alcol620

thanks Ray for reassurance re trailing rather than spacing, although there looks to be a bit of it too.

Hi Ray As my earlier posting said, I did find some screws loose, I haven't had the opportunity since to run with stars in the frame - only the 24 hour test performed. So next time out I'm hoping for the best. I know that the TSAPO60 and the ASI1600, does struggle to get round stars in the corners with the flattener/reducer even when great care is taken to get the spacing spot on.

Hi guys, I put it on the circle at the point where it should be at that time. I think that is correct. I use the Jason Day positioning app.

Thanks James, I will take great care when I next get outside, may be tonight?

Hi James When you mentioned alignment possibly being more of a problem, were you referring to polar alignment or possibly alignment of the sensor with the scope tube?

Thanks James for you input, it may have been the loose screws, I will give it another run on the next clear light to check it now the screws have been tightened. I had the SA all loaded up so your answer is reassuring.

Right then guys, the 24 hour circuit of the Earth has been completed and I require some clever feedback. I had the lazer pointer tracking and at the end of 23 hours 56 minutes and 4sec (approximately) I was 4cm short of a complete circuit. The distance from the center of the RA axis to the marks on the wall was 141.5 cms so I make the angle of rotation to be short by 1.625 degrees. Now guys tell me what this means in terms of running a scope with a focal length of 260mm and a camera with 3.8 um pixels? Is this the reason for my trailing stars with exposures above 30s? Thanks

Thanks Guys. Fully loaded mount ready to go on a lap of the universe, but waiting till this evening when I have a good chance of being here tomorrow to record the end of the lap! What I did find when I checked the mount over in preparation was 4 screws holding the Dec clutch were not tight. This certainly wouldn't be helpful, but the 24 hour test goes on.

Thanks as always Dave.I did do this check, but not very accurately. I am setting up to do it again now only very accurately this time. I saw mention of updating the firmware, I haven't done this as I am always worried about this going wrong in the download and nothing working afterwards. Thanks again

Hi folks, me back again. Had the Adventurer out last night for about 3 hours before it clouded over. This time I had: Checked the calibration of the Polarscope. A reasonably balanced set up after putting the longer dovetail on. However, even with 30s subs I could see slight star trailing, with 60s worse and obviously longer subs than this even worse. I have attached a couple of examples to illustrate subs of 60s and 300s (I know this length of sub is likely to trail but it does show the direction of trailing) All the trails appear to be in the same direction across the whole image. Not in a circle or pointing to the centre of the image. I noted that over the 3 hours of taking subs, Polaris followed the circle in the Polarscope, presumably confirming that the mount was Polar aligned OK? Presumably I should expect better Than 30s subs without trailing. Would anyone like to suggest what might be causing thetrails? Is it perhaps mechanical?

Hi Matt, good to see you are still around. I think I have sorted the balancing with a longer dovetail and no longer need to use the tube extension to aid balancing. Now need a clear sky. Thanks everyone for feedback.

Thanks Ray, that seems to be the answer, except that GuLinex can still focus with similar set up. The answer for me seems to be to remove the tube extension I added and find another way of achieving a better balance of the set up

But could put it out of the range of the focuser??

Further research suggests to me that adding an extension tube to the existing scope will move the focal point also forward by the length of the extension tube. (please correct me if I am wrong). This would have the effect of having to move the focuser tube also forward by the same amount? (quite a long way). Hence it could move the focus point so far forward that it is not possible to focus the image - the situation I find myself in. However, the only issue here is that GuLinex has an almost identical set up but can achieve focus. Regards Alec

Thanks Guys, there is obviously something else that I have introduced into the mix. I had the set up working without the tube extension. The only reason I changed things, as you can see from earlier posts, was to get better balance of the set up as I was getting star trails. But it was focusing OK. I can't see anything else that is obvious to have changed the focusing so much. Probably something I am doing that I didn't do before.

Thanks Ray When I was setting the TS60 up last year the guy from TS Germany said that the recommended back focus for the TSRED279 reducer/flattener was 70mm and I had it working with that, it gave the best "flat" image out to the corners. It seems to be the addition of the tube extender on the scope (added to get better balance of the set up) which has stopped the focuser reaching focus. I will await further feedback, thanks again for interest presumably we are increasing the focal length by adding the tube extension?

Thanks Ray, I was under the impression that with the reducer/flattener in the chain that the FL is down to 260?

Thanks for reply, bit of a mystery. I have emailed Teleskop-Service in Germany for any thoughts they might have. In the meantime I will try it out again, but I can't see how anything will change

Morning GuLinux My set up is as shown. Tube extension added, 70 mm spacing between Photoline 0.79x reducer and sensor (made up of 63.5mm spacers and 6.5mm ASI1600 backfocus). Focuser racked right in to the scope body and still a bit more required to get to focus. I am probably doing something wrong, but not sure what it is?

Very many thanks for that, most helpful. I wondered what that extra tube in the case was for! Tomorrow I will check the polarscope calibration and extend the tube. thanks again. Alec

Should have said that the stepper motor is not used as I have no controller fitted as yet, I focus manually with the stepper not connected although fitted. Obviously adds nothing to the distance

Apologies, getting in a muddle as always. The focuser is the one that comes with the TS60 but it has a stepper motor on it. Its my 120ED that has the moonlite. Will take an image tomorrow to illustrate the set up. i would have thought the distances would be the same. The distance requirement of the reducer should make the distances the same.

Hi GuLinux Thanks for your help. Extended the tube length today, improved balance as you suggested. Checked the polar scope calibration, not far out, but I had a fiddle and improved it slightly. Can't get it any better than the end result. Set up in the garden an hour ago and ran into an unforeseen problem. The additional tube length had changed the focus point and I can't wind the focuser in enough of achieve focus!! What a hobby this is!!!! Obviously out set ups are similar, but I don't have the filter wheel as I have the ASI1600MC. I have the TSRED279 reducer/flattener in the chain and a Moonlite focuser. Spacers bring everything to 70mm from the sensor to the reducer/flattener. Not sure I have any option but to remove the scope tube extender? Any comments? Thanks

Very many thanks for that, most helpful. I wondered what that extra tube in the case was for! Tomorrow I will check the polarscope calibration and extend the tube. thanks again. Alec

Hi Many thanks for getting back to me. The first thing I need to do, as you suggest, is to check the polarscope calibration. It was Ok some time ago, but I have made a small 90 degree lens so that I can more easily view polar alignment, instead of standing on my head, however, I have to push this onto the end of the polar scope and I may have put it out of calibration. Not sure what you mean by adding an extra tube section to the scope to help Dec balancing, any chance you could post an image of your set up? I am using the short vee plate that comes with the TS60 scope and this leads to some difficulty in balancing the scope.