almcl

Sorry if it wasn't clear, I was referring to the OP's question, not your response. His issue may or may not be caused by the filter. Mine isn't. It might be him worth checking.

Don't be too quick to blame the filters. I get a similar effect on bright stars with no filter in the train. Beginning to think it may be an artefact of the DSLR matrix/Baader Filter &c (single cropped sub from 1st light with my SW190MN):

Depends what you are planning on doing with the scope. If you are visual only then there's no need for EQDIR and PHD2 and the Synscan handset is all you need. A rough polar alignment should be enough to keep objects in the eyepice field of view. If you are planning on imaging then, depending on what scale, the mounts tracking accuracy probably won't be accurate enough. I started with an unguided EQ5 and did get some usable images, but moved on to guiding.

Another thing that occurred after I typed the above is that the current guidance from the PHD2 developers is to get the guide star as sharply in focus as possible. The old advice about 'soft stars' is no longer current, although it still seems to be repeated...

+1 for Laurin Dave's suggestion to increase the star mass detection tolerance. 80 or 90% may not be too much. Also might be worth increasing the search region size, so that if a momentary loss of guide star occurs, it gets found again.

If you are using one of the later versions of PHD2, the present developers (Andy Galasso, Bruce Waddington &c) recommend (sometimes on an almost daily basis on the Open PHD guiding forum) getting the guide camera focus as sharp as possible: link 1 link 2 While the centroid computation can cope with some pretty hefty distortion (fortunately for those of us using OAGs), they state that the best results come from sharp guide stars. They suggest using the HFD figure as a guide and adjusting guide scope focus to minimise this. For me that figure is seldom stable enough to judge whether an adjustment has improved matters so some sort of mask can be very helpful. To get a small 3d print, I have used 3d Hubs in the past and they were pretty reasonable and fairly quick. I think it was a case of up load the file, choose the material and some other things and they quoted there and then.

Thank you for both of those, Han. I'll have another look.

May not help, but if your LED street lights are like ours... I was mildly surprised/absolutely flabbergasted to see the council lighting contractor fitting a shade to the light outside yesterday. It hasn't quite worked, unfortunately, as the shade needs to be about an inch closer to the lamp post, but considering we didn't ask for it, well surprised. Might be worth asking if your council could do something similar

It's hard to be sure about focus as you have star trailing along the RA direction (bottom left towards top right or approximately the line from Sadir to Vega) and the star shapes are a little strange: I've never used a lens with that wide an angle but you might be able to make a suitable Bahtinov mask and use that to check the focus? The colour (enhanced red from the extra IR) is not unusual - post processing can usually deal with this.

A couple of thoughts which may not be relevant, but have you tried solving the image on astrometry.net to see if the resolution &c agrees with your figures? Second are you just using PlateSolve 2? I have found this to be very unreliable. Especially if the target is any distance off. Allskyplatesolver (ASPS), while slower, has a much better chance of succeeding with 'distant' targets, at least in my back garden. If you are using ASPS, have you downloaded the relevant index files for your new resolution and tried going through the troubleshooting routine?

Wonderful data again! But found this really hard to process, particularly without losing some of the Oiii data. Processed in StarTools 1.7.421 alpha standard work flow: --- Compose > Auto Develop > Crop > Wipe > Auto Develop > Contrast > HDR > Wavelet Sharpen > SNR-aware Wavelet Sharpening > Deconvolution > Shrink > Life > Color ----Parameter [Matrix] set to [SHO 40SII+60Ha,70Ha+30OIII,100OIII] > Wavelet De-Noise

Here's a website that predicts seeing. https://www.meteoblue.com/en/weather/outdoorsports/seeing/38.043N-77.350E It looks as though you have a strong jet stream over Virginia at the moment and that often results in poor seeing. Ironically good transparency (clear skies) is often combined with poor stability (roiling air) whilst poor transparency may be accompanied by more stable air. Frustrating isn't it? When you get a rare night that is both stable and transparent, make the most of it, in UK at least, they can be quite rare!

Fortunately a very prominent dust bunny as well as horrific amp glow showed the rotation required (anti-clockwise). Autorotation is turned off in the camera, suspicion now falls on APT which has been randomly flipping images for a little while in its on-screen display.

It turned out that the calibration files were being interpreted as portrait while the the lights were seen as landscape. I rotated the three masters in AvisFV (which was a lot quicker than rotating 50+ lights) and they then stacked. Thanks for the responses.

Thank you for responding, Han. Unfortunately, nothing was checked in the boxes you have indicated, could the Canon camera's random autorotation (see post above yours) of the flats be the cause of the problem?

Thanks for that thought, Dave. Just checked and the flats report their size as 3476 x 5208 while the lights are 5208 x 3476. Why one has been rotated and not the other seems a bit of a mystery - the master flat created by DSS is correctly oriented (long side 1st) - and while the individual raw files open correctly (landscape fashion) in Windows Photo Viewer, they open portrait style in PhotoPaint. Auto rotate is switched off in the camera which, if I understand the manual aright, should mean the image is always displayed landscape. Not sure what to so about that, but maybe ASTAP is not an option, it is incredibly slow: 20 minutes to convert all the .raw files to .fits and then another 10 or more to stack them. I'd expect DSS to have done the whole job in less than 5 usually. And then there's its inability to debayer the image...

Just having a look at ASTAP as a possible alternative to DSS, but unfortunately can't get it to debayer or apply Flats correctly. To deal with the flat problem, can anyone tell me what the message: "Warning, could not find a suitable flat for ""! De-classify flat filter or add correct flat." means? I've failed to find it in the documentation, and am not really sure what 'De-classify' might refer to in this context. I am using flats that DSS was quite happy with and it has created a master flat but then steadfastly refuses to apply it.

To amplify Happy-kat's point about the shrink module, here are two versions of the Eastern Veil, post processed only in StarTools. They are from a bi-colour (Ha + Oiii) filtered set and the second one has used the shrink module at 30 iterations to 'tone down' the stars - rather more than I am really happy with but just to show what is possible. (It's a work in progress as am debating adding some RGB star colour)

Yes, if at all possible you should avoid using Jpegs for the reason stated in the warning. Raw files, or if your camera's raw format isn't supported, tiffs will work but the algorithms don't do so well with the lossy compression of jpeg.

It certainly feels a bit slack and getting everything tight is quite a challenge. I haven't tried tape yet but may have to. Yes indeed. I wasn't convinced by it on my 200P as it never seemed to agree with the Cheshire eyepiece, but on the 190MN it agrees a lot better and makes getting the secondary centred and squared a bit easier. That's MaxSelector, available free from http://www.felopaul.com/download.htm It's a little bit quirky, but once you discover how the author does things it provides useful data (I think).

Ah, thanks for that, Wim. I had hoped you might join in, as in part it was the excellent results you have posted with your 190 MN that convinced me to get one. I should have followed up my results for the benefit of anyone else contemplating a 190 MN. I adjusted the secondary mirror position 'down' the OTA and got to this point (sorry to use diagrams but my phone cam resolutely refuses to produce a convincing image): I could see that the focuser needed tilting, but in the absence of any info about its adjustments, couldn't see how to do this, so resorted to shimming one edge with PTFE strips This gave me a view like this: After paying a good deal more attention to mounting the camera in the focuser and rotating it through 90°, I got the following results for collimation and field flatness: 3d curve tilt: while FWHM came up as: This is vastly better than anything I have ever achieved with my 200P and although clear nights have been rather few of late, early results are quite promising.

That's with the finder and tube rings. I have an aluminium bar on top of the rings which serves as a handle for lifting the OTA out of its box.

My 200p weighs in at about 7.5 kg without finder guider or scope rings. The 190MN is a bit over 11 kg but I find it rather more awkward to get hold of as the mirror end has a flush fitting plate and the eyepiece end has a cover with nothing to grip. It is noticeably more of an effort to carry out of storage to put on the mount, although I wouldn't describe it as difficult. I saw the rumour that the 190 MN was being discontinued, but FLO rather poured scorn on that idea when I enquired and ordered me one which had to come from China. Three weeks later it arrived, so as of late July they still had stock.

I agree about Telegizmos. I was given a fairly expensive one which fell apart within 2 years. A polypropylene BBQ cover (£15) lasted a lot longer and I now use patio heater cover (also PP) which has similarly proved a lot more durable.

Plus 1 for what Wim said. I recently added a SW 190 MN to my collection and it is a much nicer scope for imaging than my SW 200p. I spent a couple of days getting to grips with collimation - in some respects it's easier as there's no spider with microscopically thin support vanes to muck up secondary mirror centralisation - but there is an extra step of getting the centre circle on the secondary centered under the eyepiece, not difficult if taken steadily. In just over a month, I haven't had to touch the collimation screws. And the image is flat and distortion free across the whole of my Canon 700d's sensor with no coma corrector needed. I've been getting better FWHM figures, as well. I was told it would take a month for mine to come from China, but it was actually quicker than that.