alacant

Hi. I think so. I have measured the distance from the top of the tube on the opposite side of the tube using a laser in the drawtube. It's the same distance as the mid point of the focusers barrel.. Evidently, it's not important but I've done it anyway. I think!

Hi. Yep, the frame looks the same; worst top right. Tried that too but of course the tilt -if that's what it is- will still be present. In my case, it seems I need to move the bottom left of the sensor (top right of the snap) away from the focuser base.

Hi everyone. I'm trying to diagnose this; stars not too bad centre frame, worsening toward the top and right. The collimation looks fine and the star test is dead centre. It's not coma I don't think as I'm using a sw 4 element cc on a sw 250p, f4.7. Canon 700d. Attached jpg is a copy of the original .CR2. Tilt? Cheers and TIA for any pointers...

Hi. Deault DSS creates as file called autosave.fits or autosave.tif. Once you have it, take it straight into gimp. Do nothing with it in DSS.. Use DSS only for stacking. Your artefacts will not then show. Just my theory but HTH.

Yes, it's a doublet. You have two good ones. I had a bad one. I've a feeling the OP may have one similar to mine;)

Hi. I've suffered sw focusers too. IMHO, you'd be better sending it back and getting a proper triplet with a proper focuser: https://www.bresser.de/en/Sale/Display-Items/ED-APO-80mm-f-6-FCD-1-Alu-2-R-P-Focuser.html Hope that's not too controversial! Cheers and good luck.

Hi. A few bits to have a think about? Will it take another 8GB? If so, putting StarTools' database files on an 8GB ramdisk really flies. Or add an SSD drive and put \temp there. The only way I've found to run ST in real time on big images is on a gaming machine: €1000 sort of market. Another trick is to software bin your stack before processing. In ST of course. HTH.

Hi. Don't forget to try APT's live stack. It shows on my DSLR at 4 frames and is less fiddly than point and stretch. Almost real time too. HTH.

Ahhgghh! I promise to do my homework more thoroughly. Fearing hijacking the thread, would you allow me just one more shout? If I snap m51 with my 150 f8 and DSLR, I use the same time as with my 150 f5. The main difference is that it's smaller with the latter. What should I be doing? Increasing the time at f8?

The same, surely. You haven't changed the aperture of the telescope, so I don't think it can collect any more or less light and so can't be any brighter or dimmer. If it fitted on the chip at F10, it will simply appear smaller at f7, but you'll need the same exposure length. But that's assuming you are keeping the focal length the same and changing the aperture. The OP isn't. Don't tell me I still don't understand this! Cheers.

Hi. We started with the compulsory 80ed which was miserable compared to the 208 f3.9 with which it was replaced. If like us you'd get bored by having to return to the same object night after night then the hyperstar looks amazing value and gives you two for one value; if you want to do galaxies, use the conventional focus at the back. Maybe in London you're gonna need a CLS. Not sure if you can fit one at the front on a hyperstar... HTH.

Hi. Yes, it's rack and pinion. The screw holes line up perfectly with the existing base plate. The swap is a 5 minute job. HTH.

Got the R&P from AliExpress. Much better:

Hi. Not sure. I tried balancing it a bit but lost a lot of the nebula:( Great shot anyway:) Maybe do longer light frames? HTH and clear skies.

Hi. I don't think we can tell since we don't know the house/telescope/garage distances nor whether you'll need anything at USB3 speed. But for a small outlay it maybe just worth a go anyway?