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JGM1971

The "No EQ" DSO Challenge!

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Welcome to SGL, and I'm pleased that you find it to your liking.

Well that's a very good start to your imaging, well done. Am I right in saying that the XA-1 has a conventional Bayer filter array, rather than the Fuji X-Trans? If so, then that will allow software like DSS to work as it should. I have the Fuji XT-1, which has the X-Trans array, and that adds complication. But if yours is anything like mine, then it will have a decent deep red response so will be reasonably sensitive to the H-alpha light.

You will find that the more subs you take, the lower the noise levels. You will see from this thread that 100 or 200 or even more short exposure subs are routinely taken. Of course, it doesn't help having a light polluted sky. You may also find that doing darks with a non-temperature controlled camera can introduce more noise, and if you do them you need a decent number. Incidentally, what ISO value are you using?

Ian

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Yes, you are right, the Fujifilm X-A1 has a conventional Bayer filter array. I have bought this camera second hand at a very nice price of $150, lens included and decided to give it a try with astrophotography. So far, I like what it can show. I think I will stay with Fuji X-A1 for now. 

I do not have with me the raw files, but if I remember corectly, the ISO value I have used was 3200.

Cezar

Edited by antaeus

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19 hours ago, antaeus said:

the ISO value I have used was 3200

May be that's a bit too high. If you look here you'll see that there is some indication that gain ceases to be analogue above about ISO1600 with the X-T1, and a little higher with the X-A1. You need to avoid getting into the digital gain region for astrophotography. I generally used ISO 1600 with mine, though when I had bright stars in the field and I wanted to minimize the degree to which they were over exposed, I dropped it down to ISO400. A high ISO, contrary to what it may seem, just amplifies the noise as well, so as long as your histogram is well off the bottom of the range you should be exceeding the read noise, and there is nothing to be gained by increasing the ISO. At least, that's my take on it.

Ian

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1 hour ago, The Admiral said:

 I generally used ISO 1600 with mine, though when I had bright stars in the field and I wanted to minimize the degree to which they were over exposed, I dropped it down to ISO400. 

Thank you Ian. As soon as I will have clear skies, I will make some tests with ISO 400/800/1600.  I was afraid that my CLS filter will cut too much from luminosity.

What I wanted to try also, is increasing the distance between the focal reducer and the camera sensor.(I have ordered some T2 spacers for that). I have made some measurements and my current reducing is f/6.1. I do not know how much the improvement will be on image quality, but I have found this  discussion here about combining focal reducers. 

Cezar

Edited by antaeus

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Cheated a bit on this . I used a healing tool for the core in free photo shop app on android.  It was blinding.  28 30 second exposures , 20 darks and flats.  Wo72mm megrez,  asi294mc, nexstar evolution  mount  . Stacked and stretched in sharpcap,  tweaked in gimp and photoshop  express. 

PSX_20190212_183931.jpg

Edited by Manners2020
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6 hours ago, Manners2020 said:

Cheated a bit on this . I used a healing tool for the core in free photo shop app on android.  It was blinding.  28 30 second exposures , 20 darks and flats.  Wo72mm megrez,  asi294mc, nexstar evolution  mount  . Stacked and stretched in sharpcap,  tweaked in gimp and photoshop  express. 

PSX_20190212_183931.jpg

Superb. Wouldn't look out of place on the 'proper' imaging forum. Give it a few years and I really think cameras will be sensitive enough to mean an EQ mount isn't required.

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Cheers jim, I've flirted with the idea of an eq  mount from time to time but I really like the ease of my set up and where I can set it up.  I dont think I'll ever bother to be honest. If I decide in the future I want to spend a couple more k on equipment  I think I'd rather spend it on one of those rasa  8's than a mount.  That's  my dream scope right now.  And yes the camera's  are amazing right now, it'll  be interesting  to see what's out there in a few years.

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Finally some clear skies here in Bavaria! I wanted to test my new Sky-Watcher AZ-GTi and see what it can do with deep-sky imaging. I'm quite pleased with the result, considering it's a quick & dirty test! :) 

Final_v01.thumb.jpg.547987ccdb9b07708a5a8879bff8c514.jpg

Sky-Watcher AZ-GTi, Fujifilm X-T1, Pentax Super Takumar 200mm f/4 (stopped down @ 37mm), IDAS LPS D1.

About 50x30s subs @ISO 1600 et ISO 800, no dark, no flat. Stacked in DSS, processing in Photoshop. I cropped about 50% of the image to get rid of the heavy vignetting. 

Here's a pic of my tiny setup! The courtyard of my building isn't so bad, actually, and there's almost no light coming from the street. Apart from when someone goes to the trash, in which case it's the apocalypse. I think a couple neighbours wondered why there's a dude hiding in the bushes with a camera at night...

10a75a0e-3621-43b8-96bb-31f9491b021e.thumb.jpeg.4ddf2a3f7a26a5edec21cafc9d6bce46.jpeg

Edited by Space Oddities
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10 hours ago, Space Oddities said:

Finally some clear skies here in Bavaria! I wanted to test my new Sky-Watcher AZ-GTi and see what it can do with deep-sky imaging. I'm quite pleased with the result, considering it's a quick & dirty test! :)

Well that's come out rather well! Nice round stars, and good that an X-T1 has been used! What ISO did you use, and what processing software? Your background looks a little black, and if you could make it a fraction lighter you might reveal more nebulosity, and more noise of course ;<)

Ian

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1 hour ago, The Admiral said:

Well that's come out rather well! Nice round stars, and good that an X-T1 has been used! What ISO did you use, and what processing software? Your background looks a little black, and if you could make it a fraction lighter you might reveal more nebulosity, and more noise of course ;<)

Ian

Thanks Ian! 

I used 2/3 at ISO 1600 and 1/3 at ISO 800. I wanted to see if slightly underexposed subs could help, the stars being very bright. 

The processing was very quick and very dirty, in DSS and Photoshop. 

I'm reprocessing the picture now, with flats taken this morning, as well as older darks that should help reduce the noise (which is indeed the reason why the background is very dark, the noise was too heavy). And I'm using a different computer, with the "hasta la vista green" Photoshop plugin, which should help get rid of that green haze I had! Let's see how it goes :) 

As for the round stars, that's thanks to the step down filter! On my previous attempts with this lens, the stars were quite ugly, with diffraction spikes. I read that a step down filter could help! And luckily, the one I have fits perfectly within the rear part of the lens hood. The resulting aperture is somewhere near f/5.4 (200mm / 37mm) :) 

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15 minutes ago, Space Oddities said:

I used 2/3 at ISO 1600 and 1/3 at ISO 800.

When I imaged M45 I used ISO400. No colour in the brightest stars though. I couldn't make DSS work with my Fuji RAFs without converting them to DNG, but I switched to Astroart and it ceased to be a problem. Technically, though, the non-Bayer array of the X-Trans does cause potential issues with processing, but I've not found it to make a noticeable difference, to my relatively untrained eye.

Be careful with darks though, as they need to be taken at the same temperature as when you were imaging. And if you do them, do a good number. If neither of that can be attained they can add more noise to the image rather than reduce it. There is a school of thought with DSLRs, because they are not temperature controlled, that better results can be obtained by substituting bias frames (or a previously produced generic bias) in place of the darks. That may not be practical where there is significant amp glow, because the bias won't compensate for that, though I've not found that to be a problem with these short exposures. That's what I do and it seems to work. It's easy to do with Astroart, but I think in DSS you'd need to re-name the bias frames if you want to substitute them for the darks, because DSS won't accept identical file names, IIRC.

Ian

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I copy and rename the bias master and use that as a dark. Dark flats I do find help as well as flats.

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Thanks! Indeed, I still get a lot of noise with my older darks. Outside temperature was similar, but I guess they're still too different to be useful. Oh well, that was a quick and dirty session anyway, so there's nothing I can do! :) 

Regarding Fuji RAF files, it's indeed quite a pain to process... I convert them to TIFF, but that takes a lot of space. Anyway, I just bought a used X-A3, which is more of an entry-level camera, but unlike the X-T1, it has a 24 mpix Bayer sensor. And for astro, you don't need the better autofocus or fancy features of the X-T1. I figured it should be a better option for astro, and I'm thinking of getting it modified soon :) 

I thought about a cooled camera, but it's much more expensive and you need to carry along a laptop and a 12v battery... Right now, I value portability more than image quality. And I think it would be too soon, I still have a lot to learn before switching to a more complex setup! 

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57 minutes ago, Space Oddities said:

Regarding Fuji RAF files, it's indeed quite a pain to process... I convert them to TIFF, but that takes a lot of space. Anyway, I just bought a used X-A3, which is more of an entry-level camera, but unlike the X-T1, it has a 24 mpix Bayer sensor.

Personally, I'd be inclined to convert them to DNGs using the free Adobe DNG converter. I would imagine that converting to TIFFs would involve a non-linear transfer curve, which can be a problem with subsequent processing. Yup, storage can be an issue! Astroart sorted that one though.

I had myself wondered about the X-A series; should be fine. I've always regarded the red response of the Fuji sensors to be quite good, and I don't know how much you'd gain by conversion. If you check out my album there is an image of the Horse's Head nebula, and that shows a decent amount of H-alpha. Certainly see how the X-A3 performs in that regard before spending money. The photons to photos site shows a slightly different noise curve (http://www.photonstophotos.net/Charts/RN_ADU.htm#FujiFilm X-A3_14), but it is still nice and linear.

Ian

Edited by The Admiral

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Thanks Ian for the tips! :) I haven't noticed anything wrong with the processing of TIFF files, but I should give it a try with this DNG converter and see if that produces a better result. 

Regarding the HA response of Fuji cameras, I've heard many people saying it's actually quite good as well. I also found these curves, for the older X-Pro1 (which uses the IMX071 sensor), which are much better at 650nm than other cameras, like the Canon 550D. Which confirms what people said! See the whole test here.

However the X-A3 has a different sensor, so perhaps the response to Ha is different. That's on my list of things to test! :) 

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5 hours ago, Space Oddities said:

X-A3 has a different sensor, so perhaps the response to Ha is different

Yes, indeed that would be interesting to check out.

I assume that the X-A3 has no anti-aliasing filter in front of the sensor, like the X-T1. That is something I believe helps enormously in astro-imaging, and I've never been dissatisfied with the acuity of my images.

Ian

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Today I've decided I won't bother again with the Q200 the mount can't manage any more that 15 seconds with it and to get good star shapes it needs to be stopped to f8! So 85mm lens is my more reliable and I've a 135mm Helios as well.

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15 hours ago, Space Oddities said:

I thought about a cooled camera, but it's much more expensive and you need to carry along a laptop and a 12v battery... Right now, I value portability more than image quality. And I think it would be too soon, I still have a lot to learn before switching to a more complex setup! 

My thoughts exactly. I also wanted to buy a cooled camera, but changed my mind for the same reasons. I do not want to mod my Fuji X-A1. For the moment, I like how it performs. 

On 20/02/2019 at 18:54, The Admiral said:

May be that's a bit too high. If you look here you'll see that there is some indication that gain ceases to be analogue above about ISO1600 with the X-T1, and a little higher with the X-A1. 

In the graphic you linked, the X-A1 is starting with read noise from lower values than X-T1. Can you tell me please, that means for the same ISO, X-A1 will show less noise? 

Cezar 

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On 28/03/2015 at 00:03, AlphaOrionis said:

This thread needs to keep on living! I'm going to be buying my first Astrophotography setup soon and I really dont want to lug around a huge EQ6 wiht the weights. Im looking at an Orion ED80 or Explore Scientific ED80 and these posts are helping me consider which mount would be best for a grab and go setup!

Alpha

I have a SW ED80 on a EQ5 mount

Light and easy to transport, and use a single half size weight

Shown with solar filter

John

 

 

Skywatcher ED80.jpg

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5 hours ago, antaeus said:

In the graphic you linked, the X-A1 is starting with read noise from lower values than X-T1. Can you tell me please, that means for the same ISO, X-A1 will show less noise? 

To be honest, I don't know! I was wondering too, but the site does warn that the data for different cameras shouldn't be compared.

Ian

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On 24/02/2019 at 21:15, Space Oddities said:

Finally some clear skies here in Bavaria! I wanted to test my new Sky-Watcher AZ-GTi and see what it can do with deep-sky imaging. I'm quite pleased with the result, considering it's a quick & dirty test! :) 

 

Sky-Watcher AZ-GTi, Fujifilm X-T1, Pentax Super Takumar 200mm f/4 (stopped down @ 37mm), IDAS LPS D1.

About 50x30s subs @ISO 1600 et ISO 800, no dark, no flat. Stacked in DSS, processing in Photoshop. I cropped about 50% of the image to get rid of the heavy vignetting. 

Here's a pic of my tiny setup! The courtyard of my building isn't so bad, actually, and there's almost no light coming from the street. Apart from when someone goes to the trash, in which case it's the apocalypse. I think a couple neighbours wondered why there's a dude hiding in the bushes with a camera at night...

 

I've just bought that exact lens for £40 off ebay, yet to try it out but that image is fantastic! I'll be using mine with a cheapo SLT mount and inferior 1300d (which I'll be modding) but 30s at that focal length should be do-able. I've seen a few posts where shooting at f/4 isn't that great and you don't like the resulting stars (I love diffraction spikes personally ;) ). Was there much CA to deal with in processing?

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39 minutes ago, jimbo747 said:

I've just bought that exact lens for £40 off ebay, yet to try it out but that image is fantastic! I'll be using mine with a cheapo SLT mount and inferior 1300d (which I'll be modding) but 30s at that focal length should be do-able. I've seen a few posts where shooting at f/4 isn't that great and you don't like the resulting stars (I love diffraction spikes personally ;) ). Was there much CA to deal with in processing?

Yes, there is a bot of CA with this lens wide open. I think it's better when stopped down at f/5.6. I shot this one at f/4, but with the step-down ring in front of the lens. It worked really well for rounder stars, but doesn't seem to reduce the CA. I'll try at f/5.6 with the step down ring next time, to see if it's better! :) Anyway, I think it's a very good lens, given the price!

 

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14 hours ago, The Admiral said:

Yes, indeed that would be interesting to check out.

I assume that the X-A3 has no anti-aliasing filter in front of the sensor, like the X-T1. That is something I believe helps enormously in astro-imaging, and I've never been dissatisfied with the acuity of my images.

Ian

I'm not sure. The X-Trans sensor eliminates the need of an AA filter, so none of these camera have one, but according to this site, the X-A3 (which uses a Bayer sensor) has an AA filter.

I hesitated between several models, and ended up using DPReview's comparison tool to see how they perform at standard astro-ISO (800-1600). It's very interesting because the Bayer models (X-A) are noisier than the regular X-Trans models (X-T, X-M, X-E, X-Pro...). At very high ISO (6400), the noise is quite visible on both, but the X-Trans shows a much more pleasing "grain" effect than the Bayer sensors. I love this for daytime photography, and I'm not afraid of shooting at high ISO anymore :) 

However, the Bayer matrix is a much better match for astro work, especially when you can deal with the noise (darks, stacking). Processing X-Trans files adds a difficulty and requires much more storage space... A 16 mpix RAF file is about ~30 MB, while a TIFF is closer to ~90 MB, which quadruples the space needed if you want to keep both file types! 3

Anyway, I'll give it a try on emission nebulae and perhaps compare the 2 types of sensors :) I'd be curious to see how the smaller X-A performs! But I think it does great, I've seen lots of images with the X-A1 and they looked very good!

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Think this is my favourite  so far.  28x30 sec exposures  live stacked on sharpcap.  I cant remember  if I used darks for this as I've just found the data I did a bit ago that I thought was useless at the time.  Wo72mm megrez,  asi294, nexstar evolution mount,  0.8 reducer. Tweaked in gimp , snap seed and pc  express.

PSX_20190223_091449-02-02-01.jpeg

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This image is why I didn't  bother initially. I thought I'd  never get rid of all that red.

Stack_22frames_1730s.jpg

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