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Danjc

Have I made a mistake going OSC, a few questions

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So despite advice especially from @Adam J and reading lots of posts giving very valid reasons for mono over osc I went with a ASI294MC- Pro. 

It doesn’t arrive till tomorrow but can you helpful people please help me make my mind up on which direction to go. 

Obviously you know what I have on route and the mono needs to be in the same price bracket and absolutely no more. I’m guessing as already suggested the asi183 pro is maybe the way to go. 

I also have a few questions to hopefully help me decide. 

What else would I need to get up and running apart from the camera LRGB filters and filter wheel ?

Is a LP filter necessary as I already have a 1.25” cls ccd ?   

Imaging on moonlit nights are any additional filters required  ?

If I managed to say imagine my LRGB data in one night but ran out of time for calibration frames I take it I could effectively power down carry the rig into the garage, place the cover over it all and do the calibration frames say in the afternoon ?

Would the asi183 pro be a good choice tor my SW ED80 with FF/FR in Bortle class 6 sky’s ? 

I would be using APT DSS.

i know there’s lots of questions but any help would be great as my brain has almost given up trying to make its mind up especially as I would hopefully be able to return the ASI294 if I choose to 😐

 

 

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Questions are scattered a bit there but I'll take a crack at answering. 

Here's my stuff: http://www.astrobin.com/users/gotak/ all with OSC cameras.  I image from the edge of a subburb of Toronto and I use a IDAS D1 filter to help cut down on LP.

I keep to OSC for the simplicity of setup and processing. You can play around with more processing option with mono but you'll pay the price in the additional complexity. For mono work you'll really want an auto focusing solution. Actually for OSC you might want that as well. 

Calibration frames can be taken anytime. Once you done it once you don't have to do it again that often except for flats. Even then you can sometime just reuse and clean up the one or two motes that moved.

If this is your first cooled cmos I don't see why you have to go mono. 

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Posted (edited)
1 hour ago, Danjc said:

So despite advice especially from @Adam J and reading lots of posts giving very valid reasons for mono over osc I went with a ASI294MC- Pro. 

It doesn’t arrive till tomorrow but can you helpful people please help me make my mind up on which direction to go. 

Obviously you know what I have on route and the mono needs to be in the same price bracket and absolutely no more. I’m guessing as already suggested the asi183 pro is maybe the way to go. 

I also have a few questions to hopefully help me decide. 

What else would I need to get up and running apart from the camera LRGB filters and filter wheel ?

Is a LP filter necessary as I already have a 1.25” cls ccd ?   

Imaging on moonlit nights are any additional filters required  ?

If I managed to say imagine my LRGB data in one night but ran out of time for calibration frames I take it I could effectively power down carry the rig into the garage, place the cover over it all and do the calibration frames say in the afternoon ?

Would the asi183 pro be a good choice tor my SW ED80 with FF/FR in Bortle class 6 sky’s ? 

I would be using APT DSS.

i know there’s lots of questions but any help would be great as my brain has almost given up trying to make its mind up especially as I would hopefully be able to return the ASI294 if I choose to 😐

 

 

As I seem to have given you cause for doubt ill try to address some of your questions.

I will start by saying that I will stand by my original advice that in a light polluted environment mono is best. Its best because you can use that 1.25inc CLS CCD LP filter as luminescence and then gather RGB allowing you to mitigate light pollution without messing with your color balance.

Using luminescence you will collect data about twice as fast as you would with the same chip in OSC.

You can also bin effectively and you will retain the full resolution when imaging using Narrowband filters as they will make use of all pixels and you wont lose OIII signal as it falls between the pass bands for Green and Blue.

I am in a Class 4/5 area and I would not be without my mono camera. I imaged with a cooled DSLR for a while while I was saving up for it but I am happy I waited.

The only way to effectively image on moonlit nights is to make use of a Ha filter and that will work best with a mono. You can use a Ha filter with OSC but it just wont be optimal and I would have to wonder why would you buy a new OSC and then immediately put a ha filter on it, that makes not sense.

In terms of suitability with your scope, start by looking here:

http://www.12dstring.me.uk/fovcalc.php

You will get 1 arc-second per pixel with the 0.85x reducer, that is within the recommended 1-2 arcsecond per pixel range. As such you will be aperture limited in terms of resolvable detail as the daws limit of the scope is around 1.6arcseconds. But as its a mono camera you can effectively software bin 2x2 to give you 2 arc-seconds per pixel and that is pretty much where I would want to be with your scope. The ASI1600mm pro would be a better option at that focal length as its a larger sensor and more optimally sized pixels meaning you would not need to bin, however its outside of your price range. So given the options available ASI294mc pro or ASI183mm pro I would go for the latter. 

With any set point cooled camera you can take your dark frames at any time even inside if in a dark room.

To get running without blowing the budget you would need a manual filter wheel (although a 5-position electronic wheel is not much more and much more user friendly) and a LRGB filter set. You can use your existing LP filter in place of the UV/IR cut. So CLS RGB as opposed to LRGB, if the CLS filter is the same brand as the LRGB set then you may not need to re-focus between filters. You would also need spacers to make up the correct back focus taking into account the 6.5mm for the camera and 20mm for a ASI wheel.

With less light pollution the ASI294mc pro is a great camera, one of the lowest read noise OSC avaliable.  You could chose to buy a STC Duo narrow band filter for use on emission nebula with the ASI294mc pro (although they are so expensive and still not as effective as separate narrow band filters!) The main issue is with Galaxy imaging as once you introduce a strong LP filter in front of an OSC you are damaging colour balance.

In my opinion the only real marks against the ASI183mm pro are that you need to take care with calibration (same with ASI294) and that in comparison to the 294 its a smaller sensor so you will have a smaller field of view and with the smaller pixels longer exposures (5mins or so) are advisable in comparison to the 294mc pro, with your scope I would also bin 2x2.

You dont have to go mono, OSC is less challenging in terms of calibration and integrating multiple channels, but if you really want top end results then mono is the way to go. So really this is a question of how seriously you are wanting to take the hobby and what results you will be happy with. There is no point in going mono if it sucks the enjoyment out of it for you, but if your like me then I would always be wanting to take the best images I can on my budget and am willing to work for it. The ASI294mc pro is not a huge mistake, its a great OSC if that is what your looking for in your imaging. Its just that with a little more effort in capture and processing the ASI183mm pro will deliver you a better quality image in your sky conditions.

My final advice is that given the time of year dont let a couple hundred pounds stand in the way, just save a tiny bit longer. Summer is not the best for astro imaging anyway and if you do decide to change the camera then its ok to change your mind,just dont forget the original reasons why you chose the ASI294mc pro in making that choice.

This chap is one of my favorite imagers and I follow him on astrobin. Most of his stuff is taken using the ASI183mm pro.

https://www.astrobin.com/users/GerminianiMaicon/

Above all stop stressing.

Adam

 

 

 

 

 

 

 

 

 

 

 

 

Edited by Adam J

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1 hour ago, cotak said:

Questions are scattered a bit there but I'll take a crack at answering. 

Here's my stuff: http://www.astrobin.com/users/gotak/ all with OSC cameras.  I image from the edge of a subburb of Toronto and I use a IDAS D1 filter to help cut down on LP.

I keep to OSC for the simplicity of setup and processing. You can play around with more processing option with mono but you'll pay the price in the additional complexity. For mono work you'll really want an auto focusing solution. Actually for OSC you might want that as well. 

Calibration frames can be taken anytime. Once you done it once you don't have to do it again that often except for flats. Even then you can sometime just reuse and clean up the one or two motes that moved.

If this is your first cooled cmos I don't see why you have to go mono. 

Your points are valid, OSC is less effort in capture and requires less experience in processing, but I dont see why you would want an auto focuser. I have dont have one.

You dont have to go mono, but it will perform better, especially in light polluted conditions.

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1 hour ago, Adam J said:

Your points are valid, OSC is less effort in capture and requires less experience in processing, but I dont see why you would want an auto focuser. I have dont have one.

You dont have to go mono, but it will perform better, especially in light polluted conditions.

Auto focus for me is necessary as the temps can change by a fair bit even in an hour, with my edge 8 that means a detectable change in star size even with just 1C change. The other thing is I image whatever the weather which means I have done sessions more than a few times in sub -20C weather. One's not so interested in fiddling with focus manually when it's that cold.

With mono many people find that focus changes with different filters so if you want to tightest stars and no need to manually intervene overnight, it's a nice to have.

 

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Thanks @Adam J for taking the time to write that you have pretty much helped me make my mind up to go mono. 

I returned to this hobby recently as I missed it so much so I’m definitely in it for the long haul and one of the things I love about it is (others might not) I enjoy the learning curve, effort and research involved in moving my knowledge and ability forward. 

As I already have the 1.25” cls ccd I can just go ahead and start capturing images all be it with limited time this time of year. 

I can add the necessary LRGB filters and wheel over the next couple of months ready for the darker nights. 

I am maybe stressing a bit but this is my opportunity to get it right and really don’t want to think..... I wish I had gone mono !

now to contact FLO and hopefully get an exchange. 

More questions are probably on the way 😁

cheers, Dan. 

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8 hours ago, cotak said:

Auto focus for me is necessary as the temps can change by a fair bit even in an hour, with my edge 8 that means a detectable change in star size even with just 1C change. The other thing is I image whatever the weather which means I have done sessions more than a few times in sub -20C weather. One's not so interested in fiddling with focus manually when it's that cold.

With mono many people find that focus changes with different filters so if you want to tightest stars and no need to manually intervene overnight, it's a nice to have.

 

Understood, but I dont think it will be much of an issue with the OPs 80mm F6.3 refactor. 

With mono you can chose to refocus per filter, with OSC you dont have the ability to refocus for each wavelength as such not refocusing a Mono camera will deliver similar results to the OSC. 

The most important thing to focus on with mono is the lum filter as that determines the sharpness of the image, RGB filters just add a colour layer. 

 

 

 

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Posted (edited)
4 hours ago, Danjc said:

Thanks @Adam J for taking the time to write that you have pretty much helped me make my mind up to go mono. 

I returned to this hobby recently as I missed it so much so I’m definitely in it for the long haul and one of the things I love about it is (others might not) I enjoy the learning curve, effort and research involved in moving my knowledge and ability forward. 

As I already have the 1.25” cls ccd I can just go ahead and start capturing images all be it with limited time this time of year. 

I can add the necessary LRGB filters and wheel over the next couple of months ready for the darker nights. 

I am maybe stressing a bit but this is my opportunity to get it right and really don’t want to think..... I wish I had gone mono !

now to contact FLO and hopefully get an exchange. 

More questions are probably on the way 😁

cheers, Dan. 

I would think that FLO will sort you out especially as you have not even opened the box. 

Consider a Ha filter too when you can afford one. You will still need something to hold that 1.25 inch filter in as the camera wil connect to your corrector via T2 threaded extenders. You need to keep the FF/FR to sensor spacing at 55mm for it to work. 

Adam 

Edited by Adam J
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I would always prefer mono as it is so much more versatile insomuch as you can do narrowband whereas with OSC its really only broadband and with a bayer matrix it will be less sensitive.

I did buy a OSC once to try to save on time, but found it funnily enough far more complicated to process due to the bayer matrox settings so gave it up and stuck to mono.

Glad you are changing your mind, it is more expensive with all the "bits" and there is a bit of a learning curve to combine data (I have some You tube tutorials on this) but worth it in the end.  Some targets really show off at their best in narrowband.

Carole 

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I have emailed FLO and awaiting a reply but I’m sure it should be ok 🤞🏻

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FLO are normally extremely helpful and co-operative.  I am sure it will be fine.

Carole 

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Note that the 183 comes with a filter holder -- at least mine did! -- that threads into the interior of the adapter rings, so that you can mount a 1.25" filter without going out and buying anything else. I didn't think I'd be very happy with black and white imaging but I've been pretty happy with some of the stuff I've been able to pull off in my (red zone) back yard with a 183MM and the ZWO Ha filter. (Yes, it's RIck's Horse again. What can I say, it's my favorite image so far. 🙂 ) 

 

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20 hours ago, carastro said:

FLO are normally extremely helpful and co-operative.  I am sure it will be fine.

Carole 

They have been great, as they always seem to be 👍🏻

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Posted (edited)

Don't forget, mono doesn't always mean black and white ...

Various Photoshop methods of false colour can be used.

45 minutes in  90 second subs bottle 6 Ha filter mono.

I've dreaded (although understood the pros of mono) but am so glad I with it. This is easily the best image I have taken and only just started getting to grips with the new camera.

Good luck with your choice.

 

PSX_20190414_155456.jpg

Edited by knobby
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1 hour ago, knobby said:

Don't forget, mono doesn't always mean black and white ...

Various Photoshop methods of false colour can be used.

45 minutes in  90 second subs bottle 6 Ha filter mono.

I've dreaded (although understood the pros of mono) but am so glad I with it. This is easily the best image I have taken and only just started getting to grips with the new camera.

Good luck with your choice.

 

PSX_20190414_155456.jpg

Lovely image, did you take this with your asi1600. ?

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On 17/05/2019 at 00:09, cotak said:

For mono work you'll really want an auto focusing solution. Actually for OSC you might want that as well. 

 

Focus can drift on any telescope so reliable autofocus saves effort once you've got it working. Personally I focus manually but I'm old fashioned.

However,  I don't believe non-parfocality in mono systems comes from the filters but from the optics, so a mono allows you to refocus per colour if you wish while an OSC does not. As has been suggested already, in mono imaging the filter needing perfect focus is luminance (and any NB you shoot.)

OSC is slower than mono because it cannot shoot luminance, which is catching R, G and B simultaneously so is extremely fast, and objects which are strong in Ha build efficiently in a mono rig.

Like Carole I found OSC data to be rather difficult to process to any kind of good standard. Certainly harder than LRGB. Making an RGB in AstroArt goes like this:

1) Stack the R,G and B separately and have them open. 2) Use auto-align to align them in one click. 3) Use Trichromy, click auto white balance and auto colour balance and say Go. If this takes a minute I'd be surprised.

Olly

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2 hours ago, Danjc said:

Lovely image, did you take this with your asi1600. ?

Cheers, yes the ASI 1600 mm ... Mono beginners luck !

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Looks like you've made your decision and hopefully you can get that mono! OSC is fine and you'd no doubt get great images, especially with the 294MC,  but just for what it's worth, I went through the same dilemma and ended up going mono. To put it short I couldn't be happier. 

I have a 1600MM-pro and recently upgraded from my 150PDS to a WO GT81-ii and I'm now considering the 183MM for a smaller field of view. Your ED80 will do well with it :)

 

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Well the ASI294MC- Pro is on route back to FLO HQ hopefully it gets there all ok. 

Then all being well a ASI 183MM-PRO should be heading back in my direction 😁

Bring on the steep learning curve and say goodbye to my last saleable body part to fund filters etc. 

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Posted (edited)

I don't think you'll be sorry. The 183 demands a slightly higher game than, say, the 1600, but I can't say enough good things about mine. You probably always already process with darks, but you will never process again without them, tell you that for free -- the amp glow on the thing is pretty stark. When you look at your first light and scream "AAAAA, WHO'S SHINING FLASHLIGHTS ON THE SIDE OF MY SENSOR?!!" just breathe and repeat The 183 Mantra:

  It calibrates out.

  It calibrates out.

  It calibrates out.

But you certainly do want darks at exactly that gain, temp, and exposure!

Edited by rickwayne
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Posted (edited)
6 hours ago, rickwayne said:

I don't think you'll be sorry. The 183 demands a slightly higher game than, say, the 1600, but I can't say enough good things about mine. You probably always already process with darks, but you will never process again without them, tell you that for free -- the amp glow on the thing is pretty stark. When you look at your first light and scream "AAAAA, WHO'S SHINING FLASHLIGHTS ON THE SIDE OF MY SENSOR?!!" just breathe and repeat The 183 Mantra:

  It calibrates out.

  It calibrates out.

  It calibrates out.

But you certainly do want darks at exactly that gain, temp, and exposure!

Exact Same amp glow pattern on the asi294mc pro so that would have been something he would have needed to deal with anyway. But yes...take darks, flats and dark flats. Don't use bias and don't use dark frame optimization. 

I recommend 2x2 bin at his focal length so guiding won't be too tough.

Edited by Adam J
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6 hours ago, rickwayne said:

 just breathe and repeat The 183 Mantra:

  It calibrates out.

  It calibrates out.

  It calibrates out.

But you certainly do want darks at exactly that gain, temp, and exposure!

My Mantra is ,

No califrames, No Califrames, No Califrames. go away amp glow :) . Dont ask me why , this is humming in my head every time i start processing, may be cos Im lazy.

 

ASI294MC PRO  + Takumar 135 mm lens . HA /OXY injected to OSC. No Califrames🤩

Takumar 135 mm lens makes halos around bright stars.Stars r not round my laziness with guiding.(used previous night caliberation )

But was fun fiddling around with this OSC camera.

CS

Rush

HALRGB.jpg.55ce8e617a4ce49c5f04dcc97c46ad7e.jpg

HOOSC.jpg.2f141a79f7a5b77c95703da1bb4beba9.jpg

 

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So after posting on Monday guaranteed 1pm next day but absolutely no tracking details for 24hours it has all of a sudden reached Exeter 👍🏻

No my slight panic is over I could do with some info re settings to get me just up and running. No LRGB filters yet just a 1.25” CLS CCD, APT and DSS. I’m sure there’s a wealth of information out there but need a dummies guide to mono imaging 😁. With the dslr I knew what was what but this is a different beast !

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Posted (edited)

Can't advise on a CMOS camera settings or length of exposures.  But basically you will want for broadband targets to use LRGB.  Luminance will be the most important filter for detail as it is the most sensitive.  RGB is simply used for colour.  I always do much more and longer exposures for Luminance. 

If you are doing Narrowband, you will need Ha, Oiii and Sii (some people also use Nitrogen but I have never used one of these).  

In the case of narrowband it does tend to depend on the target as generally the most detail comes from the Ha so here again I do the longest and most exposures.   In NB you can combine the filter in a variety of ways.

1. Hydrogen (as Red), Oxygen (as green), Sulphur (as Blue)  HOS

2. Hubble palette Sulphur (as Red), Hydrogen (as green), Oxygen (as Blue)  SHO

3. there are some targets with very little Sii so you can do bicolour HOO, and some targets with very little Oiii, so you can do HSS.

Additionally some LRGB target will benefit from extra Ha, but maybe get to grips with the basics first.

You will need software which will register the various stacked filters so they will exactly fit each other (I think that was my biggest obstacle when i first started Mono imaging).  I believe Pixinsight, APP, Registar and Maxim all do this.

I have made a few videos on You tube on combining filters:

Adding Luminance to RGB

HTH

Carole 

 

Edited by carastro
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Posted (edited)

And if you want a simpler life you can go with so-called "bicolor" imaging, with just the two brightest wavelengths (for emission nebulae, H-alpha and O-III). Some folks create a synthetic green channel by mixing the H-alpha and O-III, some just let its bicolor freak flag fly.

There is an excellent reference on Cloudy Nights on initial settings for the ASI 183: https://www.cloudynights.com/topic/616524-sub-exposure-tables-for-the-zwo-asi183mm-and-qhy183m-and-colour-versions/. If you're running with just a light-pollution filter, use the "Broadband" category. Don't sweat the sky-brightness criteria too much, you'll probably wind up changing from that initial exposure anyway. This is just a recommended starting point.

Oh, and flats: Unless you're some sort of luck genius, the filter sitting so close to the imaging sensor is just a haven for little dust motes. I never appreciated the ultrasonic cleaning feature of my DSLR so much until I had to live without it. The point about sensor proximity is that the shadows' circles of confusion are actually small enough to be visible when you stretch the image (unlike those of dust on the objective lens). You won't see it in an unstretched sub-exposure, but my stretched subs often look as if my imaging train has come down with measles.

So you want to shoot flats. Calibrates right out. 🙂

 

PS: Speaking of registering R/G/B  or H-a/O-III/whatever: Siril also does a pretty decent job there. I'm super-impressed that carastro can get Photoshop to work for that, in my experience it sucks at that task. Seriously, I will never even bother trying PS for that purpose ever again. Astro Pixel Processor is absolutely outstanding.

Edited by rickwayne
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