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Walking on the Moon

About to start guided imaging - tips, tricks?


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Hello, I recently bought HEQ5 SynScan with belt modification and ASI120MM with 50mm guidescope should arrive in the next few days. I heard from other astrophotographers that PHD2 is good software for guiding. For imaging I will use 70mm f/6.78 quadruplet with Nikon D5100.

Lets assume my polar scope is perfectly collimated, my scope is well balanced and there is no backlash etc. Once I start guiding, what kind of exposure times can I expect? 5mins, 10mins, or 1 hour? Or does this become irrelevant since guider corrects mounts movements?

Or should I use polar scope at all and go straight to drift align?

Also any tips or tricks with PHD2 would be much appreciated. :happy11:

Edited by VilleM
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Getting the PA right is most of the battle, i use the handset PA option run it a couple of times, then remove the handset and use EQMod, i have never gone longer then 20 minutes but its likely it will, you sky LP will determine how long you can image before it saturates the sensor, PHD2 mine just guided so can't added anything....

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I go straight to drift alignment if I can get a reasonably close starting point. Polar scopes don't work so well in the southern hemisphere.

If you get a good PA, typically 1 arc-minute is the goal, then 10 minute exposures are achievable, maybe more. Different limiting factors then come in like flexure, cable drag, sky background.

Tips for PHD2: 

Connect it to the mount with an EQDIR cable. This lets PHD2 talk to the mount so it has more information. Also makes troubleshooting easier.  You can use a serial cable to the hand controller but I prefer a direct connection

Use the View > Display Star Profile option and make sure the guide star is focused and not saturated

Make sure you get a good calibration before guiding. PHD2 wont guide reliably without a good calibration. Too many people get a calibration warning but keep on going, then wonder why their guiding is so bad.

Spend 30 minutes once in a while to get a log from PHD2 without guiding, preferably near the equator. This will tell you a lot about how your mount performs without any guiding. I've seen too many posts thinking PHD2 has a bug or is misconfigured when it is an underlying mechanical issue or operating error. One of the great uses for PHD2 is as a data gathering tool

Learn where PHD2 stores its log files and use PHD Log Viewer to view them after a session. If you have a problem with your guiding, post the log file in the forum. Screenshots are next to useless.



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Drift alignment is the ideal way to go but can be time consuming, of course. The system you propose using should work well - aim for 2 second minimum guide exposures. 10 minute exposures will be easily achievable and more than sufficient for a wide range of deep sky objects but 15 - 20 minutes should also be within reach depending on your light pollution.

Like 'Tinker', I too would also recommend using EQMod and pulse guiding rather than using the ST4 port.

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