Tommohawk

Hi all Didn't bother with Jupiter last year and haven't had a chance one way or another to get on it this year... until yesterday. Forecast looked a bit iffy and only get about a 30 minute window, so need to get set up and focused and remember how to use the software all over again! Using Toupsky for this - its the only one that works properly with the Omegon 385 camera. This is with my converted 250 Flextube fitted with a 250mm F4 mirror from a Quattro, and the secondary removed and the camera/ 5x powermate in an adapter mounted on the spider vanes. It works very well mechanically, although focusing is a lot of fun. My conclusion with this rig is that the concept is good but the F4 mirror isn't precise enough for planetary work. I hope to rebuild another one with maybe an F5 mirror... needs a lot of custom parts though. There was minimal turbulence but sadly it was pretty cloudy - I grabbed this between the worst of the clouds. It's not great and this rig has done much better last year with Mars, but couldn't resist giving it a go. Best of 3 60s runs joined in PIPP best 50%, and then through AS!3 best 50%, tweak in PS. Whilst here I have a question and hoping someone can advise - the Omegon camera apparently has 12 bit depth, and claims 126fps at full res. The ZWO 385MC equivalent camera also has 12 bit and quotes frame rates for both 12 bit and 10 bit. Claimed rate is 120 fps for 10 bit setup. The Toupsky software offers either 8 bit or 12 bit ADC conversion. At full res the max frame rates I'm getting are 88fps at 8 bit and 49 fps for 12 bit, so nothing like claimed fps. It's not as bad as it sounds cos I get 165 fps with ROI enabled. Its the same set up that gives me max possible frame rates when used with my ASI290MM, so I dont think its a system issue. Unless theres some way of allocating more RAM.... or something? Anyhow - the question is, should I go with 8 bit in order to get higher fps but live with more noise?

That's a great Jupiter, especially if you say it was poor conditions!

TBH with APP I use the default settings I think for pretty much everything, except that I untick "neutralze background". Might not work for your set up though. BTW the other thing of interest about this image is that I didn't use any flats. There must be vignetting but it doesn't seem to show.

Hi Dave - thanks for that! Just noticed some nasty star artefacts on the rough 'n ready starless version - wil need to sort that before adding RGB stars. Are you having any particular issues with APP?

Thanks both very much and thanks for the likes. I must admit I was very pleased with the result, and weather permitting will try for some other SHO targets. The Eagle nebula and Pillars has eluded me again this year.. curses! Now I've retired, so next year I hope to spend some time in Spain and fill my boots. Well.... fill my hard drive anyhow. But who knows. Here's the StarNet starless version just for interest. If I get a moment I might whizz through the RGB stars and add those.

I chanced on Martin Fransson's image of North America nebula in SHO posted back in 2018, and was struck by the nice looking SII signal.. and with a couple of clear night though it would be worth a go. I'm set up with my 200P at the moment though so would have to be a close up. A couple of snags - always seem to be the way! First I had to extend the mount legs fully in order to track far enough - not great for stability. Also on the second night it was pretty blowy and really knocked things about a bit. I stacked both sets of data separately and together in APP, and although there was a tad less detail in the combined stack and the stars were definitely a bit bigger I went with that version because the image was definitely less noisy. Also I used PHD2 multi star alignment for the first time and between gusts it. did seem to produce better guiding. Tricky to say exactly how much improvement given the conditions but it looked like it would give maybe 0.6" rather than my usual 0.8" RMS. But maybe that's just a measuring issue - the multi star guide might simulate better guiding, if that makes sense. either way the HEQ5 is punching above it's weight given the scope and chunky ADM dual mount + 14Kg counteweights. So: HEQ5, SW200P, SW CC, ASI1600cool, ZWO NB filters (newer series) 44 x 300s Ha, 47 x 300s SII, 51 x 300s OIII. APP and PS, slight crop. Would have like to add RGB stars but ran out of time - next time maybe. Hope you like it, thanks for looking.

Very nice image - and V2 gets 👍 from me too

Lovely image, nicely processed and framed - good job!

Smashing image Olly. I've never been accused of being subtle, but FWIW I prefer the original version.

Very late to catch up with this but .... fabulous image, great processing. Nice to go the extra mile for the RGB stars too!

Did I get anywhere? ... not really! Well, I concluded the offset/misalignment is likely due to sensor tilt, but didn't actually get to resolve it. That said I found an alternative processing method which makes things look better. I found that combining RGB images and doing star calibration in astro pixel processor seemed to improve things but not sure why. The other solution I found was to ditch widefield and do galaxies and planetary for the time being! I'm hoping that a tilt adjuster will solve the problem but I have put this on hold for the moment.

+1 for PIPP

Lovely image - I'm set up for planetary at the moment but I'd love to give that a go.

Just one other quick though on this. In use, be careful not to overtighten the clutches - this "ovals" the housing and can markedly increase friction.

To me that looks like the lower tapered thrust bearing may be too tight - assuming its clean and nicely greased which I'm sure it is now! Edit - but just to add that mine is much like that too, and it doesn't seem to cause an issue.

Ok thanks for that. I don't possess an IR (pass) filter so not an option for me... but I should get one.

Yeah that looks better to my eye at least - a bit subjective. There's a lot of nice detail there - shame the RGB was poor. BTW when doing RGB do you use IR as LUM?

Super result, nice detail and colour - very envious! We've finally had a couple of clear nights and I'm laid up after a minor op. Bad timing!!

Smashing Saturn - is Jupiter maybe a bit overexposed?

Lovely result especially for an 8" scope, and nicely processed.

Craig that's remarkable given the lowly elevation of Saturn! Is the 300p a new addition? I seem to recall you had a Fullerscope previously. Also is your barlow the APM 2.7x which also works as coma corrector? I ask because I've often wondered whether uncorrected coma might impair planetary images when using a Newt. You'd think not given the small image size, but maybe it does have some impact?

If the worm is eccentric or if the main gear with which the worm engages is eccentric - any/both of these will cause variation in the speed of the drive (periodic error) and binding in some spots if too tightly engaged and backlash where it is loose. Couple of things. There are periodic error routines you can run which try and anticipate the changes in drive speed. You can read up on this BUT if you are guiding this wont be an issue. My mount has heaps of backlash in some areas but I routinely guide at sub arc-second. Not perfect but pretty good for the class of mount. Also you will notice if you set up your scope and weights as I described, ie East heavy, when you turn the gear manually (with the intemediate gears/belts removed) in the normal direction of RA drive it will be much soother than if you rotate in the other direction. It's just an oddity of how the gears mesh even if perfectly adjusted and lubes. Dont worry if it seems jerky when rotating in the opposite direction to normal - thats of no consequence. It should be smooth though when going in the normal direction. Remember when guiding the correction pulses dont reverse the direction - it just doesnt drive forward quite so fast.

Likelihood is that the main gear is just somewhat eccentric. Did you put on the belt conversion? Either way you can test the worm / big gear mesh best by removing the internediate gears or belts if you've converted, and then just turn the worm / gear to test the backlash and binding. Loosen until there is no binding. then whatever backlash you have youre probably stuck with - BUT as Ive said before this wont be an issue if you always set up East heavy. You can put your scope and weights on and make sure the East side is slightly heavier and then turn the worm manually as described above - you will always be working against the weight and consequently will not feel any backlash. You just need to make sure you always set up like that. If the backlash is massive your pointing may suffer though especially if crossing the meridian. Its more of a problem if you have DEC backlash because you have to drive both ways. (Unless you deliberately misalign PA slightly so DEC always drifts same way, but that's a skill I havent mastered)

Well done for biting the bullet and stripping down, and lots of useful comments above to guide you. One thing I would reiterate is the need to aim for smoothness in the drive and don't obsess over backlash especially in RA. RA can have a degree of backlash and it won't matter if you're always "east heavy".

Looks very nice - maybe a bit short of colour? But safer than being over-processed!