Astro-Geek

I've just found a solution 🤓 I've ordered an EOS EF-M to "C mount" adapter, (which is nice and short), and a C-Mount to 1.25" telescope adapter. They look as though they'll give me a minimal length EOS-M to 1.25" telescope adapter when they're screwed together. I'll update this thread with the result (whether successful or not !) Thanks again for the replies and suggestions...

Thanks Starlight, I've just posted some pics that might explain better what I'm trying to achieve.

Thanks for the replies everyone. I'm sorry my OP wasn't too clear, but as Michael says, I was searching specifically for a T2 adapter for my EOS M50 camera which has the slightly smaller diameter EF-M bayonet. I do already have a T2 adapter for it, but the barrel is about 2" long, so it "wastes" inward focus, which is a shame, because the EOS-M cameras have a much shorter infinity focus path than standard EOS cameras because they are "mirrorless". I am still searching for a T2 adapter ring that is of minimal length, like all of the EOS EF T2 adapters, which are just long enough to accommodate the T2 one end and the EOS bayonet at the other. I'm not sure how well a plastic 3D printed version would work, with the fine screw T2 thread and the thin EOS bayonet tags. I guess it would be possible to surgically remove the centre section with a lathe, but the rejoining might be tricky. I did manage to make a "short" EOS-M adapter for my 2 inch telescope eyepiece drawtubes by following an idea from someone who published it on the Internet somewhere (sorry, I can't remember where). It was quite a clever idea using an EOS-M to 52mm filter thread adapter and then a step down ring from 52mm to 48mm, then a 48mm extension tube.

I'm having doubts now though, I checked the "Kood" website and their image for their EOS-M T2 adapter is the long type: https://www.koodinternational.com/t2-t-2-mount-to-canon-eos-m-ef-m-mount-mirrorless-camera-adapter-uk-seller-1409-p.asp ...and looking closely at the image on Bristol cameras website of their EOS-M adapter, it is simply marked "for Canon(AF)", so I fear they have just used the wrong image..... 😥

Thanks Michael, much appreciated 👍 You should buy a lottery ticket ! I searched dozens of Astro Gear suppliers and Amazon and Ebay, and all I could come up with were the long ones. https://www.google.com/search?client=firefox-b-d&biw=1535&bih=768&tbm=isch&sa=1&ei=PgdDXZ29IaKDhbIP1o6EgAk&q=T-Ring+Canon+"EOS+M"&oq=T-Ring+Canon+"EOS+M"&gs_l=img.3...51305.54582..55528...0.0..0.49.89.2......0....1..gws-wiz-img.6L9GU_qosqs&ved=0ahUKEwid1KiqgOLjAhWiQUEAHVYHAZAQ4dUDCAY&uact=5#imgrc=oQHfgp-_wjciCM:

I'm struggling to find an EOS-M to T-adapter that isn't about 2 inches long ..... 😧 I have a mirrorless EOS M5 DSLR which has a lot going for it for Astro use compared to other EOS mirror cameras. As well as being much lighter and more compact, the sensor to lens distance is about 25mm shorter than the EOS-EF and EOS range, so it should be easier to attain infinity focus without resorting to a Barlow. I say "should" because I'm struggling to find an EOS-M bayonet fitting to T-screw adapter that is no longer than the standard EOS T adapter. The only ones I can find are about 2 inches long, as per these FLO website pics. I can fully understand the need for that length with the EOS-M to EOS-EF lens adapters, because they have to compensate for the shorter focal path, but why are they so long with the T-Adapters ? It negates the EOS-M's advantage of having a much shorter focus distance. https://www.firstlightoptics.com/adapters/t-rings.html

The design of the focus tube on the Skywatcher 200 was changed at some stage. Current models do indeed have a 2" holder with a 1.25" adapter. Earlier models though, (like my "blue tube" 200p), had a much more awkward bevelled fitting that only accepted 1.25" eyepieces. When you removed that by loosening its thumbscrews, it revealed a non-standard opening of about 54mm with a step just inside that neither gripped 2" eyepieces, nor let them be inserted more than a few mm. FLO sell a replacment fitting for these early 200p scopes that accepts 2" eyepieces (which Skywatcher should have fitted in the first place !!) https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-for-skywatcher-newtonians-m54.html It was also discussed here:

Yes, maybe the EQ1 and EQ2 wormwheel bevels are slightly different diameters with a different number of teeth. I searched high and low on the Internet, but could find no specific details on the gearing ratios, unlike all the info available for the EQ5 and 6 when they're EQ Modded....

Thanks for the second reply Alan, and the photos. Yes, I hadn't realised that the coupler on the simple drives already had a thumbscrew, and as the shaft is "D" shaped, it should be a firm fit without needing excessive tightening. If I mount it on the same side of the mount as the exposed gearwheel (as in the original Konusmotor photos), then it'll be the right way up and I'll still have the slowmo flex drive on the other side, and the thumbscrew gives me a simple clutch option. So that sounds the best way forward. The only mystery now, is why are there two different simple motors from FLO (EQ1 and EQ2) that appear to be identical (and as in the two videos linked by Bob), and why are they priced slightly differently ? The geared motor looks the same size and the coupling and bracket are the same, and they are both speed adjustable.... 🤔

Thanks for the links to those two videos Bob. They've certainly provided even more food for thought. The EQ2 motor vid shows it being fitted on the opposite side to the exposed gear wheel, necessitating the complete removal of the slowmo flexi handwheel control. It also shows that the motor box is then "upside down", which make one think that it is indeed identical to the EQ1 motor, which fits on the other side and is the right way up and they haven't bothered to make a different box and graphics for it. It would also mean that the shaft is being turned the opposite way (from the other end). The North/South switching could take care of that I suppose. To further confuse matters, the photos of the original Konusmotor 130 motor is fitted on the same side as the gear wheel, so it is the right way up.

Yes, it certainly looks different to most EQ1 and EQ2 mounts, they all seem to have open bevel gears, whereas mine are enclosed, as though it was a halfway house design towards the EQ3m, (which appears to have preceded the much more common eq3-2. I'm still struggling with the fact that it has the swivel post, large gear wheel and cam lever for the clutch mounted motor, and yet all of the original Konusmotor 130 photos show it with the simpler direct drive via the flexi-coupling locked directly onto the slomo worm gear shaft. Maybe, (just thinking aloud here 🙄), the coupling was modified to the direct drive because the earlier gear cog design suffered from "jumping" when the RA axis was stiff, and it levered itself away against the spring ? I have another cunning plan though, if the simple motorization kit's motor speed adjustment is the safer option for getting the speed right, then maybe I could swap the flexi-shaft coupling's grub screw for a knurled knob, to enable it to be released (like the clutch) for manual slowmo operation ? I'm still confused as to why the EQ1 and EQ2 motor kits sold by FLO are so specifically designated, even though they look identical (inside and out), and are different prices. I did just drop FLO an email about this, but although they answered very promptly, they were unable to throw any more light on the subject......

All feedback gratefully received !!

I've been checking FLO's other motors for EQ mounts and the delux Hand set types also come in the two flavours, EQ1 and EQ2: https://www.firstlightoptics.com/sky-watcher-mount-accessories/sky-watcher-ra-motor-drive-for-eq1-with-handset.html https://www.firstlightoptics.com/sky-watcher-mount-accessories/skywatcher-ra-motor-drive-for-eq2.html Interestingly, only the EQ2 type fits via the gear cog and spring and utilises the clutch. The EQ1 type is just the fixed bracket, with a flex-coupler straight onto the shaft, like the economy models. So it would appear that the only type that I can get that will use the clutch is the EQ2 handset model. I'm surprised it's such a minefield, considering how popular the EQ1/EQ2 mounts are.....

Thanks for the very prompt and helpful replies. It's so handy being able to tap into other people's practical experiences with this sort of thing. Alan - Yes, those two basic motors do look the same as the Konusmotor original fitment. Thanks for the two FLO links. Strange thing though, they look absolutely identical (front and back), and yet they are each specifically aimed at the two types of mount, and one is £3 more than the other ! I hear what you're saying about the fully adjustable motor (also making it seem strange that there are two types), but I really would prefer to go for the other type that has the gear wheel and spring, so that I can use the clutch that's already fitted as part of the mount's original equipment. I think it would be so much more convenient to use the clutch type, enabling the use of the RA slomo flexi cable, rather than having to loosen the clamp bolt and physically move the RA. Yes, I do understand the need to get the axial movement of the RA as smooth as possible and my rebuild appears to have achieved that, with the RA easy to turn even by just gripping the rubber flexitube, rather than the knob. Interesting what you say about the optical performance of these low cost "Bird Jones" OTAs. I must admit, I did pop in a good quality 20mm eyepiece and tried it out terrestrially in the daytime. It did indeed seem quite sharp, and that was without any attempt to check the collimation. Bob - You've confirmed something that seemed a possibility during my Google searches, the deluxe handset motors are more sophisticated timing-wise, and therefore non-adjustable. I really would prefer to go with that solution to make use of the already fitted clutch lever mechanism. I think I'd get really frustrated with the slow motion RA being permanently locked to the motor mechanism. Going back to Alan's FLO links to the basic EQ1 and EQ2 motors, I'm now wondering if the difference between them is the flexi-coupler shaft rotation, because maybe the EQ1 and EQ2 have different gearing. If so, then the appropriate EQ1/EQ2 handset type motor should match my Konusmotor's mount, as surely it is merely a clone of one or the other, albeit with enclosed bevel gears ?

I've just acquired a used Konusmotor 130 telescope and mount for a specific purpose. I know the OTA is regarded as rubbish, (with the extra lens element inside to enable a shorter OTA), but I was only interested in the EQ mount, so the OTA is going to be discarded. I already have a very nice EQ5 goto for imaging with my 200PDS, but I wanted a really lightweight EQ mount and tripod for my Lunt LS35 and maybe my Skymax 127 for visual use only that I can grab and go (even with the counterbalance weight attached). The Konusmotor came up for a good price and it appeared to have a hybrid version of the EQ2 mount with enclosed bevel gears and a vixen saddle. I stripped it down completely and rinsed the Chinese Evo-Stick grease out of it and re-assembled it carefully with lithium and adjusted the RA and DEC play and I'm now extremely pleased with it. It is very smooth on the flexi SloMos and reasonably steady with my lightweight scopes and very convenient to carry around my front and back gardens and quickly set down facing North with the Lat preset, giving me good visual tracking (and so much better than AltAz ! 🤓). Anyway, to come to the point of this post, it was lacking the original fitment RA motor drive, so I'd like to fit a replacement. I've been scouring the Internet to see what choice there is and which is the correct fitment for my hybrid EQ2 (at least that's what I think it is). I'm getting very confused however. EQ1 and EQ2 mounts appear to be available as "basic" and "deluxe", with either an integral 9v battery or with a remote handbox, 6v battery pack, and x2 and x4 speed controls. The choice is further complicated by the EQ1/EQ2 variations. One sort is connected directly to the slowmo shaft by a flexi coupling, and the other sort has a small gear that meshes with the large gear cog on the mount. I found the attached picture on the Internet where the apparently original motor fitment on the Konusmotor 130 was the flexi shaft type, which I find strange, since it makes the large gear cog and cam redundant ? I'd rather not get that type since it does not use the EQ2 clutch provision of the gear wheel, cam lever, and spring, which enable quick clutch release. So, if I got the gear cog/spring type would it turn the Konusmotor's RA at the correct speed ? (I'm thinking it surely should, since those gear wheels look like a standardised size on these small EQ mounts. Lastly ! (sorry about the length of this), is the difference between the basic and deluxe EQ1/2 motors more than just the control box and battery holders ? Is perhaps the deluxe motor more sophisticated and accurate ?

I use a laser and a long tube Cheshire (one after the other), because I find they both have advantages. The laser gets me close and is very easy to use with a long tube Newtonian because I can adjust the secondary whilst watching the dot in the collimator target, but with the Cheshire I need to keep moving back and forth, as my arms aren't long enough. Neither the Laser nor the Cheshire can be perfectly centred in the eyepiece holder tube because of the standard way that the gripping works. The thumbscrews and the brass band both push them off-centre slightly when tightened. (Maybe a Baader clicklock holder would be better, but I've never had one of those yet 🤓) My own workaround therefore is to check the spot centering with each collimator rotated in three different radial positions. I can therefore judge and adjust to the exact centre by seeing the tiny offset as the dot moves around it with each 120 degree rotation. I do this with both the initial step of centering the laser dot in the secondary mirror and also the final step of centering the dot on the lasers target disc, (effectively moving it around the "edge" of the centre hole as the collimator is rotated. I get nice concentric Airy discs when viewing stars, so it works pretty well for me.

I had a similar worry with my 200PDS, a "blurry" dark blob in the middle of the view with certain eyepieces. It only manifested itself with bright, daylight viewing conditions when testing the scope terrestrially, (is that when you get the problem ?) I Googled it, and was relieved to find it's a perfectly normal phenomenon with Newtonian telescopes, as it is the obstruction of the secondary mirror in the field of view, (not the dot on the primary). The reason it occurs is because with low power (high mm) eyepieces, the light gathering of the scope in daylight allows your eye's iris to close down to a minimum, so that it is smaller than the central obstruction caused by the secondary mirror. When you view dimmer objects ( like anything at night !), your iris opens up much more, and it's "exit pupil" is then bigger than the cone of the shadow of that central obstruction. The blurry blob also disappears when you use higher magnification eyepieces (smaller mm) even in daylight, because they give a darker image, and again, you iris opens up more.....

(Pun alert) The delay in answers to the opening question may indeed be because it was so Nebulous... 😀 Modern manufacturing processes have made pro quality kit so much more affordable these days, so the choice is much greater. My budget is much more modest (understatement of the year), and I faced the same dilemma, (Mak/SCT versus Big Dob), so I bought both, secondhand...... Admittedly on a somewhat smaller scale, but with a similar size differential, a 12" Goto Dob, and a 180 Skymax Mak. I now have the advantage of hindsight, and I can safely say that I like both equally. The 12" (flextube) Dob is just about portable and is, as they say, a real "light bucket" for distant objects. The 180 Mak is amazing with Planets and the Moon, with the 2700mm focal length enabling high magnifications without having to resort to Barlows or very short focal length eyepieces. You also mentioned that your current setup of the 8 inch Newtonian on an EQ5 is heavy and messy to carry, but the 16 inch Dob will be much heavier and bulkier, albeit on a wheeled platform. Likewise, an 11 inch SCT will require a bigger EQ mount, like an EQ6, which is a much heavier, hernia inducing beast compared to the 5. 😧 The big Dob will be superb for visual, but when your budget reaches this scale of aperture, an Equatorial mount is the most logical way to go for Astro Photography.

By coincidence, I just noticed a very nice looking used aluminum case for 8" fork mounted scopes on Ebay. It's from a private seller in Germany, but the postage is a fairly reasonable £18.87, and the buy it now price is £71.83........ https://www.ebay.co.uk/itm/Aluminum-Telescope-Case-for-8-fork-mounted-SC-telescopes-Celestron-Meade/113805817581?hash=item1a7f5af6ed:g:r-YAAOSwp~pdHKV3

I usually find Google image search a good source. https://www.google.com/search?q=telrad&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=0ahUKEwihkrH_zpXjAhV8Q0EAHX4oDwQQ_AUIECgB&biw=1535&bih=768#imgrc=oZLVCZrB6NsHgM: It turned up quite a detailed internal drawing that someone previously posted here on SGL, back in 2014 (Astrotux)

Don't get me wrong, I'm not trying to sound negative, especially given the wealth of advice from such experienced users on here, but there is a significant increase in "bulk" when considering a 250 solid tube compared to a 200. I owned a GSO 250 (solid tube) which was a great scope, but significantly bigger and harder to manhandle off the base than my 200PDS dob. It all depends on how much it will be moved, how regularly, and how strong you are. I'm a decrepit pensioner with the all too common back problems so I admit I'm biased. When I had the 250 I had to occasionally move it down a flight of stairs and it was quite an undertaking. The flextubes start to make sense in the 250 to 300 and above range, because although they are slightly heavier, they are more easily stored and manhandled bulk-wise. Ahh, variety, the spice of life, and the pain of decision making....... 😀

Now that the confusion between Kilos and lbs has been resolved, Azimul's wishlist is for something lighter than 12kg for carrying up three flights of stairs to the roof, that can do Planets, Nebulae and a little bit of Astro Photography. As has already been discussed, the reluctance towards an EQ mount is a problem with photography, because of no tracking and field rotation. The 150 Newtonian Skywatcher OTA is a good optics compromise though, being light and compact with relatively good performance. The weight problem is caused by the MDF wooden dobsonian base, (probably made intentionally heavy for stability). The two parts (OTA and Base) do readily separate though, but is there a concern about doing it in two trips maybe ? Computerized goto could be achieved with that 150 newton by getting a secondhand Synscan AZ goto mount. They can usually be picked up for around £100 in the UK. You'd still get field rotation, but it would track ok, and the remote handset for fine and coarse manual slewing. They have a payload capacity of up to 5kg (just enough) and there should be just enough offset on the arm for you to reach the zenith with the 150. Here's a photo of my Synscan AZ goto with a deforked Meade 125 on it. It has a standard Vixen dovetail clamp, so you just need rings and a dovetail for your 150, (which would then be fully compatible with an EQ, if you ever progressed to one). The main problem with the Synscan AZ goto mount is the "toy" tripod that they spoil it with. It lets down what is basically a very good well made mount, so I modified mine to fit a standard M10 thread skywatcher tripod. (but then the weight is creeping up again..... 🙄)

You're right, I always wondered why Skywatcher don't appear to have produced a solid 8 inch goto. When I was searching, I did find an Orion one, the N 203/1200 SkyQuest XT8 IntelliScope. https://www.astroshop.eu/telescopes/orion-dobson-telescope-n-203-1200-skyquest-xt8-intelliscope-dob/p,33297 (apologies for not posting an Flo link, they don't seem to do Orion scopes.) At £630 including shipping to the UK it's quite a bit cheaper than the Skywatcher 200 flextube goto, but it is a "push to" instead, which is better in some respects IMHO. The Az and Alt sensors enable the same object finding, but you push it to the indicated angles instead of the motors doing it and there is no tracking, so it will not follow an object. I found that Retro fitting goto to a Dobsonian is expensive and not straightforward. Each mount is quite specific with non-standard bearings. I therefore went for a simple DIY azimuth scale on the base and a cheapo clone of a magnetic "wixey" electronic angle gauge. Costing only a few pounds these are so simple to attach and use. Once calibrated on a horizontal surface, they just attach to the OTA near the top and give a precise alt angle of whatever it's pointing at. I then just use an android tablet (or phone) running a free stellarium type app to search for an object and then point the Dob in the expected location. It may be less accurate than an electronic goto and there's no tracking, but it gets me within a degree or so, and the additional "brainpower" steps of transferring the angles is more satisfying somehow. 🤓

Lots of good advice on here already. My thoughts are that the flextube option is no advantage with a 200p because it's quite manageable as a rigid tube and it is possible to put it in standard rings for later EQ mounting. I agree that the Bresser is halfway there already, just needing the dovetail, but it can be done with a skywatcher 200p too. (But it would be pretty much impossible with a flextube). The attached photo shows my "hybrid" 200PDS with dual Dobsonian mount and Rings/Dovetail. They do fit, both together, just. I bought it as a 200PDS with rings but then hankered for it to also be Dob mounted for quick "mobile" sessions. I was lucky enough to find someone selling most of a used 200p Dob base, (the uprights, bearings etc.., all except the circular turntable base, which was fairly easily fabricated from 18mm MDF and a lazy susan bearing). I retro fitted the large plastic Dobsonian Bearings to the OTA after careful measuring, and they happily co-exist with the standard rings and dovetail. So it can be used as a Dob or simply lifted off and fixed to my EQ6 mount for Astro or accurate tracking. I would however suggest that it's much easier to buy the Dob version and then just add the rings, then there's no DIY modding and it can always revert to a pure Dob. If I ever had to restrict myself to just one telescope (perish the thought.. 🤓), it would be this one, for maximum versatility and convenience.

I had one last year that was included with a secondhand telescope that I bought. It was the one at the top in this youtube search - https://www.youtube.com/results?search_query=tent+observatory It was quite well made, just like a medium size igloo tent with the springy interlocking fibreglass poles. Quite large really. I sold it though because my garden is quite small (but beautifully non light polluted 🤓) so I don't go to dark sites or events. I would imagine it would be very handy at events, especially if there's a bit of a chilly breeze. The circular "missing" roof was just the right height and size to swing most scopes, whether eq mounted or even Dobs. If I can't eventually aspire to a small dome like my Avatar 😍, I may try a beach type windbreak instead, which would have a smaller footprint and be quicker to set up.