Re: Focus repeatability issue
Michael Hambrick <mike.hambrick@...>
It could be due to variation in the seeing. I have been wanting to ask the experts on the forum what they are actually looking at when they talk about seeing in terms of arc seconds, and how they measure it.toggle quoted messageShow quoted text
Where are you imaging from ? I have also been watching on the weather reports where they have been saying that there is a very prominent Saharan dust cloud moving west and is already affecting the southern parts of the US (Florida & Gulf Coast states). I expect that this dust will degrade the quality of the seeing. I guess the good news is that it reduces the chances of tropical cyclone formation.
TSR Global Manufacturing Support
PO Box 2000
Orange, TX 77631-2000
Phone: +1 (409) 882-2799
From: "Jim Fakatselis" <jfakatse@...>
Date: 2020-06-23 09:06 AM
Subject: Re: [ap-gto] Focus repeatability issue
Sent by: firstname.lastname@example.org
Here’s the tabular data.
On Jun 23, 2020, at 9:53 AM, Jim Fakatselis <pashasdad@...> wrote:
I am imaging with a QSI683WS8 and a Starlight Instruments focuser with the Starlight stepper motor on an AP130mm EDF refractor Using MaximDL.
I was attempting to measure the filter offsets
with my AstroDon series E gen 2 filter set. Taking four sets of measurements
repeatedly with 5 of the 7 filters I use most, L, R,G,B,Ha. If I
try to immediately refocus, my focus setting continues to drift monotonically.
Very erratically. Can’t get repeatability at all.
The other filters behaved similarly. I can provide
Excel plot of data with linear ramp.