tooth_dr

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At least now you cant say you dont know any cameras with non-square pixels 🤷‍♂️

It's both

SX Lodestar.

Doing a bit of reading and although I’ve seen that backlash in a focuser must be accounted for, I’ve not seen a method of actually doing this. I plan to run filter offsets for my ED80 using a basic SW autofocuser and Hitec Astro DC focuser. I’ll start the night focusing on eg red using a Bhatinov mask and use offsets from there on to get better focus for green and blue filters. My other scope has a Moonlite focuser and I’m getting a non symmetrical V curve, I’ve seen described as a seagull maybe (it’s flat at the top on one side), I now understand this is the backlash being removed between first and second points. Then after the routine is complete my focuser goes back to the optimal point, but it hasn’t compensated for the backlash and therefore is not perfectly in focus. This matters at F2.8, as I can actually see the slight difference. Im getting a sore head thinking about this, but would I be right in saying this is one-off setup process. I just can’t see how to do it

It’s still total integration time that counts. You may have a complete image but it will be a poor one

Cracking image, worth a reprocess.

Thanks Wim. I will maybe check that out sometime 👍🏻

Pretty much, I suppose dust bunnies can move, if carrying about the scope, but I dont do this so I'm not sure how big an issue that is.

Both my reflectors have glass correctors, will that shift the focus? I only use them for lum so I don’t know. But I’ve seen ones on here with esprit triplets talk about filter offsets, I don’t have any experience but assumed it meant a difference in focus position?

@Rodd Degreened and a few % sharpening of core. There was definitely some unwanted green, well spotted

Thanks Dave. Kinda did it the other way wound using a layer mask. I haven’t got onto using the eraser, but I gather it’s more logical! Can it be feathered the same way as you can do to a mask after you have used the brush tool?

Totally a bad choice imho. For comparison, and I think this is one of my favourite images of my gear, this is my 250px and my 300pds. Yes there really is that much difference between the two scopes. I had my best ever visual experience through this 300pds, of m57, but as an imaging scope on an eq6, not for the faint of heart.

Never getting a completed image wears thin very quickly. And if you move the gear, you'll need new flats, and always need to ensure correct alignment of camera to match previous nights.

Nice shots, plenty of detail coming through. The FF will make a good difference to the overall appearance of the stars.

It's unlikely that the filters will each focus at the same place, so it is better to image a batch of one colour, then refocus and take another batch of another colour and finally the third colour. With an autofocuser, or no sleep, you could capture the set of RGB data in one night. I have no way of autofocusing so I accepted a compromise and cylce through the filters on each sub. This meant sub-optimal focus point on all colours - I mean it's close, but not perfect. I use a luminance layer, captured at the same time on a different scope, so I can just about get away with just so slightly iffy RGB data as the detail is in the luminance. However it results in larger stars, often with coloured fringes, so it's not something I wish to continue doing. I think there comes a point when you start doing mono + filter imaging, that an autofocuser is a key ingredient to the mix.

No no I think you’re right. I’ll run it again on the galaxy 👍🏼

Cheers Rodd. I’ll run HLVG on the galaxy. I did run it on the whole image, on the RGB data prior to combining with Lum.

Haha yes that was in relation to V1.

I image with the same scope as you, a blue tube 250px, I know the issues you speak of.

Please update your results. Very interesting thread.

Thanks Martin. Getting there 👍🏼 @Revs thanks for all the info. I’ll have a look this evening when kids are in bed.

I hashed it there now, made the stars smaller and brought the blue in the stars down a bit and brought the overall red up +1 in colour balance. Not ideal doing this to a completed image i guess. I'll check out that link, thanks for that. V3:

Great observations, thanks! I’m not sure how to go about making the stars smaller. I didn’t control them earlier on. I also don’t know the process of making them smaller when combining separate LRGB data - do you make stars in separate channels smaller or in the combined RGB data etc. The big blue stars dominate the image in my eyes. However this is a consistent thing in all my recent images so it’s either a) data capture issue or b) processing issue or both. Given than most things can corrected in processing, hopefully I can learn WHEN and HOW to control the stars

Cool project.