ollypenrice

Great target, done so well! It comes to something when I say this because I'm always being beaten up on the French forum for my high colour saturation but I might just ease the colour down a tad. However, another part of me likes it! Olly

Given the difficulties encountered by the professionals in searching for stellar parallax, and the fact that the aberration of starlight had to be factored in before it could be discerned, I think you were being quite optimistic! But well done for having the tenacity to try. Your resolution of detail shows great finesse. The images are a delight. Olly

Great image. The dust is structured and fluffy and you have captured nebulous structure right up to the edge of Alnitak which is something that sets the best renditions apart in my view. Olly

https://www.amazon.fr/gp/product/B07TD6CX1B/ref=ppx_yo_dt_b_d_asin_title_o00?ie=UTF8&psc=1 I'm about half way through this new biography and am enjoying it. While I don't think it's the best-written biography I've ever read I must say I'm finding it hard to put down. Zwicky certainly merits a substantial biography and turns out to be much more than the irascible conflict-monger which is how he often appears in histories of science. He had a considerable input into early rocketry and, in his spare time, was an accomplished and rock-hard alpinist. All interesting stuff. I bought the Kindle edition which is quite pricey but that's probably because it's a recent release. No regrets though, it's compulsive. Olly

Like Goran I'd just have a go at adjusting it. Olly

You'll need quite a big space! Olly

The problem with some of the first ones was that the mesh was inconsistent around the wheel. The one I had was too tight in one part of the rotation and too slack in the other so there was no way to tune this out. If you have a consistent mesh - and it seems that you proabably do - then you should be able to adjust it to eliminate the perceptible play. I'd be optimistic in this case. I've imaged successfully at moderate resolution on mounts with small but perceptible play in the worm and wheel. Olly

Sound advice... lly

Sometimes I'm asked about adaptive optics (indeed I think Billy asked me about this during his visit) and the only people I know who have used it are you and Peter Vesey. Have you ever posted a review of the system? I seem to remember your saying that it was both effective and a pain! Par for the course in AP, I guess... Olly

I'd agree with Michael. Focus is tight, detail is fine, but the colour would benefit from attention. Olly

Ooh yes, that's a thriller! Lovely stuff. Olly

That is deep! A splendid M27. Olly

Although you're right, it does get harder to drill with age, you do get a better hole if it's close to its maximum strength, I find. And, yes, a hefty SDS hammer drill, even a budget brand one, is a godsend. Mine's a Grup (whoever they are!) but it's been fine over a good number of years in amateur use. Olly

Greetings, Lee. In our case we simply crop the 8300 sensor's output to match the 460. Sure, that's a bit of a waste but we get the benefit of higher resolution from the 460. (So we shoot L in that and RGB in the 8300.) In your case you'll be making compromises, inevitably, as well. A complicating factor (sorry!!!) will be the optical performance of the scopes. I think the colour correction of the Altair will beat that of the Meade so, where appropriate, it would make sense to shoot narrowband in the Meade. The loss of FOV doesn't cramp our style, really. At these resolutions there are so many small targets out there that finding ones to fit isn't very difficult. Olly

Finding new targets is something folks do in different ways but, of late, I've been turning to my two volume Night Sky Observers Guide. https://www.willbell.com/HANDBOOK/nitesky.htm For visual observers it has long been a bible but it can also be a source of inspiration for the imager. The pictures it contains are all old-school monochrome film but the point is that it provides an exhaustive catalogue of deep sky objects organized by constellation. I'm a great believer in shooting objects rising in the east at nightfall so the constellation approach is perfect. The books also have huge charm. Olly

Agreed, for sure. However, from our site I think we'd soon be in the land of 'empty resolution.' When processing these images I resized them upwards when working on sharpening and noise reduction and it was almost tempting to leave them a little resized. They didn't look bad. I dare say that the 5.5 inch aperture is imposing an upper limit on resolution but a larger scope would soon find itself limited by the seeing. I'm philosophical about trying small targets for which I don't have the image scale: they just are small but they can still make enjoyable projects by way of a change. Olly

We saw and admired your image from the Liverpool Teescope, Goran. It's one of the best out there. 👋 No, we do it in Registar, making it a two-click operation and infallible in precision. One click aligns the RGB (which is from a larger chip) onto the luminance and a second 'crops and pads' the colour to fit the L. Thereafter they work together as Layers in Photoshop without any further intervention. Recently I've been giving my RGB a hefty dose of noise reduction (from Noel's Actions) which I've found provides a short cut to getting more intense colour with less messing about. Olly

The fact that you are asking this question indicates that you need a more fundamental grasp of what is going on in imaging, so take spillage's advice and read this: https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html You won't regret it. Olly

I'd retire myself, but only in order to devote more time to running our gite... 🤣 lly

Thanks, Chris. As usual with images featuring a galaxy in a starfield, I've combined two stretches above a common background sky, one a hard stretch for things fuzzy and one a soft stretch for the stars. Mercifully only a handful of stars are superimposed over the galaxy so I dealt with them individually. Olly

I think it is, yes. The arm seems to have been extended through gravitational effects and these would also disturb the interstellar gasses and trigger star formation so it all makes perfect sense. Other renditions show the blue arm as very dominant, in some cases more strikingly than in our data. I haven't done any differential processing to exaggerate it. Olly

Another image done with Billy Harris using the dual TEC140/Mesu200/Atik460/Moravian 8300 co-owned by Mr and Mrs Gnomus, Tom O'Donoghue and myself. This has 9.5 hours of LRGB data captured in a single night. The galaxy is very small on the sky so this is cropped and shown at full resolution. The upper edge of the galaxy comes to an abrupt end, something which looks like a processing artifact but isn't. This is just how the galaxy's bright matter cuts off. In the 14 inch Meade we were just able to make out the bar as an elongated streak but saw no sign of the disk. Olly and Billy.

This was done with SGL member Billy Harris. Indeed Billy did the lion's share of the capture work since I'm zapped by a revolting cough and cold at the moment. We used the dual TEC140/Mesu200/Atik 460/Moravian 8300 rig over two nights and acquired 17.5 hours in LRGB. A test sub in Ha suggested that it wouldn't be worth chasing more. It's a curious galaxy which has a contra-rotating jet visible in radio wavelengths and lots of tidal extensions indicating past interactions. It's fairly small on the sky so this is a crop presented at full size. Olly and Billy.

Irony rather then sarcasm, I think? But maybe you missed mine... We English drive the rest of the world mad with our unfathomable ironies. Why can't those darned English just say what they mean? Olly

No, I'm advocating good scientific practice! The fact of removal-refitment has has, potentially, introduced a new variable. Lots of little spacers, possibility of tilt, rotation, etc. Olly