Imaging with the 130pds

[al-alami]

17 hours ago, carastro said:

Finally got first light with my SW130PDS

Not the greatest result as I live in the suburbs of London and I had problems with guiding over 500secs.  It wasn't until after I packed up I realised that Dec was not properly balanced, so wasted a lot of time trying to find out why it was trailing and trying out shorter subs.

Since I wanted a result to se how the SW130PDS performed and we get so few clear nights I decided to cheat a little and made up two Ha images one with 15min subs with trailing and 1 with 500sec subs without trailing.  Erased the stars on the 15 minute image using Straton and overlaid the 500sec image over the top to replace the stars.  As a consequence of all the messing around trying to find out why I was trailing and trying different lengths I did not get as much data as I would have liked.  I think I really need a dark location for the Oiii, and Sii. 

Anyway - enough rabbit - taken on 5/11/2016 - yes bonfire night -  I hoped that narrowband would be OK with fireworks.

First light for my SW130PDS, Atik460EX, NEQ6, PZT
Ha 5 x 15mins + 2 x 500secs
Oiii 3 x 150secs binned
Sii 4 x 150secs binned

Looks better if you don't zoom in (ha ha) but just glad to get a first light with this new scope.

Carole 

 

 

I wish my first light was even 10% of this

[carastro]

Thanks Al.

I have now brightened and sharpened it a bit and tried to reduce the noise:

[Stub Mandrel]

2 hours ago, carastro said:

I have now brightened and sharpened it a bit and tried to reduce the noise:

Do you sharpen first, then denoise or the other way around? I can never decide which works best.

[Adam J]

I always de-noise then sharpen or you just make the noise worse. I then do that in two or three cycles. I wish I had a CCD then I would not have to muck about mono-modifying DSLR's but they are just so expensive and I am having to save for a new family car as it is anyway

Heck I would take that ability to use a filter wheel with my DSLR on a 130PDS but you simply don't have sufficient back focus when using the Baader MPCC MKIII

[carastro]

Quote

I always de-noise then sharpen or you just make the noise worse.

To be honest I have never thought about it, so I am not sure what order I do it in.  

Processing mono images is quite a different kettle of fish to DSLR images as if the noise is in the Oiii and Sii, I quite often take the finished image and blur it to reduce the noise (dust and scratches) and then paste over the the Ha image for a 2nd time and blend it as luminosity. This will sometimes wash out the colour so I slightly adjust the colour layer in curves or match colour, and then slightly adjust the Ha layer also in curves until the colour gets put back.  I think I found that on an on-line tutorial, think it was Starizona. 

It's probably at this stage I do some selective sharpening which I usually do by taking a copy of the image then do a High pass filter and then paste back the copy on top and then erase the bits I where I want the sharpening to show through, this normally prevents the stars from being sharpened.  I know you can select the stars and exclude them from the HP filter, but this tends to select only the brighter stars so the small ones still get High Passed so I find this method works better, does mean you have to avoid the stars when doing the erasing.  

HTH

Carole 

 

Edited November 14, 2016 by carastro

[Susaron]

Taken yesterday evening just after rising from my home balcony, without the children around.

Edited November 15, 2016 by Susaron

[al-alami]

Hi All, I think since I purchased my telescope we have more clouds in Jordan! ... coincidence?  

So last night I took my 130PDS up to the roof for the super moon .. and look ... clouds .. wonderful ..

I guess the results aren't too bad

 

[Susaron]

I´d like to share with you my DIY attempt to create a (cheap) flat box lamp adapted to the SW130PDS or any other scope under 160mm.

It is really simple, the bill of materials consists of: 2 cans of butter cookies, American adhesive tape, 2 (5V) usb led strips, a methacrylate sheet.

The buildind process is simple, just remove the back from one of the cans an assemble in series with the other one, perform a hole on the can top cover and glue a circular methacrylate sheet previously cut to the can diameter top cover minus 1 cm (just to give support for sticking). Perform a hole on the assemble cans to pass the usb cables, if needed add to usb extension cables. The power connection is provided by a Celestron 7Ah powertank.

The total cost has been less than 30 euros.
 

[ChrisLX200]

Looks good - well done!   Maybe a tad bright?

ChrisH

[Susaron]

57 minutes ago, ChrisLX200 said:

Looks good - well done!   Maybe a tad bright?

ChrisH

Hi Chris the brightness is an effect of the photo taken overexposed with the phone, here take a look to the flats at ISO800 and ISO1600 with the Canon 70D, let me know what do you think. First one is at ISO800 and the second one at ISO1600

Cheers.

Edited November 15, 2016 by Susaron

[wimvb]

Nice build. Be careful though, even if it looks like illumination is spread evenly across the surface, it may very well vary. It would be a shame if you find out the hard way that your flats aren't flat.

If you can measure the light intensity, you should try to verify that it really is flat. A simple photoresistor stuck in a small tube and attached to an ohmmeter may be all it takes, since you'd be only interested in variations, not absolute values.

Verifying by taking an image may not work if the optical system suffers from vignetting.

Just an idea.

[Susaron]

1 hour ago, wimvb said:

Nice build. Be careful though, even if it looks like illumination is spread evenly across the surface, it may very well vary. It would be a shame if you find out the hard way that your flats aren't flat.

If you can measure the light intensity, you should try to verify that it really is flat. A simple photoresistor stuck in a small tube and attached to an ohmmeter may be all it takes, since you'd be only interested in variations, not absolute values.

Verifying by taking an image may not work if the optical system suffers from vignetting.

Just an idea.

Thanks for the advice Wim, I have a photoresistor and an Arduino Uno board I will check the values I get. Thanks again.

[carastro]

I got my 2nd light with my SW130PDS last night.  I am planning to get a 2nd night on both of these images if we get another clear night soon.

I did Melotte 15 while I was waiting for M45 to rise above the houses.

Both images from the Suburbs of London.

Carole 

Mapped HOS
Ha 8 x 900 + 1 x 600
Oiii 6 x 300
Sii 5 x 300
WIP
SW130PDS, NEQ6, Atik460

 

followed by:

M45 The Pleiades cluster

M45 with SW130PDS, NEQ6 & Atik460 Baader CC
Lum 8 x 600secs
RGB 6 x 300secs binned x 2 each

Edited November 27, 2016 by carastro

[wimvb]

That's a "spikey" m45. And I love the detail you got in melotte 15.

[al-alami]

On 11/27/2016 at 11:31, carastro said:

I got my 2nd light with my SW130PDS last night.  I am planning to get a 2nd night on both of these images if we get another clear night soon.

I did Melotte 15 while I was waiting for M45 to rise above the houses.

Both images from the Suburbs of London.

Carole 

Mapped HOS
Ha 8 x 900 + 1 x 600
Oiii 6 x 300
Sii 5 x 300
WIP
SW130PDS, NEQ6, Atik460

 

followed by:

M45 The Pleiades cluster

M45 with SW130PDS, NEQ6 & Atik460 Baader CC
Lum 8 x 600secs
RGB 6 x 300secs binned x 2 each

gorgeous

[al-alami]

some more practice runs with my scope, considering my mount is misbehaving not too bad .. I think 

I guess you learn from your mistakes

[Adam J]

Finally fixed my extra diffraction spike issue! I have confirmed the cause as focuser tube ingress into the light path. So for future reference both this and twisted spider vanes can cause the problem. The fix was to move the primary up the tube hence moving the focus out.

I got some more data on M45 in the process using my mono 1000D and combined it with my original RGB as a luminescence channel. Although I had a processing misshap with the stars on the right of the image.

Edited November 30, 2016 by Adam J

[Adam J]

23 hours ago, al-alami said:

some more practice runs with my scope, considering my mount is misbehaving not too bad .. I think 

I guess you learn from your mistakes

What exposures did you use? Is the camera modified?

[al-alami]

17 minutes ago, Adam J said:

What exposures did you use? Is the camera modified?

this is about 20 seconds (more than that I get trailing at ISO 3200.  Am using a canon 1200D in which I removed the IR filter.  baby steps

[al-alami]

7 hours ago, Adam J said:

Finally fixed my extra diffraction spike issue! I have confirmed the cause as focuser tube ingress into the light path. So for future reference both this and twisted spider vanes can cause the problem. The fix was to move the primary up the tube hence moving the focus out.

I got some more data on M45 in the process using my mono 1000D and combined it with my original RGB as a luminescence channel. Although I had a processing misshap with the stars on the right of the image.

beautiful

[Adam J]

1 minute ago, al-alami said:

this is about 20 seconds (more than that I get trailing at ISO 3200.  Am using a canon 1200D in which I removed the IR filter.  baby steps

Ah still not got the guiding working then. Nice one removing the IR filter yourself its easy and too many people scared to do it.

Edited November 30, 2016 by Adam J

[al-alami]

1 minute ago, Adam J said:

Ah still not got the guiding working then.

unfortunately not yet ... for some reason there seems to be a shift in the polarscope ... so it looks like I might have to take the mount apart and check everything on the inside .. plus I didn't get the chance to try out the guiding before I went to this dark site (I didn't want to be trying things out with lots of people around)

[Adam J]

2 minutes ago, al-alami said:

unfortunately not yet ... for some reason there seems to be a shift in the polarscope ... so it looks like I might have to take the mount apart and check everything on the inside .. plus I didn't get the chance to try out the guiding before I went to this dark site (I didn't want to be trying things out with lots of people around)

Do you know how to correctly adjust and calibrate the polar scope reticle?

[al-alami]

Just now, Adam J said:

Do you know how to correctly adjust and calibrate the polar scope reticle?

I do, I found several links to it (using the three little grub screws)... but every time I correct it one way, it shift almost the exact opposite when I return, and it sort of seems like its not rotating properly, hard to describe, but its almost like its elliptical and not round.

[al-alami]

6 minutes ago, Adam J said:

Do you know how to correctly adjust and calibrate the polar scope reticle?

am using astro baby's one .. 

http://www.astro-baby.com/HEQ5/HEQ5-1.htm