rotatux

Can't be sure about the MPCC because I have the SWCC (which collar can't be removed -- softly), but from what I see you could use some small M48 extension (3-5mm ring or filter) camera side, so that it would be locked above the bevel. It's quite cheap and would also make it sunk deeper in the focuser, and so would reduce the "protruding focuser tube" problem.

Just to add precision, but PNG is the open spec/rights successor to GIF. JPEG is still perfectly adequate and valid as a lossy compression. BTW like other comments, use JPEG for web publication, since it will display by a browser and on 8-bit displays mostly. PNG has 8- and 16- bits variants, all with lossless compression, but 16-bits isn't much used. PNG produces (much) bigger image files than JPEG at about any given size, and is much slower to compress (at save time). And again for display / publication to others it's limited to 8-bit, so process your work files correctly and publish as Jpeg at the end. Adjust the JPEG compression in relation to your resulting image quality : no need to use q=95%, for most images between 65 and 80% is perfect and will produce as much lightweight files as is possible.

Again check the No-EQ challenge thread, you will find successful shots of both wide to narrow fields. Field rotation is essentially the same whatever the scale, but its speed varies depending on sky location : Typically east and west, low to moderately high, are free from rotation, and that's where some people with good tracking mounts could achieve subs of 1 or 2 minutes (not my case ); There's a PDF somewhere which gives max sub times per sky area for several latitudes. 20 to 45 seconds subs is most typical, but is enough for many deep sky objects. With wider fields you get more easily out of the rotation-free zones (so field rotation is actually *more* noticeable with wide fields in principle)

Very natural color, high detail... And amazing how many fuzzies are in the background ; Some reddish ones seem really far away. Thanks for sharing.

AP with AZ tracking mounts has proved to be possible within certain limits and constraints, typ. with 20s-60s subs. See / Search the (huge) thread here : for examples, techniques and general advice.

You've got it, so try it :) I have one too, first shots at f/3.5 were encouraging though I was starting my astrophoto at the time, but the diaphragm broke before I could test it further. In vintage lenses 24/2.8 can be found, 24/2 exists but would be quite rare (saw only two on the french market in 7-8 years -- at decent prices) ; I can't remember any vintage 24/1.8 so for this you have to go modern lenses IMO.

At 135mm you should find f/2.5 at more or less moderate prices, depending on the brand, such as : Vivitar Series 1 : http://allphotolenses.com/lenses/item/c_819.html Takumars (most recommandable I guess) : http://allphotolenses.com/lenses/item/c_1522.html or http://allphotolenses.com/lenses/item/c_2466.html or etc Fujinon : http://allphotolenses.com/lenses/item/c_2566.html but they probably need to be closed at f/4 or f/3.5 ; At 200mm apart from the infamous Makinon at f/3.3, you can most easily find f/3.5 glass. I own the Vivitar by Komine one (28xx serial) and it's pretty good -- for an old lens -- but still testing it at various apertures between 3.5 and 5.6 when weather permits. If relative aperture or optical quality of old lenses don't satisfy you (I must admit with experience that few are good enough for astro work), good modern lenses are often much better, although pricier too.

Basically : far too short exposures. 1/ use longer "subs" luke ! ISO between 800 and 3200 (varies with camera models, I'm not a specialist of Canons), and longest duration you can with no or moderate trailing (do some test shots)... This depends on focal length (lens) and pixel size (camera) : the longer focal, the shorter possible duration => start with a wide field, such as your Tokina, and 5-15s subs, to get something at least (take many subs and stack them !). Then move on progressively to a longer focal and shorter subs until you don't get enough signal to stack any more => that will be your untracked limit. 2/ for a starter until you know better, use a remote in continuous shooting mode (an intervalometer will also do it usually, but is not required)

It may have something to do with color management : the cheapest for cams is to output images with a color model similar, if not identical, to our display devices, which are near exclusively RGB. Using alternative color models at capture time such as LRGB, (L)LRB, (L)Lab, Cmyk, Yuv etc would incur an in-camera processing cost which means more complex embedded code, more power consumption, more latency to display image, and so on. Now we start to have S-log light curves and the like used at capture time in some devices, which has a non null processing cost too, so lines are starting to move. Maybe a few years from now we could hope for other color models to appear.

I'm in for the star-full version. Not only for context -- density of stars gives a sense of depth, e.g. you can can visually see that the america's top is in fact a hole between obscure dust clouds ; So your first image is more 3D-ish ... always a matter of taste of course

Ok I don't have much experience but I can relate on what I've read so far. About matching with 130PDS : I don't think there such a thing as matching filters per instrument, photographically speaking, since they will darken the sky background more or less, and hence allow more or less long exposures. Visually that's another story : their filtering intensity should match your instrument diameter, roughly small or big, e.g. you're probably not going to add a dark-colored filter to a low (<=80) diameter tube. On matching targets : galaxies are more wide-band so you should not use nebula filters (usually more narrow-band) on them. So on nebulas go for the IDAS (though it's still wide-band, just somewhat less than Neodymium), and for galaxies check visually the Neodymium first then swap with the IDAS to see the difference.

Hello Kaelig and welcome here. I'm sure you'll find a cheerful hand to help here, just as I got a few years ago. Not answering directly, but just a few remarks... 1) I am afraid CEM25P production has stopped, if I understood correctly, so it's getting difficult to get anywhere. 2) CLS ≠ neodymium; neodymium or "moon and skyglow" are a very wide band, glass-tinted kind of filter, which efficiency I found has dropped these past years with new generation led-based lighting (but is still good depending on your conditions); while CLS is a kind of interferometric filter, between wide and narrow band, much like UHC but more dedicated to cameras rather than visual. (won't comment on others)

IMO You should instead really try stopping down with the lens' own diaphragm : I have tried step-down rings too, surely they cut down on light (affect aperture geometrically, if I can say like this) but mostly don't enhance optical properties as much as the native diaphragm (I was still having coma and CA in sides and corners, shooting RGB on OSC camera)

Threads are different between T2 (×0.75mm) and M42 (×1mm); I can screw my T2 adapter in full only on half of my M42 lenses, others only screw half or third of the "bayonet". I have the Vivitar equivalent of your lens and like you can only screw part of a T2 adapter on it (but I'm using this as lens2scope to put oculars, not for camera) In doubt you would buy a specific M42 adapter for your camera.

I advise in favor of the Baader adapter : https://www.teleskop-express.de/shop/product_info.php/info/p3676_TS-Optics-Optics-T2-Adaptor-Ring-for-Cameras-with-Micro-Four-Thirds-bayonet--Panasonic--Olympus-.html (This one is from TS as I can't find the Baader page for it atm.) Without the extension it allows to rack the focuser out a bit more to reach focus, avoiding much of the known problem of focus tube protuberance in the fov. Also with the SW ComaCorr it allows for several reduction factors (w/ or w/o ext, w/ or w/o M48 filter). BTW you could find this useful too : https://www.teleskop-express.de/shop/product_info.php/info/p3504_TS-Optics-Adaptor-from-M48x0-75-to-T2---low-profile.html

Very well explained ! Complete and precise enough that I could fill in the few little gaps. I still have to work out how to adapt to my color-aberrated stars, but for the most part it does the job quite nicely.

Only my 2nd attempt at Perseus Double Cluster with that tube. I had this in stock since last year but didn't put online. Now the more time passes the more I like it, and no good night since, so here it is. Gear: Olympus E-PL6 with Skywatcher 130PDS and SWCC at 600mm/4.62 and dydimium filter on Omegon EQ-300 tracking RA Capture: 22 lights × 20s × 2000 ISO, master bias, at 1.28"/px Site: deep country 26km from Limoges, France Processing: Regim 3.4, Fotoxx 12.01+