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Old 21-02-2016, 12:41 PM
raymo
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DARV polar align question

When doing the altitude adjusting part of DARV, how far above the horizon can the selected star be to still get accurate results. I have
very limited low down views to both the east and west.
raymo
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Old 21-02-2016, 01:12 PM
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ZeroID (Brent)
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Me too, just as far down as is practicable. I used Diphda at about 30* West one evening. I don't have an East Horizon at all.

Is this a permanent setup or do you take it down after each session ?
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Old 21-02-2016, 03:14 PM
raymo
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Thanks Brent. Unfortunately I have to tear everything down every time.
I also have no East, and will be lucky to get down to around 35-40
degrees to the West.
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Old 21-02-2016, 05:18 PM
kens (Ken)
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The main issue is that azimuth error will also show. If you have a good azimuth alignment you should be ok but it will still take longer to home in. Usual recommendation is to be within 20 degrees
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Old 21-02-2016, 05:55 PM
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ZeroID (Brent)
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Do you have a marked place you always use ?
Before the Ob I used solar noon to paint a N/S line on the driveway then crossed it with my big square for E/W. Build a small levelling platform that sat on marked points and just placed the tripod on that. Then did the usual aligning process and left things alone. I only ever had to tweak things a little bit after that. A simple drift align at meridian would do it if even required. The levelling 'platform' was just a big 'T' square I made from timber. Just left the tripod legs fully homed and that was it.
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Old 21-02-2016, 07:02 PM
raymo
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Thanks Ken; I can't get anywhere near 20degrees, so it'll have to be trial and error.
I can't put anything where I use my scope Brent, it is a high usage walkway. I originally did a good drift, and painted small dots where the tripod feet stood, so I am usually within a couple of degrees.
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Old 22-02-2016, 05:19 PM
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Camelopardalis (Dunk)
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raymo, the lower the better but if you can't get low down just lengthen the period of time you're slewing for. I usually start at 10 seconds and push it out to 30 seconds for final checks/adjustments. I mostly image with my 4" refractor though, so any drift will likely show up in your scope more obviously.

Like Ken says, if you don't adjust the altitude bolts in-between sessions, you should be pretty close the next time you setup, it'll mostly be azimuth.
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