Imaging with the 130pds

[Susaron]

It´s been a long time since I did my last picture with the Sw130PDS. I switched temporarely to the ED72 for Winter big nebula season. Also the pinch problems and astigmatism put the SW130PDS aside. I did a huge overhaul to the scope, fitting finally an Arduino controlled focuser (that one from Bob Brown), and also I checked the position of the secondary.

Last Saturday though there were high clouds around Madrid, there was a cloudless window of 2hrs, so I tried something.

40x60s subs + darks + bias, SW130PDS+AZEQ5+QHY168C+Optolong L-Pro+ countless gadgets fitted around the scope.

M3 globular cluster.

[Major Canis]

@Uranium235 - You seem to be the SME on this. I've been using the 130PDS for imaging with a Canon 100D for a while a want to move to mono/narrowband imaging so I can actually get out more than once a decade. Considering my budget of around £1000, what would you propose? I've considered a few cameras in this range (the Hypercam 183M Pro Tec, ZWO 183MM pro and the QHY 174M) that all use the Sony IMX178 sensor but fear the pixel size might not be a good match for the optics. I see you've had some incredible results with the Atik 314L +, which although out of my price range Im wondering might be worth saving the extra dollar for. Is there anything in between the aforementioned cameras that warrant a look?

[Adam J]

13 minutes ago, Major Canis said:

@Uranium235 - You seem to be the SME on this. I've been using the 130PDS for imaging with a Canon 100D for a while a want to move to mono/narrowband imaging so I can actually get out more than once a decade. Considering my budget of around £1000, what would you propose? I've considered a few cameras in this range (the Hypercam 183M Pro Tec, ZWO 183MM pro and the QHY 174M) that all use the Sony IMX178 sensor but fear the pixel size might not be a good match for the optics. I see you've had some incredible results with the Atik 314L +, which although out of my price range Im wondering might be worth saving the extra dollar for. Is there anything in between the aforementioned cameras that warrant a look?

Ill keep this short and leave Uranium to answer as you directed the question at him, but ill correct you in that none of the cameras you listed use the IMX178 sensor. The Hypercam 183 and the ZWO ASI183mm pro both use the IMX 183 (no shock there) and the QHY174 uses the IMX174

In general the two things that are important in a dedicated DSO imaging camera are 1) Mono sensors and 2) Set point cooling. 

If you can afford it get a camera that offers both, if you have a lower budget get a camera that offers one or the other. 

But what you don't want to do is get a "dedicated" camera which has neither set point cooling or a mono sensor as you are no better off than a DSLR in my opinion. 

Adam

 

[Major Canis]

2 minutes ago, Adam J said:

Ill keep this short and leave Uranium to answer as you directed the question at him, but ill correct you in that none of the cameras you listed use the IMX178 sensor. The Hypercam 183 and the ZWO ASI183mm pro both use the IMX 183 (no shock there) and the QHY174 uses the IMX174

In general the two things that are important in a dedicated DSO imaging camera are 1) Mono sensors and 2) Set point cooling. 

If you can afford it get a camera that offers both, if you have a lower budget get a camera that offers one or the other. 

But what you don't want to do is get a "dedicated" camera which has neither set point cooling or a mono sensor as you are no better off than a DSLR in my opinion. 

Adam

 

My bad.  I think I have been staring at numbers too long and I've gone a bit mad (though looking at the model numbers it does kind of give away which sensor its using haha). Noticed that @Uranium235 isn't using the 314L either - Just spurting numbers now it would seem. Thanks for simplifying, though I do still worry somewhat about the pixel size/sample rate.

[Adam J]

34 minutes ago, Major Canis said:

My bad.  I think I have been staring at numbers too long and I've gone a bit mad (though looking at the model numbers it does kind of give away which sensor its using haha). Noticed that @Uranium235 isn't using the 314L either - Just spurting numbers now it would seem. Thanks for simplifying, though I do still worry somewhat about the pixel size/sample rate.

The 130PDS + IMX183 variant will resolve down to that level in terms of optical resolution, but the reality is that you will struggle to guide with sufficient accuracy and the seeing probably wont allow you to resolve anything to that accuracy even if you did have really good guiding. In essence when matched with a 130PDS the 183 is not going to do anything perticually well. The 178 will be better for small galaxies due to the 14bit A/D and the ASI1600mm pro or a KAF8300mono camera will be better for nebula work, I would not discard something like a 460EX either.  

That's not to say that a 183mm is a bad choice, its cheaper that the other options after all, its just probably not optimal with the 130PDS. 

Adam

[Uranium235]

On 16/04/2019 at 17:23, Adam J said:

 The 178 will be better for small galaxies due to the 14bit A/D and the ASI1600mm pro or a KAF8300mono camera will be better for nebula work, I would not discard something like a 460EX either.  

 

Exactly what I would have said

The 1600mm and KAF8300 have roughly the same sized sensors, so it should work (with a little tweaking to get the flattest field possible). The 1600 is cheaper, so that will allow extra headroom for a couple of filters etc if the budget is around 1k ish. Get a Ha filter first, that will do the most for you (well... in about 2 months when the MW swings back around). Even so, the resolution with the 1600 is 1.2" p/p - which is still pretty damn high, but not so high as to exceed the resolving power of the telescope aperture (~0.9").

The 178 is best used either as a galaxy buster on the 130, or if you want a larger FOV - mount it on something like a Samyang 135mm f2 or the 200mm Canon EF lens.

 

The 178 with a 135mm lens:

 

And the 178 with a 130pds:

Massively different FOV sizes there.

 

 

[al-alami]

I am sad to say that my 130pds has seen the last of it's imaging days.  I very strong gust of wind blew it and my mount (HEQ5 Pro) over.  The tube has got good selections of bends in it, and the focuser is a mess. ?

I took everything apart and rebuilt it, but it seems the metal under the focuser is so bent out of shape that the focuser doesn't sit right anymore. I won't even talk about the focuser needing a helping hand to focus properly, so focusing is a 2 handed process.

So basically it's easier and cheaper to buy a new one than to fix it. ? 

Unless someone has a used one they don't want any more!  

[Uranium235]

On 19/04/2019 at 00:10, al-alami said:

I am sad to say that my 130pds has seen the last of it's imaging days.  I very strong gust of wind blew it and my mount (HEQ5 Pro) over.  The tube has got good selections of bends in it, and the focuser is a mess. ?

I took everything apart and rebuilt it, but it seems the metal under the focuser is so bent out of shape that the focuser doesn't sit right anymore. I won't even talk about the focuser needing a helping hand to focus properly, so focusing is a 2 handed process.

So basically it's easier and cheaper to buy a new one than to fix it. ? 

Unless someone has a used one they don't want any more!  

Sounds awful mate.... that must have been some gust of wind! Ive never heard of an NEQ5 being blown over before.

To look on the bright side, the 130 isnt an expensive bit of kit to replace and your camera was not damaged. Just think what it would be like to have a nice APO and CCD camera hit the floor!... ouch!  

[al-alami]

9 minutes ago, Uranium235 said:

Sounds awful mate.... that must have been some gust of wind! Ive never heard of an NEQ5 being blown over before.

To look on the bright side, the 130 isnt an expensive bit of kit to replace and your camera was not damaged. Just think what it would be like to have a nice APO and CCD camera hit the floor!... ouch!  

Ohhhh I definitely would have been  .... well .. not in a good state.

I'm trying to decide if I want to get another 130 or move on.  Lets just say that it's quite a difficult decision.

And from now on, no matter what the weather is like, I will have sand bags on the tripod legs!!! 

[Adam J]

6 minutes ago, al-alami said:

Ohhhh I definitely would have been  .... well .. not in a good state.

I'm trying to decide if I want to get another 130 or move on.  Lets just say that it's quite a difficult decision.

And from now on, no matter what the weather is like, I will have sand bags on the tripod legs!!! 

wow I would not have thought it possible, was it a dust devil or something?

[al-alami]

6 minutes ago, Adam J said:

wow I would not have thought it possible, was it a dust devil or something?

Apparently the night we were hit with winds gusting at around 45 or 50km per hour. 

I tried rebuilding but the focuser is too messed up, and the metal under the focuser got really bent. So, collimation of the focuser is next to impossible. ?

Edited April 21, 2019 by al-alami

[Uranium235]

30 minutes ago, al-alami said:

Apparently the night we were hit with winds gusting at around 45 or 50km per hour. 

I tried rebuilding but the focuser is too messed up, and the metal under the focuser got really bent. So, collimation of the focuser is next to impossible. ?

Just had a bit of a brainwave..... in future get a couple of dumbell weights and hang (or place) them on the accessory try/leg spreader, that would provide a bit more protection.  Or maybe a way to anchor the tripod?

[al-alami]

1 minute ago, Uranium235 said:

Just had a bit of a brainwave..... in future get a couple of dumbell weights and hang them from the accessory try/leg spreader, that would provide a bit more protection.

Well, in addition to the sandbags, I ordered this funcky sand bag.

[Andywilliams]

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Posted 20 hours ago

Hi all,

Having read a fair bit of this thread and also being impressed by the quality of the images, I am very tempted to buy a 130 PDS and give it a crack !

A couple of questions though and I apologise in advance if these have already been asked ad nauseam.

I have enough money to invest in a HEQ5 pro. I also have enough to put my first steps into mono ccd imaging.

I don't have enough left over for the recommended 80mm esprit, so I thought I might have a go with this impressive scope.

1) I will need to saw off the focussing tube from the get go ? I find this a little bit scary.

2) do you need to do the sawing if you buy a 150 PDS?

3) this scope vs a 6 inch RC? any major differences? the thing putting me off the 6 inch RC is the reduced FOV. Is this necessarily an unsurmountable issue?

4) can you please recommend a ccd mono camera that will not under/over sample with this particular set up?

So many questions !!

Thankyou one and all and clear skies !

Andy

[Andywilliams]

Hi All,

Actually, ignore the RC question as I have now read and understood enough about focal length to see that this would be a bad idea !

I have also been looking at the GSO 150mm f4 scope. Does anyone have any experience or top tips on the GSO vs the SW 130 PDS ?

Clears skies all.

cheers,

Andy

[RolandKol]

1 hour ago, Andywilliams said:

• Hi all,

Having read a fair bit of this thread and also being impressed by the quality of the images, I am very tempted to buy a 130 PDS and give it a crack !

A couple of questions though and I apologise in advance if these have already been asked ad nauseam.

I have enough money to invest in a HEQ5 pro. I also have enough to put my first steps into mono ccd imaging.

I don't have enough left over for the recommended 80mm esprit, so I thought I might have a go with this impressive scope.

1) I will need to saw off the focussing tube from the get go ? I find this a little bit scary.

2) do you need to do the sawing if you buy a 150 PDS?

3) this scope vs a 6 inch RC? any major differences? the thing putting me off the 6 inch RC is the reduced FOV. Is this necessarily an unsurmountable issue?

4) can you please recommend a ccd mono camera that will not under/over sample with this particular set up?

So many questions !!

Thankyou one and all and clear skies !

Andy

HI Andy,

And welcome to the darkside!
1) Maybe yes, maybe No - it all will depend on the camera Focusing distance. If you will get cam in focus with Focuser's Drawtube rolled out a lot, - you will not need to "Circumcise" anything as the drawtube will not cast much shadow on the Primary mirror.

2) 150PDS - the same issue

4) Have you done any imaging before? if not, I would suggest trying any DSLR camera you've got for the start, or the second hand one... As you will spend lots of nights learning things which are not Related to Imaging Directly (guiding, platesolving processing and etc etc). However if you want to skip this part with cheap DSLR and dive directly into MONO, look at something like ZWO ASI1600MM or Similar. Note: for mono camera you will need FilterWheel and Filters, all brand new around £1800 in total.

P.S.

With ASI1600MM you will need to chop off a bit of the drawtube for the Perfect Results, but if you will use Coma Corrector which does not work as Reducer (for example Skywatcher CC is 0.9 reducer) you will be able to live without circumcision as distortion will be quite little, - probably...

"Circumcision" of the drawtube is not the Most challenging task with PDS, in fact, it takes around 10 - 15mins and I doubt someone managed to damage the scope during this procedure. If you will need to, do not chop a lot, go with 1cm first.

The most challenging thing with PDS is collimation of the Secondary Mirror (not Primary, but the smaller one). So if you will get a New One, at the start, adjust just a Primary Mirror if needed, - do  not touch bolts of the secondary at all.

Edited April 25, 2019 by RolandKol

[Andywilliams]

25 minutes ago, RolandKol said:

HI Andy,

And welcome to the darkside!
1) Maybe yes, maybe No - it all will depend on the camera Focusing distance. If you will get cam in focus with Focuser's Drawtube rolled out a lot, - you will not need to "Circumcise" anything as the drawtube will not cast much shadow on the Primary mirror.

2) 150PDS - the same issue

4) Have you done any imaging before? if not, I would suggest trying any DSLR camera you've got for the start, or the second hand one... As you will spend lots of nights learning things which are not Related to Imaging Directly (guiding, platesolving processing and etc etc). However if you want to skip this part with cheap DSLR and dive directly into MONO, look at something like ZWO ASI1600MM or Similar. Note: for mono camera you will need FilterWheel and Filters, all brand new around £1800 in total.

P.S.

With ASI1600MM you will need to chop off a bit of the drawtube for the Perfect Results, but if you will use Coma Corrector which does not work as Reducer (for example Skywatcher CC is 0.9 reducer) you will be able to live without circumcision as distortion will be quite little, - probably...

"Circumcision" of the drawtube is not the Most challenging task with PDS, in fact, it takes around 10 - 15mins and I doubt someone managed to damage the scope during this procedure. If you will need to, do not chop a lot, go with 1cm first.

The most challenging thing with PDS is collimation of the Secondary Mirror (not Primary, but the smaller one). So if you will get a New One, at the start, adjust just a Primary Mirror if needed, - do  not touch bolts of the secondary at all.

Hi Roland,

Many thanks for your reply.

I have been doing quite a bit of astrophotography, mainly dslr with kit zoom lens mounted on a skywatcher star adventurer mount. Also a dslr mounted on a 127 Mak for planetary stuff.

This means I am happy with polar alignment and also with dslr camera settings for captures.

I feel like I am ready for the next step.

I had decided to look at the ZWO ASI1600MM so the fact that you mention this camera gives me some confidence with my decision making !

I will have to read about collimation of the secondary mirror. Hopefully it is not too painful !

Here is a small selection of some of my little victories  but I cant wait for the next step !

best wishes,

Andy

 

[RolandKol]

 nice

as per ASI1600MM, - it is probably the cheapest cam with quite a large sensor to give you a nice FOV, but there are alternatives like Altair Astro Hypercam 1600 which has even 4GB DDR3 RAM (not sure if it does any difference, for me even 256MB is enough).

Also, there are some "quite cheap" CCD cams with smaller FOV.

You probably know this web http://astronomy.tools/calculators/field_of_view/ , but check what you would like to have at the final image before you pull the trigger!

P.S.

Also, always keep an eye on the backfocus of the camera you choose. For example ASI1600 backfocus is only 6.5mm which allows to use small 31mm Filters without vignetting. The larger the backfocus of the camera the larger vignetting you will get with small filters... And if you will be made to go for a larger filters, - like 36mm, - check their prices first 

Edited April 25, 2019 by RolandKol

[Whistlin Bob]

1 hour ago, Andywilliams said:

have been doing quite a bit of astrophotography,

Looking at your 'victories' (I get the same feeling when an astro photo goes well) I think you'll do great with a 130pds and some of @RolandKol's advice. Please be sure to share your results with us!

On the subject of collimating the secondary, at least for the first time, it's worth using a Cheshire instead of a laser. The other key advice is try to be relatively delicate when you adjust it- my problems with this process used to arise from being heavy handed and over tightening.

Also- sorry to wander off topic, but how do you get on with the SW AZ mount and the 127? I've been trying to use one for some short exposure (to manage field rotation) DSLR work and it struggles to hold images centrally for very long.. Do you get the same problem?

[Andywilliams]

4 hours ago, Whistlin Bob said:

Looking at your 'victories' (I get the same feeling when an astro photo goes well) I think you'll do great with a 130pds and some of @RolandKol's advice. Please be sure to share your results with us!

On the subject of collimating the secondary, at least for the first time, it's worth using a Cheshire instead of a laser. The other key advice is try to be relatively delicate when you adjust it- my problems with this process used to arise from being heavy handed and over tightening.

Also- sorry to wander off topic, but how do you get on with the SW AZ mount and the 127? I've been trying to use one for some short exposure (to manage field rotation) DSLR work and it struggles to hold images centrally for very long.. Do you get the same problem?

Hi Bob,

Many thanks for getting back to me.

I gave up on the alt az mount very early on indeed.

I had my planetary successes by mounting the 127 mak onto my star adventurer. The scope, coupled with my dslr took it to just about capacity for the SA mount but it still seemed balanced and worked well.

I look forward to buying my 130 PDS and sharing any notable results with you all.

I have a project in mind which is imaging  M45.

I find the diffraction spikes really attractive and I am hoping to capture some good star colour as well as nebulosity.

It is for a Maori friend of mine and I hope to get such a good image that I can make it into a nice sized printed canvas for her. 

M45 is known as Matariki in NZ and is a new year celebration when it first rises at dawn.

I will also, no doubt, be begging for advice should I need to do secondary collimations !!

Clear skies !

Andy

[Andywilliams]

Can I also ask for advice on coma correctors.

There seem to be different types.

Could you all recommend a CC for the 130 PDS that wont break the bank?

thanks again,

Andy

[RolandKol]

There are 2 types which are mainly  used, - Skywatcher Coma Corrector (which is also 0.9 reducer) and Baader MPPC  (no reduction)

Not sure which is a better one.

There are some more, but usually more expensive.

Edited April 25, 2019 by RolandKol

[Susaron]

We had clear skies last Saturday in Spain, so there was the time to shoot something.

Markarian Chain 34x300s subs, taken with the SW130PDS (Moonlite Focuser)+ AZEQ5 + QHY168C + Optolong L-Pro + Lots of DIY things.

Cheers

Mario.

[JohnSadlerAstro]

Hi,

Just a small offering for today, I have a Markarians Chain image in the works at the minute, its very poor quality though so looking at the above I might wait until page 105 . I also want to work on identification of galaxies in it etc before releasing. Part of a 3h integration with my 1000d and NEQ6. 120 and 200 sec subs, iso 800.

However, I can confirm that it the 130pds can indeed show the relativistic M87 jet, even when a newb with a potato for a camera is operating it, who is by no means a collimation expert! ? This is right at the bottom corner of the image, so theres quite nasty coma, which I think reduces the resolution of the jet somewhat. Overall, a very strong testament to the performance of the 130PDS.

John

Edited April 30, 2019 by JohnSadlerAstro

[Stub Mandrel]

Excellent - sent me scurrying for last year's data. unfortunately I seem to have cropped M87 out of the finished images!