How long for UNGUIDED imaging with non AE mounts?


Bob
 

Following on from an earlier thread, does anyone have any info on the length of unguided imaging possible using a 1100GTO or similar with a focal length of up to about 700mm? Assuming the mount is very well aligned.

Thanks
Bob


Roland Christen
 

I have gone up to an hour with 1000mm FL and 5.4 micron pixel camera. Some nights and in some places in the sky it doesn't work out as well. Theoretically if you have a good path mapped, you can go all night. Practically you will probably need to refocus every 20 minutes. In the early part of the night you will also have satellite trails, so it's better to have lots of 15 minute shots that can be Median combined to eliminate them.

Rolando



-----Original Message-----
From: astro@...
To: main@ap-gto.groups.io
Sent: Mon, Feb 8, 2021 10:49 pm
Subject: [ap-gto] How long for UNGUIDED imaging with non AE mounts?

Following on from an earlier thread, does anyone have any info on the length of unguided imaging possible using a 1100GTO or similar with a focal length of up to about 700mm? Assuming the mount is very well aligned.

Thanks
Bob

--
Roland Christen
Astro-Physics


Bob
 

On Tue, Feb 9, 2021 at 11:15 PM, Roland Christen wrote:
I have gone up to an hour with 1000mm FL and 5.4 micron pixel camera.

--
Roland Christen
Astro-Physics
First, excuse me for asking for clarification/confirmation of what you just stated. My excuse is I am a virgin with AP gear.

So I have a gto1100 (hopefully soon) without Encoders. All other things being equal, and at moderate focal lengths, I can expect to achieve good unguided images with exposures in the tens of minutes? Maybe even up to 1 hour?

Cheers
Bob


Peter Nagy
 

Bob,

With or without pointing model using APCC Pro?

Peter 


Roland Christen
 


I can expect to achieve good unguided images with exposures in the tens of minutes? Maybe even up to 1 hour?
Probably not. I was doing unguided imaging with an encoder mount. I apologize if I misled anyone.
A mount that does not have shaft encoders is open loop and is at the mercy of the periodic error that is produced by the gearbox. One can minimize that error using PEM but that does not guarantee that it will track to sub-arc sec levels for an hour.

Rolando


-----Original Message-----
From: astro@...
To: main@ap-gto.groups.io
Sent: Thu, Feb 11, 2021 2:01 am
Subject: Re: [ap-gto] How long for UNGUIDED imaging with non AE mounts?

On Tue, Feb 9, 2021 at 11:15 PM, Roland Christen wrote:
I have gone up to an hour with 1000mm FL and 5.4 micron pixel camera.

--
Roland Christen
Astro-Physics
First, excuse me for asking for clarification/confirmation of what you just stated. My excuse is I am a virgin with AP gear.

So I have a gto1100 (hopefully soon) without Encoders. All other things being equal, and at moderate focal lengths, I can expect to achieve good unguided images with exposures in the tens of minutes? Maybe even up to 1 hour?

Cheers
Bob

--
Roland Christen
Astro-Physics


Bob
 

On Thu, Feb 11, 2021 at 10:20 PM, Peter Nagy wrote:
Bob,

With or without pointing model using APCC Pro?

Peter 
Hi Peter

With a pointing model. I would assume several minutes would be achievable? How large would the model need to be?

Thanks
Bob


Worsel
 

Bob

I have a 200 point model for a non-AE 1100 (PEM enabled) with a 2500 mm scope. I have been able to image (0.54 a-s/pxl) unguided for 15 minutes, but not consistently.  With a 700 mm scope, I think you could easily do the same and more consistently than me.


Bryan


Bob
 

On Fri, Feb 12, 2021 at 12:19 PM, Worsel wrote:
Bob

I have a 200 point model for a non-AE 1100 (PEM enabled) with a 2500 mm scope. I have been able to image (0.54 a-s/pxl) unguided for 15 minutes, but not consistently.  With a 700 mm scope, I think you could easily do the same and more consistently than me.


Bryan
Thanks Bryan

So how long does it take to create a 200 point model?


Ray Gralak
 

So how long does it take to create a 200 point model?
That depends somewhat on image download time and plate solve time. Faster downloads will reduce time. A faster computer will usually plate-solve faster.

Typically it takes about 2-3 points/minute, so probably in the range of 65 to 100 minutes. If the setup is not moved or changed the model can last for months.

-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 astro@dinoworld.com.au
Sent: Friday, February 12, 2021 12:20 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] How long for UNGUIDED imaging with non AE mounts?

On Fri, Feb 12, 2021 at 12:19 PM, Worsel wrote:


Bob

I have a 200 point model for a non-AE 1100 (PEM enabled) with a 2500 mm scope. I have been able to
image (0.54 a-s/pxl) unguided for 15 minutes, but not consistently. With a 700 mm scope, I think you could easily
do the same and more consistently than me.


Bryan

Thanks Bryan

So how long does it take to create a 200 point model?


Worsel
 

As Ray notes, it depends...

Following is likely TMI!

For my 200 point model, it took 88'.  This is based on the time delta between first and last image, which is all captured in the model file (*.PNT) in C:/Program Data/AstroPhyscis/APPCC/Models (if you do not change the default folder).  The actual time is a bit longer to initialize SGP and APPM and load the model after.

About 25" to take a 5" image (19 M full-frame), plate solve, slew to next position, 2" settle time.  This can vary, mostly with the slew time.  I use SGP to take the image and plate-solve either with ASTAP or a local install of Astrometry.net.  ASTAP is much faster, but does not always solve.  AN is slower, but has never failed, if I set it up correctly.  Fairly fast PC.

If you go back through threads from last 6 months or so, you will find a discussion of doing localized sub-models in the areas you plan to image on a given night.  A valid approach, but open to discussion as to any time savings.  I recall Roland using a technique where he used a filter (H-alpha ?) during the model build that allowed him to start taking images for the model long before it was dark enough to take long-exposure images.

Bryan


Emilio J. Robau, P.E.
 

I guess you should also remodel every time you do some load changes or tweaking of balance?   

 

I have to comment, potentially adversely to AP sales.   The non-encoder option is so freaking accurate that sometimes I don’t know why people even buy it.   I love my mount.  In fact, I am thinking of giving it a bath for Valentine’s day.  You know, a private thing in the observatory…. 

 

Seriously, the other item I want to comment on is the fact that it is kind of silly to set tracking times on PH-2 of 5 seconds when you can really go much much longer without doing supplemental tracking at all.  How long are people setting the exposure times?


Does the model add that much more accuracy to the tracking?

 

Finally, I guess having the encoders is like once you have the encoders you really appreciate their functionality?   If so, I am just going to avoid them, because right now my love for my 1600 is deep and there is no need to ruin a good relationship.

 

Emilio J. Robau. P.E.

Professional Engineer

Florida, Montana, North Carolina

www.robau-designs.com

 

Designs for Human Habitation and Environmental Conservation

Civil Engineering - Project Management – Permitting – Consulting  Ph: 239-206-8000 Direct: 239-204-4322

2770 Horseshoe Drive S, Suite 7, Naples, Florida 34104

 

This e-mail message is sent from Robau and Associates, LLC, and is intended only for the addressee. This message and any attachments may contain information that is confidential or privileged. Upon receipt of any electronic file/data from Robau and Associates, LLC, you are agreeing to the following: This file/data is for informational purposes only. It is the responsibility of the recipient to reconcile this electronic file/data with the actual project site conditions. Recipient agrees to indemnify and hold harmless Robau and Associates, LLC for any defects or errors in this file/data.  Unauthorized use, dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this email in error, please notify the sender by reply e-mail and delete the message and any attachments.

 


 

Emilio,

 

While the mount can tolerate a light sprinkle, I suggest strongly against full submersion in water; as fun as it may sound on a special day.  

 

Perhaps flowers, a wipe with soft cloth and no-bleach window cleaner, chocolates, or a good regreasing would be a better way to show you mount affection. Glad to hear you have such a strong relationship with your mount!😃

 

Liam Plybon

Astro-Physics

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Emilio J. Robau, P.E.
Sent: Friday, February 12, 2021 1:33 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] How long for UNGUIDED imaging with non AE mounts?

 

I guess you should also remodel every time you do some load changes or tweaking of balance?   

 

I have to comment, potentially adversely to AP sales.   The non-encoder option is so freaking accurate that sometimes I don’t know why people even buy it.   I love my mount.  In fact, I am thinking of giving it a bath for Valentine’s day.  You know, a private thing in the observatory…. 

 

Seriously, the other item I want to comment on is the fact that it is kind of silly to set tracking times on PH-2 of 5 seconds when you can really go much much longer without doing supplemental tracking at all.  How long are people setting the exposure times?


Does the model add that much more accuracy to the tracking?

 

Finally, I guess having the encoders is like once you have the encoders you really appreciate their functionality?   If so, I am just going to avoid them, because right now my love for my 1600 is deep and there is no need to ruin a good relationship.

 

Emilio J. Robau. P.E.

Professional Engineer

Florida, Montana, North Carolina

www.robau-designs.com

 

Designs for Human Habitation and Environmental Conservation

Civil Engineering - Project Management – Permitting – Consulting  Ph: 239-206-8000 Direct: 239-204-4322

2770 Horseshoe Drive S, Suite 7, Naples, Florida 34104

 

This e-mail message is sent from Robau and Associates, LLC, and is intended only for the addressee. This message and any attachments may contain information that is confidential or privileged. Upon receipt of any electronic file/data from Robau and Associates, LLC, you are agreeing to the following: This file/data is for informational purposes only. It is the responsibility of the recipient to reconcile this electronic file/data with the actual project site conditions. Recipient agrees to indemnify and hold harmless Robau and Associates, LLC for any defects or errors in this file/data.  Unauthorized use, dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this email in error, please notify the sender by reply e-mail and delete the message and any attachments.

 


Worsel
 

Emilio

1. I set my PHD2 exposures to 4 s (when I am guiding...see 2), but I also set a delay in between exposures.  I continue to experiment with that delay from 3s to 10s. 
2. Yes, my experience with the model is that it does improve both tracking and GoTos.   I had the 1100 since 2016.  I would not have been able to image Un-guided before implementing modelling in 2019.  I still guide at times, especially for longer exposures.

Bryan