vineyard

An epic session - and that's dedication at -7C in the middle of nowhere.  Good idea on the drysuit undersuit - you can also get them electrically powered (a bit like electric blankets) if you want.

I tried it @AKB.  Here are the results.  4 images (240s lights w 294MCPro).  The first is 4h HA on the first night.  The second is 2h56 HA on the second night.  The third is all 6h56 stacked in one go in APP (but shown as two sessions in APP).  The last image is the pixel math version of 1 & 2 (weighting being 60/104 of Night 1 + 44/104 of Night 2).  All images have only had ABE & HT done to them (2nd image has been registered to the first to allow the pixel math to work).

Not sure my eyes are good enough to tell much of a difference but maybe pixel peeping will reveal more?

That's interesting @AKB - so I could just PixelMath the nightly stacks using the weightings of the number of subs from each night divided by the total?  That would save time as I could do that as I go.  Ofc I guess as @vlaiv says if the SNR is different night-to-night that might not be as accurate as stacking them all together when each light's SNR presumably gets factored in by the algorithm?

(I'm just trying to figure out ways of optimising my workflow - eg: now I blink & calibrate lights on a session-by-session basis, and will soon just start deleting my raw lights after that so that all I have are calibrated lights which can be used at any time in the future w/o having to do it all again)

Hello,

I was just idly musing on a couple of Qs which I couldn't figure out the answer to, hence this post!

1.  If I have say 8h of NB data on the same target, same filter over 2 nights.  Is there a mathematical difference between stacking 8h of data in one, or stacking each night separately and then adding them together (normalising each of the two nights stacked images to each other)?

2.  Linked to Q1, I notice that program like APP also allow you to specify if the lights are w different filters (rather than just different sessions).  So is it mathematically better to put all the lights into a single pile in a program like that, or to stack each filter separately and then combine via eg PixelMath?

Thank you!

Vin

(PS: not sure if this should be in Imaging Discussion or Imaging Image Processing subsection so apologies if its in the wrong place)

Wow!

Beautiful - are the last two double-stacked?

Btw is there something slightly odd about the shape of the solar disc in the SW quadrant (it doesn't seem circular (especially the higher up images)?  This is not a criticism, more just to check whether my eyes are working or if I need to go to the optician!

Hello,

After this c 7h image, I added more data (ok about 2x!) just to see what difference it might make.

Here's 13h43 more or less processed the same way (using the GHS script) - also including a star-reduced crop.

I guess its aesthetics as to whether you prefer 7h vs 14h, but the difference in data seems quite clear?

Cheers,

Vin

That's just gorgeous. Wow - absolutely luscious colours. Have you had any leakage problems with your 2600 btw?

Thanks @tomato - that's a v good point.  I'm in Bortle 8, so the visual obs that @Saganite you were describing is sadly probably impossible without NV.  But I will now keep gathering data every so often just to see how long it takes for the tail to emerge (hopefully filters will make up for Bortle 8?).  Cheers!

Hello,

Leo Triplet w ASI294MCPro & TV102iis reduced/flattened by 0.79x.  APP & then PI (with photometric colour calibration).

I'm not sure it's worth getting more data at this FOV (would anything change radically in the image?) but someday it would be nice to go deeper on each of those galaxies with a larger aperture.

Cheers,

Vin

That's a v interesting M81 - the arms in particular👍🏾.  Could you do an HDR composition w separate (quicker) exposures for the core and then combined?

Thanks @Pete Preslandthat's v kind.  I am missing the sun - I really hope its clear tomorrow/Sat as was looking possible at some stage b/c I am going to go sit outside!

That third image is in particular 👌🏾- the light that you've captured on that region is lovely (like catching a fleeting glimpse before parts start getting hidden in shadows)

Hello,

Took my laptop on recent travels and managed to process my first ever attempt at Rosette.  This is 9h47 of OSC data (ASI294MCPro) taken with Astronomik UHC & CLSCCD filters double-stacked.  An old TV102iis scope - f/8.6 native but reduced & flattened to f/6.8.  But even so, the combination of the FOV & the camera sensor size mean that the Rosette can't fit fully in, but I'm still quite happy w what has emerged.  I cropped top & bottom a sliver to take out effects of different days (can only get about 2-3h of data on a given day due to trees etc) and a bit left & right to remove some gradients that were there (from memory from the direction the moon was in).

Three images below (JPG'd for size) - the first a partially star-reduced one, the second a more star-reduced one to draw out the nebulosity further, and the third the non-star reduced one.  I think this target definitely benefits from some star reduction to bring out the nebular features more - I like how the Bok objects stand out & there are definitely regions I'd like to look at more deeply with a larger aperture some day...ah well.

All c&c welcome.

Cheers,

Vin

Cracking images - the silhouette & the close-up video in particular (the terrestrial heat shimmer in the video is great at conveying a crackling sense of energy!).

That is a superb image.  So clear & sharp yet subtle that it makes you draw a breath.  And 👍🏾for introducing the young man to the night sky early - even if he doesn't grow up to be interested in astronomy, he'll no doubt have a better sense of perspective than many about the universe & Earth's little place in it!

4 hours ago, ONIKKINEN said:

How long did you wait from bringing the scope inside to taking flats? Dew can take an hour or more to go away.

I would guess its the outside of the sensor window thats dewing up rather than the inside, unless your camera is old and the desiccant is really saturated.

I took the flats much later (days).  It may have been that the camera chills v quickly indoors & that sudden drop draws out some moisture?  Although I leave the camera permanently attached to the back of the flattener.

The camera is old (pre-owned 294MCPro that I bought almost 2y ago) so I probably should remove the desiccants and zap them in the microwave!

57 minutes ago, david_taurus83 said:

What kind of light source is it? Is it a bulb? Could it be warming up the sensor window temporarily causing dew until the temp goes back down again?

Its a Huion LED Panel Pad (my better half uses it for her art & making work but I, ahem, borrow it occasionally  ).

Yes it was a problem w the flats  I noticed that when I switched on the lightbox, that central pattern wouldn't be there but would then start to appear, and then reduce gradually.  I just waited and eventually it disappeared.  So either its something weird with the light sources in the box (highly unlikely) or its dew on the sensor.  I learned something new there b/c I didn't appreciate that that could happen - luckily it went away quite quickly but yes maybe time to recharge the desiccant tablets (have seen the videos on YT) - is it worth getting one of the ZWO cooled camera dew heaters or is that overkill?  There isn't that much humidity here normally.

Here's a quick w-i-p DBE+HT jpg without the halo, which means the new flats will also work with all the other data I took this last month (phew!)

Thanks again for the help @ONIKKINEN& @david_taurus83 🙏🏾

Thanks @ONIKKINEN that's v thoughtful reply.  Yes that's a refractor.  Not sure it's dewing b/c I took the flats indoors from a light box.  But, I did have the light box not quite perpendicular to the objective, and it was also set back some (rather than flush with it).  I didn't think it would make a difference (since I believe sometimes people just point their scope at a panel mounted on the wall of their obs?).  But I'll try with that & see what happens - will report back.

Thanks again - you've given me a pointer to explore further.

Hello,

Slightly scratching my head about this.  No doubt missing s/t obvious so apologies in advance if so!

Here's w-i-p (only about 5h44) on Leo Triplet.  APP w flats, darks & dark-flats.  Just DBE & then HT in PI.  JPG'd for size.

What is that strange oval thing in the middle.  I'm attaching a FITS of a single flat image - some bunnies etc do show up in that area of the flat FITs (you can see the other bunnies too).  But how come this central bit doesn't get calibrated out?  (In fact I did a test of stacking just a small number of lights and the oval is there, but more faintly - ie stacking more & more lights seems to make it worse).  What could it be that doesn't get calibrated out like other bunnies & instead gets more pronounced as more lights are stacked?

Thank you for any light (if you'll forgive the pun)!

Flat neg10g125o16_Flat_0.041_secs_2022-01-24T15-16-30_001.fits MF-IG_125.0-E_0.041495s-ZWO_CCD_ASI294MC_Pro-4144x2822--all_sessions.fits

That's gorgeous.  Only 3h each panel - yowsa.  NGC 1333 looking particularly inviting for deeper imaging (as is that little bluish region that's 3'o clock from it)!👍🏾👍🏾

@maw lod qan yes it was!  That line from Jaws came to mind when I first saw it..."we're going to need a bigger boat"😂

I didn't have a chance to do any viewing today, but did manage to get some time yesterday.  JPGs for size.

The whole disk is w/o a GPC, the closeup w a 2.6x GPC as per @Rustedsuggestion earlier.

Its ginormous - I guess we can't tell how deep it is, but that would probably be 20-30 Earths in cross-section not including the plumes?

Your CaK images are 👌🏾 - the framing on the 4th one is excellent, a real sense of motion & energy 👍🏾