ollypenrice

Well I haven't got it!!! Olly

Agreed on both counts. Olly

A canny manufacturer might make a siamese OTA with advantage... Olly

Honorable??? 😆lly

If it's taking an astrophoto you're talking about then fine: it's taking you on in a video-making contest that I'm smart enough not to risk! For one thing I don't have a video camera, which might be a disadvantage... 😁 Of course Ha targets tend to be widefield ones, less dependent on ridiculously precise mounts... but I'll negotiate. Ha with RGB stars. How about that? If you accept, the first item in my posh kit armoury will be this: Oh yes! Any serious astrophotographic endeavour begins with a blank cheque made out to those good people at FLO. And my suggested target? The double cluster in Perseus. Ha with RGB stars... 👹 Olly

You know what Hollywood actors say: Never work with children or animals! That bunny could sell bat-burgers in Alabama... Olly

🤣 I'd be up for it but for one thing: that damned bunny is a natural in front of the camera... Olly

In your post you describe your scope as a refractor when it's a reflector. Just a typo I guess. Saturn has always had a warmish yellow-orange colour to my eye, in any instrument I've ever used. The image quality of your second example should be within the grasp of a well-collimated 130mm reflector, though, with a decent eyepiece. Olly

I doubt that there is much difference between CMOS and CCD imaging. The two that stand out are: - CMOS has no need of long exposures because of the low read noise, so experiment with 5 minute subs to start with. Occasional targets will need short subs to blend with long. (M42 for sure.) - CMOS needs dedicated darks for flats. If you take a set of flats at a particular setting you must take a set of darks at precisely those settings. (With CCD a master bias will work as a dark for all flats.) You will need flats and darks in the usual way. On general imaging Steve Richards can be your guide with Making Every Photon Count and on processing, predominantly in Photoshop, with Magic Bullet. Both available from FLO. https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html https://www.firstlightoptics.com/books/dark-art-or-magic-bullet-steve-richards.html Olly

The issue of mat black paint came up some years ago. It transpired that paints using dyes tended to be reflective in some wavelengths. I think it might have been IR from memory. To avoid this it was recommended that we use pigment based paints such as are used in high temperature applications like stoves. I don't know the paint under discussion here. Olly

If you can find one second hand (and don't expect it to be cheap!) the Cassady T-GAD alignment device is very robust and carries a TEC 140 on our dual TEC140 rig. It's no longer in production. Olly

Keep away from counting pixels when comparing chips and don't think of 'magnification.' Stick to these key numbers: In given optics... Pixel size. Smaller pixels increase the resolution of small details and make a larger screen image of an object. This is going to 'get you closer.' Chip size determines what will fit in your field of view. Having a small chip which holds only a part of your object or makes it fill the frame does not 'get you closer.' It just crops your field. Olly

I hadn't thought of diff spikes! Curses!! Olly

Ah yes, that's a universal problem. It's not just the saturated core you're talking about, then. One thing that looks promising is using Starnet or Straton to de-star a copy of the stretched image then put the linear original on top as a layer in Blend Mode Lighten and stretch in situ till you have the stars as large/bright as you want them. In Blend Mode Lighten only the stars will appear during the stretch. Olly

We had a maths teacher called Killer Dawson. Doubtless he earned this name through his patience and willingness to help others... 🤣 Olly Actually I'm only joking. He was (rightly) called 'Killer' but he was an exceptionally effective teacher...

I say this because the Iris itself has the progenitor star entirely under control - we see it as a round star not dissolving into the nebula through saturation. We also see the elusive pinks which are often missing and the dust is at once deep and smooth. This is one of those targets which presents very clear challenges! Olly

Improved colour and definition. I can't help suspecting that a little more sharpening could extract extra detail from the core if done selectively. Olly

I have a book bought second hand which has an excellent section on Quasars. If I could remember which book it is this would be a much more itneresting post! Give me a day or two... 😁lly

Well, looking at your version doesn't fill me with the conviction that I could do any better! Nice of you to post the data but your rendition is very convincing. Olly

😆 When astronomers call something 'The smudge' we need to be on our guard!!! 🤣 Olly

So did ours in the south of France. Hopeless chrome. Olly

Lovely and the arc is a strange affair. Mr and Mrs Gnomus and I gathered a lot of data on this target - 35 hours - but even so, and when using the equalize filter to exaggerate local contrasts, we could find no sign of a fuller circle. I was fairly convinced it would extend further but if it does we didn't find it. That's a great link to the MDW survey. I checked a couple of my more extreme Ha efforts against it, including the Ha background to the Double Cluster. I had to process that so brutally that I've always been fearful of having created some of it myself 🤣 but, to my great relief, the images concur very closely. Phew. It's a super resource. Thanks for that. Olly

Nice one. It is indeed a very curious object. There is a great deal of IFN in the area as well, certainly in a slightly wider field. It's quite hard to believe that this is a galaxy since it so closely resembles an open cluster but a galaxy is it is, even if dwarfish. It would be worth a longer and less moon-infested visit, methinks. Olly

I rarely use flats-per-filter anyway because I find they make no difference except on very rare occasions when a filter gets a unique contaminant. My bunnies are not coming from the filters but from the chip window so my L flat is used for all. Olly

Target dependent. If there really is nothing but background and stars in places you could skimp on the time. The trouble is, truly faint-free and fuzzy-free regions are few and far between (strictly they're non existent) and getting a really smooth and consistent background is tricky anyway. Personally I'd avoid the moon for this reason. With our 35 panel Orion Tom and I gave it the full Monty on every one. Olly