Stefan73

It's pretty hard to do that for something you can't easily see in a view finder / live view, like most galaxies. You might be able to find it with an eye piece and centre it but then you have to refocus for the DSLR which is hard without a bright star and a mask to help. Or you end up taking endless trial photos to try and frame whatever you're interested in. I 'm guessing the PAE uses the delta from the chosen object to GOTO nearby objects rather from your initial alignment star. My workflow pre-astroberry was to do the usual alignment to get started and make sure polar alignment was ok. GOTO a nearby star to what I wanted to photograph, get the focus right on that and PAE if necessary, then GOTO to the object I wanted. If your 3-star alignment is getting you where you want then obviously don't worry about PAE. These days I just wait until it gets dark enough for plate solving to work. You don't need a guide scope at all to get value out of astroberry and the like. For the price of two USB leads and a PI (I'd definitely go at least 2GB pi-4) you can get plate solving to work which takes the guess work and much of the frustration out of framing pictures, and it will function as an intervalometer too. Having spent an evening photographing completely the wrong area of the sky it was a welcome enhancement for me! I think a lot of its value depends on how much of a computer person you are though. If you aren't then it's probably easy to end up replacing one source of frustration with another... Also I'm not sure plate solving would work just with camera lenses, but probably exact positioning is less important then.

I'm using an Eq3 pro and Canon 550D and I'd definitely echo getting a Bahtinov Mask, eg https://www.firstlightoptics.com/bahtinov-focus-masks/starsharp-bahtinov-focus-masks.html is the one I use. Then get the telescope pointing at a bright star, zoom in on live view and use the mask to focus. Finding galaxies can be a challenge as you won't see much or maybe anything in the view finder or live view. I tended to use the GOTO functionality to find the nearest bright star in the catalogue, and I could identify, to what I wanted to photograph, and then do a Pointing Accuracy Enhancement on that unless it's spot on. Then goto the object of interest. It's worth having an illuminated reticle eyepiece to help with all the aligning. You can use an intervalometer as suggested or it looks like magic lantern supports your camera and that has a built in intervalometer and very long exposures for bulb mode. See https://magiclantern.fm/. I certainly had success with that. I don't think I've reliably managed longer than 1 minute exposure with the Eq3 Pro and even then some frames end up with star trails due to periodic error (but that's with an F5 scope so easier than yours). Just take lots and lots of photos without touching anything and delete then ones with star trails. An hour or twos worth of total exposure should show something nice after a bit of post processing. You'll have to experiment to see what exposure length you can get away with. These days I've discovered the wonders of astroberry which is a whole bundle of useful astrophotography software. It can handle the goto via plate solving and has camera control to deal with the intervalometer side of things (and much, much more).

There you go: https://drive.google.com/file/d/1oEGCroWx943lPP1IE0IwpKr1Cgzea4MO/view?usp=sharing All I did is put a muslin cloth left from when the children were babies over the telescope and a tablet with a light app on that.

Hi, If it's still useful I'm happy to provide flats taken with a 550D and a completely unmodified 130 PDS. I think the sensor sizes are the same. No filters involved or modifications to the DSLR.

Are you using a bahtinov mask to help focus? I found it really hard trying to focus just looking at the live view on a DSLR and I kept getting it slightly wrong before I used a mask. Zooming in the live view on a star with the mask on is the only way I've reliably got focus right.

So can you manually slew the mount at 8 but not at 9? Even though the battery says 12V I'd try it with a decent mains power source and see if that makes a difference. I presume you're not over weight with what's on the mount?

In the end I just bought a set of T2 spacer rings and a set of T2 extension tubes and spent some time trying to focus on chimney pots and satellite dishes with various combinations. I was hoping there was something which could be adjusted on the fly like a smaller version of the baader click lock but I guess you only need to do this once. Just need a clear night to see if I've got the focus good enough for guiding....

Ok after some more investigations I think my ZWO can't move in far enough to focus. It's got a nosepiece that came with it which screws onto it then gets inserted into https://www.firstlightoptics.com/adapters/baader-click-lock-125-inch-eyepiece-adapter-with-t-2-thread.html which then attaches to the OAG and it looks like it's all too long. I can bring it to focus if I screw the ZWO directly to the OAG and move the focuser about but with that there's no way to adjust the relative distance between the DSLR and the ZWO. The DSLR comes to focus when the draw tube extends about 11mm and the ZWO about 8mm so is there some attachment which would add an adjustable length of around 3mm which would join the ZWO to the OAG?

Hi, I'm trying to get OAG working for my Explorer 130P-DS. I'm using the TS Off-Axis-Guider here https://www.firstlightoptics.com/off-axis-guiders-oag/ts-off-axis-guider-tsoag9-length-only-9-mm.html with a Canon 550D and a ZWO ASI 120MC-S USB 3.0 Colour Camera as a guide scope. It all goes together OK and I can bring a satellite dish to focus in the Canon successfully. Using Astroberry, I can get a live view from the ZWO and, with the lense it comes with, I can see with it happily with exposures about 0.005s. What I can't do is bring it to focus when directly attached to the OAG (without its lense). I've checked the OAG prism is the right way (ie flat side towards the telescope) and I can see up the bit the camera attaches to and out of the telescope ok (well the spider at any rate) but all I can see on the ZWO's live view is varying tones of grey through the OAG as I change the focuser or move the prism up and down in the OAG. Should this work? Or do I need stars? Or some sort of attachment for the guide camera? Any help appreciated...

I don't have personal experence but I've read there's an issue with ZWO USB2 cameras and Linux (FLO don't recommend them for use with Linux on their website). USB3 seems to be fine. There's apparently a firmware update available which people claim have fixed their issues. Might be worth a go if google can find it for you. See https://indilib.org/forum/ccds-dslrs/4596-temperamental-zwo-asi120mm-usb2.html

I'm a beginner too so this might be a bit blind leading the blind... but my understanding is beyond a certain ISO there's no point in increasing because you're just increasing noise too. See http://dslr-astrophotography.com/iso-values-canon-cameras/ I think what you're aiming for is a histogram which isn't clipped to the left or right when you take a photo and not worry too much about how light or dark it looks. The magic of post processing can sort all that out when applied to the stacked image. The night 2 one looks quite noisy but I'm not sure if post processing could save it.

Not remotely as good as everyone else's pictures but here is my first galaxy picture ever (up to now I've been practicing on the Orion nebula but that's behind a tree now). About 45 1 minute exposures with a EOS 550D through an Explorer 130PDS and some colour stretching in gimp. My OAG is still on order... I'm guessing the elongated stars away from the centre are due to coma?

I don't have a coma corrector at all at the moment. The skywatcher one https://www.firstlightoptics.com/coma-correctors/skywatcher-coma-corrector.html was one I was looking at and it sounds like alacant is using https://www.firstlightoptics.com/coma-correctors/ts-newtonian-coma-corrector-10x-gpu-superflat-4-element-2-nosepiece.html successfully. I might leave that for now and concentrate on the auto guiding first. Then see how much the coma ends up annoying me in practice once I've got better guiding. The main thing is I could add a suitable coma corrector to the OAG if I wanted to later, which it sounds like I could as long as I chose well. It's all an expensive business so it's really good to have an upgrade path which doesn't involve having to get new everything! Anyway I really appreciate all the guidance here from everyone.

So would something like these two would work for connecting an EOS to an OAG while preserving other camera options and coma corrector possibilities? https://www.firstlightoptics.com/adapters/ts-eos-connection-ring-for-ts-off-axis-guider-tsoag9.html https://www.firstlightoptics.com/off-axis-guiders-oag/ts-off-axis-guider-tsoag9-length-only-9-mm.html Certainly if it looks possible I'd like to go OAG since everyone seems to agree it's the best solution if it can be got to work. What guide camera do you use? Would a ZWO 120mm be enough?

Yes sorry cross posted... oh no I was hoping for complete consensus! 😀 It looks like I can't get OAG to work with a coma corrector which I could live with but as a plus the weight would be more manageable and it's more future proof and accurate. And on the guide scope side there's someone with a working setup with the same OTA and mount. I'd certainly be interested if anyone out there is using a DSLR, OAG and the 130PDS successfully.

Thanks for your thoughts! I guess you've both persuaded me against OAG... My main worry with using a guide scope was weight on the EQ3 but if you've got it to work then I'm reassured and I'd be very happy with being able to take 10mins exposures. What do you use as a guide scope and camera? The obvious choice I guess is something like https://www.firstlightoptics.com/guide-scopes/zwo-mini-finder-guider-asi120mm-bundle.html as a combination but I've read to go for something more sturdy to attach to the OTA than the finder-shoe base.

Hi, I have a Skywatcher Explorer 130P-DS on a unmodified EQ3 PRO Go-To and a Canon 550D for imaging. I can manage 1 minute exposures that seem OK but want to improve on that. I know the eq3 isn't ideal but first I wanted to get auto guiding working for that setup. I was thinking about getting an OAG since it's not massively more expensive than a guide scope and will presumably future proof me. Is the best OAG here just the thinnest one possible? eg https://www.firstlightoptics.com/off-axis-guiders-oag/ts-off-axis-guider-tsoag9-length-only-9-mm.html Will this work ok with that scope, a DSLR and a coma corrector (https://www.firstlightoptics.com/coma-correctors/skywatcher-coma-corrector.html)? I know some setups won't work at all. Then for cameras would I get away with ZWO ASI 120MM-S, eg https://www.firstlightoptics.com/zwo-cameras/zwo-asi120mm-s-usb-3-mono-camera.html? I read somewhere you need a better camera for OAG than a guide scope. Thanks for any help!