Telescope Setup for PH2

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Graeme1858 Great Britain
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Telescope Setup for PH2

#1

Post by Graeme1858 »


Hello

My guide scope is on my Christmas list so I'm still at the research stage. Astroglide65's thread (viewtopic.php?f=42&t=4088#p34377) raised a question in my head but I didn't want to pirate his thread.

KathyNS states, as others too have said, "If you will be guiding with ASCOM pulse guiding, you want to calibrate with the scope facing south,"

So how does that work in practice if you're imaging an object that isn't to the south and the guide scope is mounted on and parallel to the imaging scope? Are the calibration star and the imaging guide star two separate stars? Is the PH2 calibration something that is done prior to setting up for the imaging run?

And if that's the case why does everyone go for pulse guiding over ST4 guiding if you can calibrate on your guide star with ST4 guiding?

Cheers

Regards

Graeme
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JayTee United States of America
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Re: Telescope Setup for PH2

#2

Post by JayTee »


This is from one of my posts over at AF.net.

PHD2 was written (according to its authors) to maximize the connection provided by using the ASCOM drivers. Here are the authors reasons for using pulse guiding vs ST4 guiding. Remember, they have nothing to gain from choosing one format over the other unless one is significantly better at performing its job of guiding the telescope.

From the PHD2 manual:

If you're running on a Windows platform, you'll probably be better off using an ASCOM connection for guiding your mount. This advice may be contrary to some old-school experience or folklore on the Web and probably isn't what you'll hear from the manufacturer of the guide camera. But the benefits of doing so with PHD2 are substantial, and you should use this alternative unless you have specific and credible information against it. Here are some of the primary benefits:

1. A drastic reduction in the number of re-calibrations you'll need to perform. Changing targets will not require another calibration because PHD2 can know where the scope is pointing and automatically make adjustments to the guider calibration. Most users get a good calibration and then re-use it until they make hardware changes of some kind.
2. Automatic adjustment for meridian flips - no need to remember to manually flip the calibration data.
3. Automatic adjustment of RA calibration to handle targets in different parts of the sky (declination compensation)
4. Elimination of the ST-4 guide cable as a point of failure - this is a surprisingly common problem because the cables can be damaged or confused with similar-looking cables (e.g. telephone cables)
5. Elimination of a moving cable that can snag, drag, or bind as the scope is moved around.
6. Improved ability for PHD2 to sanity-check calibration results and warn of possible problems before you waste hours of imaging time.
7. Better diagnostic and troubleshooting information, which is particularly helpful if you need to ask for assistance
8. Availability of scope-slewing options during drift alignment which can further speed the process of polar alignment

FWIW, I no longer recommend using the ST4 port unless it is your only option. As shown above the pluses for using pulse guiding severely outweigh the simplicity of ST4 guiding.


Cheers,
JT
∞ Primary Scopes: #1: Celestron CPC1100 #2: 8" f/7.5 Dob #3: CR150HD f/8 6" frac
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Baskevo
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Re: Telescope Setup for PH2

#3

Post by Baskevo »


viewtopic.php?f=42&t=914
viewtopic.php?f=42&t=2276

Those two posts by that admin. ^ right there helped me a lot (thanks JT!).

Calibrating is what you do before you start guiding. You connect your equipment, and before you can start guiding, you have to calibrate your guide camera with PHD2 (done automatically when you click the guide button for the first time). When you calibrate, you will want to point your guidescope to the celestial equator and meridian (in the south), and because it is attached to your telescope, you will just slew to it with your telescope.
After it's done calibrating, and done everything else you might need or want to do to improve your guiding, you will be ready for imaging, so you will slew to your target, and select a star or auto-select a star, and then you will guide :) You will likely be using ASCOM, so you can reuse the calibration for different nights.
-James W.

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Graeme1858 Great Britain
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Re: Telescope Setup for PH2

#4

Post by Graeme1858 »


Thanks for the links and verbose answers. That helps hugely with the research!

Right, I'm going to go read all that I can find on the CGX mount PEC.

Regards

Graeme
______________________________________________
Celestron 9.25 f10 SCT, f6.3FR, CGX mount.
ASI1600MM Pro, ASI294MC Pro, ASI224MC
ZWO EFW, ZWO OAG, ASI220MM Mini.
APM 11x70 ED APO Binoculars.

https://www.averywayobservatory.co.uk/
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