kirkster501

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.

Hi Dave, many thanks. Yes indeed, I am going to give the filters and camera glass a good clean.

Wow odd socks. I will check into that. This was using my Atik 460/EFW2 on TEC140 + EFW2. The BIAS and Dark are from my dark library - admittedly three months old - but at the same temperature as the lights. Would not have thought that this mattered that much but since I am at the end of my own ideas then that is something I will check. Focus between lights and flats is spot on - or as much as it can be with autoficus that changes through the night by a few points.

Thanks. I am not familiar with that technique. It is 18 x 10 mins of luminance from two nights imaging and I am loathe to throw all that away so looking at how to remove that wide arc bunny.

I've made the imaging cardinal sin of not doing flats in a timely manner after the imaging run - a few days later. I did them such due to various day to day upheavals....... I have a thread running on Pixinsight forum as a result. https://pixinsight.com/forum/index.php?topic=12416.0 The OTA, camera, focuser, FW have had not moved. Consequently, the flats I did take have moved most of the bunnies and vignetting, but a few larger bunnies (the ones on the front objective) are faintly visible in a couple of places, probably due to a few motes of dust (I made the second cardinal sin of not covering up the objective since the run finished 4 in the morning and I was rushing as needed to get back to bed after locking up the obs). I was thinking of using Photoshop blur to get rid of it. Any thoughts on that please or any alternate method? I suppose I wil give it a try. The bunnies are not that bad and are large and faint. Would you correct the final resultant image or correct the individual offending channel(s) immediately after pre-processing? Thanks, Steve

Hi all, Could someone recommend some upgraded springs please for the back of the mirror cell? One of the springs on mine, because it has been compressed so long (and they are rubbish to start with) has lost its "springiness" and it is almost impossible to collimate the scope since it is not pressing the mirror sufficiently. Thanks, Steve

Excellent! The first of many I am sure. Well done.

Enjoy. I have done a lot of visual from outside of San Diego, out in the semi desert, and it is spectacular. Watch for snakes and scorpions if you go a-wandering with the bins glued to your eyes.....!

True, but you need DATA to work with. Not much of that been incoming this last month or so....

Yep, I had a few projects in mind. Markarian's chain, Leo Triplet amongst others (he laughs). Looks like it ain't happenin'. Again..... ? Before long it won't be dark until 11PM and the skies will then clear for weeks and I'l no doubt have a lot of 5AM morning starts with work.....

Appreciate your point (as a road biker ). However, your analogy is not strictly correct because whilst I'd always prefer to ride in the nice sunny zephyrs of a balmy summer evening, I can at least bike in the wind/rain etc if I want to. With astro, if it is cloudy, you are screwed. There is no plan B. And we have been screwed for rather a lot of time these last few years. But yes, have to persevere. There looks like no clear sky in the next week or so either.....

Galaxy season is so far a write-off. I never feel I have wasted it, no. But I do often think about all that gear just sitting doing nothing for seemingly weeks at a time.

Ou get to it from the connect screen in PHD2. Click the spanner thing and it takes you to the setup screen. Note, sometimes this gets hidden behind other windows....

This is the ASCOM driver I am using as advised to me by Steve. I kept getting the "double guide stars" on my rig with the newer driver. I have no idea why. The binning must be 2x2 as well.

I got to the bottom of this. It is something to do with the interlacing of the CCD chip and the driver software. I regressed the driver back to 5.5.1, made sure binning was set to 2x2 and it all seems to be OK after a brief play about last night in terrible seeing. Will need a proper clear night to thoroughly test but I think I am there at last. Many thanks to @gnomus Steve, for his suggestions on this. This was a very tricky problem to get to the bottom of. I still owe him the bottle of gin when I next see him for helping me with my mount FWIW, I am not sure the huge investment in the Lodestar X2 is such an improvement over the venerable QHY5 that has proved utterly faultless and bulletproof at a quarter of the cost.

Tearing my hair out with this problem, same tonight and wasting multiple precious clear nights. It is a silvered mirror on the OAG and the thing is mounted as solid as a rock. I just cannot think what could possibly cause such a problem, but a problem there is.... The guiding is all over the pace because PHD just not see a circular star, it sees both the main star and the mirror of it that seems to fade in and out, so the "centroid" is a oblong and PHD cannot be sure what it is guiding on. All my drivers are the recent ones etc. Going to try a different guide cam, back to the trusty QHY5 that has worked perfectly for years.

Yes Dave, appears to be but i will recheck it. Will look into painting it black on the back though as per Zakalwe's suggestion.

Thanks guys. Could someone send me a acreenshot of the ascom driver you are using please?

Guys, what ascom driver do you use for your lodestar x2 and which guider do you select from th3 drop down in PHD2 please?

Thanks, I will check into that. Another theory is that I have done much of my tinkering in rubbish skies. Last night was a quite misty and murky and not an AP night at all and I was playing with the OAG, hence this issue. Could the fading in and out of the "double" star be atmospheric in some strange way? I need a clear, reasonable night to test this.

Hi all, Following my "half moon" stars thread. I've noticed a strange "double" star effect when guiding with my OAG. This is a FSQ85 scope with Moravian OAG, G2-8300 camera and Lodestar X2 all properly balanced on a MESU 200. So this is a reasonably high specification rig (more so since also have a full compliment of Astrodons too.) There is the main body of the guide star as expected. However, there is another version of the star either above or below the main star. This "second star" sometimes disappears. It's really weird. Sometimes the "second" star comes in above, then fades out and appears below the main star. It appears on all stars so that rules out genuine double stars. However, the images on the main G2-8300 are absolutely fine and focused perfectly without this doubling, so this is something to do with the OAG or Lodestar. My TEC scope (double mounted side by side on my rig) guides perfectly without this "double star" effect. The guiding graph looks rather poor and since I am within 8 minutes of PA of the pole and with a MESU mount, I'd expect it to be a bit flatter. I think PHD is trying to lock on to this transient "star" sometimes and it then wrecks the guiding. It is mill-pond flat with my TEC scope with its Atik OAG. I am focused properly. Bare in mind the "half moon" stars I discussed on my other thread. Any thoughts guys please? I plan on swapping the guidecam to see if that is causing this effect. Pics as below. Thanks for looking. Steve

My thoughts too. I love this wide-field stuff very much. However for only a bit more money could pick up a good used HEQ5 and that will be more versatile and allow me to get my C9.25 on it for planetary. Accepted that it will be less portable but that does not bother me really. The SA looks a great piece of gear though.

Why make a snap decision Steve? Why not dither for six months? In all seriousness I had made my mind up to get the QSI a while ago and was awaiting the funds. As soon as I got them and pressed the go button QSI stop selling them for reasons we all know.

Yes indeed. Thanks. I'm looking into that option. Another thought is to go with the a 16200 chip camera and maybe upgrade the scope to the FSQ106 with its larger imaging circle since I don't think the baby-Q will cut it with a sensor that size. That starts getting very expensive since the delta to upgrade my 85 to the 106 will be in excess of £1500 on the used market - and that's before I bought the camera/filters. I was also going to go with the Astrodon filters 31mm filters with the 8300 chip options but that starts getting pricey at the 2" filter sizes. Decisions, decisions....