vineyard

Enough Ha on this I think - next step to add the colour (OSC again)

2h40 on the Eastern Veil with a 6nmHA & 294MCPro.  Its WIP, so this is just messing around with PI (ghs script) & GIMP.  Cheers

Ingenious.  I'm toying with the idea of using these cake boards to make the retaining rings: https://www.amazon.co.uk/Culpitt-Round-Cards-Silver-Boards/dp/B09RKM257Q/ just need to figure out the holding cylindrical cardboard contraption.

Excellent idea of the hobby boxes to store them carefully in.

Noticed that yesterday evening - well played.

A sad loss & a beautiful eulogy.  V good of them to share those photos too, to convey a sense of the person behind the art.

15 minutes ago, edarter said:

But doesn't that mean that the CLS is effectively doing nothing? 

If the Astronomik curves are correct, the CLS is cutting off the long-pass.  The Astronomik UHC seems to be somewhat akin to a long-pass filter above 630nm so the CLS would cut that off at about 700nm.  (The Baader UHC curve seems to have a shut off in it unlike the Astronomik UHC, at least going by Semrock curves: https://searchlight.semrock.com/?sid=a08a1af9-84ee-49d2-959d-153d7e7c0eb8#)

Thanks @vlaiv - nuanced explanations such as yours is part of why SGL is so rich to learn via.

From my clumsily phrased perspective, I was just really surprised at the difference in the two images.  For my crude mental model, in the OSC+double stack, all the 4 Bayer arrayed pixels are being used for 4.5-5h yet so much of the structure still doesn't come close to emerging - whereas in the OSC+NB (which to my mind means akin to a mono camera with 1/4 of the pixels, albeit with interpolation between the pixels which a pure mono wouldn't need to do) one night gave so much richer data.  Maybe "NB is faster" is a better formulation for what has surprised me.

I hear you on the set-up & flats - people's mileage will vary but for me <2h in one night vs 4 nights to get 4-5h is much more convenient, especially with that much difference in data.  (I'll admit I'm lazy and if I haven't messed with the setup & no big changes have happened wrt dust bunnies, I just use the same flats for a few nights - I suppose slight focus changes night-to-night should mean I should take new flats).

Cheers!

I think it would depend on which filters you stack @edarter & @tomato.  If I had 2 proper NB filters, I wouldn't stack them b/c they'll be working on different parts of the spectrum as you say.

I can't remember where I first read of this double-stacking but I think it was in some obscure CN thread.  Based on the logic described therein, I double-stacked an Astronomik UHC & CLSCCD filter.  I've pasted their respective band-passes below - I think b/c they work on v similar parts of the spectrum (as you surmised @ollypenrice) but w slightly tighter passes in the UHC, the combined effect is a bit closer to a dual-band like L-Enhance (still not as tight as that & nowhere near as tight as an L-Extreme).

The interesting thing is that in solar, double-stacking HA etalons does tighten the bandpass but perhaps that's because of a different physics being used wrt the filtration mechanism?

Thanks too for that image @The Lazy Astronomer - v v helpful.  I'll try and do a Pixelmath comarison later, but at quick glance I think there's more finer detail in that than even w the OSC+NB, which would be another validation of mono?

While I save for a fuller frame camera, the eternal debate of mono vs OSC (+dual band filters) wages on in my head.  And a point often made is that mono is actually faster not slower.  I think I just saw an example of this.

Two images below - the colour is about 4.5-5h of OSC over 4 nights last autumn (w dual-stacked filters to synthesise a dual-band) on NGC 6888.  The red one is only 1h48from last night via a 6nm HA filter and the same camera 294MCPro on the same target.

The difference in data gathered is shocking.  Clearly a tighter NB filter will be helping (vs synthetic dual-band), but this is as a semi-mono w c 60% less capture time than the OSC - so I'd imagine a proper mono would have captured even more data?  And btw this is on full moon night at a time of year when astro dark doesn't exist (even if the moon wasn't out).

Mono really is faster!

That's dedication - bravo!

That is...just stunning.  Wow.

20 hours ago, peter shah said:

  The 'tilt' is actually an artefact of the stacking procedure caused by the objects altitude....I am looking into it to see if I can get better registration by tweaking the alignment settings. The stars are actually pretty round from corner to corner in the single frames. This object is very low down and is effected by atmospheric refraction. The frames were captured starting from at around 18 degrees and I think peaked at around 29. 

Yes I'd noticed that those shapes only seemed to be on the bottom edge not the top, hence my curiosity.  Interesting re it being an altitude-related stacking artefact.  I'm afraid I don't understand the subtleties of stacking algorithms anywhere near remotely but intuitively yes I can see how higher refraction lower down while the image registers based on stars higher up could do that.  It's almost like there's a need for adaptive registration for stacking purposes.

Looking fwd to seeing the fuller project.  And cracking vistas from the obs.

That's stunning.  Is there any justification left for mono when OSC delivers that?

Couldn't help pixel peeping (it's that good an image!) and is there some v v slight tilt (there seem to be some trails towards the bottom edge)?  (That's not a criticism btw - I'd be over the moon w an image like that - more curiosity)

4 hours ago, Doversole said:

Just ordered mine today @FLO  AZ version for £489 hoping I can reuse the WO wedge.

There will be a few SkyGuider Pro on the second hand market!

 

Huh, its not priced on the FLO website yet.  Crikey - I'd better get in there.  Did they give a lead time?  You're right on the SGPros.

On 06/06/2022 at 20:37, TBRHussaR said:

Afocal - so no eyepiece used...

Do you mean prime focus (I think afocal involves an EP)?  Great images of the most recent 2 galaxies too.  You're definitely motivating me to take the 7"+NV on a galaxy hunt   What f-ratio are those galaxy observations running at?  (If its a Celestron 8" with NV at prime focus then that suggests f/10?)  Thanks!

I'd echo the step change that NV makes - I use it in Bortle 8/9 skies with a 7" Mak, 5" Mak and 3" frac.  It's a complete game-changer for visual.  I haven't had a chance to run it on any galaxies yet (mostly globs & some nebulae) so your report on M51 w an 8" is v encouraging.  Can I ask what f/ratios you were effectively running your NV at (ie, the native f-ratio of your scope & if you were doing this afocally, which EP you were using?)?

Thanks

Continuing clean up of data from old imaging setup.

Here's c 3h of HA on Jellyfish Nebula.  Definitely hoping to spend more time on this target when the winter comes back.

Cheers

Thanks Steve, that's v kind.  IKWYM about what is out there.  I actually hadn't appreciated how many other objects are out there even just around M101 - have started capturing some data w the newer wider-field imaging setup & there's quite a few other things up there even in just that bit of sky.  To think there's probably creatures out there looking at/towards us wondering the same thing.  Or else it's all just a simulation😂

Am in the process of changing imaging scope, so just cleaning out data captured with the old setup.  Here's 9h44 of M101 roughly equally split between CLSCCD & HA filters.  This is a crop of about the central 1//3-1/2 (from memory) of the aggregate image taken w an ASI294MCPro & a TV102iis w a 0.79 reducer-flattener.  Rescaled jpg for size.

Cheers.

3 minutes ago, PadrePeace said:

Where did you find this offer? What was the price point?

$488 (plus shipping etc I guess) direct from them: https://www.ioptron.com/product-p/shaz.htm - delivery to US should be straightfwd, getting it back from there...

9 minutes ago, Doversole said:

Actually I hadn't thought about the AZ bundle. I already have a WO wedge I am using the with Skyguider Pro, I might actually reuse it on this new iOptron mount!

That's exactly my plan too.  I wonder if there are any projects for the old SGP motor unit...

Agreed @Doversole, the US bundles & pricing are v interesting - also v good to see that they're offering an AZ bundle only (ie, without either the wedge or the iPolar).  Hopefully same will apply here - @FLO any idea of UK pricing & timetables that you can share?

Just a quick note to say thanks for this thread all - have found it v useful as recently switched to a Pegasus Motor Focuser & have been v puzzled by the focus behaviour.  Having stumbled across this thread, I suspect it was indeed backlash - have hopefully calibrated it along the lines suggested, will find out the next clear sky🤞🏾

Cheers all!

Yes I've noticed horizontal bands in my flats as well (with an artist's light panel, so I guess that's LED) - and they definitely affect the final image.  You can post-process them out more or less, but it's not ideal.  I haven't got round to it yet, but will test a t-shirt over the objective facing the light panel to see if that diffuses it enough as per @ONIKKINEN suggestion above.

After a quick go at M13 about 10 days ago, I tried a few more GCs over 2 nights - one night w the STF7 & the TV55 but w/o the 0.5x reducer, so running at about f/4.7.  The second night with a wee Meade ETX125 (f/15) with a TV40 plossl (so running at about f/10).

For the STF I tried an Astronomik CLSCCD filter since looking at its transmission profile, its seems a bit like a long-pass filter.  For the ETX I used a 642nm lowpass filter.

Targets both nights were M13, M92 & NGC 6229 in Hercules, M3 in Canes Venatici, M53 in Coma Berenices & NGC5466 in Bootes.  As well as M57 in Lyra (ok its a PN but why not ).

The first night I just did one-star alignment on the MiniTower II, the second night (since I knew the FOV would be tighter w the ETX) two-star alignment.

Both nights were great.  Successfully managed to view all the targets - except NGC5466 which I could not find both nights.  Needed to do a little bit of panning when only 1-star alignment was used but that was to be expected. As expected 2-star alignment brought the scope much closer to target.

If I had to compare the two (just from memory) I'd say the STF7 but that's to be expected w better framing (wider FOV) and more aperture.  But the Meade ETX even at f/10 did its job v well - more than sufficient for clusters, & a lot lighter & easier to setup.

Seeing the clusters jewel-like hanging in the sky was v nice.

Not a chance I could have seen those w/o NV in Bortle 8/9 here.