windjammer

You could try 'The Astrophotography Sky Atlas' and 'The Astrophotography Planner' both by Charles Bracken. It took me a while to get into them, but now I find them v useful.

How much did you move the mirror up? If it is more than just a bit (scientific term) it might be worth getting an oversize secondary as well if you are missing a lot of the light cone. You can lose a lot of light quite quickly with even small movements. Simon

It is best if the focuser is a tight fit. The screws won't have to try too hard to keep the focuser flopping around. I think I read about the sanding in the reviews for the steeltrack on the FLO web site! Obviously a bit of an issue if the OTA is a premium item... I am pretty happy with the focuser since fitting - it has resolved a whole bunch of issues with trailing in long exposures.

I bought a new diamond track for my SW Startravel 150/F5 a few months back. I guess the same/v similar products? I had to sand with fine sandpaper the inside of the OTA to get the ring to fit. It really is only the depth of the paint I removed to insert the ring. It definitely would not go in otherwise! Have the OTA focusser end down and stuff the OTA with paper kitchen towel to stop filings going where not intended - and a vacuum cleaner to suck any stuff out.

>> Posted 14 hours ago (edited) Still no astro darkness for another two to three weeks. So, apart from tinkering in my observatory and things to do around the house, I'm reprocessing old data with new tools in the PI toolkit. This is data that I collected back in 2021, Melotte 15. The Xterminator suite of processes allowed me to create a version that is closer to what I had intended when I captured the data. BlurXterminator for sharpening, StarXterminator to allow stars and nebula to receive their own processes, and NoiseXterminator to clean up. I even tried GHS stretch but found a much simpler solution to stretch the nebula. After star removal, I simply used Histogram Transformation ("levels" in PS) to bring in the white point and black point for each channel separately (avoiding clipping). After that, some local contrast enhancement and colour saturation boost. Then brought the stars back in (stretched with masked stretch). >>I goofed around with the data some more and found a simple way to fake a Hubble SHO palette. If you have a standard HaRGB image, you simply invert it, apply SCNR green, and invert it back. Voila!<< What an absolutely brilliant trick! I had a go on your image and it works a treat! (hope you don't mind). I will put this in my toolbox.

I'll go for the reduced mustard!

Thanks for the info - an interesting trick to use the stars from only one filter. I never thought of that ! I have to say I use the same tools as you, but never get that kind of colour balance out of SCNR - does the Ha as a luminance layer make much of a difference ?

Well Mr T - I am amazed that you produced a great image from the starting point you had. Well done. The raw star images were terrible! I would have given up. So, after all that, we have a bit of a bodge around a very bright and over exposed star (who knew!) and not much else *demonstrated* as artefact or spurious ? Amazing. Simon

That is lovely. I am a complete sucker for those shades of blue. Is there a short version of the processing details ? Simon

I don't think it is a matter of winning or losing - no one should mind when fair points are made on processing. And it helps people like me pick up on where we go off-track: my stars are nearly always crap so the info on star tools was very interesting (I might even buy it). False detail/colour and over sharpening generally is another issue for me - I never get the same answer twice if I repeat the processing. So any discussion on how to avoid artefacts is v. interesting - more useful even than looking at more images: generally no-one posts enough info on how they did their processing. I had a look at my own Veil after your post - compared before and after BXT on the master lights and didn't see anything obvious. So I think you should go ahead and post, you would have a willing audience of least one! Simon

@ Adam >> The problem with your hypothasis of how it works is that I have seen examples of bright nebulocity been turned into stars by Blur XT. I have seen a section of the witches broom recently posted on here were a fillement of nebula has been turned into a something that looks like stars on a string like a pearl necklace. Those stars dont exist, there is nothing for it to corrected, its added them from scratch into the image. Ill go find you a good example of that. << Go on then! Simon

I had a look at star tools web site - I hadn't heard of it till now (duh) - from the description given, AI isn't mentioned. It sounds more like a deconvolution tool. If so, what would be your objection to that ?

I think you will have to paint the blur out and mask in some part of the original! BTW is your collimation/focus dialled in - some asymmetrical flaring on the star images of the original stack ? Simon

>>With my 460EX I used to aim for 1/3 to 1/2 way along the histogram, 22000 to 30000. I use similar with my 460 - perhaps a little higher, 50% to 60% of full scale reading using the native Atik software, Artemis capture. If your ADU scale is 0 to 65,536 (ie 16 bit), and full well is 65,536 then an adu count 30% to 60% of the full well value is what you are looking for. If your ADU scale is different, then shoot for 30% to 60% of the saturated, full well value. So, your 490 is 16 bit: the Atik software would have its histogram 0 to 65,536. So 20k to 40k counts would be fine. I can see there is room for confusion between the well depth in terms of electrons, and the pixel value measured in terms of what the 16bit A/D returns. I would guess the 'ADU' value your are looking for in your software is the A/D value in range 0-65,536. So 20k to 40k counts - 8k sounds far too low unless your ADU scale is totally different. What is the full scale deflection value - that would be the clue? HTH Simon

tremendous!

>>Here is a quick raw to remind you of the days without ABG camera'Here is a quick raw to remind you of the days without ABG camera' oooh - how long are we talking ??

Hi - Scroll down through this thread from the diy forum. I posted quite a few pics there... https://stargazerslounge.com/topic/408025-high-spec-computerized-equatorial-mount-building-from-scratch/page/2/ Simon

Some lovely Jupiter time lapses on your flickr site ! Very nice ! Simon

I think your starfield 102 will be fine to kick off with - I did a lot with an evostar 90mm F10. Barlow and eyepiece projection is needed to expand the image size which can be quite tricky to accommodate - see pic! You need very short exposure frames (lucky imaging) and lots of them to stack (1000's). So huge image file sizes are best avoided - just from a practical point of view: so fewer pixels, smaller sensor size. Getting a faint and large planet image located on a small sensor can be a trial (I used an OAG inserted right to the centre of the FoV and eyepiece to land the planet, then withdrew the OAG stalk to start capturing). Active guiding with PHD or similar - the moons make good guide stars - really helps keeping the planet in view, though a bit of moving around the sensor helps mitigate the effects of dust bunnies and the like. Stacking software will sort out the movements. GoTo isn't necessary, though handy for Neptune as someone suggested! Monochrome is fine, just need a filter wheel. Your 120mm in 12bit mode would be suitable for this actually to get started. Run for 1 minute capturing gets 3000 frames at 50fps. Change filter and repeat, and keep on going. Jupiter or Mars do not rotate so far as to spoil the final images. As somebody else said, aperture is key to getting high res on eg Mars, and the albedo features on Jupiter's moons! This link is to a time lapse of Jupiter done with the 90mm and a home made black and white video camera (hacked 1004x board camera, 8 bits mono). It looks a bit crude now 5 years on, but shows you don't need a huge amount of kit to get going. https://www.flickr.com/photos/31131978@N00/44809619474/in/photostream/lightbox/ Here is the 90mm ready to go planetary... Simon

My vote is for the slots - 1mm wide and about 1-2mm deep as suggested. See pic. Simple hacksaw is all you need, just make sure the blade cuts a slot wide enough for the ruler or flat steel piece you use as the spanner. Stuff tissue paper into the hole to stop metal swarf going inside, and have a vacuum cleaner handy to suck any stuff out. If it really is recalcitrant, put the ruler or steel piece into a vice with only 1-2 mm protruding, locate the article on top, lean into it and twist. My standard procedure now is to cut slots into every adapter, extension ring etc that comes along, just for this situation! Simon

The G filter certainly did its stuff - I'll start saving up for one. The detail - both images - is v impressive. But I'm sleepy now!

Here is M109. I have been fiddling with this image ever since taking exposures throughout April and May (a wet Spring). Still can't get the galaxy or the stars looking right. A bit grumpy seeing the effort it took (16.7 hrs exposures), but time to let it go. Three pics here: M109, M109 plate solved and annotated, and NED (Nasa Extragalactic Database) entry. On the upside, a personal distance record - a billion light years, give or take Galaxy PC37796 (the speck, lower left of the image) has a NED entry for its Hubble distance as 275.2 Mpc, or 900 Mlyrs, and recession velocity 18,600 km/s !!! Imaging scope: SW Startravel 150mm F5 Refractor, Atik 460EX mono Ha: 32x600s - 5.3 hrs R: 36x300s + 60x180s - 5.5 hrs G: 39x300s - 3.25 hrs B: 32x300s - 2.7 hrs Simon Plate solved: NED-dy:

Oh yes, duh! Thanks for the clue! Lanning is a catalogue of UV bright stars (Google) - doesn't appear in the list of catalogues for PI's annotate script. The PK planetary catalogue should have it though, last updated in 2000. Simon

Spectacular. Tarantulas on the sun, who knew ? Any more image details esp first image ? SImon

>>There is a faint PN Lan 21 top left, which is just starting to appear. I looked and looked and looked, but eventually gave up and got the big guns. Is it the same as PK059-00.2 ?