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Poll: What's your preferred method to focus?

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11 replies to this topic

#1 kevinbreen

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Posted 19 May 2017 - 06:14 PM

For AP, is it

A) Bahtinov Mask
B) Visual

If A, are you viewing the cross-lines in capture software?
If B, manual or motor-focus?

#2 George Bailey

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Posted 19 May 2017 - 06:26 PM

Visual using JMI motofocus.

I use the moons of Jupiter or Saturn to focus on.


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#3 xiando

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Posted 19 May 2017 - 06:53 PM

B. But that's mainly because it's simpler than fumbling around in the dark with my mask

 

In the end though, unless one is using a program to interpret the bahtinov image and tell them they've achieved focus, we're all using B. I just do it without adding a mask.


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#4 Sunspot

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Posted 19 May 2017 - 07:42 PM

I focus on the planet, set the Gamma to 1 to increase contrast and go for it. But my confession, after 14 years of doing it it gets pretty much second nature. Definitely use electric focusing however.


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#5 Jeff B1

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Posted 20 May 2017 - 08:23 AM

Before cataract surgery and new corrective lenses I didn't.:)


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#6 kbev

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Posted 20 May 2017 - 08:30 AM

My method is somewhat similar to Paul's - I bump the exposure so the brighter areas are a bit overexposed but the darker areas are still visible then adjust the focus to get the sharpest edge along the interface between the two.  I just have to remember to drop the exposure back down before I start my captures.  And if there is a moon near the limb of the planet it can be a good focus aide.


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#7 djhanson

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Posted 20 May 2017 - 10:08 AM

I use a Moonlite DRO (digital readout).  Initially, I adjust focus manually by adjusting my secondary mirror (rough focusing).  Next, with the Moonlite I rack in and out (until just out of focus), note both readings, and take the half-way point for starting imaging (math in my head or via calculator).  This range is generally 700-800 steps (half way is about optimal focus).

 

Lastly, with my CFF350 the CFZ is larger than my previous C14HD and I do find achieving good focus easier and more fore-giving now (i.e. f/17 vs f/11).  DJ


Edited by djhanson, 20 May 2017 - 10:09 AM.

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#8 Rapier

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Posted 20 May 2017 - 11:22 AM

I use a hand made Bhatinov mask and manual focus. But, my scopes are small and my meager AP utilizes a Phillips SPC900 so this is sufficient.


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#9 kevinbreen

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Posted 20 May 2017 - 12:20 PM

Thanks for all the responses, folks. Interesting that a lot of you are using a visual on the object over using a Bahtinov mask.
I've a 8SE and the mount that came with it. The mount is fine for tracking but wobbly as hell. I tried out the cable tie method the other night, which was an improvement over my fingers on the focusser, but I have my sights on a motorised focusser now.

#10 Sunspot

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Posted 20 May 2017 - 01:50 PM

Thanks for all the responses, folks. Interesting that a lot of you are using a visual on the object over using a Bahtinov mask.
I've a 8SE and the mount that came with it. The mount is fine for tracking but wobbly as hell. I tried out the cable tie method the other night, which was an improvement over my fingers on the focusser, but I have my sights on a motorised focusser now.

Back in the "good old days" before motorized focusers, we would clip a clothes pin on the focusing knob and use that for fine focus. (Anyone else remember doing that?)



#11 Rapier

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Posted 20 May 2017 - 04:08 PM

 

Thanks for all the responses, folks. Interesting that a lot of you are using a visual on the object over using a Bahtinov mask.
I've a 8SE and the mount that came with it. The mount is fine for tracking but wobbly as hell. I tried out the cable tie method the other night, which was an improvement over my fingers on the focusser, but I have my sights on a motorised focusser now.

Back in the "good old days" before motorized focusers, we would clip a clothes pin on the focusing knob and use that for fine focus. (Anyone else remember doing that?)

 

 

I've fashioned a double sized knob from 1/2" plywood, twice the diameter of the original. It's 2:1, not 10:1 but it was free.


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#12 jgraham

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Posted 20 May 2017 - 04:19 PM

I use a Bahtinov mask and set my focus on a nearby star. I use my guide scope as a sort of remote finder to make it easy to slew between the reference star and planet.


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