TheSkySearchers

AstroBee wrote: ↑Sun Aug 20, 2023 3:52 pm Glad the night was mostly successful.

Cheers Greg.

And thanks for your help.

It's clear again tonight. Think I'll probably have another go!



Graeme

Best of success Graeme!

SkyHiker wrote: ↑Sun Aug 20, 2023 4:38 pm Congratulations! I would expect better guiding from a CGX than 0.78 RMS, once you get it nailed. You need better performance for an SCT. One suggestion, while PHD2 can compensate for DEC backlash to some extent, it cannot achieve the rapid motor speedup provided by the Nexstar backlash compensation. You may want to give it a try for DEC, though it can backfire when not set accurately. I did this with my AVX, and it seemed to work OK. First of course I would check if the DEC worm can be tighter without binding up.

Cheers Henk

I can tighten the belts a tad more, I didn't want to over do it! I've got 3mm-4mm deflection. The CGX worm drive shaft is held against the brass cog by a spring, I don't know if the AVX is the same and I haven't taken it apart enough to adjust it except to check the recommended 1mm movement of the worm drive/motor block assembly.

The next step is either strip down the worm drive end, clean it up and lap it as per Joe @OzEclipse's suggestion and re-grease again or to dismantle the other end of the shafts and inspect and re-grease the roller bearings. I don't fancy either if I can help it! So I'll see how it goes for a while and then decide!

Of course the other option is to pay someone else to do it! I found www.DarkFrameOptics.com they provide the service and they're only an hour from me. Anyone heard of them?

The PHD advice is to not use the Nexstar backlash compensation because they fight against each other.

Graeme

Graeme1858 wrote: ↑Sun Aug 20, 2023 6:02 pm Of course the other option is to pay someone else to do it! I found www.DarkFrameOptics.com they provide the service and they're only an hour from me.

Adjusting gear boxes should be second nature, I think. Here's a detailed tutorial of someone who reported getting a CGX to the 0.2s. Pretty interesting.

BTW my AVX did not have springs as far as I remember. I did get it to lock up once to the point where I had to turn it in to Celestron. They were quite helpful and reasonable. Also BTW, I wonder how many people have tried the Nexstar backlash compensation. It should be transparent so long as the compensation is proper for any telescope position. Clearly, if it is too tight it can start kicking away due to the nature of it.

Hi Graeme, congrats on getting at least decent guiding.

Just a quick question because sometimes this is overlooked when we're down in the weeds are trying to figure stuff out, but have you rebalanced your setup to make sure you've got it as good as you can?

JayTee wrote: ↑Sun Aug 20, 2023 8:07 pm Hi Graeme, congrats on getting at least decent guiding.

Just a quick question because sometimes this is overlooked when we're down in the weeds are trying to figure stuff out, but have you rebalanced your setup to make sure you've got it as good as you can?

Thanks JT.

Good shout, but, yes, I rechecked both the balance and the PA prior to starting.

I'm hoping at least half the problem is the Jet Stream, it was over head last night and it's overhead tonight. And I'm getting similar figures tonight too.

Here's the Jet Stream right now:


That's about as bad as it gets!

Graeme

Graeme1858 wrote: ↑Sun Aug 20, 2023 11:18 pm Here's the Jet Stream right now:

Yowee!

I'm sure that a lot of us forget to look at conditions such as the jet stream to understand why our Imaging might not be as good as it should be.

Good luck, and keep us posted.