Jupiter 29/12 from Bembridge - looked good until I stacked the data

[SnakeyJ]

Wonderful clear conditions down here last night, so with promise of the best of the year so far, I set my alarm for 2:45 so I could catch Jupiter due south.      To save the flip, I started with a forced goto with the scope on the west side and tweaked the collimation with the Hotech.     Jupiter looked very nice, with good trans and pretty good/stable seeing in comparison to recent conditions.     I thought I was in and recorded 12 LRGB captures, pausing only to use the hair dryer once when the levels dropped.    The ota had a heavy frost and there was a slight mist apparent after 2hrs when I closed up and headed back to the kitchen for a cup of tea and quick process.

I was really confident that I had captured some good data, but two hours of mucking around with the processing has left me very disappointed and a little bewildered.      The results are flat and noisy/grainy however I process the data, despite good consistent levels, high frame rates and low gain on capture.   More annoying is that I can't really figure where I went wrong - there is detail in the stacked images, but the processing just seems to flatten and loose contrast.      I'm thinking I may have had a fine frosting on the secondary, though I also changed firecapture to record in UT Lossless AVI last night and could have screwed up a setting somewhere - although the file sizes looked about right at 650-700MB for 640x480, 6000 frames at 100fps.

No point ranting without posting a couple of examples, but will have to wait until I get back from work.      Though must work this one out before committing to another early morning before work!

[si@nite]

No luck here Jake wonderfull clear sky but seeing & trans were cack this end so gave it up as a bad job!

[mitchelln]

It did look very promising. Set all my kit up in plenty of time. Used my Bahtinov mask on Sirius to get precise focus. Then at 10pm went back out in time for the GRS. Slewed onto Jupiter and it was just a smudge. Optics frozen over! Gah!

[scopekid1325]

hi same in cornwall -4 last night 4 hours all rubbish the frost was forming on my dew shield like snow   too much moisture in sky i think hence rubbish results ??  moon was same not quite so bad though  glad i wasnt the only one i thought i was doing something wrong colin far west cornwall

[scopekid1325]

by the way no  dew on my optics thanx to my dew shield cost 15 quid to make colin far west cornwall

[SnakeyJ]

No luck here Jake wonderfull clear sky but seeing & trans were cack this end so gave it up as a bad job!

Fortunately conditions are looking good for tonight and the high pressure may just bring some better seeing

It did look very promising. Set all my kit up in plenty of time. Used my Bahtinov mask on Sirius to get precise focus. Then at 10pm went back out in time for the GRS. Slewed onto Jupiter and it was just a smudge. Optics frozen over! Gah!

Although I don't usually have much need, a hair drier can be very handy for these occasions - usually a minute or so will clear my secondary and it settles enough to resume imaging after 3-4 minutes.   Never had to use it on the primary though.

hi same in cornwall -4 last night 4 hours all rubbish the frost was forming on my dew shield like snow   too much moisture in sky i think hence rubbish results ??  moon was same not quite so bad though  glad i wasnt the only one i thought i was doing something wrong colin far west cornwall

It was cold enough for me down here at -1.5C, though it felt colder with the northerly breeze.    Definitely need more layers and soup to stay out in anything colder.  

[Space Cowboy]

Cloudy in Cheshire just in time for the GRS but the stars were going crazy before that. Tonight may be better.

[astroman001]

Don't worry, it was the same over here in Sussex. Looked good during capture, but processing revealed soft detail and poor contrast. I think it was the seeing conditions rather than your gear or anything you did.

regards

Peter

[SnakeyJ]

Don't worry, it was the same over here in Sussex. Looked good during capture, but processing revealed soft detail and poor contrast. I think it was the seeing conditions rather than your gear or anything you did.

regards

Peter

Thanks Pete, nice to have the reassurance - I'll venture out again tonight and see I can get some improvement!

[Barv]

Wonderful clear conditions down here last night, so with promise of the best of the year so far, I set my alarm for 2:45 so I could catch Jupiter due south.      To save the flip, I started with a forced goto with the scope on the west side and tweaked the collimation with the Hotech.     Jupiter looked very nice, with good trans and pretty good/stable seeing in comparison to recent conditions.     I thought I was in and recorded 12 LRGB captures, pausing only to use the hair dryer once when the levels dropped.    The ota had a heavy frost and there was a slight mist apparent after 2hrs when I closed up and headed back to the kitchen for a cup of tea and quick process.

I was really confident that I had captured some good data, but two hours of mucking around with the processing has left me very disappointed and a little bewildered.      The results are flat and noisy/grainy however I process the data, despite good consistent levels, high frame rates and low gain on capture.   More annoying is that I can't really figure where I went wrong - there is detail in the stacked images, but the processing just seems to flatten and loose contrast.      I'm thinking I may have had a fine frosting on the secondary, though I also changed firecapture to record in UT Lossless AVI last night and could have screwed up a setting somewhere - although the file sizes looked about right at 650-700MB for 640x480, 6000 frames at 100fps.

No point ranting without posting a couple of examples, but will have to wait until I get back from work.      Though must work this one out before committing to another early morning before work!

Interesting Jake and I'm glad you posted this.

I was in the same position as you and thought I had got some decent data. I found exactly the same problem and have put the raw up on my post for people to look at and play with. Mine, may be just my processing though as I think I'm probably a little rusty! My optics definitely didnt due up though but I could see detail on the 80 percent of the disc when running through the avi.

Regards

Harvey

[SnakeyJ]

Interesting Jake and I'm glad you posted this.

I was in the same position as you and thought I had got some decent data. I found exactly the same problem and have put the raw up on my post for people to look at and play with. Mine, may be just my processing though as I think I'm probably a little rusty! My optics definitely didnt due up though but I could see detail on the 80 percent of the disc when running through the avi.

Regards

Harvey

I haven't played the AVIs in comparison to any of my previous, but the captures certainly looked ok in the preview window - expecially at full frame rates when focusing (the preview rate is set @ 5FPS during capture.   Looking at your post  http://stargazerslounge.com/topic/232666-the-shrinking-grs-on-morning-of-the-28th-with-picture/#entry2517236 the effect is strikingly similar, though I have pushed the wavelets harder creating more noise.

I've seen many comments re bigger apertures being more affected by poor seeing, though thermal stability seems to be the major factor with the big 12"+ SCTs and Newts for that matter.     Thermal blanket seems to be one popular trick for improving thermal stability of the SCTs, though I have no direct experience!

I'll post some of my channels up later this evening.

[SnakeyJ]

Not sure if this the best of the bunch, but certainly representative of the issues:

LRGB Channels:

   

These are 1500 frame stacks from 6000 frames/channel in AS!2 (no drizzle), with linked wavelets and histo stretch in R6.

Pants!

[theo]

Just shows what 24hrs does Jake (between this and your most recent post). I've been struggling with misty conditions giving poor histograms for Jupiter. Seeing was good earlier though so I grabbed a load of Lunar data for a change as it's been a while since I imaged the Moon.

Pete

[Pete Presland]

thet look pretty decent to me, some very nice detail showing.

[SnakeyJ]

thet look pretty decent to me, some very nice detail showing.

They don't look bad on the video or when stacking - but theres no depth to stretch or process. Not enough SNR I think.