discardedastro

Good to see some progress - I'm particularly heartened to see the ILP involved, since their guidance is what the bulk of local councils rely on for evaluation of lighting solutions.

Bit of a mixed bag, this. This is a shot of M33 (Triangulum) with quite a lot of dew on the Paracorr outer lens during acquisition. My OTA lives outside and was pretty wet when I started imaging, and the dew heater didn't clear it all, exacerbated by poor seeing and clouds. I also had some interesting artefacting going on top left which seems to be related to my OAG prism. Still working that one out - need to push it a little further out, I think, or get it perfectly flush on the "long" side of the sensor. Flat correction helps, but clearly struggled with the dew. 200PDS, ASI183MM-PRO, TeleVue Paracorr, ZWO OAG, ASI174MM guiding, Baader LRGB filters + ZWO Mini EFW, EQ6-R Pro, KStars/Ekos+PHD2 guiding. I also further pushed the processing for saturation. Exacerbated the artefacts but got the colours "popping" a little more, artistically!

LP filters will help with indirect illumination, is my understanding. So sky glow and illumination of the atmosphere from the ground. Direct illumination, you're not going to fix that with filters. That's where you want to put barriers up to block local light. Obviously a dome will do best in this regard, but it's quite an undertaking - so panels etc will be order of the day! The IDAS D2 is a very solid LP filter and will help with the skies if you've got issues higher up.

I believe so, yes - you will need the extension tube for sure but I've done a similar arrangement and it works using a Z6 and FTZ adapter which should be the same flange distance as Nikon F-mount DSLRs.

Yep - EQ5's definitely the limit. EQ6-R Pro here and I still suffer from wind affecting guiding somewhat and it does take a fair bit of active correction. The dual-speed focuser is a must even for visual if you ask me, but easy enough to retrofit if you need to with only basic tools. I retrofit a Baader Steeltrak Diamond to my 200PDS and the improvement is quite drastic (as you'd expect for a £200 focuser!) visually, but with a focus motor for imaging (with a dedicated astro camera) it's been flawless as a focuser. There's lower-cost options, of course, and they'll still be a big step up from a single speed focuser for getting the focus dialled in right.

Quite right, my mistake - field of view/number of pixels is what I was trying to get at there!

Probably not ice but dew, and likely on the front of the sensor window rather than on the sensor itself. ZWO sell a dew heater specifically to warm the front of the camera, which may be all you need to add to fix this in future - alternatively a heater to wrap around the frontmost element in your imaging train. If you can confirm it's inside the sensor window then you may need to consider dessicants - I'm not sure what the ASI1600 uses (if anything) on that front.

... and finally, after a lot of mucking around and reassembling bits by the side of the scope in the cold, this works (in the spirit of documenting my failures!): So - long story short, I didn't need to chase for inward focuser travel compared to my old set-up but actually outward travel. I put the tunable top back on the Paracorr and used my TeleVue Delite 17mm to give me a visual way to look at focus rapidly and just moved it till it looked right with the focuser racked out halfway and locked it off there, then re-fitted the imaging train and confirmed I could achieve focus - which I could! Light at last. Then I realised I needed the OAG to be the absolute first thing in the train, so that got switched around, putting my spacer in the middle of the EFW and the OAG. Then I realised (!) that the ZWO helical focuser was a bit marginal for inward travel - I think removing the included 3mm spacer would've done it but I couldn't get it to shift so replaced it with the standard adapter and again adjusted by hand till it looked right. Ran autofocus on the main camera, then adjusted the guide camera by hand to bring it parfocal. I've now got to do some adjustments in PHD2 to get the OAG doing its thing correctly, but it's all coming together now. Just wish it were a little less windy tonight!

OK, further staring at things led me to add in my 11mm spacer from the camera so I now have Paracorr - spacer - OAG - EFW - ASI183MM which gives me 55mm backfocus mechanically. Which also tallies with the ZWO guidance I found on the topic. However, I've now set it all up outside and can't get any stars to appear in any focus position. I've tried fully inward focus, fully out, everything inbetween, and even offset further back (not that that should improve matters). I normally have the focuser 20mm or so from the inward position (using the MPCC) and have s een some reports the Paracorr requires about 20mm of inward travel to get focused, but as far in as I can go I can't get any stars to appear. Losing my mind slightly and would welcome any suggestions or thoughts - I'm probably doing something stupid.

I'm a plonker, I think - the 11mm number I'm not sure where it came from but I need 6.5 from flange to sensor. Which means that I'm off by 4.5mm - the amount which I thought I needed to offset by. So the answer is to entirely remove the excess spacer and all will be well, in theory! I've found a tiny 3mm spacer from TS which I'll nab along with some 1.5 to 0.5 steel spacers just in case the Paracorr demands further adjustment on the lens-to-flange front, but I think I'm sorted. Just need some clear skies! https://www.teleskop-express.de/shop/product_info.php/info/p5731_TS-Optics-T2-extension-M42x0-75---3-mm-length.html

Rather foolishly forgot to take photos before doing a rough test assembly but shiny new Televue Paracorr mated up to the optical train (more or less) with the new OAG. Much fiddling to do now!

I'm now the happy owner of a Paracorr and OAG, which means guaranteed hours of realising I have the wrong bits/not quite the right spacer/etc! Slightly blurry photo below of the overall setup. Basically I've got an ASI183MM-PRO as the imaging camera, an ASI 174MM Mini as a guide camera, the ZWO OAG and helical focuser, and a Mini EFW. The measurements are hard to make precise because - in rather un-Televue fashion - the measurement offsets for the Paracorr's T2 adapter aren't specified. However I've estimated at about 4mm of air between the front flange and the top of the uppermost Paracorr lens. The imaging train in theory looks like 11mm for the flange-to-sensor, 20mm for the EFW, 16.5mm for the OAG, and I need to achieve 56mm backfocus from the lens (or 52mm from the T2 flange) meaning I think I need a 4.5mm spacer - which is hard to find! I've put a ~7mm spacer in for now as the closest approximate thing I own. I could just buy a set of 1mm/0.5mm aluminium spacers and insert these between the EFW and OAG and OAG and Paracorr but wondered what approach others might have used in similar situations. I also need to adjust the rotation of the OAG insert, so will need a spacer to offset this so the pick-off prism is at the top of the long edge of the sensor in any case. The guiding side of things I'm much less worried about given I've got the focuser and a range of different spacers - bit harder to work out but I think I have it set fairly close and can in any case experimentally arrive at the right answer there! Clouds have rolled in so no testing to be done just yet...

Think you can plug the GPS "cursor" into the hand controller - the ST4 port is just for guiding. I just use the Synscan init app on Android which gives you all the values in the "correct" formats without any guesswork.

That's the one, though I've not got the eyepiece tray fitted. All happily nipped up and guiding now. I think if I were mounting this more permanently I'd put something tacky/adhesive between the mount and tripod top to resist any slewing, or drill the bottom bolt for a rod so I could apply a bit more torque to tighten that, maybe with some blue Loctite. I'm averaging about 0.75" at the mo, so doing OK - I did guiding assistant near the equator and adjusted accordingly. I'll drift align once I'm done futzing with the optical train and switching to OAG and get it dialled in perfectly for the rest of winter since this lives outside.

Just because there's nothing more annoying than not finding out the answer - I figured this one out. The lower bolt (i.e. on the bottom of the tripod) had worked its way loose, and so in some telescope motions and positions the whole base of the mount was slewing sideways slightly, leading to the above "fun"! I've now tightened this, gotten the Polemaster running on an old Windows tablet I had lying around, done PA with that (good to 4.5 arcminutes, according to PHD2 guiding assistant) and I'm guiding at 1" RMS on a cloudy night, so all is right with the world again!

Shiny new Televue Paracorr arrived today, along with about half of the bits for my off-axis guiding setup! Also got a Rigel Aline, a Televue 2" extension tube to replace a decidedly poor Sky-watcher bundled one I got with the telescope, and a ADM camera mount so I can pop the Nikon on the back of the scope in lieu of the guidescope for some widefield shooting. Lots of careful dust removal to look forward to soon as I dismantle the optical train and rejig it all...

I've been going slightly mad trying to get my mount setup in a new home, around 20 feet from where it previously was, with a new guide camera (same guide scope). My Polemaster unfortunately is limited to the Android client as I've got no Windows PC I can drag out to use, and despite being pretty much spot on Polaris (I think!) couldn't get the template to match. However, I then went and tried PHD2's polar drift alignment - while it took a while to settle, it did eventually get me close to aligned. I then did drift alignment. During drift alignment I noticed PHD2 was "zigzagging" a lot but it averaged out enough for me to make adjustments for a straight trendline - looked pretty good, all told. Then I fired up an imaging session and calibrated and got some very funny graphs out: Thought "that's odd", and tried guiding but ended up with terrible performance: I ran a 120s exposure to see what that translated to, which got me this (at 0.5"/px): Doing a star-cross test seems to suggest something quite fundamentally wrong with mount motion: I'm at a bit of a loss and probably missing something obvious - there's no obvious issues with the mount motion, no noises or anything, etc, it looks like it's aligned fine... what next to troubleshoot?

Having left it for a day, on the scope it's dry again (even with some rain showers) internally, or at least not full of water any more, so presumably OK. Will keep an eye on it and see how I go.

Good to know! We have had weeks of heavy rain and I suspect some water ended up sat on top of the cover as it was covering just the mount (though I tried to avoid this with my positioning of the cover). I'll let it sit for a few days now the scope's back in place and see how it looks thereafter I guess.

OK, fun one I figured I'd ask around about before going back to the manufacturer/FLO. I've left my TG365 cover out for a couple of years now - it's spent the last month just protecting my mount outside while I had the OTA in for servicing. I took the OTA back out tonight and on taking the cover off felt quite a bit of extra heft and sloshing noises. It looks like there's water trapped between the outer layer and the inner metallic layer - not a lot, but maybe half a litre or so. I rotated it around, held it upside down etc but couldn't get the water to drip out (at least not that I could see), and no leaks internally so it's now back on the scope put away for the night. I figure it's all pooled in the bottom of the cover so if it leaks only the tripod is getting wet, and the gear inside all appeared dry. Has anyone else had this happen? Is this "normal"/expected?

They planned on doing both - but the expectation was that most of what they'd capture is dust, which would be trapped in a hard-to-observe "rim" around the collection head. As it is, they've picked up both a lot of dust and debris (they think, visually) as well as larger chunks of rock, which they can see visually - meaning they have a lot more sample than expected. So they're now skipping the spin-measurement procedure and getting it stowed away ASAP, since it's acting as a liquid right now and may "slosh" out again unless they pack it up. The sampler head:

I've still got the scope waiting in the house for my latest FLO order (Paracorr and OAG bits) since I'll have to dismantle the optical train and strip the guidescope off to convert to OAG for this winter, and was considering putting it all out tonight to try for some imaging in the meantime but it looked marginal and has stayed that way. FLO order still nowhere to be seen, sadly, so I'm still in for more clouds 😞

First crack at a pure narrowband colour image. Armed with only one Baader Ha filter at home, I captured about 70 exposures of OIII and 20 exposures of SII (more to follow) from iTelescope's T21 telescope in New Mexico to produce a SHO dataset. Post-processed pretty simply in PixInsight - each set of lights was processed separately to a master (usual cosmetic correction, subframe selection, etc) and then integrated using ESD or LinearFit with local normalisation. Masters were DBE'd, registered/cropped to the Ha master, and linearly fit to the Ha. Colour processing involved ChannelCombination to start, a histogram transformation to get everything stretched out to work with, curves to adjust hue to de-emphasise greens, colour saturation to emphasise the blues and reduce magenta a little, light application of local histogram equalisation to improve contrast on the edge of the clouds, and (non-complete-removal) SCNR and a curves contast pass to finish. Definitely an interesting process and definitely more to learn - need to get a bigger filter wheel and some more filters to get some better data to work with!

Bit late to the party but I'll +1 Stathis. Proper Schott Borofloat 33 blanks and great service/support. Very well packaged.

Yeah, agree with Dave, if they were running continuously or doing a lot of switching or just pushing up against current limits, could easily have burned them out - hard to say for sure without knowing more about the motor ratings. You can definitely get these off the shelf - ~£8 for a bag of 5: https://uk.rs-online.com/web/p/non-latching-relays/3998225/ Probably worth a punt for a very quick bit of soldering.