Mach2 Unguided imaging results from last night


Roland Christen
 

Hi Astronuts,

I have been busy assembling and testing Mach2 mounts and software and getting a better feel for how well the mount tracks unguided. The scope is my 160 with Quad TCC running at 1.16 arc sec per pixel. Last night was 2/5 seeing, heavy smoke from the West coast fires, and with clouds constantly running in and out. Makings for very poor imaging but excellent for unguided imaging tests.

The target was the Bubble Nebula and M52. I took quick pointing data of 5 stars each on opposing Dec lines instead of taking data along the object's path. This way the modeling program could better calculate orthogonal errors, polar alignment error, scope flexure, as well as the drift error due to atmospheric refraction. The result was surprisingly good. I was able to take 1 hour exposures with the object 4 hours before the meridian, where the tracking rates were quite far from sidereal. The cropped image below shows the result of a single 1 hour exposure:

Rolando




Konstantin von Poschinger
 

Hi Roland,

thats sound absolutely great. With guiding I also got such good results.
When we will be able to use the new Keypad software?
Is the instruction also ready, so we can read and find out how to build a Dec line model or a model that follows the object path?

Konstantin

 
Konstantin v. Poschinger

Hammerichstr. 5
22605 Hamburg
040/8805747
0171 1983476

Am 07.10.2020 um 00:03 schrieb uncarollo2 <chris1011@...> via groups.io <chris1011@...>:

Hi Astronuts,

I have been busy assembling and testing Mach2 mounts and software and getting a better feel for how well the mount tracks unguided. The scope is my 160 with Quad TCC running at 1.16 arc sec per pixel. Last night was 2/5 seeing, heavy smoke from the West coast fires, and with clouds constantly running in and out. Makings for very poor imaging but excellent for unguided imaging tests.

The target was the Bubble Nebula and M52. I took quick pointing data of 5 stars each on opposing Dec lines instead of taking data along the object's path. This way the modeling program could better calculate orthogonal errors, polar alignment error, scope flexure, as well as the drift error due to atmospheric refraction. The result was surprisingly good. I was able to take 1 hour exposures with the object 4 hours before the meridian, where the tracking rates were quite far from sidereal. The cropped image below shows the result of a single 1 hour exposure:

Rolando

<dummyfile.0.part>




Marcelo Figueroa
 

On Tue, Oct 6, 2020 at 05:04 PM, uncarollo2 <chris1011@...> wrote:
The target was the Bubble Nebula and M52. I took quick pointing data of 5 stars each on opposing Dec lines instead of taking data along the object's path. This way the modeling program could better calculate orthogonal errors, polar alignment error, scope flexure, as well as the drift error due to atmospheric refraction. The result was surprisingly good. I was able to take 1 hour exposures with the object 4 hours before the meridian, where the tracking rates were quite far from sidereal.

That's fantastic. 
 
I'm still learning the best practices for an encoder mount and not using guiding. It seems like a good idea to make a model every night instead of relying on last week's model, because when I do, I get mixed results. Some nights my stars are perfectly round, others a little oval.
 
(5 minute exposures and I still don't have an environmental device that measures the local conditions, but I'm using openweathersmap.org to extract the data)


diogenes ofsinope
 

I took quick pointing data of 5 stars each on opposing Dec lines instead of taking data along the object's path. This way the modeling program could better calculate orthogonal errors, polar alignment error, scope flexure, as well as the drift error due to atmospheric refraction.
Roland

M52+61°42'32.7"

Bubble Nebula +61°19'02.0"
 


diogenes ofsinope
 

Sorry ... I pushed Reply before typing out my question for Roland and/or other unguided imagers:

Given Roland's scenario of M52/Bubble, these "opposing Dec lines" would be what exactly?

I'm looking to replicate your quick point data modelling for my non-permanent 1100GTOAE setup with APCC/APPM.


Roland Christen
 

If the object is on Dec 60, then opposing dec lines would be 50 and 70.

However, if you are using APCC Pro (APPM) then just do an automated all-sky model. Doesn't take long.

Rolando



-----Original Message-----
From: diogenes ofsinope <ofsinope@...>
To: main@ap-gto.groups.io
Sent: Tue, Oct 13, 2020 1:19 pm
Subject: Re: [ap-gto] Mach2 Unguided imaging results from last night

Sorry ... I pushed Reply before typing out my question for Roland and/or other unguided imagers:

Given Roland's scenario of M52/Bubble, these "opposing Dec lines" would be what exactly?

I'm looking to replicate your quick point data modelling for my non-permanent 1100GTOAE setup with APCC/APPM.


Larry Phillips
 

Rolando, any suggestions on how many data points (in general) should be enough with APPM?

Larry


Roland Christen
 

Ray would be the best to answer that one.

Rolando



-----Original Message-----
From: Larry Phillips <llp41astro@...>
To: main@ap-gto.groups.io
Sent: Tue, Oct 13, 2020 4:01 pm
Subject: Re: [ap-gto] Mach2 Unguided imaging results from last night

Rolando, any suggestions on how many data points (in general) should be enough with APPM?

Larry


Dean Jacobsen
 

I suspect that the answer would depend on the focal length or pixel scale that you are imaging at.
--
Dean Jacobsen
http://astrophoto.net/wp/
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/ 
Amateur Radio Call Sign - W6DBJ


Ray Gralak
 

Rolando, any suggestions on how many data points (in general) should be enough with APPM?
It depends on the equipment you are using, especially repeatability.

With only 42 points last night I was able to get 30-minute unguided images in several different sections of the sky with just a pixel or so trailing with my A-P Traveler and STT-8300.

I'm waiting for a couple adapters from Precise Parts to push the limits since the STT-8300 I recently bought on Astromart has a full set of narrowband filters. My San Jose skies would blow out my unfiltered images in 30 minutes, so that limited the duration that I could test.

-Ray Gralak
Author of PEMPro
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Larry Phillips
Sent: Tuesday, October 13, 2020 2:01 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach2 Unguided imaging results from last night

Rolando, any suggestions on how many data points (in general) should be enough with APPM?

Larry


Bill Long
 

That really depends more on the scope you are using vs the modeling software and encoder system. On a refractor you can get extremely long subs with a very small model. On an SCT you can build very large models if you desire but the nature of those scopes can limit the exposure length on their own.

I personally use an 82 point model for all of my imaging. That seems to work perfectly well for me. The only problem I encounter is the lag in plate solving due to APPM not supporting lighter weight plate solving solutions like ASTAP or PS2.

-Bill  


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Larry Phillips <llp41astro@...>
Sent: Tuesday, October 13, 2020 2:01 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Mach2 Unguided imaging results from last night
 
Rolando, any suggestions on how many data points (in general) should be enough with APPM?

Larry


Dean Jacobsen
 

That is about what I am doing with my all sky models Ray   - between 45 and 50 - with my short focal length setup and small pixel setup.  Most of my imaging is done at either 530 mm [~1.5 arc sec/pixel]  or at about 380 mm [`2.05 arc sec/pixel].

My images are only 240 sec. max though.

APPM plate solves using SGP and PS2 only take one or two seconds each.  Only occasionally do I run into a long solve and it is a rare occasion that I get a failed solve.  So APPM runs pretty fast on my laptop.
--
Dean Jacobsen
http://astrophoto.net/wp/
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/ 
Amateur Radio Call Sign - W6DBJ


CurtisC <calypte@...>
 

On Tue, Oct 13, 2020 at 01:25 PM, uncarollo2 <chris1011@...> wrote:
However, if you are using APCC Pro (APPM) then just do an automated all-sky model. Doesn't take long.
But you aren't using APPM for this project, are you?