Re: PHD2 "Use Dec compensation" on or off?

Eric Weiner

I agree it was a good explanation of declination compensation. The question was if this option is relevant if an APPM high density all sky model is operating. The model would account for the variation in Dec tracking rates as a function of Dec. So it seems any math PHD2 applies will interfere with the APPM tracking rates. Hence my original post.

Eric

Re: large donut in Ha image

david w pearson

TPO RC-12, SBIG STF-8300m with filter wheel w 37mm filters, AP 0.67x reducer, shooting at 1700mm, off axis guider, AP1200 mount on permanent pier
group observatory, 10 min consecutive ha subs

Re: PHD2 "Use Dec compensation" on or off?

Steven Panish

Second that!
Steve

On Sun, Jan 30, 2022 at 7:58 PM michael mccann via groups.io <mmccawsprojects=icloud.com@groups.io> wrote:
Great explanation Wade 👍

Re: PHD2 "Use Dec compensation" on or off?

michael mccann

Great explanation Wade 👍

Re: PHD2 "Use Dec compensation" on or off?

W Hilmo

Consider what's happening when the RA axis moves.

If you are pointed at the celestial equator (0 degrees declination), moving the RA axis 1 arc second will move the field east or west 1 arc second.  If you are pointed at the celestial pole (90 degrees declination), moving the RA axis 1 arc second will just cause 1 arc second of field rotation.  The center of the field won't move at all, no matter how much the RA axis moves.

The purpose, then, of declination compensation is to calculate the effective movement rate of the field in RA, based on the declination of the target.  I believe that the math is pretty straight forward trigonometry:  The effective rate is the cosine of the declination.

At 0 degrees declination, the movement rate is cosine of 0, which is 1x.  At 90 degrees declination, the effective movement rate is cosine 90, which is 0x.  At 45 degrees declination, the effective movement rate is cosine 45, or about 0.707x.

The guide software needs to make this calculation so that it knows how the field will change with a given movement command in RA.

Does that make sense?

On 1/30/22 4:32 PM, ap@... wrote:

On Sun, Jan 30, 2022 at 07:12 PM, Eric Weiner wrote:
"Automatically adjust RA guide rate based on scope declination."
My understanding is you should check it, so that the adjustments are scaled by DEC.  It is not changing the tracking rate (i.e. what APPM is governing) but the guiding adjustment pulse.

Here from their manual:

'Use Declination Compensation' - ifPHD2 can get pointing information from the mount via an ASCOM connection ('Mount' or 'Aux'), it will automatically adjust the RA guide rate based on the current declination. This box should normally be left checked except in unusual cases. For example, SiTech mount controllers may apply a compensation automatically, in which case the box should be left un-checked. Don't confuse this option with 'Declination backlash compensation', which is an entirely different feat

Though this has always baffled me a bit, as it is unclear to me what sort of adjustment it makes, one day I need to look at the code and see how the math works.  Is it more aggressive at high DEC because a smaller arc second displacement needs more RA movement to correct?

But I'm going on instinct (and that document) not knowledge, is it right for AP/APCC?

Linwood

Re: PHD2 "Use Dec compensation" on or off?

Richard Hennig

Hi Linwood,

I would expect that this compensation corresponds to the cos(Dec). At higher declination, an RA guide pulse of a fixed time will corresponds to fewer pixels on the guide camera. That geometric ratio is cos(Dec). So, just like you are thinking, at higher declination, the guide pulses should become longer by 1/cos(Dec) compared to a reference guide pulse at the celestial equator.

I have no idea how this will work when guiding very close to the pole where this correction and equatorial mounts have a singularity.

Clear skies,
Richard

On Jan 30, 2022, at 7:32 PM, ap@... wrote:

﻿On Sun, Jan 30, 2022 at 07:12 PM, Eric Weiner wrote:
"Automatically adjust RA guide rate based on scope declination."
My understanding is you should check it, so that the adjustments are scaled by DEC.  It is not changing the tracking rate (i.e. what APPM is governing) but the guiding adjustment pulse.

Here from their manual:

'Use Declination Compensation' - ifPHD2 can get pointing information from the mount via an ASCOM connection ('Mount' or 'Aux'), it will automatically adjust the RA guide rate based on the current declination. This box should normally be left checked except in unusual cases. For example, SiTech mount controllers may apply a compensation automatically, in which case the box should be left un-checked. Don't confuse this option with 'Declination backlash compensation', which is an entirely different feat

Though this has always baffled me a bit, as it is unclear to me what sort of adjustment it makes, one day I need to look at the code and see how the math works.  Is it more aggressive at high DEC because a smaller arc second displacement needs more RA movement to correct?

But I'm going on instinct (and that document) not knowledge, is it right for AP/APCC?

Linwood

Re: PHD2 "Use Dec compensation" on or off?

ap@CaptivePhotons.com

On Sun, Jan 30, 2022 at 07:12 PM, Eric Weiner wrote:
"Automatically adjust RA guide rate based on scope declination."
My understanding is you should check it, so that the adjustments are scaled by DEC.  It is not changing the tracking rate (i.e. what APPM is governing) but the guiding adjustment pulse.

Here from their manual:

'Use Declination Compensation' - ifPHD2 can get pointing information from the mount via an ASCOM connection ('Mount' or 'Aux'), it will automatically adjust the RA guide rate based on the current declination. This box should normally be left checked except in unusual cases. For example, SiTech mount controllers may apply a compensation automatically, in which case the box should be left un-checked. Don't confuse this option with 'Declination backlash compensation', which is an entirely different feat

Though this has always baffled me a bit, as it is unclear to me what sort of adjustment it makes, one day I need to look at the code and see how the math works.  Is it more aggressive at high DEC because a smaller arc second displacement needs more RA movement to correct?

But I'm going on instinct (and that document) not knowledge, is it right for AP/APCC?

Linwood

PHD2 "Use Dec compensation" on or off?

Eric Weiner

Did a search and couldn't find any info on this.  If using an APPM tracking model (with Mach2) should the "Use Dec compensation" in the PHD2 advanced Guiding option be on or off?  This is not the backlash option.  The description states, "Automatically adjust RA guide rate based on scope declination."  I'm guessing this should be off if the tracking model is active.  Anyone have input?

Thanks,
Eric

Re: APCC and MGBox V2

Larry Phillips

Ray and Brian, it looks like it is fixed.  On the MGBox web site with a file listed below the previous V2 version that I thought was part of that older version, but is the file I needed.  Thanks, Brian for making me look again at the web site.

Larry

Re: APCC and MGBox V2

Check out their website Larry

On Sun, Jan 30, 2022 at 2:42 PM Larry Phillips <llp41astro@...> wrote:
Brian, where do I find those drivers?  The only thing I get from MGbox is a .hex file which I have no idea what to do with.
Larry

--
Brian

Brian Valente

Re: APCC and MGBox V2

Larry Phillips

Brian, where do I find those drivers?  The only thing I get from MGbox is a .hex file which I have no idea what to do with.
Larry

Re: APCC and MGBox V2

Hi Larry,

A couple other things. Make sure you aren’t connected to the MGbox app directly, instead of using the Ascom driver for the app. And of course also make sure you install both the driver and the Ascom driver for MGbox

On Sun, Jan 30, 2022 at 12:46 PM Ray Gralak <iogroups@...> wrote:
Larry,

Did you configure the Environmental settings in APCC to use MGBox? (via APCC's menu: Settings->Environmental Settings).

-Ray

> -----Original Message-----
> From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Larry Phillips
> Sent: Sunday, January 30, 2022 11:50 AM
> To: main@ap-gto.groups.io
> Subject: [ap-gto] APCC and MGBox V2
>
> Ray, after all the trouble I have had getting APCC up and running with Eltima and Serial to USB adapters, it
> appears I have one last problem (I hope) with APCC now trying to communicate with the temp sensor MGBox
> V2.  There are two attached screen shots.  The first shows the initial error message about the ascom driver
> ascom.OCH.ObservingConditions not connecting.  Also, in this image it does show the sensor communicating
> with their software.  In the next screen shot it shows it cannot create an ActiveX component.  I do not know
> what to do next.  I tried to find a download but was unsuccessful.
>
> Larry
>

--
Brian

Brian Valente

Re: APCC and MGBox V2

Larry Phillips

Ray, no I had not.  But when I just tried, there is no choice except for a simulator.  See the two screen captures.

Larry

Re: APCC and MGBox V2

Ray Gralak

Larry,

Did you configure the Environmental settings in APCC to use MGBox? (via APCC's menu: Settings->Environmental Settings).

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Larry Phillips
Sent: Sunday, January 30, 2022 11:50 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] APCC and MGBox V2

Ray, after all the trouble I have had getting APCC up and running with Eltima and Serial to USB adapters, it
appears I have one last problem (I hope) with APCC now trying to communicate with the temp sensor MGBox
V2. There are two attached screen shots. The first shows the initial error message about the ascom driver
ascom.OCH.ObservingConditions not connecting. Also, in this image it does show the sensor communicating
with their software. In the next screen shot it shows it cannot create an ActiveX component. I do not know
what to do next. I tried to find a download but was unsuccessful.

Larry

APCC and MGBox V2

Larry Phillips

Ray, after all the trouble I have had getting APCC up and running with Eltima and Serial to USB adapters, it appears I have one last problem (I hope) with APCC now trying to communicate with the temp sensor MGBox V2.  There are two attached screen shots.  The first shows the initial error message about the ascom driver  ascom.OCH.ObservingConditions not connecting.  Also, in this image it does show the sensor communicating with their software.  In the next screen shot it shows it cannot create an ActiveX component.  I do not know what to do next.  I tried to find a download but was unsuccessful.

Larry

Re: StarAid

Eric Weiner

And mirrorless 😉

On Jan 30, 2022, at 10:41, Konstantin v. Poschinger via groups.io <poschinger@...> wrote:

﻿Hi,

only DSLR!

Konstantin

Konstantin v. Poschinger

Hammerichstr. 5
22605 Hamburg
040/8805747
0171 1983476

Am 30.01.2022 um 18:40 schrieb Eric Weiner <weinere@...>:

The new StarAid version supports dithering with certain cameras.

Re: StarAid

Konstantin v. Poschinger

Hi,

only DSLR!

Konstantin

Konstantin v. Poschinger

Hammerichstr. 5
22605 Hamburg
040/8805747
0171 1983476

Am 30.01.2022 um 18:40 schrieb Eric Weiner <weinere@...>:

The new StarAid version supports dithering with certain cameras.

Re: StarAid

Eric Weiner

The new StarAid version supports dithering with certain cameras.

Re: StarAid

richard payne

I forgot to mention I have used it on both
my AP400 and AP1100

On Jan 30, 2022, at 7:59 AM, Greg Salyer <astronutcase@...> wrote:

﻿
It does work with the AP900.

On Jan 30, 2022, at 9:56 AM, Don Price <don@...> wrote:

﻿I came across this unit at a recent video presentation and was very intrigued. This is my single biggest challenge in using my really nice instrument (AP900/127mm refractor). They list a few AP mounts where the unit has been tested but the AP900 is not listed. So makes me wonder if the StarAid has been used with the AP900 and if it works. So, if you have experience with the StarAid on an AP900 it would be very nice to hear from you. This could be a really nice addition to my instrument collection and the single largest impact towards improving my observing time.

Don

Re: StarAid

richard payne

Hi, I have a Staraid I bought from the inventor while at Tivoli in  Namibia a couple of years ago. It works great but.... you will have to manual dither . No issues except you use a phone and tablet to control it.
Richard Payne

On Jan 30, 2022, at 7:59 AM, Greg Salyer <astronutcase@...> wrote:

﻿
It does work with the AP900.

On Jan 30, 2022, at 9:56 AM, Don Price <don@...> wrote:

﻿I came across this unit at a recent video presentation and was very intrigued. This is my single biggest challenge in using my really nice instrument (AP900/127mm refractor). They list a few AP mounts where the unit has been tested but the AP900 is not listed. So makes me wonder if the StarAid has been used with the AP900 and if it works. So, if you have experience with the StarAid on an AP900 it would be very nice to hear from you. This could be a really nice addition to my instrument collection and the single largest impact towards improving my observing time.

Don

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