help please, poor images last night

[TiffsAndAstro]

5 minutes ago, 900SL said:

Dual narrowband is good if there is no moon and low to moderate light pollution.

Once you have a bright moon phase and/or B8/9 it can really mess up your Oiii channel if you are targeting near the moon (like in the same quadrant)

DNB should be good in B5 though. Not a lot of point in using it just for Ha, you are only using 1/4 pixels

Yeah but 1/4 pixels is better than no pixels by not imagining? I can separate out Ha and Oiii via a siril script, but need to look into how I could combine multiple sessions, some Ha+Oiii some just Ha, if that makes sense?

[900SL]

1 minute ago, TiffsAndAstro said:

Yeah but 1/4 pixels is better than no pixels by not imagining? I can separate out Ha and Oiii via a siril script, but need to look into how I could combine multiple sessions, some Ha+Oiii some just Ha, if that makes sense?

I'm predicting you will go full mono within a year, subject to (a) bank robbery (b) windfall (c) lottery win (d) selling a kidney

[TiffsAndAstro]

23 minutes ago, 900SL said:

I'm predicting you will go full mono within a year, subject to (a) bank robbery (b) windfall (c) lottery win (d) selling a kidney

I can't sell a third kidney I'd have to give up the booze.

Bank robbery is a good shout though.

Edited August 17 by TiffsAndAstro

[Ouroboros]

I tried imaging near Sadr last night using an ASKAR dual band (Ha, OIII, 6nm) filter.  I measured 6000 stars in Subframe Selector compared with 8000 stars in the same field a few days ago. I don’t know whether that was down to high cloud or moonlight or a combination. I’m seriously thinking of ditching last night’s data. I suppose It might be worth putting the data into WBPP to generate separate  images for night 1 and 2 to compare before ditching. 

[WolfieGlos]

With the strength of the Moon currently, have you considered imaging star clusters Tiff?

Whilst some people don’t find them as “spectacular” as nebulae or galaxies, they don’t suffer under Moon conditions, colour comes through, and with your short imaging times they also won’t suffer as badly from stretching in post. And you get an image out of it 👍

Give the double cluster in Perseus a go, or Graffs or the Tweedledum clusters in Aquila, even Carolines Rose in Cassiopiea will frame nicely with your setup. Globulars I also find are OK, M13 is still doable in Hercules. And get a nice shot of the Moon while you’re at it

Edited August 17 by WolfieGlos

[TiffsAndAstro]

10 minutes ago, Ouroboros said:

I tried imaging near Sadr last night using an ASKAR dual band (Ha, OIII, 6nm) filter.  I measured 6000 stars in Subframe Selector compared with 8000 stars in the same field a few days ago. I don’t know whether that was down to high cloud or moonlight or a combination. I’m seriously thinking of ditching last night’s data. I suppose It might be worth putting the data into WBPP to generate separate  images for night 1 and 2 to compare before ditching. 

Now you mention that, I did notice fewer stars than I expected, though hard to quantify.

I will bin mine after couple more tests 

[TiffsAndAstro]

17 minutes ago, WolfieGlos said:

With the strength of the Moon currently, have you considered imaging star clusters Tiff?

Whilst some people don’t find them as “spectacular” as nebulae or galaxies, they don’t suffer under Moon conditions, colour comes through, and with your short imaging times they also won’t suffer as badly from stretching in post. And you get an image out of it 👍

Give the double cluster in Perseus a go, or Graffs or the Tweedledum clusters in Aquila, even Carolines Rose in Cassiopiea will frame nicely with your setup. Globulars I also find are OK, M13 is still doable in Hercules. And get a nice shot of the Moon while you’re at it

Honestly I don't like globular star clusters. I've imaged ok (or so I though) with a fuller moon so I'm not 100% convinced it's the cause of both targets showing similar results. 

But I did come outside, I think, about 1030 and thought "oooh the bright yellow moon looks nice".

It was low between houses.

If my telescope can't see it, it can't see my telescope ;(

Edited August 17 by TiffsAndAstro

[Mr Green]

I see that you're up north (as am I).

The visibility was terrible last night and I was itching to try out my new mount but packed up after an hour.

I think you likely had the same issue (poor seeing conditions even without cloud).

Rushing to process just a couple of hours on a subject with a OSC and no filter rarely works out (I've been there).

 

[TiffsAndAstro]

4 minutes ago, Mr Green said:

I see that you're up north (as am I).

The visibility was terrible last night and I was itching to try out my new mount but packed up after an hour.

I think you likely had the same issue (poor seeing conditions even without cloud).

Rushing to process just a couple of hours on a subject with a OSC and no filter rarely works out (I've been there).

 

sorry to hear that, but its also good to know ty

can i ask how you know visibility was terrible? it looked good to my eyes - obvious passing clouds aside of course 

[TiffsAndAstro]

43 minutes ago, WolfieGlos said:

With the strength of the Moon currently, have you considered imaging star clusters Tiff?

Whilst some people don’t find them as “spectacular” as nebulae or galaxies, they don’t suffer under Moon conditions, colour comes through, and with your short imaging times they also won’t suffer as badly from stretching in post. And you get an image out of it 👍

Give the double cluster in Perseus a go, or Graffs or the Tweedledum clusters in Aquila, even Carolines Rose in Cassiopiea will frame nicely with your setup. Globulars I also find are OK, M13 is still doable in Hercules. And get a nice shot of the Moon while you’re at it

didn't mean to sound dismissive about globular clusters, its more my least favourite dso. i don't think less (or more) about people who do really like them

[Elp]

1 hour ago, TiffsAndAstro said:

I can separate out Ha and Oiii

Technically you can use separate ha/S2/o3 filters with an OSC but as mentioned the received signal is hindered by the Bayer matrix pattern.

[Mr Green]

7 minutes ago, TiffsAndAstro said:

sorry to hear that, but its also good to know ty

can i ask how you know visibility was terrible? it looked good to my eyes - obvious passing clouds aside of course 

The two things that I always look out for is how many constellations are visible to the naked eye when setting up, along with how much detail I get on a target with a 2 minute exposure. The moon can also be a good giveaway as to whether visibility is good. If the moon has a bit of a white haze over it rather than looking crisp sharp, that's another sign that you might struggle.

After a while, you just pick up on little things and learn from them with a bit of time.

The images you took might still be of use for when you get more data to add to it. 

I used about an hours worth of naff data collected last night with other data collected the night before and was pleased with the result.

[TiffsAndAstro]

22 minutes ago, Elp said:

Technically you can use separate ha/S2/o3 filters with an OSC but as mentioned the received signal is hindered by the Bayer matrix pattern.

Yeah it's doable but would make me sad to waste so many pixels

[TiffsAndAstro]

10 minutes ago, Mr Green said:

The two things that I always look out for is how many constellations are visible to the naked eye when setting up, along with how much detail I get on a target with a 2 minute exposure. The moon can also be a good giveaway as to whether visibility is good. If the moon has a bit of a white haze over it rather than looking crisp sharp, that's another sign that you might struggle.

After a while, you just pick up on little things and learn from them with a bit of time.

The images you took might still be of use for when you get more data to add to it. 

I used about an hours worth of naff data collected last night with other data collected the night before and was pleased with the result.

Maybe I could use the stars. Background alone has almost nothing but grey. Just a tiny hint of elephants trunk. 

[TiffsAndAstro]

19 minutes ago, Mr Green said:

The two things that I always look out for is how many constellations are visible to the naked eye when setting up, along with how much detail I get on a target with a 2 minute exposure. The moon can also be a good giveaway as to whether visibility is good. If the moon has a bit of a white haze over it rather than looking crisp sharp, that's another sign that you might struggle.

After a while, you just pick up on little things and learn from them with a bit of time.

The images you took might still be of use for when you get more data to add to it. 

I used about an hours worth of naff data collected last night with other data collected the night before and was pleased with the result.

I saw constellations before 1230, the w Cassiopeia I think and others. 

I think a big thing is I need more experiences good and bad so I can tell.

Also I've never done any purely visual observing and i think that would be of use now. To some extent 

[WolfieGlos]

43 minutes ago, TiffsAndAstro said:

didn't mean to sound dismissive about globular clusters, its more my least favourite dso. i don't think less (or more) about people who do really like them

Not at all, but the fuller Moon nights really hinder imaging, so it’s the best time to capture them. I love the Globs, open clusters less so but that’s because I think they’re nicer images with diffraction spikes. Frame them right, they make for lovely simple images. Great also for practising focusing, learning new tricks (say dithering or meridian flips if they’re new) and getting an image rather than wasting a clear night.

Try the Coathanger asterism, or Kembles Cascade.

5 minutes ago, TiffsAndAstro said:

I saw constellations before 1230, the w Cassiopeia I think and others. 

I think a big thing is I need more experiences good and bad so I can tell.

Also I've never done any purely visual observing and i think that would be of use now. To some extent 

I’ve never done any observing either, but I used to manually star hop to find targets before GoTo. Which is kind of clutching at straws 😆

[TiffsAndAstro]

7 minutes ago, WolfieGlos said:

Not at all, but the fuller Moon nights really hinder imaging, so it’s the best time to capture them. I love the Globs, open clusters less so but that’s because I think they’re nicer images with diffraction spikes. Frame them right, they make for lovely simple images. Great also for practising focusing, learning new tricks (say dithering or meridian flips if they’re new) and getting an image rather than wasting a clear night.

Try the Coathanger asterism, or Kembles Cascade.

I’ve never done any observing either, but I used to manually star hop to find targets before GoTo. Which is kind of clutching at straws 😆

Yeah these are all good points and makes it worthwhile. At least at my level. 

Are any globular clusters known to have many  red stars? Betelgeuse was the last I saw way back early this year.

[WolfieGlos]

10 minutes ago, TiffsAndAstro said:

Are any globular clusters known to have many  red stars?

I don’t know myself, generally they are blue and yellow stars from the images I’ve captured. 

[Stuart1971]

7 hours ago, TiffsAndAstro said:

so i imaged ngc 6604 and ic 1396 last night and got almost just stars, almost no nebula. i've culled subs, search for cloud, used different flats, just stacked lights and can't for the life of me work out what's wrong.

maybe frosting on the glass of my camera? histogram view of a stack below. histogram seems less extreme than normal. could there have been a layer of thin cloud or could this be extremely bad seeing, maybe? it seemed pretty clear until about 1230am.

maybe someone can discern a problem from these? its not a huge deal, just want to make sure i haven't messed something up before next clear night in a few years time. 

 

 

 

 

Looks to me like you had the gain way too high, and no cooling on the camera at all….🤔

[TiffsAndAstro]

17 minutes ago, Stuart1971 said:

Looks to me like you had the gain way too high, and no cooling on the camera at all….🤔

They are histogram views and look much less intense than my usual stacks. More gain would make it more intense? No cooling would increase noise and maybe result in a sort of evening out? I'll check file names

[PhilB61]

I also imaged the same night, managed to get just over 3 hours of good data to add to my Veil mosaic, this was in North Wales, but I did notice that humidity and hence dew was the worst this year. Fortunately my heaters kept the glass clear but everything else was dripping and the bushes and trees looked like covered in frost with the dew beads. Did you check if your glass was dew free?

[TiffsAndAstro]

15 minutes ago, PhilB61 said:

I also imaged the same night, managed to get just over 3 hours of good data to add to my Veil mosaic, this was in North Wales, but I did notice that humidity and hence dew was the worst this year. Fortunately my heaters kept the glass clear but everything else was dripping and the bushes and trees looked like covered in frost with the dew beads. Did you check if your glass was dew free?

I didn't actually check, but both dew heaters were on.

[900SL]

Autofocus and then FWHM will give you a good idea of how your seeing is. Mine goes from 1.6 px to 2.something px (in Asiair units). 1.6px is sharp, good stars and detail. Above 2px it's usually bloated stars and mushy.

Last night started off at 1.7 and floated out to 1.9 over a couple of hours. Might have been the odd thin high cloud, and aurora too. Shooting Ha on the mono, moon was on the horizon and I was going for the crescent which is high alt here

[Stuart1971]

2 minutes ago, 900SL said:

Autofocus and then FWHM will give you a good idea of how your seeing is. Mine goes from 1.6 px to 2.something px (in Asiair units). 1.6px is sharp, good stars and detail. Above 2px it's usually bloated stars and mushy.

Last night started off at 1.7 and floated out to 1.9 over a couple of hours. Might have been the odd thin high cloud, and aurora too. Shooting Ha on the mono, moon was on the horizon and I was going for the crescent which is high alt here

Doesn’t FWHM vary anyway from one scope and set up to another with different f ratios an and imaging scales…? So what is a good number on one set up may not be on another 

[TiffsAndAstro]

12 minutes ago, Stuart1971 said:

Doesn’t FWHM vary anyway from one scope and set up to another with different f ratios an and imaging scales…? So what is a good number on one set up may not be on another 

I Use hfr in Nina which is vaguely similar.

2.09 is the best I've gotten on my gear, so I aim to get close to that.

 

Edited August 18 by TiffsAndAstro