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標題: Lessons learned from recent imaging trip to Taiwan [打印本頁]

作者: anguslau 時間: 2009-11-14 23:01 標題: Lessons learned from recent imaging trip to Taiwan

Just want to document the lessons I learned from the recent Taiwan trip. Hope this will help me do better in the future.

What worked well:

1) Taiwan high mountain may be an ideal imaging location for HK amateurs
   - better chance of clear sky since low clouds are non-issues
   - air pollution mostly avoided since worst haze below 2000m
   - column of air needed to penetrate much reduced
   - relatively close to HK; air + car travel within several hours
   - good accommodation, food and internet access at some locations
   - not too expensive for a 4-5 days' trip (within $2-3000)
   - equipment going through customs not an issue

2) Takahashi equipment close to ideal for travelling
   - both mount and scope extremely robust, reliable, trouble-free
   - very simple to setup and use, near perfect quality
   - astrographs (eg FSQ) much much better than best camera lenses
   - a little expensive but well worth the money in long term
   - FSQ-106ED in particular is a dream scope for travel imaging
   . fairly compact and light weight, easy to fit in carry-on bag
   . pin point stars corner to corner, with or without reducer
   . near perfect stars, no perceptible abberations of any kind
   . extremely high contrast, allow pull out of faint details

3) Bahtinov mask an excellent tool for focusing
   - it really works! the greatest tool for focusing in the field
   - very easy to use, very accurate focus can be achieve within a few minutes
   - the grabber software helps a lot too, no guess works anymore

4) Plan your imaging sessions ahead
- plan ahead will save a lot of precious imaging time
- can achieve optimal framing without trial-an-error in the dark

5) miniBORG + QHY5 a competent autoguider
- worked very well for short to medium focal lengths
- light weight, no flexure observed, quite easy to find guide stars

6) Using camera lens or small scope as counterweight works
- only need to carry a small counterweight for fine balancing
- saves luggage allowance
- doesn't seem to affect EM-11 stability at full-load medium focal lengths

7) Kiboko bag a near ideal carry-on bag
   - custom design to fit carry-on luggage size
   - very light weight (2.1Kg), but strong and comfortable
   - very roomy compared to similar camera backpacks
   - my bag carried: FSQ-106ED, 0.73x, 2 x 5D bodies, Vega PC,
   300/4, 24-105/4, 16-35/2.8, 135/2, 1.4x, hoods, batteries etc

8) Gitzo carbon fibre tripods excellent for travelling
   - 1325 worked well with EM-11 fully loaded
   - very light weight at 2Kg, fits into medium luggage case

9) Lipo batteries a good solution for field power
   - fairly light weight and compact
   - short recharge time (~2 Hours)
   - allows hot swap of batteries with appropriate cable harness

10) Goto a great help for travel imaging
   - saves a lot of time to locate objects
   - allows very accurate framing

11) PHD Guiding my favourite autoguide software
   - simple but very effective algorithms
   - probably the best DEC guiding algorithm, works reliably

12) Hand warming packs an excellent dew preventing device
   - light weight, compact and cheap
   - does not consume power

What doesn't work so well:

1) FSQ-106ED + 1.6x extender not too suitable for travel imaging
   - too slow at f/8
   - some CA and minor distortions near corners, but still not bad
   - 850mm a bit long, many potential problems may creep in

2) Vega PC insufficient at times
- a bit slow when running TheSky + PHD Guiding + MaxIm simultaneously
- screen a bit small, a bit hard to see awkward to switch applications
- awkward to enter text or number since no keyboard
- a larger and more powerful netbook would be better

3) Large pixel camera much better than small pixel
   - try to avoid small pixel DSLR (<6um), may be very noisy
   - modify your DSLR, makes huge difference
   - eg images from my 5D Mark II is not in the same league as my modified 5D

4) Focal ratio is king
- this is especially true for travelling since imaging time is limited
- try to image < f/6; forget about f/8 or higher; best if <= f/4
- forget about extenders, much better to have good image at smaller scale

5) Focus on short focal length
- too many potential issue for long focal length: guiding problems, slow, framing
- time better spent with focal length < 600mm or image scale > 3 arcsec/pixel

6) Beware of bus-powered devices
- may draw sizable current from USB port
- eg QHY5 caused PHD Guiding to hang occassionally
- may overload USB port of notebook
- best to connect via powered USB hub

7) Watch luggage weight
- many airlines become very strict on luggage allowance
- excess allowance may be just 1-2kg
- excess luggage fairly expensive, try to cut down as much as you can

作者: oldfield 時間: 2009-11-14 23:58

:g17

作者: apo 時間: 2009-11-15 13:13

想問下個 kiboko 袋邊度買? 要幾錢呀?

作者: anguslau 時間: 2009-11-15 13:37

原帖由 apo 於 2009-11-15 13:13 發表
想問下個 kiboko 袋邊度買? 要幾錢呀?

I know you'll be interested.

Its a bit expensive, but much better than the Lowepro bags. It can fit both a 600/4 and a 500/4 in the same bag!
http://www.naturescapes.net/stor ... page=1&featured

作者: apo 時間: 2009-11-15 13:42

原帖由 anguslau 於 2009-11-15 13:37 發表

I know you'll be interested.
Its a bit expensive, but much better than the Lowepro bags. It can fit both a 600/4 and a 500/4 in the same bag!
http://www.naturescapes.net/store/product.php?produc ...

好貴.....

不過可以揹多 d 野跟身....
唔知天祥有冇呢....

問過....係冇...

[ 本帖最後由 apo 於 2009-11-15 13:46 編輯 ]

作者: apo 時間: 2009-11-15 23:33

買唔到(唔捨得去外國訂), 唯有再執下個 Lowepro Comp Trekker Plus, 勉強都算做可以放到支天狗 + 兩部 body + 幾支鏡 + 埋支 45ED guide scope...

圖片附件: IMG_9595_resized.jpg (2009-11-15 23:33, 194.54 KB) / 下載次數 211
http://astrohome.net/attachment.php?aid=19810&k=60eae72f2efc8e680ae49e096a14c44c&t=1727518879&sid=Eti1c6

作者: noodle 時間: 2009-11-16 04:30 標題: 回覆 1# 的帖子

參考價值非常高，多謝分享:u_15

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