Topics

EXOS-2 PMC Eight, displacement planets and the moon #EXOS2 #TECHNICAL #OpenGOTO #ExploreStars #alignment


Jerry Hubbell - Explore Scientific VP Engineering
 

On Wed, Nov 13, 2019 at 01:05 PM, @aemytty wrote:
How can i post or make a new topic?
This is an off-topic post.
I would remind those new to Groups.io that there is a "Help" button at the top right side of the window. Please use it as needed.
 
--
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!


Chris Tardif
 

Over on the left....5th selection down.
--
Mounts: Explore Scientific IEXOS-100 w Celestron CG5 tripod, iOptron CEM 40
Scopes: Explore Scientific FCD-100 ED-102CF, Various Canon lenses, ZWO mini-guidescope, StarField 60mm guide-scope.
CameraASI120MM Mini (mono), Altair GPCAM 130
Control PC: Intel NUC
Loc: 44 -79


Arelius
 

How can i post or make a new topic?


Jerry Hubbell - Explore Scientific VP Engineering
 

On Tue, Nov 12, 2019 at 06:00 PM, Wes Mcdonald wrote:
As for cone error you should eliminate it using the method posted by Jerry with a link to the Astronomy Shed YouTube channel.  
Here is the excerpt from message #3646 where I mention cone angle

Also, you need to correct for another error where your telescope is mated to your mount called Cone Angle. This is a condition where the telescope is not in optical alignment with the mount's RA axis.  You can find more about that here: https://www.youtube.com/watch?v=WatdQlPp22Y  . You can get a fairly good polar alignment (within a couple of degrees) without doing a cone angle adjustment, but it will throw things off a small amount.

Here is the link to the whole message

https://espmc-eight.groups.io/g/MAIN/message/3646

 
--
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!


Wes Mcdonald
 

Rodrigo

I have been modeling the alignment procedure and have arrived at several conclusions.  

1.  Irregularities can occur in go-to based upon errors in your Dec home position.  Similarly errors in cone angle will persist even after three star alignments.  Thus you need to assure these are minimized before you perform the alignment.  I note the cone angle is correctly compensated for in the three stars used in the alignment but not across the sky.

2.  Your precision of centering during the alignment can affect your result.  So use a cross hair eyepiece and get close during alignment.

3.  When you sync on an object you bake in the Az El rotational error imposed by home error and measurement error.  These errors get rotated around the sky and affect other objects.

4.  The residual errors discussed above affect some objects more than others depending upon where they are in the celestrial sphere.  Thus you can have good results in one object and poor in another.  

My simulations suggest that the cone error and Dec home.error are to blame for the things you are seeing.  It suggests you have Dec home error likely on the order of 1 or 2 degrees.  You can eliminate Dec home error using the procedure I posted in the mounts subgroup in the files section.  Do this before you start after you have.set up and leveled the mount .  It only takes a a few minutes.   As for cone error you should eliminate it using the method posted by Jerry with a link to the Astronomy Shed YouTube channel.  

I don't believe there is anything incorrect with the planet vs DSO pointing.  While possible, the results you are seeing are far more likely due to one or both of Dec home or  cone angle.

Wes



--
Wes, Southport NC
PMC-8, ES ED 127, 10" LX200GPS, Astro-Tech 8" Newt, ETX-90
Polemaster, Orion ST-80 and SAG
Electrical Engineer, Retired