locked Re: Guiding questions

Jaimie Murdock

Hi Mirko,

I'm also fairly new to astrophotography, but I am also using the same software setup as you with the ES PMC-8 iEXOS-100 and included a screenshot below. Your RMS numbers are very high.

The first thing I noticed with your screenshot is the focus on your guidecam - it is very out-of-focus. While the guidecam is more tolerant to being out-of-focus, a 2-second exposure should show pin-point stars.

I guide with Via set to "ES iEXOS-100 PMC-Eight". This uses the USB cable for pulse guiding. I have not tried to use the ST-4 cable at all. It is not a part of my setup.  

The five biggest factors for successful guiding, so far:
1. Balance - ensuring that the scope is balanced in both RA and Dec, using the instructions in the manual.
2. Guidecam Focus - Having pinpoint stars reduces variance between exposures, increases accuracy.
3. Box Size - 16 has worked really well for me
4. Star selection - A star that is bright and stretches to the box size is ideal.
5. Remove Guidescope Flexure - make sure the guidecam is mounted securely to the primary scope. Mine was a little loose, causing maddening issues when the slightest bit of wind hit the scope and wobbled the actual camera.

I hope this helps!



On Fri, Mar 12, 2021 at 11:54 AM Mirko Gude <mgude@...> wrote:

because I've made some progress in setting up my equipment, I'am now able to spend some time for guiding. At the beginning there was no time for this, there were so many other questions so solve :-)

In the past months I've made some attempts to use guiding to achieve longer exposures. I'am using Indi/EKOS with a Raspberry Pi and EKOS provides a guiding function. First, I had the idea, that guiding will compensate a rough polar alignment, but after some attempts, I think that a good polar alignment is also important for guiding :-)

Very often I get a message like this:
"Guide DEC: Scope count not reach the start point after 21 iterations
Possible mount or backlash problems"

How could I check, If I have a issue with the mount (iEXOS 100 in this case)?

There are also two options to use the guiding camera. EKOS offers "via Camera" or "via ES iXEOS 100" in a menu. I've chosen via ES iEXOS 100, because i was to lazy to search the cable. My second question is, If it makes an important difference If I use this way or If it is better to connect the guiding camera directly with the mount (from Autoguider (ST4) Port camera to Autoguider (ST4) Port mount) ?

Third question is about the guiding rate. EKOS has an option for this and the default ist 0,5. Should I change this? (s. screenshot, it shows also the setting for guiding via, but this is in german). I found in the PMC_Eight_ProgrammersReferenceManual that the sidereal rate is 48. So maybe I should adjust the value to 0.48?

I will also attach a second screenshot, in this case guiding was working for some time. Maybe somebody has a hint what I could improve? 

Thanks and best Regards,


Mounts: ES PMC-8 IEXOS 100, ES EXOS2-GT 
Scopes: Skywatcher 80/600, TS Photoline 72/432mm-Apo
Cameras:  Nikon Z6, D7000, ZWO ASI385 Color, QHY 5L-II-mono
Lens: Sigma 150-600mm, Sigma Art 135mm/1,8, Nikon Z 50mm/1,8, Tamron 70-200mm
Msc: LRTimelapse Pro Timer 2.5, Raspberry Pi4, Polemaster, GPS Dongle, QHY miniGuideScope
Software: PixInsight, Kstars, Starry Night, Redshift

Mount: ES PMC-8 iEXOS-100
Scope: William Optics ZenithStar 61II w/ UniGuide 32mm
Cameras: Canon EOS 1100D (Rebel T3), QHY-5-III-462C
Software: KStars on Astroberry, DeepSkyStacker and Photoshop

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