aleixandrus

Wow, it looks amazing but, to be fair, a bit overkill IMO given the pixel scale. I use the Astrodymium kit and it just works out of the box. However, I'm thinking adding support to the camara (ASI183MM) because despite having the Canon bayonet replaced with the M54 (M48?) adapter, I think I'm having some tilt... Regarding EAF, I use NINA with 50 step size (I think I can lower this) and 150 backslash using the overshoot method. I also set 4 steps displacement from initial focus position (I try to set the initial focus manually good enough for plate solving). I'm talking from memory but I can share some screenshots if you need more details.

I have taken the liberty of playing a bit with your shots. I'm not an expert by any means and take this with a grain of salt but, to me, while the shot from @Petrol seems quite nice by my standards, the one from @SAW has some lateral tilt. Based on star shape, to me, right side is too far from the sensor while left side is too close. I concur with @Adreneline This is the star elongation direction I see (by eye) in the corners: While ASTAP provides some actual measurements, which seem to confirm the same tilt orientation: Considering @Petrol shoot, tilt is just perfect to me. Also, star size, they are smaller so maybe you can double check total backfocus besides tilt (although using different cameras, sensor size and already stretched images may misrepresent this conclusion). Hope this helps. I also need to address the same issue as I get new SHO filters and all my image train has changed. But I was hoping for a single clear night one month ago with no luck and next weeks prediction is just awful Oh, by the way, I shoot with an ASI183MM Pro but maybe an ASI533MC could match well. Many people says wanders about that sensor.

These corners make me VERY jealous, @Adreneline 😁 @SAW: I think it depends on the direction of the elongation... If the stars are elongated towards the edge, you are probably too close so you can add some shims in that corner. However, if the elongation is perpendicular to the corner-to-center direction, you are too far away... which is more difficult to address as you need to 'subtract' distance and you will mess up the other corners. If they have a good shape, maybe you can live with one ugly corner. Do you have some pic to show?

This is a very good point. I was aware of that and I get this quote from the seller, which also point in this direction: "How much chromatic aberration has your Samyang? Did you tested it with a color camera? I believe the filters are right and not mixed. I think your Samyang is tuned for the OIII (501nm) and Ha and SII (656, 672nm) are focused a little fair away on the focal plane. as well because it is intended to be used in daylight use with color cameras, that are cutted around 650nm, so maybe it's the design who doens't take care to give a good correction on bandwidth after 600nm. This is my idea, based on what I saw with photo lenses." The key is knowing if my filters are ok or not... and it seems they are just fine. Not a big problem as I have autofocus but this is a bit disappointing. I suppose I have to live with it. So now I need to check the "signal weakness" issue, I need a clear night to add more subs and make some actual measurements. If you use NINA, you can try the Hocus Focus plugin. It provides some measurements of backfocus and tilt you can use for fine tuning. I'm still testing how it goes... However, the procedure @Adreneline indicates seems the best to me: start from scratch and add different spaces until you past 'perfect' focus. This may be where you focus with your Canon camera or not, just check your images and use the backspace you see it performs better, whatever the focus mark is in the L mark. I also have the Astrodymium mount but I also add the focuser, filter wheel, a mini PC and a powerbox. For these tests I also removed the guidescope. So... I know disassembly everything so I temporally move to a laptop and a mess of cables, it is a pain in the ass but you only have to do it once. I did it with my LRGB filters, I will do it again with my SHO (if weather helps, I was waiting for 2 months ) I bought a similar kit from Artesky but I don't quite happy. I suspect I have some tilt issues due to poor construction, but I'm not sure. In addition, they are not labelled so it is not easy to figure out the thickness of the thinner even with a caliper. There is a similar kit from Baader which seems more user friendly. Just my 2ct.

Well loss some signal and not taking fully advantage of the f2 ration is what I hoped. Right now, it makes not sense to me buy some of those expensive 'highspeed' filters because my next rig will be (probably) a more traditional 80/90mm 'slow' refractor. Regarding your question, corner stars are not worse in O3 than Ha... but my image train has significant issues with backfocus and tilt, specially in one corner, so possible issues due to the O3 filter are completely invisible. Thank you! Very illustrative, this gives me a good view on how my subs should be. Those Astronomik filters are the "MaxFR" or the traditional ones? Yeah, the weather was awful and there was moon. I know they are not the best conditions to test the filters but it was rainy and cloudy for 2 months and the prediction for the next weeks is similar. But I needed to test the filters before the ending of the refund window... I know I need more tests and I don't want to return them (I was very happy with my Baader Ha) but I also need to know if I'm doing something wrong... Regarding focus position, I don't get your point... Despite R and GB focus are of on the Samyang, when shooting mono this should not have major impact. Although refocusing after filter swap is a good idea, if filters are parfocal focus position should be similar anyway, at least with narrowband filters. Based on your star diffraction patter, they are (well, somehow). But check how are the stars in my second picture... they are not in close focus but no means! In fact, using my EAF, based on my tests I achieve focus in the ~6500 position for Ha and ~6600 position for S2/O3, which are a lot of motor steps. I'm missing something? For the moment, I think I should: 1) More text with better forecast and more integration time. 2) Stop down the lens to f4 to discard band shift issues.

A small break in the clouds allow me to test my recently acquired narrowband filters (Baader 6.5nm SHO 31mm unmounted). However, results seem not very promising... I already had the H-alpha filter and it worked perfectly but: They are supposed to be parfocal but focus position is quite different from H-alpha to S2/O3. Transmission from H-alpha is what it is expected but S2/O3 signals are very weak. One example from yesterday night: single uncalibrated 300s subs with ASI183MM Pro @ -10ºC gain 111 and the Samyang 135 ~f2.7 (using a 49mm step-up ring). So... May I have gotten defective filters, from different batches? Serial and part numbers seem fine but not having the same focus position worries me. May I have done an incorrect installation in the filter wheel? I don't think so, H-alpha works fine and S2/O3 are mounted identically, I even double checked which is the correct side. May I have issues due to band shift as I'm using a faster focal ratio (~f2.7) than the filter specification (>f3.4)? I'm aware of preshift filters but I read that band transmission loss is "acceptable" with the Samyang @ f2.8. I am wrong? Is this valid for H-alpha but not for S2/O3? Is everything OK but I'm just using very little integration? I expect more signal in S2/O3 despite being just one single 300s sub. Weather is awful so I don't expect having a chance to test them again in the next days. Any help is welcome. This Samyang 135 is driving me crazy, specially due to bakcfocus and tilt problems, so adding one more issue is tempting me to sell it and buy a proper scope Edit: I just added a pic comparing Ha and S2 subs using the same focus position at 100% magnification.

2 clicks per stop if I'm not wrong. However, I'm using a 77>49mm step down ring. Much (much) better than mine! I think I'll need to check spacing again 🥲

I bought a set of metal spacing rings from Artesky to add ~1.6mm additional spacing to get reasonably good stars with both ZWO LRGB and Baader Ha filters (I have some tilt in one corner, not sure how to fix that). I also use the M48 adapter and I measure from the face of the adapter, as you show. It is safe to say the focus mark should be near the 'L' mark on the lens. However, as each lens vary, best approach is to try different spacing rings until you get the one best fits your particular unit. It is a bit tedious but it can be done in one night. ASTAP or any other aberration inspector (such as NINA or PixInsight) helps a lot. In my opinion, in the end what matters is having a 'good looking' image and don't worry too much achieve a perfect 44mm spacing. A 0.1mm spacing difference may have huge impact and it is difficult to handle. In fact, if you mix filters you may be interested in having *less* spacing to get focus with all filters inside the mechanical limit of the lens although you don't get perfect spacing for any of the filters, you know, a compromise solution. If this helps, my setup is configured in this order: SY135 + M48 adapter 16.5mm ZWO extension tube 1.65 spacer rings 20.0mm EFWmini (+ filter) 6.5mm ASI183MM (without the 11mm ring) Total: ~44.65mm Note: Those Artesky metal rings feel a bit cheap and they are not labelled, it's hard to differentiate between 0.1-0.15-0.2mm even with a caliber as they flex a lot. There are better (more expensive) ones but in the end, they do the work... Although the tilt I have may come from them. I don't know for sure 🥲

And what about guiding camera vs main camera orientation? I know that rotate the guiding camera is not big deal (in most cases) and I suppose having same orientation than the main camera eases guiding math but... it is truly necessary rotate the guide camera when rotating the main camera at this low focal length?

So nice cable arrangement! I'll probably go that route if I had a permanent pier... I could use a more powerful 'full' PC. My camera also has a USB hub but I need one additional port as I'm adding a filter wheel. My focuser needs a dedicated 12V power input, so more cables. For now, maybe putting everything over the OTA and using a flexible cable conduit tied at both ends to avoid damaging the connectors, as you point out, will hopefully ease (dis)assembly) the whole OTA as it should be "one single package". Right now I have all pieces (except a 2.1mm>2.5mm short power cable for the Mini PC I forget buying, shame on me). I'll investigate how I can attach the PC and the powerbox together and post some pics of the result

Same here! Thanks for the pics, I think I get some useful ideas I'll try to put into practice soon. Hopefully I'll edit this post with some photos

Thank you so much for this very detailed reply! My mini PC is about ~11x11x4cm, ~280g and 12V. My initial plan is to tie all cables to a fixed point in the mount (EQ6R Pro) head: mount USB to PC + mount power from powerbox + main power from ground to powerbox. I can attach them to each other using one of those flexible cable conduits. This way, I skip the USB hub (the PC has enough ports), the powerbox handles everything (so I only need one power supply), I reduce cable weight on the connectors (using that fixed point) and I can disassembly the whole OTA in one piece except for 3 connections. I know I may have problems mixing data and power or even overpowering the Mini PC USB controller but I think it worth a try. However, I'm not sure if this reasoning has any flaw, that's why I started this thread. The mount to head cable loop causes me some issues and it seems easier to just let those cables go to the ground, as you say. However, I still having a loop from the PPBA to the ground and I have to add USB hub and power supply so I still don't see a clear advantage...

Hi! I'm tryting to get rid of the cable mess I have in my setup (EQ6-R + Samyang 135mm + ASI183MM + focuser + filter wheel + guiding). I also having problems with my laptop as it turns off due to the low temperature or humidity (I think is the battery). So, I've got a PegasusAstro Powerbox Micro and a Mini PC (the Eagle solution is just too expensive and I like NINA so ASIAIR is not my first option). However, I think this route will simplify the cabling but now I'm trying to put everything together, it is not that easy. I see this routes: 1. Put the Mini PC and Powerbox on the OTA, cable the mount (power+data) to the OTA and cable the OTA (power) to the ground. 2. Put the Powerbox and a USB hub on the OTA, cable the mount (power+data) to the OTA and cable the OTA (power+data) to the ground. 3. Same as 1) or 2) but cabling the mount to the ground instead to the OTA. I know it may be a personal preference and depends on the particular equipment. For instance, my OTA is quite small and I struggle to fit everyting over it. I also read a lot of topics in this forum and saw many (many) pics of complete setups and no consensus is reached. I'm trying to decide ASAP as I'm in time to return the Mini PC and the Powerbox Micro and get the Powerbox Advance, which includes a USB hub. Removing the Mini PC from the OTA will allow me use a larger/powerfull/cheaper one despite I may not need it to run NINA. All equipment will run from the backyard, I'm not going to a dark site, no battery needed. I really appreciate any commets or hints as I'm sure most of you have/are having this issue. I'm also wondering when the manufacters will start using mounts with cabling inside by default and USB Power Delivery to remove most of the cabling! PS: Please, feel free to move this topic to another forum for better fit

Hi! I've gotten (for free) a SV106 guidescope (Svbony 60mm f4) and I'm wondering if it makes sense using it with my Samyang 135 + ASI183MM. I don't have (yet) a guidecam so I can't try... I feel it is quite a bit an overkill but, hey, its free! 😅 I'm just wondering if it makes sense try to make this "odd thing" work or if I should let it go and just get a 30mm guidescope... Update: I'll use an EQ6-R with this setup

Thanks @geeklee! I got the mount one month ago and (as expected) it was rainy every single day and more rain is expected in the next 15 days at least. Yesterday I view a crearing in the sky so I jumped, unprepared at all, outside the house without a plan in mind... It was a miracle everything worked! By the way... A general question: How long can you make the subs without guiding? With the EQ6-R I tested 120s ok for my standards but those at 240s were terrible (I may had messed up things), which is a bit dissapointed as I also achieved 120s with my StarAdventurer...

Can't coment on dithering as I've just did yesterday my very first light with the samyang and my new setup but from my almost-zero experiencie, it is worth it. This is the result of a quick-and-dirty processing of that very first light without calibration frames but using dithering: Some info: Equipment: EQ6-R + ASI183mm Pro + Samyang 135 + EAF + EFW + LRGB filters + NINA 16L, 3R, 3G, 3B @ f2.8 @ 120s each (50min total), dithering after each sub, no guiding, no sub rejection, no darks, no bias, no flats, no noise reduction, no nothing, in summary. Bortle 4-5 (probably 5+ nowadays). Editing: Stacking, background extraction and channel combination in PixInsight. Some color saturation increase. (Note: I barely know how to use PixInsight 😅) To be fair, the image is (quite) a bit so-so but I'm quite happy everything worked somehow together as this was ther first time all equipment was plugged at a time. In fact I had some issues with power and cabling management and also with humidity and cold (my laptop freeze 3 times in 2 hours span). I also have to improve the logistic as I lost count of how many trips inside-outside house I did 😂 Oh god, I need an observatory ASAP!

Hi! Very interesting topic. I don't want to divert the main discussion topic but... - Size and roof opening system may condition the material. @Stuart1971, love you obsy! Do you feel 5 feet too narrow? What about wall height? - Have you considered 'sandwitch panels' as this one? I don't know if this is the correct term in English but I'm considering this material for roof and walls as it is an all-in-one solution (wall structure, thermal and water insullation, decoration...). You only need a simple metal framing for the main structure.

I don't want to steal this post with more comments but I just want to say this is mind-blowing and it deserves a separated post in the forum. I need to read it again... more carefully Regarding the original question (because I'm also facing similar issues), I'm exploring something such as the Motel o'Scope enclosure: https://www.pierplates.com/motel.html Despite this is a fancy enclosure, there are similar but cheaper options: https://www.cloudynights.com/topic/469778-my-mini-observatory/ https://www.mark.dahmke.com/a-backyard-telescope-mount-enclosure/ https://www.primalucelab.it/blog/osservatorio-nel-giardino-di-casa-a-backyard-observatory/ https://www.cloudynights.com/topic/660246-my-tilt-off-roof-observatory/ There is also the so called 'box observatory' approach: https://stargazerslounge.com/topic/248181-the-box-observatory However, I'm particularly interested in something such as this one (more kind of micro-full-observatory, check pictures in the last page) but I'm no ready yet for a DIY project like this: https://www.astroforum.nl/threads/eindelijk-weer-een-sterrenwacht-bouwen.1470438/

Out of my budget! But they seem to perform excellent 😅

I came to this post as I'm interested in the @RugbyRene original question... but now I also need additional details about THAT equipment 😅

Love it! May I ask which filters are you using? Thanks

Oh, the Antlia filters.... I read good things about them but they are quite expensive in my local shop 😥Anyway, thanks @AcapulcoRolf! PS: Love that shot @Phillyo, very inspiring!

Yeah, there are some issues as you go toward the edges... same happens to me despite having replaced the canon mount by the Astro Essentials M48 Adapte, I'm still trying to get the optimal backspace. But... the image looks fantastic! Love it. No need at all to go 1:1 to enjoy it. Could you please share what SHO filters (brand, diameter, bandwidth) are you using? Thanks a lot

I use ASTAP through NINA (but configuring ASTAP independently). I use the SW Star Adventurer tracker and, as it has no GoTo, plate solving allows me to considerably speed up locating objects in the sky (set in NINA telescope as 'simulator', connect Stellarium with 'simulator' using ASCOM, take picture, blind solve, sync mount, Stellarium updates automatically showing framing with Oculars plugin). The configuration I use for my Samyang 135 + ASI183MM Pro is the following. I have many issues with the 'Alignment' tab until I set the search radius and FoV but now it works very well with the H18 database (the W17 never worked for me).

I am not the most appropriate to give advice but: Going f2.8 is safer than f2. I have some tilt and backspace issues with that same setup at f2 which are less pronounced at f2.8 (check post here). As far as I know, LRGB is superior to RGB even with mono cameras. I think L subs are more important than RGB subs as luminance tends to be more important than color. It depends on the camera characteristics and light pollution. You may expose as longer as possible the LP (and mount) allow you. Unity gain is usually the recommended starting point, tweaking the exposure length and/or gain as needed based on environmental conditions and equipment. Then, stack as many frames as possible. In addition, if the scene has more dynamic range than the camera support, take other series of stacks with shorter exposure and/or gain. You can blend the two final stacks (I did this before with my DSLR and Photoshop, never with PixInsight, DSS or other astro software). Not sure if this is necessary with M31 if you exposes carefully, by the way. Please, anyone, feel free to correct any of my comments! I probably made some mistakes but, as @woldsman has any answer yet, I tried my best 😅 BTW, I shoot M31 with the Samyang 135 but using an unmoded Sony a7III... Not sure if that experience may help you, but feel free to ask.