kirkster501

Thanks Vlaiv, I have done this and using the ASCOM driver now. I have also set the DEC to Hysteresis and with 90/10 just like in RA. It was getting late so did not have time to really test this out but it was looking promising. I will look into the Z-filter algorithm suggested by kens too. I'd be interested to know what other MESU users have their guiding parameters set to.

Thanks guys, definite progress tonight and some great tips. Many thanks. Feel I made some progress with this.

I find yo have to STOP the guiding. Let things settle down and THEN start again to get teh graph flat again.

It is so termpermental; I reduce the minmov to 0.1 and it all goes crazy. I put it back to 0.2 and it remains crazy. Look at this start of crazy swinging of the DEC......

Thanks vlaiv/folks, will check into your suggestions. How do I stop the Saturation of the stars? A lower exposure?

Correct I meant aggression and yes, a MESU. Guided with a 600mm FL Celestron guidescope.

Been really struggling with guiding recently after moving over to guidescope in anticipation of a dual rig imager, it has been all over the place. Not had the best of winters to experiment really. Anyway, it was crap again tonight. Increasingly depserate, I increased the hysteresis from the default 70 up to 90 on 5.8 sensor and 600mm guidescope. Wow. Pancake flat. Will keep my eyes on this before I get too smug prematurely! Please let this be the fix I have been looking for......!

Indeed. Extremely good seeing - which we hardly ever get anymore in the UK - and precise collimation are what is required to see such details.

^^^^ All the above. I have one. It is a superb instrument for planets, the moon and deep-sky smaller objects. It is useless for wide fields. You may want to read this article by Damian Peach. If he says it's good, then it's good. Mine is in my observatory and is always at temperature and ready to go. Collimation is straightforward and easy http://www.damianpeach.com/c925review.htm

Hi all, any thoughts as to why my guiding is better after the flip because after numerous observations, it most assuredly is. Mount is MESU 200 and using PHD2 and using a guide scope. Everything is balanced as far as I can tell - not the easiest of mounts to balance is the MESU. I do not appear to have any flexture either and in any event, this also applies when I am using OAG as well. What tinkering do you guys do with PHD2 settings such as min move, Hysteresis and aggressiveness?

Leave the spots alone!!!! They will make absolutely no difference whatsoever.

This was whilst gathering subs on M1 trough the TEC140 and the FSQ85.

Lovely scope, I have looked into getting one of those for small objects. However, the skies of late have hardly been conducive to splurging more hard-earned on this. On another note, two dogs on the back seat of a 911? ? Dude, do you know how much they cost to reupholster? I am very sorry to hear of Storm's passing

It would almost certainly be because the focuser was not aligned with the primary Olly. Without the additional focuser collimation ring - not included with the budget RC scopes - there is no way to adjust the focuser's alignment with respect to the mirrors and this is crucial in the RC hyperbolic design. This is a glaring oversight in my opinion. All too complex and too much bother? Yes (to me at any rate). Plus other issues that I do not like about reflectors in the context of imaging. That's why I flogged it and moved to my TEC refractor. Each to their own. Others love the RC design.

I put some of these videos up, I did them when my late wife was very poorly in 2013. I sold the RC long ago but never really had an issue collimating mine once I got the hang of it. There are three planes that need to be in sync. 1. The focuser needs to be aligned with the primary (not possible when an adjustment ring to do this is not provided as default on the cheaper RC scopes) 2. Align the secondary with the primary. 3. Then realign the primary with the secondary to produce concentric circles on the wall. Having said all that, you can get 99% of the way there, much more conveniently, with a Cheshire - as I also describe on the videos. Once you get them collimated they will stay that way for months. I could deliberately wreck the collimation on mine and get it back within 20 mins or so, most of the time.....! As I explained to people, no one is going to die if you get it wrong... You won't break anything! It's twisting a few screws! Remove the emotion and work the problem as we say in engineering.... However, I agree, this is all too much for a beginner - a refractor is the way to go. With a refractor, you know any issues with your images cannot be attributed to collimation. I think RC scopes are more trouble than they are worth for an inexperienced imager, despite the apparent attraction of a largish apperture for reasonable cost.

If you are new to imaging I feel very strongly you need to start with and ED80 atop the EQ5 and forget RC scopes. Collimation worries need to be off the table completely whilst you learn the other nuances of imaging.

Then you'll see Orion directly overhead Steve with Canopus to the South and Auriga to the North with Leo to the East looking large. Spectacular! I remember that well when I was in Oman many years ago and look back very fondly. Caribbean in New Year is much clearer than in the summer months (June - October is extremely humid [hence hurrince season]). You should be in for a treat and I would definitely use some of your luggage allowance to pack the bins and a star atlas for the southern sky.

Yep, we think we are the only ones to get cloud. Clouds are live and well everywhere in the world. It was patchy cloud for three consecutive weeks in the Caribbean.

Last week I was in the Middle of the Caribbean sea at the very front of the ship on the bow (Freedom of the Seas). The front of the ship is kept dead dark so the bridge can see where they're going. The overhead sky - Sagittarius and Scorpio and the southern constellations we never see were spectacular. Would love to go to Namibia one day and when I jack work in, I intend to.

Use Linux at work on our servers. But Windows and OSX (yeah I know is Linux) at home. Never need to touch linux on the MAC unless you want to get deep and dirty. Speaking frankly, I find linux a complete PITA to use. It may be "free" but not my cup of tea personally. We are all different.

There is a "sheen" to them Olly that I think could be slightly reflective. I am clutching at straws to be honest since I cannot fathom why I am getting those large donuts that are not processing out. I will flock the adapters with flocking material that i have ordered off of ebay.

I've stretched the flat to within an inch of its life. Those large, faint circular bunnies look pretty darned consistent in size to me and as Olly says, they must be quite close to the sensor. And they look almost like they are in a line. I reckon I have internal reflections going on here caused by the FF...... EDIT: I just checked this again. Before I installed the the FF the inside of the TEC tube is as black as your hat - pitch black. The introduction of the adapters needed for the FF to mate to the camera/EFW2 and 2 nose-piece at the required distance has introduced some semi-glossy surfaces with the two Astro-Physics adaptors that I think is shining back onto the inner FF glass and causing a reflection with the brighter light needed for the flats. I am convinced this is what is causing the problem. I need to get some flocking material and blacken everything aft of the FF. Will report back.

I am reshooting all my calibration frames and will just have to live with the fact that the M101 and M51 will have to be cosmetically fixed in Photoshop (aka "cheat" ? ). Photoshop is a wonderful thing, you ought to see my six-pack abs..... ? The FF from TEC is spot on immaculate optically. I am wondering, though, if I might need to matt blacken the two adapters I needed to adapt the scope to the FF 85mm backfocus and maybe even blacken the FF metalwork??? I wonder..... It's all that shiny black metal and with extra optical surfaces and bright light to create flats, I wonder if I've had some reflections in the tube. I never had this problem before the FF.

Used the manual way of doing this in Pixinsight as opposed to using the Batch Pre-processing script. Same results. I think I need to completely redo my calibration frames and start again and cosmetically fix this luminance. I don't even think the vignetting is being completely removed - it is there in the corners still.

Wow, thanks guys/Olly. What a wealth of genius this forum is. Run that past me again @ollypenrice please? So you use a master BIAS as your dark for the flats? Do you not use a BIAS as a "bias" for the flats as well? You develop this flat before you start fiddling with lights? First, the focus between lights and flats is pretty darned close. The range of Lakeside focuser movement due to temperature change on my autofocus rig in the FITS headers is 11330 > 11310 - so the flats were taken at 11320 - the median value. Lights, darks, bias all done at at -15C CCD temperature. The BIAS and Darks are three months old but surely the BIAS and DARKS - even old ones - could not cause this effect, they'd cause more general sensor noise, not stop flats working? I read the temperature does not matter so much for the flats. I could not get the CCD on the Atik to -15C and only to -9. I really don't think this should matter so much? Should it? The FF of the TEC is brand new and immaculate. It has been inside the focuser as soon as I got it and the ATik 460 has not been off of it. I concede probably time to give the filters a clean and Atik 460 window perhaps. But the flats for this run at least should take care of it... I have done several sets of flats and varied the ADU from 7000 up to 49000 in increments of 7000. All of them show this "arc". So the lights are not being properly calibrated by the flats. Anyway, for now, I will use Olly's cosmetic correction fix since I am loathe to bin and otherwise good luminance data set. I will reshoot my BIAS and Dark calibration frames. And I will ALWAYS from now on do the flats at the latest the following morning. So that leaves what? The only thing I can see is something to do with my calibration software? I may give the AstroArt trial a go. Or Deep Sky Stacker.