so it won't affect (3) and visual observation at all. Again, maybe visual first and then photography as a way of detecting any of the above events could be nice! It ensures visual observation, and at the same, allow easier detection of the event, if there's any.

3. White light: I'll use a Canon 200mm f/2.8 together with a Kenko 2x teleplus, camera will be a Canon 450D, a white light filter will be used before and after the total eclipse. It will be used to capture the critical moments, like the totality, those diamond ring, etc.

For the above three, I will only be operating (2) and (3). (2) will only be operated well before the totality, and (3) will be my choice during the totality. (1) is automatic basically. I'll spend more time for visual observation than photography.

During totality, I will concentrate on (3) and visual observation. For (3), exposure bracketing should be used to enable wider dynamic range. I also wish to do a wider field shot, let say with the kit lens for over 10s to capture the background stars. Of course, I will give this up if it costs too much of my visual observation time.

Visual:- A simple 10x30 Canon IS binoculars with white light filter before and after the totality.

Hardwares are more or less fixed, some small items are still pending, some integration tests are yet to be done.

Software is the next, I mean what I will have to shoot at night during the two days in the site which is supposed to be pretty dark - at least way darker than Hong Kong sky. I'll use the kit lens to capture a few milkyway shots and that would not require carefully planning, but I also plan to use the 200mm f/2.8 to take some wide field shots. Time to look for some colorful regions and interesting targets. I know unmodified DSLR is not going to do a very good job for those red areas, so I will try to keep my target list on those other areas, like bigger star clusters, galaxy, and colorful nebula, etc.

Finally, I guess that since I'll be bring a DMK, I will also take a couple of very fast c mount prime lens to play video astronomy, and it should help especially on those H-alpha rich regions where a unmodified DSLR might feel limited.


If the weather, or whatever on-site condition prohibits the above plan, I will go back to 200mm f/2.8 + 2x + 450D combination on a TG-SP II. If even this one is not very practical, the Canon 10x30 IS is the last tool, of course, with my eyes.

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