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Re: 3-4" RA wiggling while PHD2 guiding with EXOS2-GT PMC-eight #EXOS2 #astrophotography

Walter Vinci
 

Hi Jerry,

Thanks for looking at the logs. I went for the Orion guiding package because of its popularity. I thought it would be more than enough to guide my ED 80 at a 2 arc-sec/pixel imaging scale, but this seems will not be easy according to your comment.

I should then use a Barlow lens as Doug suggest or use a guiding camera with smaller pixels if I wanted to push guiding to seeing/mount limits?

Walter

On Jan 12, 2021, at 8:35 PM, Doug Doonan via groups.io <dougdwd@...> wrote:


Hi Jerry and Walter,
Would it be possible to use a 3X Barlow in the guiding scope to increase the guiding to  the 2 to3 arc-seconds you suggest?
Doug Doonan



-----Original Message-----
From: Jerry Hubbell - Explore Scientific VP Engineering <jrh@...>
To: MAIN@ESPMC-Eight.groups.io
Sent: Tue, Jan 12, 2021 2:11 pm
Subject: Re: [ESPMC-Eight] 3-4" RA wiggling while PHD2 guiding with EXOS2-GT PMC-eight #EXOS2 #astrophotography

Hi Walter,

I am just starting to look at your guide log, but I did notice that your guide camera (an Orion Starshoot Autoguider) with a 5.8 um pixel coupled with your very short focal length guide scope (162 mm) makes you image scale very large at 6.6 arc-sec/pixel. This is a big problem if you are trying to auto guide to < 2-3 arc-seconds and is very difficult to get any better performance. This will especially the case if you seeing is poor. 

I will spend some more time looking at your guide log to see if I see anything else.
--
Jerry Hubbell
Vice President of Engineering
Explore Scientific, LLC.
jrh at explorescientific.com
www.explorescientificusa.com
1010 S. 48th Street
Springdale, AR 72762
1-866-252-3811

Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
             Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home


Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Wilderness, VA
Mounts: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
Cameras:  QHY174M-GPS + FW, QHY163C
Misc: 3-inch 0.7x Focal Reducer Field Flattener, Filters: Luminance,
Red, V-band Photometric, Diffuser, 200 lpmm Spectral Grating
Software: MaxIm DL 6, Cartes du Ciel, Astrometrica, AstroImageJ, AutoStakkert!

--

Doug Doonan
HomeBru  6 inch Reflector  f 6.6
HomeBru  85 mm Refractor  f 5.6
PMC-8, EXOS 2
Long retired EE.

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