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To finish the long story, some images below The cocoon, FMA 180 with EOS 80D, the lion nebula with WOGT81/SX694 and the crab with the C8 (with FR)/SX694)

PHD2_GuideLog_2023-09-09_184041.txt PHD2_GuideLog_2023-09-01_185832.txt

Hi, so it looks like my filter leak the IR. I imaged it again, placing it on the bottow left corner of my frame, and one can see it is different (a shorter sub, clouds were coming in). So indeed huge IR on this star!

unfortunately I cannot check my Oiii filter IR leak topic by stacking my L IR/UV cut... it won´t fit in my FW to stack (and I have no kind of adapter to get my 2 filter stack (small one) and using same set with my SCT/FR.... a bit stuck to check up... Nervertheless, my Oiii filter is of that kind in case it would be known for IR leakage: Baader 8.5nm (claimed "IR blocked"). on normal stars of strong magnitude, i have not noticed over years halos (note there has been a bad serie of this filter known giving extremely strong halo, but that´s not my case). Here is a crop of 5.65 mag star I find with strong magnitude star example, all rest is same set up using same filter/camera/10 min Oiii with other scope (FMA 180) and on stronger star, no issue at all with Menkib (3.95): And referring to the link above, I took just few weeks back the RS Cygni with my WOGT81 and no issues neither (10 min Oiii) while reported as well strong IR carbon star type if I understand the CN thread (and its overall magnitude is lower than V AM Cygn -but the latter may be then way stronger in IR as you mention) I looked at quite my Oiii files and cannot find any halos, but I have no image with magnitude below menkid or can think of other example than RS Cygni above

just a post to add a bit better comparison of the Ha and O than my previous crop on single sub (here as the stack, unprocessed apart STF autostretch in PI) Ha left and O right. Also forgot to mention I think, that was taken with SCT C8 and starizona FR, so about 1430 mm FL calculated back from measured image scale by astrometry.

thanks. Indeed interesting and always exciting to find out some new things whstsoever 'stellar' or optical artefacts!. I will give it a try with stacking my L uv/ir cut on top of the Oiii to check up on this same star ( if weather allows...). Curious to check also on other such mira stars. I will give it short Ha sub to see (many strong ha part of planetary nebula are almost totally blown up at 10 min) I have never seen that behavior before ( some 10 years using same equipment). Even if this is a halo effect/IR leak effect on the O filter, i am still amazed by such big difference on such star between the 2 signals (if one take away the halo on the O filter, then it has a very little tiny dot as compared to the blown big Ha star)

Thank you for your comments and link to cloudynight threads reporting similar. As additional comments: - Camera is SX694 mono and I use Ha and O baader narrowband filter. I have been using this for more than 10 years, and I never had issues of halos apart on extremely bright stars on my O filter, but not the kind anyhow I report above (the Ha is clearly "round" star like, while the O is a very little dot with a faint spread around). - This specific star is reported on magnitude 10 or 12 for what I have seen, so not that "bright" for giving halo from my experience. If it was a halo/filter issue, one would see similar behavior on the other 3 simialr brigthness star on the crop picture, or? I am strucked by the huge difference in intensity of this particular one (Ha vs O) if you compare to the neighboring ones of similar magnitude. - the B&W cropped are from 1 single sub and without processing apart visual stretch, this is not from some processing and no AI (as reported by Cloud night thread as hypothesis for such artefacts)

found it in the simbad database. It looks like a Mira type of stars (interesting, some 7000 known). Very interesting type of stars https://en.wikipedia.org/wiki/Mira_variable Such stars would turn into planetary nebula, so I was not far! Or has it turned into such planetary nebula now?? regards David

Hi, A short one as the nights are getting short up in scandinavia. 6*10 m each Ha and O, and HaOO combination. One thing that strikes me is on the upper right, it looks like a planetary nebula and not a star (or simply an artefact). Any ideas? On Ha, it just looks like a star, but Oiii definitively not. David O filter: Ha filter:

good point, checking up, it looks my old lenovo has 1 3.0 USD... just need to figure out which one!

Hi, I have one as well for many years (I think not long time after they released it) on my C8 (after testing 3 Celestron....). No comparison, way better than original celestron and I would put it among all my best buy of astro stuff. below a quick b color with SX694 camera.

Elp, thanks. Longer is only a matter of convenience, faster overall processing and less storage space (especially from canon raw files which is my main intention for such set up/short focal). I run up to 5-10 hrs total exposure, so it matters, especially with my laptop when I am out at our summer house over several nights or somewhere on vacation and without a stationary computer (and no patience to wait going back home to process the data on stationary). I have been running out of space several time on the laptop (during processing with pixinisght, I need to delete intermediate files after the debayered, cosmetized, alignment etc... before the whole processing is completed). Alternative would be a new higher end laptop, or external disk which is of course feasible (yet still slow also to process due to very large amount of files). My current laptop is an old lenovo (U330p, i5, 8GB ram) example below is 8,5 hr on Iris with FMA180, Canon raw with avx 4 min exposure sub, non guided. 126 files of 30 MB to start with, so already 3,4 GB.... (which "explodes" into several 10´s GB when processing those into all intermediate files of pixinisght and I only have some 40 GB availale unfortunately). With 2 min, I would not be able to process this on the laptop and it would take ages... I would prefer investing in a new mount than a new laptop (apart the space limitation and a bit slow on big job, the lenovo serves me extremly well -must be about 8 years old and spent many night down below -15 to -20 and it has never let me down!)

Hi, I am looking for a mount for telescope/lens of focal length say below 200 mm without need of guiding and for say 3-5 min exposure if possible keeping 100% subs -so to say reliable and not just luck to have a "good copy". if this is too demanding focal leng down to 130mm, yet> 100 mm would still be interesting above 3 min (reliably again). My pixel size if 3,7 to 4,5. This would mean a resolution of 4.7 "/pixel or higher, so it shall accept long sub even with a periodic error which could be smooth enough over 8-10 min period and p2p of 8-10 ". would there be anything out there doing the job? Note: - it does not need to be a compact small mount type (Adventurer type, which I understand would not manage in most cases), as above set up with short FL would be occasional (I also have a WOGT81 and C8 which would be used guided in such cases), yet something one could transport easily - I believe the key is a mount with a smooth long period. For example: Belt driven (e.g. avalon Evo Zero? Or what about the new harmonic mount type AM5 and the like? Those are to be guided, but I wonder if really needed for FL 200 or below for few min. The reasons behind: -convenience, so to avoid having to guide (no oag nor guiding scope/additional camera to handle) - replacement of the AVX (very happy with it, I do manage up to 3-5 min unguided at 180 mm keeping most sub (75%), it has only a 1-2 very steep minutes in its PE, the rest is good to give <5" over 3-4 min), but It is now getting rusty after 10 years -it stays outside- and when I use it guided, its backlash is just a pain (e.g. forget automatic meridian flip, I am running it also east heavy + slightly misspolar aligned so I guide in 1 direction -in such way I do manage RMS of 0.8-1.2 which is I think pretty good -I have not use the PPREC in phd2 yet, but I think it shall work good on RA as I have a well reproducible PE). So hopefully there are mount out there today that can do better today? Alternatively: would any have a suggestion for a compact guide scope (I have asi 224 mc I could use)? thank for some idea!

Don´t have the 135, but the FMA 180 (which I understand was similar construction but I may be wrong). Regarding the comment above, I guess it depends the copy, I have no particular issue with the FMA 180 (only need to refocus on B or the O in SHO mono channel), Yet even OSC camera is good. Below Iris (with canon 80D, 9hrs) and the veil (HOO, Sx694). Anyhow if it is better than the FMA180, then cannot go wrong

Hi, I am quite happy for this little affordable lens. Below my first light, NGC7822 with SX694 mono. 2 hrs each SHO (10 min subs). Processed in pixisnght (stars have been reduced). Well corrected for this chip size, fast. One need to pay attention to get right focuse. Very well built lens. I did a quick test on RGB and it looks also good in RGB. Will try on APS-C later on. David