Hi Robin
I used ConeSharp and found my cone error to be 0 15'59", with the front of the telescope pointing out away from the mount. I was planning on adding a shim in the back of the scope to correct this but I have 2 issues: 1) my scope is over 12ft up in the air in my observatory and is heavy and 2) it is on a Losmandy dovetail which does not have a set screw or other convenient way/opening to even add a small shim. So, other than doing plate solving when I slew across the meridian to find out where I am, are you aware of a better, non-physical way, to correct for cone error using software (e.g., pointing model)?
Regards,
Bruce
Software solution for Cone Error?
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Re: Software solution for Cone Error?
Hi Bruce,
I'm not aware of any good way of correcting for cone error in software – in theory if you do a three-point alignment on your go to Mount then it should calculate and correct for cone error but my experience has been that this is a pretty hit and miss affair and that it's better to correct it. In situations where I have difficulty with an adjustable thread I have used one or more washers behind or in front of the dovetail to add some extra spacing.
Hope this helps, Robin
I'm not aware of any good way of correcting for cone error in software – in theory if you do a three-point alignment on your go to Mount then it should calculate and correct for cone error but my experience has been that this is a pretty hit and miss affair and that it's better to correct it. In situations where I have difficulty with an adjustable thread I have used one or more washers behind or in front of the dovetail to add some extra spacing.
Hope this helps, Robin
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Re: Software solution for Cone Error?
Thanks for the info, Robin. I will play with it some more and see what I can come up with.
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Re: Software solution for Cone Error?
Hi Again Robin
One more question which may be obvious to everyone but me. When the error popped up, it also said: ...."with the front of the telescope pointing out away from the mount." What is the front? Where the objective/eyepiece goes or the corrector plate/secondary mirror end (I have a SCT)? And if pointing out away from the mount, I am assuming adding the shim on the opposite end to raise it is the fix.
Thx
Bruce
One more question which may be obvious to everyone but me. When the error popped up, it also said: ...."with the front of the telescope pointing out away from the mount." What is the front? Where the objective/eyepiece goes or the corrector plate/secondary mirror end (I have a SCT)? And if pointing out away from the mount, I am assuming adding the shim on the opposite end to raise it is the fix.
Thx
Bruce
Re: Software solution for Cone Error?
Hi Bruce,
The next version of Astro-Physics hand control firmware is supposed to have a new feature that allows cone error correction to be saved so that your AP mount will automatically correct for cone error. I agree that shimming a heavy OTA like yours or my 14Edge is a pain. I saw this new feature mentioned by Roland in the AP GTO Yahoo forums recently.
In the meantime I have used thin stainless steel shims on the rear of my 14Edge OTA, placing them underneath the rear radius block that sits on top of my Losmandy rail. I have also used Conesharp and found it to be a nifty tool.
-Robin Clark
The next version of Astro-Physics hand control firmware is supposed to have a new feature that allows cone error correction to be saved so that your AP mount will automatically correct for cone error. I agree that shimming a heavy OTA like yours or my 14Edge is a pain. I saw this new feature mentioned by Roland in the AP GTO Yahoo forums recently.
In the meantime I have used thin stainless steel shims on the rear of my 14Edge OTA, placing them underneath the rear radius block that sits on top of my Losmandy rail. I have also used Conesharp and found it to be a nifty tool.
-Robin Clark
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Re: Software solution for Cone Error?
Hi Bruce,
By the front of the telescope I mean the bit that points towards the sky
Cheers, Robin
By the front of the telescope I mean the bit that points towards the sky
Cheers, Robin
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Re: Software solution for Cone Error?
WOW... Two Robins to help me out!! That is what I call service
Thanks much. What makes this so much worse for me is my scope being 12 ft off of the ground in my observatory. So, I have to use a safety ladder to make such changes. That is why I want to get this right the first time and be done with this issue. At least lifting weights 5 days a week should help pay dividends for this fix. I did not see that about the new AP hand controller. I sold mine a year ago as it does not help in the observatory.
Anyway, thank you both for coming to the rescue and I will remember what is the front of the telescope
Thanks much. What makes this so much worse for me is my scope being 12 ft off of the ground in my observatory. So, I have to use a safety ladder to make such changes. That is why I want to get this right the first time and be done with this issue. At least lifting weights 5 days a week should help pay dividends for this fix. I did not see that about the new AP hand controller. I sold mine a year ago as it does not help in the observatory.
Anyway, thank you both for coming to the rescue and I will remember what is the front of the telescope
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Re: Software solution for Cone Error?
Hi,
I think that if you are using an Ascom driver for your scope that can accept multiple synchronisations and build a pointing model then you will be able to correct the cone error by synchronising in a range of positions in the sky. Personally I've never tried that, but I believe EQMod and other advanced Ascom driver support this idea.
Cheers, Robin
I think that if you are using an Ascom driver for your scope that can accept multiple synchronisations and build a pointing model then you will be able to correct the cone error by synchronising in a range of positions in the sky. Personally I've never tried that, but I believe EQMod and other advanced Ascom driver support this idea.
Cheers, Robin