Craig a

It’s A I’m looking at, that’s your secondary it’s not circular so that means it’s rotated, B is the reflection of the Cheshire’s silver diagonal

I can see the rotation error just by looking at the pic you posted of the view through the focuser, it’s laying left up right down in the view, hard to judge which way it’s rotated from the pic but I’m 99.9% certain there is a error there it’s not a circle but more oblong indicating a rotation

That’s not entirely correct, squaring the focuser to the tube does need taking off and marking on the opposite side then putting the focuser back on with a Cheshire then adjusting the focuser so the cross in the Cheshire is pointed at the mark, a concenter won’t do that but will sort the secondary out with tilt or rotation, I use a concenter myself and agree it’s a must have particularly for the secondary but it won’t sort the focus tube out

To me it looks like you have some rotational error in your secondary Mirror that will cause some problems, to set the focuser tilt properly you need to take the whole secondary assembly out and mark the point directly opposite the centre of the focuser hole in the tube it’s easier to take the whole focuser off aswell. Bit of a faff but once done it shouldn’t need doing again. Re the rotation error in your secondary can be sorted with a good Cheshire

dont know why but for some reason when i try to copy and paste the share to forum link to show the thumbnail from astrobin it wont show thumbnail just the link address that doesnt do anything 🤔, so i had to use the simple link

Only my second image taken with my 533mc pro so I’m still getting used to it but I like it so far, only managed 3 hours on Saturday night, I have a 10 month old baby so getting out is a struggle at the moment till he gets abit older and stops waking up in the night 😂 taken with my skywatcher Quattro 10cf and 533mc pro comments and criticism welcome https://astrob.in/qyvsqk/0/

What a fabulous image this is, it’s smooth as silk superb detail and the colour and depth is amazing, stunning

Yes I have the Quattro 250cf and the offset is already built into it I believe, just centre the spider in the tube and center the secondary under the focuser and when it’s collimated it will look offset naturally looking through the Cheshire or collimation cap

Hi, I’m using a 10 inch Newtonian and asi533 mc pro with a uv/ir filter, I put a t shirt over the scope and place the panel over that, and yes I mean the one of the channels is further over to the right than the other two channels in the histogram, thank you for replying

Yes I love these kind of shots too, this is my kind of imaging you can keep all them bright nebulas these faint far away places is where it’s at, it’s amazing what we can capture from our amateur equipment in our back gardens

That’s beautiful Peter

Hi everyone, I use a tracing pad for my flat frames but noticed that the rgb channels don’t match up one channel is always way more exposed than the other two, would this matter to how they affect the image after they are applied to light frames? Or would it be a good idea to align the channels on the master flat before applying to the light frames?

Right now I know that I will sell the 2 inch uv/ir filter and buy the 1.25 inch one, until then I will try the neodymium filter and see how that works out. thanks so much for your help vliav

Well I never! I didn’t even realise the cam came with the adapter that fits inside one of the spacers to accept a 1.25 filter here is what I’ve got now

That’s a great idea, I have a baader neodymium filter that might do the job and not cut as much of the spectrum out as a lp filter would I shall check if the 533 accepts a filter there

That’s what I didn’t want to hear as I got the 533 to image the smaller galaxies out there, I think I’m just going to have to try without the filter the next clear night, a bit of colour distortion is better than having the image ruined by them rings

I me an would the coma corrector itself cause fat stars not using the filter?, as it’s a 4 element lens basically

You say trouble, how much trouble are we talking getting colour balance?

Would that cause fat stars?

The point you make about not needing a coma corrector with the 533 is a good one, I may actually try without it the next clear night and check the stars in the corners, also will try without the uv/ir filter, but as the 533 doesn’t have the uv/ir glass in front of the sensor would that be a problem on a Newtonian?

I’m pretty sure I have correct spacing as I’m using the zwo OAG and that replaces the one of the spacers that comes with the 533 and the spacer brings me to 55mm back focus so with the OAG in place not sure I can fit the filter behind the coma corrector, regarding the mirror I would have to move it up at least 15mm to take the corrector out the tube and I don’t think the collimating screws are that long.

Would that matter? as the focus point would still be the same position? If using the stock focuser it would just be racked in further

I find it incredible that skywatcher produce a coma corrector designed for this scope that protrudes Into the tube, but that may not be the issue at play, I was thinking that the led panel is too bright even with a t shirt on the tube and bouncing light off the IR/UV filter as my exposure for my flats was 0.3 of a second.

Ok yes the front lens of the cc is highly curved and obviously the filter is flat, so Newton rings are possible, it’s strange because I’ve used this scope for years and never had an issue like this so was wondering if the led pad maybe was causing the issue because that’s a recent thing I’ve started using

But it was in my stacked image which I’ve now binned in a rage