waylander

So that sounds like what most people do for M42 which is a large scale structure. So you can just cut out the blown out core and replace with the other shorter exposure segment- but the OP is talking about "stars" in general, how easy is it to combine the properly exposed stars from one image with the galaxies from another. Can Pixinsight do this do we know? I'm facing similar issues, short exposure not enough DSO detail, long exposures blown out stars with no color.

Have just been back over old guide logs and have seen a few examples of great guiding in RA (like 0.5-0.6") for long periods so looks like the mount is capable of it if set up by a competent person.

Noticed that my RA balance was very very out - like the counterweight was 1/3 of the way on the countershaft (3 inches?) out according to the handsets auto balance routine. That could have contributed to the rubbish RA...

Yes boss

Right tomorrow night I’ll do this again. I’ll adjust the worm and try bigger minmo and lower aggression for both axes.

It just recommended 20 minmo for R.A. and 30 for dec. didn’t seem right to me. oh one other thing... I don’t level my mount at all... should that matter?

Ga didn’t recommend to turn on backlash compensation so I’m assuming it didn’t think that was bad enough to mention?

I was kind of happy with the dec to be honest! Do you think reducing the guide rate for R.A. will help at all? The R.A. was the thing that most concerned me as any changes seem to aggressive and cause a bounce. Thought if I reduced the R.A. guide rate and hence hopefully reduced the effect of any changes it might settle down a bit. I’ll make the slight change mentioned to the R.A. end cap too. Forgot to do a ga run... didn’t do one till the end of the night just to see what it said.

Went out last night and tried again to get better guiding. Moved both axes to 0.9x guide rate to sort backlash, which proved effective. Calibration went better, seeing was better so lots of stars. Guiding was generally very good in DEC (0.3-0.6" ish) but worse in RA all night (1-1.2"). I feel i understand the DEC axis now, but RA is another thing entirely. I noticed i do have some binding at one point in the RA rotation, so im gonna very slightly slacken off the RA rocker adjustment screw (like 1/32 of a turn). Perhaps that could also be causing too much friction in RA generally too? Warned to improve guide star focusing, which may be fair, so gonna buy a helical focuser for the OAG. However - with regards to the RA i just cannot get it to settle down, i've tried high agg, low agg, high minmo, low minmo. So im gonna try and set that axis to a lower guide rate, it could be it just needs less "work" to keep it in the green. So gonna go for 0.3x on RA next outing and keep DEC at 0.9. Any thoughts, let me know! Have attached logs. PHD2_GuideLog_2020-04-11_204631.txt

My mental load was at Max though. Lots of things to remember!

Hi Michael. I did offset the balance a little, but noticed that due to updating the firmware on the handset it reverted my 0.9x guide rate... didn’t check it. no I didn’t get chance to run north for a while to take up the backlash. Honestly I spent a lot of time just trying to find stars at dec 0 in the clouds! For such a clear night they knew where to cause maximum damage. and yeah. Trying to resist fiddling too much with settings! Once I get a clear night next week away from the full moon I’ll try focus properly (hard!) and redo everything again. I’ve got a good feeling about this. Thanks again, I’ll post a pic on here to show my progress once I get better skies.

A question on this then. What signs in my guiding am I looking for which will tell me my mount needs adjusting? My ra binds occasionally and guiding has always been worse on the axis with random spikes too. how much deflection should the belt have? Ie how can I tell if it does need adjusting tightening whatever?

Ill try that - actually i do get binding sometimes so i reckon mine needs backing off a bit. How to adjust the allen head screws though? You mean the ones where the belt is?

I havent - is there a guide on how to do this? Im completely allergic to hardware... completely inept!!

Ok managed to do some imaging last night - they aren't really usable as it was almost full moon (not enough contrast). Tried to calibrate at DEC 0 but too many clouds so had to shift it around a bit higher. Still kept losing guide stars - but again the seeing wasn't great and i struggled to get decent focus with either camera. Tried an imaging run of M101, guiding was initially around 1.3arc sec, but later on in the night after id enabled PPEC and tweaked the settings i did see my guiding get down to 0.7-0.8 for a while. RA seems worst, need to tame it, hence changing the settings a bit - tried to get the OSC value to 0.5. I should also point out the calibration wasn't great - phd2 warned me to do it again as it was sub-optimal. I also noticed after going through the logs that my guide rate had reverted to 0.5x, so next time ill put that back to 0.9 which would improve the backlash situation and obviously guiding in general. Any focusing tips very welcome - i find that the hardest thing of all - tried the bahitnov mask but it just kept jumping between + and - values. Here's the guide log: PHD2_GuideLog_2020-04-06_204427.txt

Don’t think so - South is blocked by my house unfortunately. Can do south west though. Will give it a go tomorrow.

Michael i really appreciate the feedback - thanks for taking the time. To get Dec 0 ill use my astro app on my phone, looks like as low on the horizon as i can get it in the south west. I know thats the phd2 recommendation - presumably if i calibrate there thats going to give me better cal? I'll also try PPEC (used that before too). I'll adjust my dec balance too - pull the scope back a bit in the saddle. As i say it was a bad night with some high level mist, i couldn't even find decent focus. One other issue i had is that i had to use my main camera with sharpcap for the PA as i could never get the 290m to solve - but im guessing thats prob just due to the bad seeing and therefore lack of stars. I'll post back prob tomorrow night when its clear - gonna try some m101 but think it will be too bright with the moon even with my filter (optolong lPro). Thanks!!

Lessons learned: 1. Take cap off telescope when trying to do astrophotography... 2. Use a bahtinov mask, i was out of focus for both guide and main cam. Seeing was bad last night - kept losing stars, so i upped the exposures... but even then the star choice was poor. I did notice that my guiding is now going to have to be better than the above as my px error was around 1px. I used to get 0.5px when using the guide scope. Any further tips willingly received. Thanks all! PHD2_GuideLog_2020-04-04_114733.txt

Right. Just been out. Managed a 1 minute pa error. Set guide rates to 0.9x. Awful seeing tonight with a bit of high mist and 85% moon. Managed to calibrate properly! Guide at 1.3”rms. not many stars visible though so that’s ok for the conditions I think. Didn’t bother imaging due to conditions. But it seems to be sorted now! Thanks all!!

thanks a lot for that - ill go through those now Looking at the phd logs it certainly does seem the higher guide rate gives better results yes.

I think so - i will double check both the oag imaging train threading and the guide cam in the little 1.25 holder on the oag I should also point out i tried Metaguide, but this failed calibration too... Also - i read the increasing guide rate can combat backlash - shall i use 1x guide rate? I normally stick to 0.5x.

Hi mate, thanks for the info - yeah i did a new equipment profile unfortunately. When i get my next clear sky i will create another profile, do a proper sharpcap polar align and see what that gives me. I did notice that in some cal runs it seemed to be going backwards... what confuses me is why now? If i go back to the guide scope i bet it works "fine" as before...

Thanks almcl - ive used sharpcap previously to do the static polar align - i can try that again. Would this cause the issues visible in the cal log? Ive never seen anything like this with guide scope usage... is it just because of the longer FL?

thanks - as far as i know this is the latest version of the mount - its a 2018 model.

Hi everyone, Now i seem to have more time to image i bought myself a ZWO OAG to use instead of my 50mm Guide scope. Main scope is 80mm altair ED doublet, ZWO 290mm guide cam. My mount is on the heavy duty pier. Unfortunately i'm not able to get a successful PHD2 calibration no matter what i try. My guiding has never been great - usually 1.3" RMS with the guide scope no matter how good my PA was, so i thought perhaps i could get some improvement using an OAG - and also not have to set up the guide scope, dew heater, balance it etc. OAG set up was quite easy, focusing accomplished - "awesome" i thought, that's the hard bit done I started with a new profile, put the main scope focal length in (454) and hoped for the best. Now it must be said i rarely do any form of polar alignment - I generally just align north and be done (slack i know) because i have found it not to make that much difference. I've been getting orthogonality errors for almost every cal run (i tried altering guide rates to see if that helped) - you can see in the attached log. 1. From reading the PHD2 manuals this might be backlash? And if so should i just make sure i run the max guide rate to minimise this? Anything else i can do? 2. Why am i seeing errors now, it was "OK" with the guide scope? Why cant i even calibrate at all? 3. Will PA align make more difference with the longer focal length? 4. Will my mount need "fixing"? Many thanks to everyone in advance, Clear skies, stay healthy! PHD2_GuideLog_2020-04-02_191021.txt