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02-21-2016, 02:27 AM   #1
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Astrophotography on a K50?

Hello so in an ironic twist, I bought the K50 for astrophotography in the first place largely because of the massive ISO setting (IK, IK, I've already figured out that was a stupid thing to base a first DSLR purchase on.) and now seeing as how it's actually supposed to be somewhat bad at low light I'm kind of stuck. On the one hand, I love this little beast, it's an amazing camera that I'm having a ton of fun with and I definitely won't sell/trade this till it's dead. HOWEVER, I did buy it for the purpose of astro and now I actually want to use it for that despite the low light problems.

I've searched barn door trackers, the GPS unit that fits in the hotshoe and read more than a few articles but I'm still somewhat conflicted on what to get. Should I just build a barn door tracker, skip the GPS unit, and go from there? If I get the GPS unit, how well will it work? I'm looking to eventually image nebulae and the like, deep sky objects, so should I go ahead and chip in a telescope too? What good telescopes have a few of you used? Or should I go a completely different route, skip using the K50 for astrophotography, buy a cheap canon and send it off to get the IR filter modified and run from there?

As you can see I have no idea what I'm doing so any help is seriously appreciated.

02-21-2016, 03:59 AM   #2
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Owning a K50 myself i certainly would not say its bad at low light at all - it beats the **** out of canons rebel / eos xxx cameras many of my friends and family own.

If you want to use it for astronomy purposes the most important thing is to lower your expectations, like with all similar cameras.
Barndor tracking or GPS / astrotracer will work fine for star fields and bright objects.
But unfortunately you can forget about nebulae completely because all consumer DSLRs do not have enough sensitivity in the important wavelengts.

For shooting nebulae get a dedicated astrocamera or modify a DSLR (remove the internal filter), get a fast and long enough lens like a 200mm f2.8 and find a solution to precisely track for at least two, better 20 minutes and learn to master astronomical image postprocessing.
And most important for nebulae: Have a really, really dark sky!

I would suggest starting with Andromeda, Plejades, Perseus double cluster and similar targets with a fast 50mm lens stopped down to 2.8 and astrotracer or barndor and learn about image stacking, dark, light and flat exposures. If you managed that to your satisfaction, think about spending more money and time shooting nebulae
02-21-2016, 05:23 AM   #3
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QuoteOriginally posted by Bewatek Quote
. . . But unfortunately you can forget about nebulae completely because all consumer DSLRs do not have enough sensitivity in the important wavelengts.

For shooting nebulae get a dedicated astrocamera or modify a DSLR (remove the internal filter) . . .
I don't know much about astrophotography, but I think you'd be hard-pressed to find a better combination of "cheap" and "low noise" right now than the K-50. The only way to get a significant reduction in noise from that camera is to go full-frame.
02-21-2016, 05:31 AM   #4
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QuoteOriginally posted by Bewatek Quote
Owning a K50 myself i certainly would not say its bad at low light at all - it beats the **** out of canons rebel / eos xxx cameras many of my friends and family own.

If you want to use it for astronomy purposes the most important thing is to lower your expectations, like with all similar cameras.
Barndor tracking or GPS / astrotracer will work fine for star fields and bright objects.
But unfortunately you can forget about nebulae completely because all consumer DSLRs do not have enough sensitivity in the important wavelengts.

For shooting nebulae get a dedicated astrocamera or modify a DSLR (remove the internal filter), get a fast and long enough lens like a 200mm f2.8 and find a solution to precisely track for at least two, better 20 minutes and learn to master astronomical image postprocessing.
And most important for nebulae: Have a really, really dark sky!

I would suggest starting with Andromeda, Plejades, Perseus double cluster and similar targets with a fast 50mm lens stopped down to 2.8 and astrotracer or barndor and learn about image stacking, dark, light and flat exposures. If you managed that to your satisfaction, think about spending more money and time shooting nebulae
Would a telescope help at all with nebulae? Attaching a filter or some such to bring out the right wavelengths?

02-21-2016, 06:05 AM   #5
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You can get an image of a nebula (not super massive without a telescope/t-mount) with a consumer zoom/tele-prime and a cheap tripod without any camera modifications on the k-50. The astrotracer is also limited in effective angle due to the sensor. If you go past a certain angle, the sensor won't be able to move for the tracker to adjust it. Tracker also works best with lenses 300mm or below.
02-21-2016, 06:23 AM   #6
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Read up on stacking, that is a workflow you will have to master which ever route you take.
02-21-2016, 06:32 AM - 1 Like   #7
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Manage your expections....

Of course ... Starting off you have no frame of reference and so managing expectations becomes a somewhat ethereal concept !
The K-50 will be able to capture nebula, but compared to a mod'ed camera the results will not be so good.


How good do you need?

A well made barn door tracker will work for you, but you will still need to go through the process of alignment every time you use it - That's one of the trickier things to master.
The O-GPS1 makes alignment easier for the beginner (no polar alignment required - Just a silly dance twisting your camera around!)


The following links helped me out when I started playing with Astro...


https://www.pentaxforums.com/forums/38-photographic-technique/263550-astrotra...out-field.html
https://www.pentaxforums.com/forums/38-photographic-technique/199177-astropho...cer-worth.html


There are others but being new here, I'm not sure if posting external links is frowned upon or not !


For the Northern Hemisphere (especially this time of year) the easiest to start off with would be M42 - Orion nebula It's easy to find, and produces a nice image.


Here's one for you to aim at ....


K-30 (pretty much the same as the K-50) + O-GPS1
800 ISO
Stacked for a total integration time of about 512secs. No stretching of curves or levels done on this image ('cos I'm terrible at that!) I did blend the centre of the cluster as it was blown out.


Grrr... Having trouble loading an image ( told you I was new here !)


Here's a flickr link that I hope is allowed and that works....
https://flic.kr/p/DMBNn2


Regards,
Michael.
02-21-2016, 07:24 AM - 1 Like   #8
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QuoteQuote:
I don't know much about astrophotography, but I think you'd be hard-pressed to find a better combination of "cheap" and "low noise" right now than the K-50. The only way to get a significant reduction in noise from that camera is to go full-frame.
Yes the K50 is excellent but thats not what its about. Full frame or a different camera with even lower noise than the K50 or even a camera with no noise at all would not help because all consumer cameras have an IR/IF filter that cuts out the non-visible or even some visible wavelengths. If you put in a lot of effort you maybe will get a faint purple glow from most nebulae.
Removing or replacing these filters is the key to nebulae photography.
Another problem will be long exposure noise. Even the K50 will become extremely noisy in a 600seconds exposure without active sensor cooling.
QuoteQuote:
Would a telescope help at all with nebulae? Attaching a filter or some such to bring out the right wavelengths?
Been down the same road. Unfortunately a telescope only makes it much worse for a beginner. Telescopes start at 400mm f5, many cheaper models are even 700mm f10 and above, good luck tracking those focal lengths for the needed exposure times. Just for an orientation i spend 1500$ and a lot of learning and DIY to track 200mm for 600 seconds with confidence.
Attaching a h-alpha filter for example means stacking filters. It helps by cutting out all non-nebulae wavelengths like light pollution but again the exposure times will get ridiculous. Its just a guess but the ~ 90minutes total i need with the filter removed at f2.8 for some decent exposure would expand to... i dont know, two days? Those filters are for filterless cameras only and help getting rid of light pollution or are used with monochrome cameras which are the way to go if you can afford it.

I really would like to encourage you to engage yourself in astrophotography but the no.1 lesson i learnt over the years is to start small and not to have hubble-like expectations. Astrophotography is a complex matter and nebulae are the most difficult targets.
Oh but i almost forgot - the Orion nebulae emits some visible light, you wont be able to see it in all its glory but its possible with a non-modded camera. If you manage to get an image of it with your K50 and lenses and have some fun or satisfaction doing it you can get deeper into the hobby.

I attached a picture of the California nebulae. Its far from perfect but its the result of years of learning and a my-girlfriend-would-kill-me-if-she-knew amount of money.
The California nebulae is probably the easiest, its big, its bright and it has low dynamic range, nontheless it took 3 hours of work outdoors and another 3 hours postprocessing
Its made of approx. 50 exposures total, 16x600seconds at f3.0 actual light exposures, 5x600 exposures for calculating long exposure noise, 16 1/4000s exposures to calculate readout noise and 16 exposures against a flatfield lightfoil for calculating lens errors like vignetting. Its processed with the free software IRIS 5.59.
Camera is DIY, sensor, shutter and processors from a Canon 1100D. Hated it for daylight shooting but unlike Pentax its built like pre-war farming machines which helps modding it. The low megapixel count also helps. The sensor is cooled to 20 degrees C below ambient by a watercooled peltier cooling to keep sensor heating = long exposure noise down. The internal filter is removed, a Astronomik CLS-CCD filter is attached in the lens mount to block light pollution, it helps a lot in spite of me living in the countryside.
The lens is a Canon 200mm 2.8 L ii with a precision focus rig attached. You can say a lot about Canon but they make some decent lenses too. Its also weather sealed.
Mount / tracking is a Sky-Watcher HEQ5 PRO Synscan controlled by SkyMap through a Poseidon POEQ5-USB adapter.
The required autoguiding / tracking controll ist done by an astrolumina ALccd5-II camera attached to a small and bright guiding scope, autoguiding software is PHD guiding.
Of course there are many more small devices and helpers (like a polar finding scope for polar aligning the mount, a two staged optical finder for star-aligning the mount and a lot of heaters (+0,X C above ambient) for the neverending fight against dew.
Long story short: Quick and dirty. It really is, compared to what other people do or what i would like to do.

But again, it all started with a used first Canon rebel / 300D, the kit lens and a cheap tripod

Edit: Michael2012 thats a great image and properly processed, it also shows both the K30/K50s quality and the general improvement in the last years. I could only dream about results like that just with my DSLR.
But the "red stuff" will be hard without modding

Attached Images
 

Last edited by Bewatek; 02-21-2016 at 07:41 AM.
02-21-2016, 08:26 AM   #9
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As others said, fow high ISO noise, the K-50 is as good as it gets in APS-C format.

QuoteQuote:
As you can see I have no idea what I'm doing so any help is seriously appreciated
Well, it certainly would helps if you knew what you want to do!


If you're really serious about astrophography, there's no way around the telescope route. But, as explained by Bewatel, this involves spending a decent amount of money and, more importanly, having the will to put a lot time to learn how to set things up and use them. Astrophography isn't exactly point and shoot and requires a lot of work and time to master before getting good results.

The O-GPS 1 isn't close to what you will get with a telescope but, as shown by Michael, could easily and rapidly get you very interesting results. This is also my experience with the O-GPS1: lot of fun, easy to set up and much cheaper than a telescope and accessories. It's great to begin with and see if you're really interested in this kind of photograophy. The O-GPS also is really useful for milky way shots with a wide angle. You can look here for some very good examples by Mike Oria (MikeSF on PF). A telescope will not be of any help for this kind of shots...
02-21-2016, 05:32 PM   #10
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QuoteOriginally posted by Bewatek Quote
Yes the K50 is excellent but thats not what its about. Full frame or a different camera with even lower noise than the K50 or even a camera with no noise at all would not help because all consumer cameras have an IR/IF filter that cuts out the non-visible or even some visible wavelengths. If you put in a lot of effort you maybe will get a faint purple glow from most nebulae.
Removing or replacing these filters is the key to nebulae photography.
Another problem will be long exposure noise. Even the K50 will become extremely noisy in a 600seconds exposure without active sensor cooling.


Been down the same road. Unfortunately a telescope only makes it much worse for a beginner. Telescopes start at 400mm f5, many cheaper models are even 700mm f10 and above, good luck tracking those focal lengths for the needed exposure times. Just for an orientation i spend 1500$ and a lot of learning and DIY to track 200mm for 600 seconds with confidence.
Attaching a h-alpha filter for example means stacking filters. It helps by cutting out all non-nebulae wavelengths like light pollution but again the exposure times will get ridiculous. Its just a guess but the ~ 90minutes total i need with the filter removed at f2.8 for some decent exposure would expand to... i dont know, two days? Those filters are for filterless cameras only and help getting rid of light pollution or are used with monochrome cameras which are the way to go if you can afford it.

I really would like to encourage you to engage yourself in astrophotography but the no.1 lesson i learnt over the years is to start small and not to have hubble-like expectations. Astrophotography is a complex matter and nebulae are the most difficult targets.
Oh but i almost forgot - the Orion nebulae emits some visible light, you wont be able to see it in all its glory but its possible with a non-modded camera. If you manage to get an image of it with your K50 and lenses and have some fun or satisfaction doing it you can get deeper into the hobby.

I attached a picture of the California nebulae. Its far from perfect but its the result of years of learning and a my-girlfriend-would-kill-me-if-she-knew amount of money.
The California nebulae is probably the easiest, its big, its bright and it has low dynamic range, nontheless it took 3 hours of work outdoors and another 3 hours postprocessing
Its made of approx. 50 exposures total, 16x600seconds at f3.0 actual light exposures, 5x600 exposures for calculating long exposure noise, 16 1/4000s exposures to calculate readout noise and 16 exposures against a flatfield lightfoil for calculating lens errors like vignetting. Its processed with the free software IRIS 5.59.
Camera is DIY, sensor, shutter and processors from a Canon 1100D. Hated it for daylight shooting but unlike Pentax its built like pre-war farming machines which helps modding it. The low megapixel count also helps. The sensor is cooled to 20 degrees C below ambient by a watercooled peltier cooling to keep sensor heating = long exposure noise down. The internal filter is removed, a Astronomik CLS-CCD filter is attached in the lens mount to block light pollution, it helps a lot in spite of me living in the countryside.
The lens is a Canon 200mm 2.8 L ii with a precision focus rig attached. You can say a lot about Canon but they make some decent lenses too. Its also weather sealed.
Mount / tracking is a Sky-Watcher HEQ5 PRO Synscan controlled by SkyMap through a Poseidon POEQ5-USB adapter.
The required autoguiding / tracking controll ist done by an astrolumina ALccd5-II camera attached to a small and bright guiding scope, autoguiding software is PHD guiding.
Of course there are many more small devices and helpers (like a polar finding scope for polar aligning the mount, a two staged optical finder for star-aligning the mount and a lot of heaters (+0,X C above ambient) for the neverending fight against dew.
Long story short: Quick and dirty. It really is, compared to what other people do or what i would like to do.

But again, it all started with a used first Canon rebel / 300D, the kit lens and a cheap tripod

Edit: Michael2012 thats a great image and properly processed, it also shows both the K30/K50s quality and the general improvement in the last years. I could only dream about results like that just with my DSLR.
But the "red stuff" will be hard without modding
How difficult in terms of getting the case off, resilience of the motherboard to accidental static electricity/damage, removing the filter, etc was it to mod your camera? Were there any tutorials/videos that you watched that really helped you to understand everything about replacing the filter, cooling the sensor, etc? I'm pretty confident I could open a used camera up and do it myself but I'm curious what your experience was with it. I noticed you said your camera is DIY, so you completely built a new camera/case using parts from the Canon?

Also I've heard good things about the astronomik filters, but do they only fit Canons or can they clip in to pentax cameras also? I am definitely interested in astro, like I said I bought the K50 specifically for it in the first place.

I imagine for right now I'll probably end up just getting the GPS unit and playing with that for a while and save up for a modded camera in the meantime.
02-22-2016, 04:02 AM   #11
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QuoteOriginally posted by Rai93 Quote
How difficult in terms of getting the case off, resilience of the motherboard to accidental static electricity/damage, removing the filter, etc was it to mod your camera? Were there any tutorials/videos that you watched that really helped you to understand everything about replacing the filter, cooling the sensor, etc? I'm pretty confident I could open a used camera up and do it myself but I'm curious what your experience was with it. I noticed you said your camera is DIY, so you completely built a new camera/case using parts from the Canon?

Also I've heard good things about the astronomik filters, but do they only fit Canons or can they clip in to pentax cameras also? I am definitely interested in astro, like I said I bought the K50 specifically for it in the first place.

I imagine for right now I'll probably end up just getting the GPS unit and playing with that for a while and save up for a modded camera in the meantime.
Back in the day i started with removing the internal filter of a canon eos 300D and putting it back together. There are numerous pages and even full manuals about it. Basically its about finding all screws, removing some ribbon cables and soldering off one metal sheet.
I paid zero attention to ESD.

After a while i became unhappy with the 300Ds low light performance and the long exposure sensor heating problem.

So i stripped a 1100D from its plastik case, removed the filter, attached a copper sheet to the back of the sensor to connect it with the cooling system and put the whole thing into a fitting universal electronics
case. Of course i installed ports for power and usb and sealed every possible gap with industrial silicone.
After some testing i had to open it up again to install a mirror chamber heater (+0.x C above ambient) against dew inside of it.
As far as i know my camera is quite unique, especially with the water-based second cooling stage


The astronomik clip in filter should fit in a pentax mount too, either you have to remove a bit of its frame or secure it somehow like with an additional frame glued in.

If you can manage to mod a K50 it will surely become a much better astrocamera than the canons but i dont think it is built that simple. I had no instructions for modding the 1100D but it was essentially still the same like the 300D.
For example the K50s metal frame and its image stabilisation system will become a problem. You may have to mechanically disable it and im not sure if the back of the sensor is just freely accessible like in the canons, if you want to mod it any further which i would strongly recommend. No cooling - no single exposures over ~ 60 seconds.


Edit:
http://dslrmodifications.com/
This is where i got the 300D modding manual and many ideas from.
Have not visitet gary honis pages in a long time, this must be a new domain, but it seems that the manuals and tutorials are still the same. They even have manuals for newer cameras and thoughts about cooling now.

Last edited by Bewatek; 02-22-2016 at 06:23 AM.
02-25-2016, 06:18 PM - 1 Like   #12
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1st step. Learn to use DeepSkyStacker. (what images you need to shoot)
2nd step. Learn how to navigate on the night sky (direction)
3rd step. Learn when to shoot the night sky. (day of month, time)
4th step. Learn where is the least lightpolution nearby. (place)
5th step. Grab few beers and let the k50 shoot 100-300 with interval.
PROFIT
https://scontent.fath2-1.fna.fbcdn.net/hphotos-xtf1/t31.0-8/q83/s960x960/122...74815368_o.jpg
02-25-2016, 06:25 PM   #13
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QuoteOriginally posted by insomniac Quote
1st step. Learn to use DeepSkyStacker. (what images you need to shoot)
2nd step. Learn how to navigate on the night sky (direction)
3rd step. Learn when to shoot the night sky. (day of month, time)
4th step. Learn where is the least lightpolution nearby. (place)
5th step. Grab few beers and let the k50 shoot 100-300 with interval.
PROFIT
https://scontent.fath2-1.fna.fbcdn.net/hphotos-xtf1/t31.0-8/q83/s960x960/122...74815368_o.jpg
How much of an interval?
02-26-2016, 03:22 AM   #14
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QuoteOriginally posted by insomniac Quote
1st step. Learn to use DeepSkyStacker. (what images you need to shoot)
Deep Sky tracker can be daunting when just starting off - There are so many things you can change within the process, and the program can crash a fair bit.
Whilst It does seem to be what a lot of people gravitate to as their free stacking solution, as a beginner who is not much further forward in the learning curve than the OP, I would actually recommend SEQUATOR instead as their stacking program.
It's a lot easier to get to grips with, has fewer actual stacking options, but they are described in layman's terms rather than "techno babble", and it even does a few things that DSS does not ! The lights and darks of the photo in my previous post were stacked using it.


It can be found here:- https://sites.google.com/site/sequatorglobal/


(I have no affiliation to the program or it's creator, just a happy user)


regards,
Michael.

Last edited by Michael2012; 02-26-2016 at 03:31 AM.
02-26-2016, 07:53 AM   #15
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QuoteOriginally posted by Rai93 Quote
How much of an interval?
3sec interval
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