Spaced Out

Sounds good ! I'm interested in Sigma glass. I bought the cheapy 2nd hand canon 50mm to see how it would work with this set up. If it goes OK then longer term I'd like to invest in a Sigma 50mm. I have an old sigma 105mm macro I use mainly for insects and flowers, I was thinking about maybe giving that a go with the SAM too.

Yeah it's a modded camera.

I’ve just got myself a 2nd hand star adventurer mini. This is my first image taken last night from the back garden, it was just to test things out. Some nasty light pollution from Newcastle (35 miles to the south) was a right pain, I did my best to process this out but really struggled. Anyway, first impressions - I really like this little mount ! I struggled a little with initial polar alignment but apart from that it seems very user friendly. 👍 Canon 6D & Canon 50mm 1.8 STM (nifty fifty). 1x 90 sec exposure at F4, ISO 1600. No calibration frames.

Thanks for this reply. Yes I have cut down the focuser tube but it was for the DSLR I was using at the time and then it was completely out of the tube at the point of focus. With this new camera it does protrude back in a little but not by very much, perhaps 1cm.

Thanks mate. I'm fairly sure when I rotated this a couple of weeks ago (when I was faffing about with spacing) the ropey stars switched to the other side of the image, would this rule out the camera and point towards tilt at the focuser ? I need to double check this after the winds have dropped !

Thanks. I'm using Baader MPCC Mk-III and I think the spacing is good, I have measured it carefully with calipers and tested by adding & reducing spacers.

Thanks, I've already done this, and at one point I was over spaced but I think it’s good now, the right hand side looks OK at least. I'm left thinking this has to be tilt somewhere ? It is a heavy imaging rig on a standard SW focuser. I wonder if a free trial of CCDInspector might help me identify the problem ?

Thanks. I took your advice last time, I have 3 thumbscrews and I wind the focuser right in before putting the CC & camera in firmly and tightening each screw bit by bit. It works well. I've got the focuser tensioned reasonably tight with an autofocuser. I'm guessing if I rotate the camera and the wonky stars stay on the same side of the frame then it could be a camera issue but if the stars move to the other side then it's likely a tilt issue somewhere ? I know it's not terrible but I'm keen to get things as good as I possibly can before I start using it properly, it's just bugging me at the moment !

Thanks for your reply. I will try rotating the camera, what will that prove ? Sorry I'm a bit of a learner/duffer !

I used APT with my Canon DSLRs and it worked really well. I have no experience of BYEOS tho.

+1 I'll second that, learnt my basic PS astro processing from youtube tutorials.

Hi all I’ve been wrestling with my new camera for ages now trying to get nice round stars. I’ve got it as good as I can get but there are still ropey stars on the left, particularly the bottom left. These are squashed looking almost triangular shaped stars with little tails ?! Initially I thought it might be mirror clips pinching optics so I removed the mirror and loosened them slightly. That made no difference. I spent ages on CC spacing but I think that is OK now, the right side of the image looks OK. Next I thought about focuser tilt. I used a bahtinov mask, perfectly focussed a bright central star, then moved the star to each corner, expecting focus to change a little but it didn’t, just remained in perfect focus. A pretty crude test I know but I read somewhere it could show up tilt ?............ Or is that wrong ? I collimated and collimated again, using a sight tube and a laser. It all seemed OK with a quick star test. I’m left scratching my head now. Any ideas ? Thanks

An amazing image. You have skills !

I have been spending a while trying to get my first dedicated astro camera (ZWO ASI 1600 pro) set up properly with CC spacing, filters, OAG etc.... Still not quite there with it but after many nights of faffing on I decided it was just time to point it at something. Rosette Nebula was overhead so this is my first ever narrowband image. It’s a rough and ready affair taken in bright moonlight with very little understanding of camera settings ! I definitely need to learn more about using this camera (I’ve come from a DSLR) but this first image makes me believe there is some potential there. 15x 300 sec subs no calibration frames.

I'm back on this one ! OK, I've got the MPCC spacing as it should be, turns out I was over-spaced, I've started again and measured it very carefully, it should be bob on now. Here is a new test image and I think this shows that I do have tilt going on ? The stars on the left look not too bad, but on the right we have coma like comet tails. I’m guessing there is tilt somewhere and most likely the stock SW focuser as it has a heavy camera hanging off it ? If this is focuser tilt, what is the best way to fix it ? Is there an easy way of shimming the focuser slightly ? Or is there a better way to sort it ? Wondering if something like this might help ? https://www.amazon.co.uk/TS-Optics-ZWO-Tilter-tilting-compensator/dp/B07BZJ4989 Thanks

Thanks. I asked on here a little while ago about using one of those adaptors V adding a third thumb screw. Decided to go for the third thumb screw in the end.

OK, I've just had another go at reversing the spindle tonight and success ! I mucked about for a while with the tensioning of the focuser. For me there seemed to be a fine line between too loose and too tight when using this skywatcher autofocuser with a heavy camera. Too loose = focuser tube slippage and too tight = autofocuser slippage/clutch. As you mentioned the tube rings may well get in the way now when I come to balance it, I'll take a look at that tomorrow. Thanks 👍

Thanks Adam, I tried this but the skywatcher autofocuser seems extremely fickle with tensioning. When I did that I couldn't get it to carry the weight of my camera & filter wheel so I had to put it back again. 😕 I thought this should work too tbh, am I missing something ?

I've fitted an autofocuser and it sticks out the front of the tube. I'd rather it was facing the other way, it would help with routing the wiring.

Just wondering....... Can I simply reverse my Skywatcher 130PDS focuser ? I mean just by undoing the 4 screws holding the whole focuser unit to the tube, rotating it 180 degrees then screwing it back on to the tube again. Is it that simple or would I need to do focuser collimation of some sort afterwards ? Thanks.

OK, no replies ! Here's an update then. I've dibbled on with this and started using AllSkEye software to take some more test shots to try and find the best settings before running it for real. I've used a hot pixel map in the software too and I have discovered that those red dots in my first image are actually stars. It was cloudy last night but another test shot revealed no hot pixels where there was cloud, but the small areas of clear sky has the same stars including some orange looking ones ! I have also improved the focus to get tighter stars, I did this by focusing in the daytime on a house chimney over 30m away, seemed to do the trick. Next job is to see if I can improve the white balance a bit and then learn more about the AllSkEye software which looks really useful. 👍

Hi All I’ve just bought some gubbins to make a DIY all sky cam, hoping to knock something up this week. I’ve got a ZWO ASI 224 MC for this little project and I used it for the first time tonight just to test it out. I’ve only really used DSLRs before and never used sharpcap either so not a clue what I was doing with it all tbh ! Anyway, this is my first test image from my back garden. Thin cloud, perhaps focus isn’t perfect but I was happy that I got some stars and even a bit of Milky Way in there. I do have 2 questions..... 1 - I was quite shocked at what appears to be LOTS of hot pixels (red and blue dots). I assume these are hot pixels I am seeing here and not bright stars ? The colours seem too bright but I can only see one red dot in the dark corners of the image ? If they are hot pixels, is this normal for this sort of camera ? It was a 30 second exposure with gain set to around 320. 2 – What is the best way to achieve perfect focus ? I am using the Arecont 1.55mm lens which is really fiddly (it shifts when you lock the focus), especially outside in the dark with cold fingers ! I am just wondering whether it’s worth trying to set up the focus in the daytime which should be easier, and if anyone knows the infinity focus distance for this particular lens ? Thanks for any advice you can offer !

Ok, I thought I’d post a little update here just in case it is helpful to anyone. As suggested by Waldemar above I bought some boot warmers/dryers. https://www.amazon.co.uk/PYapron-Heatable-Electric-Sterilizetion-19-5X6-5X4-5cm/dp/B08254M8FN/ref=sr_1_17?keywords=shoe%2Bdryer%2Belectric%2Bgreen&qid=1578930095&sr=8-17&th=1 I have placed these by the mount under a breathable waterproof cover. I put a Velcro strap around the cover below the mount to stop it blowing away, this is loosely tied to allow some airflow. A sensor at the mount tells me the boot warmers raise the temperature under the cover to around 4°C above ambient and the humidity under the there is 15% less than the ambient humidity. After a couple of weeks monitoring day and night this has remained pretty constant. I have checked under there a few times on mornings when everything is dripping wet and the mount is dry so I think this approach is working for me. 👍

Thanks for this reply, good to know that USB2 works OK for all sky stuff with these cams. 👍

That's great info, thank you !