Re: Drift Alignment To Help With Unguided Images
Love the CDK scopes (or in my case iDK) they are a joy to use and produce excellent data. Congrats! The 1100 will enjoy it too.
From: email@example.com <firstname.lastname@example.org> on behalf of Tony Benjamin <tonybenjamin@...>
Sent: Sunday, August 30, 2020 3:51 PM
To: email@example.com <firstname.lastname@example.org>
Subject: Re: [ap-gto] Drift Alignment To Help With Unguided Images
Thanks for the input W.Hilmo! Tiny font btw J
I have gone ahead and ordered a Planewave 12.5” and will sell the C11. Drastic measures, but will put an end to mirror flop!! J Looking forward to the cloudy skies!
From: email@example.com [mailto:firstname.lastname@example.org]
On Behalf Of W Hilmo
I image with an 8" EdgeHD 800 and I get about the same performance that Tony does unless I guide with an OAG.
The thing about the EdgeHD scopes is that they do not have mirror locks at all. They have mirror clutches that consist of two flexible rods installed on the back of the scope at 120 degrees from the focus knob. This provides some support for the mirror to keep it from tilting (although since the rods are flexible, they can and do bend if the focus knob is turned while they are set). But they do nothing at all to prevent the lateral movement that Roland describes.
The end result is that if I go either unguided or with a guide scope, I get elongated stars. They are clearly noticeable on two minute exposures at 0.5 arc seconds per pixel. As such, my EdgeHD requires either an OAG on ONAG any must be guided.
And this is on my AP1600 with absolute encoders and a pointing/tracking model built through APPM.
No, we have not changed the way the CP4 controllers interface with APCC Pro. However, there is a new version of APCC Pro that might be what you want to update.
If you are using a C14 for unguided, you may run into mirror shift issues that cannot be solved with modeling. I think trying to do unguided imaging with such a scope might be stretching things. First you have very long focal length, next you have an optical/mechanical system that is prone to differential flexure, and then you have possible mirror shifting, even if it's locked down. Reason for the shift is not because it tilts due to gravity, rather that the entire mirror slides sideways due to the clearance between the mirror's central hole and the shaft that it rides on. The mirror is quite heavy and slides around sideways because it is not glued down to the metal shaft that it sits on.
Will do, tonight hopefully.
It says I need to contact AP to get the CP4 firmware updated? Might this play into my issue?
On Behalf Of uncarollo2 <chris1011@...> via groups.io
"Pretty sure" will only be confirmed if you do what i suggested - do a guider graph for 10 - 12 minutes with guide pulses turned off. See what your guide graph looks like, maybe even post a screen shot so we have something to work with.