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 |
發表於 2009-11-14 23:01
| 
