Beginners, monochrome is fastest and easiest!

[Astrosurf]

Due to having to set up each time, and all the faffing about that causes, I don't have much time and don't get the best out of my Atik. I might get an hour's worth of Ha or L but then the colour is always the bit to suffer even with 2x2 binning as I run out of time. I don't trust my skill at setting up to do 30min subs. I do max 10 each. I love my 600D, even though I get red rings around the stars. Yes, the quality isn't so good, but I can just leave it running. I leave the darks for when I'm packing up and driving home (no heater on in car!). Works fine. Here's my Triangulum. 18 x 5min subs. F5 set-up. The Ha regions are very clear. Some noise, but I love it.

Alexxx

 

[geoflewis]

1 hour ago, Astrosurf said:

Due to having to set up each time, and all the faffing about that causes, I don't have much time and don't get the best out of my Atik. I might get an hour's worth of Ha or L but then the colour is always the bit to suffer even with 2x2 binning as I run out of time. I don't trust my skill at setting up to do 30min subs. I do max 10 each. I love my 600D, even though I get red rings around the stars. Yes, the quality isn't so good, but I can just leave it running. I leave the darks for when I'm packing up and driving home (no heater on in car!). Works fine. Here's my Triangulum. 18 x 5min subs. F5 set-up. The Ha regions are very clear. Some noise, but I love it.

Alexxx

 

 

 

Hi Alexxx,

That's a very nice M33, please could you clarify whether it was taken with the 600D with or without Ha (clip) filter. I too have a (modded) 600D, but never saw that much Ha using it. Maybe the light pollution at my former suburban Surrey home was just too much; perhaps I should try the 600D again to compare with what I recently took with my new QSI583 mono... :-|

Regards, Geof

[John78]

First light - this is shot from indoors with the kid watching TV behind me through an open window, no polar alignment other than levelling the tripod and putting the north leg north.  

Shot straight over houses and straight over a sodium streetlight, red filter only - just checking plate-solving etc... is working (which it is)...  IC410 the only thing of interest at the minute in the FOV.

88 Lights 15sec, 5 darks, no flats, no bias - kit as detailed above.

[Stub Mandrel]

I've come to this one a bit late...

1 - Very nice picture Olly (but you don't take crap ones).

2 - You disn't include the saving up time.

3 - or the extra setup time

4 - or the getting eth experience to achieve these sort of results time

:-)

You asked for DSLR images for comparison, this is only 30 minutes and a DSLR in August warmth it's more than a bit noisy, but some nice yellow and blue stars. I don't know if the blue in the nebula is real or not:

 

[Scott]

On 11/22/2016 at 22:54, ChrisLX200 said:

Remember that for RGB (and thus OSC cameras) you really want a dark, moonless sky. If you have any light pollution it plays havoc with your raw data and can be very difficult to process effectively - colour bias/gradient is common and an utter pain to remove. The Moon only adds to your woes and reduces the number of possible nights you could be imaging (at its best anyway). Think about your local conditions before deciding..

ChrisH

the same can be said for rgb filters in a mono camera though  . I myself have a mono camera but my lp is not great so I'm pretty much only a NB imager. there are some brilliant dslr images on here. a few by yves spring to mind.

[ChrisLX200]

32 minutes ago, Scott said:

the same can be said for rgb filters in a mono camera though  . I myself have a mono camera but my lp is not great so I'm pretty much only a NB imager. there are some brilliant dslr images on here. a few by yves spring to mind.

At least with mono you get the choice - with OSC you'll be left twiddling your thumbs when the moon is up   There are some excellent DSLR images posted, from dark sky sites I'm guessing, UK suburban astro-imagers might not be so lucky (that includes me last time I tried!)

ChrisH

[Scott]

3 minutes ago, ChrisLX200 said:

At least with mono you get the choice - with OSC you'll be left twiddling your thumbs when the moon is up   There are some excellent DSLR images posted, from dark sky sites I'm guessing, UK suburban astro-imagers might not be so lucky (that includes me last time I tried!)

ChrisH

I agree entirely regarding NB being the way around lp and this is why I went for mono. My point was/is that if conditions aren't suitable for osc, they won't be right for lrbg either.

[ChrisLX200]

2 minutes ago, Scott said:

I agree entirely regarding NB being the way around lp and this is why I went for mono. My point was/is that if conditions aren't suitable for osc, they won't be right for lrbg either.

I know - but only up to a point. With mono I can choose when to collect my blue channel - at it's highest elevation for best effect, Green either side of that, with Red being least sensitive to atmospheric dimming. You can't do that with OSC.

 

[Tim]

A colour camera is faster and easier than using a mono, it's just that the results aren't usually as good. There are exceptions of course. 

Colour cameras aren't great in light polluted skies I find. At UK based star parties with a mono camera you run the risk of not enough dark sky time to gather all four bands of data, much better chance with a colour camera to get it in the bag.

In an ideal world a choice of cameras for the particular location, target, conditions and weather forecast and telescope would be available. This is kind of why I prefer the choice of mono and OSC in CCD's, and sold my kidneys to obtain a matched pair. Couldn't afford a matching OSC to go with the Atik 11000 though so had to settle for a full frame DSLR instead, which only cost 1/3 of my liver.

If I could just have one camera, it would be a mono, but they involve a lot more faffing about than a good old simple colour camera.

Mono camera =Faster and easier? No. Better? Yes.

[Tim]

5 hours ago, John78 said:

First light - this is shot from indoors.............. with the kid watching TV behind me..................... through an open window,....................... no polar alignment............... other than levelling the tripod and putting the north leg north.  

Shot straight over houses .........................and straight over a sodium streetlight,.................. r  IC410 the only thing of interest..............

88 Lights 15sec, 5 darks, no flats, no bias - kit as detailed above.

You really know how to sell it !

[ChrisLX200]

The comparison here is always for an RGB image to be the end result - well, the OSC by its very nature cannot easily do much else I suppose (you can add an Ha filter to OSC but it's terribly inefficient). A mono camera adds so much more flexibility - bi-colour images, LRGB (you can't get a proper luminance channel with OSC), and hi-res mono images themselves are beautiful to my eyes with many of my 'finished' projects being left as mono H-alpha. I've never owned a OSC camera, though I did borrow one for a short while years ago. I do have DSLRs but was never impressed by their performance when I tried astrophotography with them. I also don't see why it's so important to get a 'finished' image all in one session, I never do that.

These were a couple of my early DSLR adventures, some folk might consider these a success but I was never happy with them. A OSC camera was never going to get me any further forward.

[Stub Mandrel]

7 hours ago, ChrisLX200 said:

At least with mono you get the choice - with OSC you'll be left twiddling your thumbs when the moon is up   There are some excellent DSLR images posted, from dark sky sites I'm guessing, UK suburban astro-imagers might not be so lucky (that includes me last time I tried!)

ChrisH

I know my DSLR image above isn't the best, but it was taken in the Peak District, about Bortle 3 - but I'm no expert on judging sky darkness.

For comparison this one is 224 minutes of DSLR 'underneath the clear suburban skies' (probably about Bortle 4.5 while the nearby street lights are off):

[Astrosurf]

21 hours ago, geoflewis said:

 

Hi Alexxx,

That's a very nice M33, please could you clarify whether it was taken with the 600D with or without Ha (clip) filter. I too have a (modded) 600D, but never saw that much Ha using it. Maybe the light pollution at my former suburban Surrey home was just too much; perhaps I should try the 600D again to compare with what I recently took with my new QSI583 mono... :-|

Regards, Geof

Thank you! It was taken with the modded 600D and just an Astronomik EOS Clip-in LPF. It was taken at a dark site. My mod is a hot mirror removal where the anti-aliasing filter has been kept in place.

[Tim]

18 hours ago, ChrisLX200 said:

 I also don't see why it's so important to get a 'finished' image all in one session, I never do that.

At home I go for weeks or months on one target with the mono cameras, but at star parties, with typically short and far between clear patches I prefer to grab as much OSC data as possible.

Also, in remote locations, and campsites, my personal preference is for minimum technology to go wrong. Hence the 10 Micron for unguided images and no need for planetarium on the laptop. No filter wheel with the OSC. I've just upgraded my DSLR so that hopefully can go laptop free too, eventually.  I usually spend a month a year at dark sites, and this method has been born of untold wasted nights of frustration as things go wrong in the middle of a field!

But at home, in the obsy, the first time I used a mono camera (Starlight H9) I could hardly believe my eyes, my exact thoughts were "What on earth have I been wasting time with the DSLR and QHY8 for!!!"

Without mono + narrowband I would be limited to a few hours per year of useful skies from my home obsy.

[Tim]

For balance here's a shot from my colour 460ex, consisting of 24x10 mins at a dark site, a one night only image from 2013

NGC 206

And this one from 2014. However....at this star party I bought a Pentax 75 and used my mono 460 to grab a couple of frames with a Ha filter to go with my 150ED shots

http://astrob.in/127808/0/

[Tim]

Maybe of interest to casual readers, I just found a folder of single shot images from my Atik 460ex One Shot Colour at a dark site.

They are all single shots, uncalibrated, just debayered and processed as normal. They range in length from 5 to 30 minutes per exposure, the filename revealing the length. I think this demonstrates quite well that brighter DSO's make for better OSC/DSLR targets, with less noise, whereas the Horsehead (low in the sky here) and Pickerings Triangle exposures demonstrate the limitations.

[ollypenrice]

Tim, I didn't find my OSC Atik 4000 to be as fast as my mono. I did a magazine test years ago but imaged M42, where I found little to choose. However, on fainter targets I always found the mono faster. I can only reiterate the calculation: OSC captures at best a third of the light per pixel always. While shooting luminance you're catching all the light on all the pixels. That, to me, explains the difference I observed.

Olly

 

[Stub Mandrel]

25 minutes ago, ollypenrice said:

Tim, I didn't find my OSC Atik 4000 to be as fast as my mono. I did a magazine test years ago but imaged M42, where I found little to choose. However, on fainter targets I always found the mono faster. I can only reiterate the calculation: OSC captures at best a third of the light per pixel always. While shooting luminance you're catching all the light on all the pixels. That, to me, explains the difference I observed.

The 'dbayering a DSLR thread' is interesting. Now people are doing tighter comparative tests they are discovering that for LUM the loss of microlenses reduces sensitivity by about as much as removing the filters increases it. This does not apply as severely to narrowband such as Ha where four times as many pixels get the signal.

Obviously a custom mono camera has microlenses and no bayer filter, best of both worlds for sensitivity.

[John78]

Gathered some data last night with the ASI120MM and a 200mm SMC Takumar lens...  M33 40x30sec L, 10x30sec RGB so quite a short overall exposure, and short subs - I need more RGB data I think and the stars go a bit bloaty on the B and L channel, probably the lens.

Given this is my first ever LRGB image - I found the post processing workflow is pretty simple a few button presses in GIMP gets it sorted.  Data gathering I was quite surprised how much you need to adjust the focus between the colour separations and moving back and fro from a bright star to focus on is a bit of a faff, this tiny sensor is significantly more sensitive than my Canon 1000D.

So as a total noob - I don't think you can say post processing is hard, its easier to deal with than OSC images from my Canon.

M33 L2.TIF

[iapa]

On 22/11/2016 at 13:33, ollypenrice said:

If it's any consolation it's been bucketing down here for three days, Al! The sky will soon be empty, I hope!

Olly

I do not believe that I'd relish the prospect, let alone the actuality, of an empty sky. 

The purpose, of this hobby, is to record the various objects in the sky is it not?

[ollypenrice]

8 minutes ago, iapa said:

I do not believe that I'd relish the prospect, let alone the actuality, of an empty sky. 

The purpose, of this hobby, is to record the various objects in the sky is it not?

Indeed. A sky empty of contaminants, though, is to be desired! That's what we have tonight, I'm glad to say...

Olly

[iapa]

In which case I should express my wish in your success, whilst I continue to fantasize experiencing such conditions and bemoan the fact, ignoring the limited visibility due to the contaminates you mention, that the airspeed is such that it renders any attempts less than futile, and potentially life threatening; 140 lbs of tripods, mount and OTA smacking me in the head after being accelerated in a random direction by 60mpg wind gust is not going do my collimation any favours, nor my cranium. LOL.

In the mean time I will consider estimating a reasonable pixel size to match the 8" SCT with 0.63 focal reducer, that I can use with the other 'scopes as well, and gauge next spring purchase. Not too many high (>75%) multi mega pixel sensors with 10-12um pixels under £2k.