groberts

The Samyang 135 is ideal for busy widefield areas such as that around Sadr. This is my first fully calibrated image with the Samyang lens + mono camera after previously using it with a DSLR camera last year and a recent quick and dirty mono Veil Nebula uncalibrated image taken just prior to this one. I'm pleased with the outcome which holds great promise - the FOV and detail such as the Crescent Nebula are excellent. There's much to see here which is partially described in the attached astrometry image but would be interested if anyone can ID for me (i) the small Ha rich area left of the Crecent between 10 and 11 o'clock, and (ii) the wispy blue / green area also left of the Crescent at about 8 o'clock? Graham Samyang 135 @ f2.8 Ha 36 x 300s OIII 36 x 300s Total: 6 hours 10th & 12th August

Thanks guys, very helpful.

I would like to image WR134 - can anybody direct me to a relevant Wolf-Rayet catalogue that can be installed in Carte du Ciel? Graham

It's been nearly two years since acquiring my Samyang 135 but have since only played around with it in combination with my modded 550D DSLR. Whilst impressed with the results, my main objective was always to combine it with my ASI1600 mono camera but as that was tied-up with my main William Optics rig it just didn't happen, until now. After upgrading to the ASI294MM Pro in May, at last I was able spend the early part of summer working on the aforesaid Samyang 135 + ASI1600 rig and now astro darkness is (just) back managed to catch a vfew photons of the Cygnus Loop with the new set-up. I had originally purchased a x2-ring Astrokraken 3D-printed clamping system for the lens + DSLR combination from Philippe but since then he's tweeked the design and, in particular added x3 M4 built-in nuts on either side of each ring for attaching ancillary equipment, which for me has been a game changer. I therefore bought a new x3-ring Astrokraken bracket, with the said bolt holes, around which to build my new rig. The bracket already allows a guidescope to be fitted immediately above the lens and with the third ring holding the camera firmly behind but now I've also been able to add an RDF on the left side to assist with navigation and framing, all nicely bolted onto a Losmandy plate which makes handling and storage easier. Whilst the recent heatwave produced clear skies, it was not ideal for astronomy, furthermore hampered by a full moon. However, with just over two hours integration time and only a few darks calibration, I'm still very impressed with the outcome of this quite amazing lens. For me context is everything, so I just love the FOV and can't wait for better conditions, greater integration and more widefiled targets to point this wicked little lens at. Graham Samyang 135 f2.8 + ZWO ASI1600MM-Cool Ha 27 x 180s OIII 20 x 180s Total: 2h 21m

You don't mention what mount and camera you're using but I presume you're tracking, though + guiding too would probably help to ensure best possible image capture in order to come to any fosussing conclusions. I understand that f2 is generally regarded as undesirable for this lens with astro, so your observation between f4 & f2 are perhaps what might be expected; I recall something about this in the mega thread you refer to. Ordinarily with terrestrial images the depth-of-field increases with decreasing aperture, though as this is being shot at infinity I'm not sure that's relevant? Personally, I'd track + guide + use the smaller aperture setting f2.8 / f4.0 and see what you get. You also don't say how you actually focus? Whilst many use autofocus, when using this lens with a DSLR I've been successfully using a micro-focus ring from AstroKraken, which allows very fine adjustments + the ability to lock the focus ring setting once achieved. If you are just focussing by hand + without locking this could also be your problem? Graham

Well as the saying goes - you learn something new every day! Thanks Olly, much appreciated, I feel myself going down a rabbit hole here but clearly this is a critical feature that I need to understand better. Graham

Thanks for the comments so far, like the album idea too but really wanting to achieve high quality wall pictures this time, which might require some experimentation first to see what works - was looking for first-hand experience of such a task. I can say that when printing my calendars using Photobox I found that what looked OK on screen came out a bit dark and subsequently a bit of a boost to brighness and contrast to the orginal made all the difference. Notwithstanding, I'd like to raise the game with the wall pictures, which I imagine will require a better printer + materials etc. Thanks for your comments Olly which are interesting. Pardon my ignorance but what exactly do you mean by "colour settings" and how should I use this information? Graham

I'm interested in getting some quality prints of some of my better images to put on the wall and for family presents; I already produce an annual astro calendar for the family using Photobox which is very popular! I'm thinking perhaps A1 or A2 size, either framed, poster or edge to edge? Can anybody help with any relevant guidance: Recommend printers who from personal experience print quality astro images; I've seen White Wall mentioned elsewhere? What sort of file format would be best - for online I change the format to PNG and reduce the file size but maybe for a quality print a large TIFF file would be better? Format: apart from size, what sort of finish and / or material e.g. I've seen aluminum used? Print type e.g. is giclee worth using? How do you control or at least ensure that the colour reproduction is maintained? Any other tips? Graham

I purchased this variable extension locking ring, which with a 13.85 - 18.00mm range is right in the sweet spot, thus providing plenty of scope for fine adjustment. https://www.harrisontelescopes.co.uk/acatalog/altait-t2-varex.html#SID=1664 I have set it at 17.5mm from the adapter flange to the EFW, thereby plus the EFW thickness (20m) and 6.5mm back-focus results equals 44mm, which is the general guidance for this lens. Using it in daylight & some distant trees, it looks like it's close to focus but will probably need some further tweeking when I'm next out at night. Graham

Thanks, much appreciated. Here's a starless version too, which I like and shows up some of the details better:

Located about 2,500 light years from Earth is the star forming region NGC 2264, consisting of the Christmas Tree Cluster (an open cluster), the nearby so-called Cone Nebula and in between the Fox Fur nebula. I've used the popular SHO Hubble Palette but adapted here by using synthetic SII and OIII channels in PixInsight’s Pixel Math to enhance the related colours. The colours and details successfully highlight the aforesaid central objects as well as the wider complexity and beauty of the flowing dust and gases that abound in this region, which also includes Hubble’s variable nebula and LBN 902. Graham WO GT81 + 0.80FF, ZWO ASI1600MM-Cool, Chroma 3nm filters SII 39 x 300sec Ha 39 x 300sec OIII 83 x 300sec Total Time: 13hr 25min

Can somebody reccommend where I can get a suitable step-down ring(s) / aperture stop ring to use with the Samyamg 135/f2 lens - I'm thinking of ~2.8 or 4.0? Graham

OK thanks, I completely understand the principal but need to clarify some details please: Is the 44mm back focus taken from the flange or the rear optics of the lens? Either way, it seems to mean a spacer of about +/- 17.5mm: 44mm minus (camera sensor to EFW 6.5mm + EFW 20mm). If this is correct can somebody point me to a suitable source of spacer i.e. M42/T2 male + female, to screw onto the lens adapter at the front and the EFW behind. I'm thinking slightly shorter so that I can then use thin spacers to finesse the distance if required, if that makes sense? Would still like to hear from anyone who has the ZWO 1600 camera + ZWO EFW + Samyang 135 set-up and what their experience and solution to this issue was? Graham

Good news, thanks. Whilst I'm on the subject, can anyone recommend a set of step-down rings that will fit this Samyang 135/f2 lens?

Not sure I understand your question but if you mean the adapter it's an NSA M42/T2 which replaces the Canon fitting fitting on the lens and screws directly into the EFW providing a more stable connection betwen the lens & EFW: https://ensoptical.co.uk/index.php?route=product/product&product_id=13220 Otherwise everything else is standard ZWO camera and EFW. Hope that helps? Graham

I'm planning to fit my Samyang 135/f2 to a ZWO ASI1600MM-Cool camera via a ZWO x8 EFW with ZWO filters using screw in M42/T2 adapter between the lens and EFW. I'm fairly sure that someone will have this popular set-up and would appreciate guidance on focussing - will I need any spacers etc to achieve focus, if so what thickness? Graham

Over an eight week period from mid-January this year, very unusually I managed four images with total integration time of nealry 55-hours! I appreciate that this is nothing to some but if you live in the UK close to Gatwick airport it's quite a feat, certainly unprecedented for me during the time I've been doing this astrophotography malarky! There are therefor more in the processing pipeline, which works very slowly here, but after Lowers Nebula posted here in March, the next one off the production line is the Horsehead Nebula. The dark silhouette of the Horsehead Nebula against the surrounding rich HII-region, is one of astronomy’s most iconic images. Surprising then that I’ve never imaged this object in broadband wavelengths before with my mono camera: the first image was in February 2015 using a modded Canon 55OD camera, then in January 2018 with the ASI1600MM + narrowband filters and most recently in January 2021 using a widefield Samyang 135/f2 rig and modded Canon DSLR. Therefore, somewhat belatedly and with the aforesaid long spells of clear skies, this February I set out to rectify this omission from my astrophotography repertoire and am pleased with the result - hope you like it? Graham Image Details: WO GT81 + ZWO ASI1600MM Cool camera x35L x35R x34G x35B @120s exposure x 78Ha @300s exposure Total Integration: 11hr 8min

Can't recommend this scope enough but one small issue - I've always found the focus lock screw a bit too weedy i.e. difficult to get good purchase on the small knurled knob to lock it down firmly. Does anyone know what the thread size / type of this is + a source for a replacement with more bite i.e. probably just a better knob which provides better purchase with which to lock it down? Graham

FYI here's the HOO version - I prefer the SHO-HOO colours + brings out more detail

Thanks for the comments + keep persevering. IMO this is an interesting & rewarding target, only surpised it doesn't get more attention. Graham

Located in the outer regions of the Orion constellation above Betelgeuse, Lower's Nebula consists of mainly ionized hydrogen. It’s surprising that this interesting, quite large but faint object does not get more attention from astrophotographers, who are perhaps too busy collecting photons from the more famous objects that flourish within nearby Orion itself? For once clear skies were abundant here during January which allowed for some 17-hours integration time, albeit mostly accompanied by a waxing to full moon. The data lends itself to various processing approaches and I played around for a long while with a number of different combinations, in the end favouring an SHO + HOO blend as the main image and am pleased with the result. Graham Ha 44 x 600s OIII 30 x 600s SII 28 x 600s

Some were, some weren't.

It's embarassing but it seems like it was just overexposed and I wasted +5 hours imaging time, but I still don't really get it? Spent two days checking setup and, as far as I can see, all's fine. So with clear skies went out again on Friday and tried exposures at 300s = better, 180s = much better and 120s OK but probably a bit higher works best. I therefore imaged 4-hours luminance at 180s + preliminary process (to check) and it seems good. Attached below are 600s L sub (others were worse) and 180s stack + stretch. Notwithstanding, I went back to the original 600s L subs and although 90% were saturated some are actually OK + just to repeat, I originally researched other's work on this object B22 and was pursuaded that being a dark nebula the most popular exposures used was 600s or higher made sense. The bottom line is (a) I'm still not sure what's going on but the camera etc seem OK (b) I will be continuing @ 180s and chalking it up to experience + unexplained! Thanks for the thoughts.

The Fits header is fine and reflects the correct setting - waiting to hear back from Ivo 🤞

Thanks Lee, one of those 'astrophotography problems' I expect, i.e. it's staring me in the face but will take forever to sort! No I did not have to reinstall any drivers and at first all seemed fine, as after sorting things I completed imaging a narrowband image without (as far as can see as it's not been fully processed yet) any problems. As I initially said, the RGB subs seem OK imaging B22 and it appears to be only the luminace. I've only ever used APT and don't use any other capture software for mono imaging but I'm suspicous of the gain / offset settings, that seem to work a bit diferent with APT v3.90 which I updated to after the crash from v 3.88 and have posted a query on the APT forum for Ivo = watch this space! Graham