knobby

7 hours ago, vlaiv said:

Calibrate at around 0 DEC.

Sorry, typo I meant 0 as in celestial equator which here is about 30° up.

7 hours ago, malc-c said:

Have a look on YouTube for Dions guide to balancing the OTA. 

https://youtu.be/hGduG2jB9ec?t=131  and his recap https://youtu.be/uK2bXfVNoQU  They are old videos, but the information is current.  It deals with one issue that is often overlooked and that is the Centre of Gravity (CoG)

Basically with the mount as sweetly balanced, either with or without the bias for imaging it means that the guide system doesn't have to work harder or over compensates.  With belt modified mounts there are less items in the drivetrain to create backlash.  If the mount has been converted to a Rowan belt mode by the retailer, then the worm meshing and backlash should not need touching as they would (should) have set this up prior to selling the mount. 

My scope hadn't been used for nearly three years until recently when I gave it a full overhaul and set it all back up from scratch and then went through lots of fine tuning over several nights with PHD in order to get the best out of my finder guider.  Now the scope is performing really nice given the limitation of using a finder as a guide scope.

Cheers, I'll watch those later.

8 hours ago, Thalestris24 said:

By the way, I take it the mount is pointing close to North when you calibrate (always have DEC Compensation checked too)

Louise

Ah, interesting ... I've always calibrated at around 30° Dec ... Sort of South South East and up towards celestial equator.

39 minutes ago, Thalestris24 said:

Might there be any nearby members that could give you a hand / fresh pair of eyes?

Louise

Maybe after COVID ... 😁

9 minutes ago, Thalestris24 said:

Hi Knobby

You shouldn't need to nudge a belt driven mount in order to calibrate - that probably indicates a likely balance or setup problem. You should be able to get a perfect L-shape calibration, especially with an oag (the RA and DEC axes can be assumed to be orthogonal and obviously should be with an oag).

Louise

See what you've done 😁 there I was , prepared to accept the fact that I'm at the limit of the mount so living with it ! Now I'm going to be picky again 😂

Thanks Malc, I think it's a combination of things to be honest. Loss of confidence , poor weather / seeing, skill, expectation, mount limits.

It will calibrate pretty well on the replaced mount so long as I manually nudge North first.

Need a few nights of decent weather.

Hi Alan, reminds me of my tinkering with. Skywatcher 250 dob. I can't believe I've been dobless for 6 years 😂 I used a wixey digital angle gauge on the OTA and similar on the base, managed to find M13 for the first time using it. Wish I could find the pictures though.

Edit - found pics

Very good questions Malc, I use an oag, lynx eqmod cable, PHD2 on laptop, pulse guide. The mount has been replaced and will now calibrate ok if I nudge North first. I prefer to use the Synscan app as I got used to it with my AZ-GTI. But the last 2 attempts were with EQ mod to rule out the Synscan app.

With the counterweights removed it's fairly easily carried about. I leave mine assembled minus the weights, takes just a few minutes to carry from the garage to garden.

If it won't open, re install java.

Extract the zip to a folder - then right click the jar and run as administrator... I'll check on my laptop in a min😃

Thanks for all the help / comments, I'll make a list and try these next clear night ... probably some time in August  🙂 

This ones from the 5th, bad night - windy etc, i'll dig out last nights when I finish work ... it was very short though as clouded over.

edit - added 6th

PHD2_GuideLog_2020-07-05_230017.txt

PHD2_GuideLog_2020-07-06_175601.txt

17 minutes ago, Thalestris24 said:

Remember, it has to be balanced vertically as well as in RA and DEC 🙂 . Always make sure guide star is not saturated and has a good snr (or best you can get). Not sure what you mean by "the best tighter than the 2mm flex" ?? So with oag what fl are you using in PHD2? I've never used either a oag, or a SCT, or other long focal length scope, so I don't know how good the guiding would be expected to be. I'm sure someone else on here will have had the appropriate experience 🙂.

Louise

 

Sorry, was multitasking 🙂 should have read 'belt' i'll edit post

Thanks Louise, target points very random, using oag so guide star fairly iffy but was round and value in PhD was 5.8 (best I could get it). Mount is nice and free so I'm fairly sure balance was good.

Noticed another thread where @vlaiv suggests that a heavy scope needs the belt tighter than the 2mm flex with light finger pressure? I've emailed Rowan to see what they suggest. Really appreciate your time helping 😊

Starting to feel pretty despondent 😞 tried again last night, got nowhere fast, PA spot on in 20 mins (Sharpcap) quick align, calibrated PHD2 (With correct cam) usual dec backlash messages ... ran guide assistant, accepted suggestions and guiding up and down + and minus 2 or 3 ... well balanced, no cables flapping. Guess I'm really asking too much of the mount although others do use the combo successfully. I'm starting to wonder if it's just my seeing is too poor here. Good news is that this mount is better / more consistent than the one it replaced 👍 

Saga continues, since the replacement mount arrived had nothing but clouds! In desperation I set up last night but was pretty hazy and the gusts of wind got progressively worse all night. To compound the problems PHD2 chose my 1600mm instead of the 290mm to guide with ( not the mount or PHD2 fault but operator error) very frustrated.

Thinking of taking up cross stitching 😃

Ha, not too bad but Oiii not too good.

I use the Star adventurer bar and weight with an M12 to M8 adaptor, works well.

Agreed, I couldn't get a decent image from my bottle 6 (nearly 7) garden, bit the bullet and got the 1600 mm and Ha, Oiii and Sii filters. I won't be going back to OSC.

Or better still a used C9.25 ... As for getting a planet on a small chip, make sure finder is aligned as well as possible to camera, defocus the scope a bit and ramp up the gain, it's much easier finding a big bright donut than a tiny planet.

I think they're old fashioned camera tripod top screws, but someone will know for sure.

1/4-20 UNC

The filter wheel is as close as possible to the camera and I get very slight vignette but could be the scope or the filters so not sure.

All my imaging so far is with the 72ed on an AZ-GTi but the C8 will be having a crack on the HEQ5 soon. It's my second one as the first tracked well but intermittently had a wobble so went back for exchange. Haven't tried the replacement yet as cloudy since it arrived.

1.25 " ZWO filters mounted LRGB and Ha Oiii and Sii

Mmmmmm disturbing !