Imaging with the 130pds

[Jonny_H]

19 hours ago, BrendanC said:

As we come to the end of another astro season, and the light nights mean no astro darkness from end of May until end of July (in the UK at least), I thought I'd post some of my shots taken over the past year since I got a second-hand NEQ6 and sold my 130P AZ. It was a huge step-up and I had to improve my technique because the improved accuracy of the mount really showed up all the things I was doing wrong. Anyway, now I've learned about guiding, calibrating, dithering, polar alignment and whatever else, I love my little 130PDS. The only thing I wish I could change is those iddy-biddy little bitemarks the focuser tube takes out of stars. All photos taken with an EOS1000D with IR filter removed, some are guided, others not, captured with APT, stacked in DSS, post-processed in Affinity and Topaz AI Denoise. They're all pretty much 'the usual suspects', they won't win awards, but I've really enjoyed taking them (as well as being very, very frustrated a lot of the time!). I hope it's OK to share so many in one post...

Absolutely cracking images.

What sort of integration time do you typically aim for with your images?

[BrendanC]

Thanks! It depends. For clusters I can generally get away with a couple of hours. Galaxies about five. Nebulae about seven. More integration means less noise but also, oddly, I've noticed that the colours also definitely improve a lot with integration time too. I also use calibration frames - darks, dark flats, and flats, no bias. I take 25 flats on the night, have a 25-frame-based master dark flat that I re-use, and then a darks library for different temperatures. I know you're not supposed to use dark libraries with DSLRs, but what I've found through extensive testing is that they really do work, for me at any rate.

[geeks]

My latest one, had the data for a short while but hadn't had a chance to process it until now. My love affair with the 130PDS continues. This isnt my greatest image but I am still really pleased with it.

Unmodified Canon 6D,
Optolong CLS filter,
40 x 180s lights @1600 ISO
20 x darks, flats and bias,
SW 130PDS 
EQ5 Pro 
T7C guide cam
SVBony SV165 guide scope

DSS no drizzle and a solo process in Gimp.

[Jamgood]

22 hours ago, BrendanC said:

As we come to the end of another astro season, and the light nights mean no astro darkness from end of May until end of July (in the UK at least), I thought I'd post some of my shots taken over the past year since I got a second-hand NEQ6 and sold my 130P AZ. It was a huge step-up and I had to improve my technique because the improved accuracy of the mount really showed up all the things I was doing wrong. Anyway, now I've learned about guiding, calibrating, dithering, polar alignment and whatever else, I love my little 130PDS. The only thing I wish I could change is those iddy-biddy little bitemarks the focuser tube takes out of stars. All photos taken with an EOS1000D with IR filter removed, some are guided, others not, captured with APT, stacked in DSS, post-processed in Affinity and Topaz AI Denoise. They're all pretty much 'the usual suspects', they won't win awards, but I've really enjoyed taking them (as well as being very, very frustrated a lot of the time!). I hope it's OK to share so many in one post...

Fantastic images Brendan. Well done. 👍

[Jamgood]

I've not had much imaging time lately but managed a couple of hours on the East Veil Nebula last week.

Grabbed some obligatory shots of the moon as well, just because. 

I got round to doing the mirror clip mod yesterday and I'm looking forward to see what difference that makes to the brighter stars.

[alacant]

37 minutes ago, Jamgood said:

mirror clip mod

Hi

It maybe worth mentioning a quick method for the same modification....

Simply remove the clips and place the mirror back in its cell with 3 blobs of silicone sealant. 

Viz, lose the clips altogether.

Cheers

Edited May 5, 2021 by alacant

[BrendanC]

Interesting idea! But I wonder how undoable that is? 

Edited May 5, 2021 by BrendanC

[Jamgood]

3 hours ago, alacant said:

Hi

It maybe worth mentioning a quick method for the same modification....

Simply remove the clips and place the mirror back in its cell with 3 blobs of silicone sealant. 

Viz, lose the clips altogether.

Cheers

I've read arguments for and against that method. I opted for the 3D print version. Only took 5 minutes. 

[alacant]

4 minutes ago, Jamgood said:

for and against

What are the arguments against? 

But yeah, absolutely. Both will give the desired effect. Go with whichever.

Cheers

[Erling G-P]

19 hours ago, BrendanC said:

Thanks! It depends. For clusters I can generally get away with a couple of hours. Galaxies about five. Nebulae about seven. More integration means less noise but also, oddly, I've noticed that the colours also definitely improve a lot with integration time too. I also use calibration frames - darks, dark flats, and flats, no bias. I take 25 flats on the night, have a 25-frame-based master dark flat that I re-use, and then a darks library for different temperatures. I know you're not supposed to use dark libraries with DSLRs, but what I've found through extensive testing is that they really do work, for me at any rate.

Very nice images for sure!

Envious of your star colours in the Rosette shot; in my own with the 130PDS, the blue stars remain completely white, no matter how high I crank the saturation.  Very nice Orion Nebula too, but am puzzled by your Andromeda Galaxy - is it a mosaic?   In my own image, also with a DSLR 'crop sensor' & 130PDS, I can barely fit the galaxy across the image, so wondering about your much larger field of view.

[BrendanC]

Thanks! I use StarTools which seems to bring out the colours nicely. Having said which, I never seemed able to get enough of the nebulosity towards the outer fringes of the Rosette which I see other people getting. You're right about the Andromeda shot - well spotted! It's a mosaic of four shots for the skies around it, plus a central pane which I captured much more time on. Here it is:

[Erling G-P]

48 minutes ago, BrendanC said:

Thanks! I use StarTools which seems to bring out the colours nicely. Having said which, I never seemed able to get enough of the nebulosity towards the outer fringes of the Rosette which I see other people getting. You're right about the Andromeda shot - well spotted! It's a mosaic of four shots for the skies around it, plus a central pane which I captured much more time on. Here it is:

Nicely done!

And it was hard not to spot, when using almost the same equipment - this single shot's field of view looks a lot more like mine

[alacant]

9 minutes ago, Erling G-P said:

never seemed able to get enough of the nebulosity towards the outer fringes

Hi

Lovely shot.

To get the faint stuff, make sure you employ AutoDev twice, A first instance simply to 'see what's there'. Then a second instance after Wipe which should include a roi with a fair amount of said therein.

Cheers

[kaelig]

I have installed a new camera: ASI 183MM cooled 

It is Visual assisted, hence the integration time is very low: 285 s

[Jamgood]

Started working on my first Mosaic last night. 4 panels of 30minutes and 1 of 10minutes. (I ran out of time to do all 6 as the sky started to get bright) Looking forward to adding to and working on this.

This is straight from APP. No extra processing as yet.

[Jamgood]

Two nights worth of data so far on my first 6 Panel Mosaic of the Veil Nebula. I'm really pleased with this so far. I've also learned a few new processing tricks along the way. 

10x300sx6 Light Frames (50mins Per Panel) Cooled -10°
40 Darks
40 Flats
40 Dark Flats
Sky Watcher 130PDS
HEQ5 Pro with Rowan Belt Mod
ZWO ASI294MC Pro
TS-Optics GPU Superflat Coma Corrector
Optolong L-Enhance
Orion 50mm Guide Scope & Orion Star Shoot Auto Guider
Pegasus Powerbox Advance
Astro Photography Tools & PHD2
Astro Pixel Processor & Photoshop

[alacant]

On 05/05/2021 at 20:31, BrendanC said:

how undoable that is

Hi

To remove the mirror, simply use a thin knife to slice through the silicone. An artist's palliate knife is ideal.

Cheers

 

[edarter]

A question on the silicone method for securing the main mirror. Does this not cause issues with collimation? Silicone stays a little 'squishy' once set and surely this allows a small amount of movement of the mirror as the mount rotates? 

[alacant]

58 minutes ago, edarter said:

this allows a small amount of movement of the mirror

Hi

Once pressed lightly against the silicone in the cell, I'd say it creates far less movement than if allowed to sit freely and 'slide' as the mount turns. The layer of silicone is only 1mm or so, depending upon the mass of the mirror.

FWIW, it was the only best way we fount to tame a f3.9 to hold collimation both during and between sessions; the silicone can be allowed expand up and around the sides of the mirror, thus providing control for lateral movement too. Tested on mirrors up to 254mm.

No theory. Very much hands on only evidence. I'm sure there are better ways, but this modification takes only 15 minutes and just works. 

Our 130 is out on loan ATM but here is a 200pds mirror cell which had awful diffraction spikes and would not hold collimation.

 

Edited June 11, 2021 by alacant

[rnobleeddy]

I tried to use my 130PDS to image the recent eclipse, but the cloud said no. However, in case anyone wonders about this, this was with cheap solar film on the front.

[BrendanC]

Finally managed to get the imaging from the eclipse sorted.

[edarter]

On 11/06/2021 at 09:05, alacant said:

Hi

Once pressed lightly against the silicone in the cell, I'd say it creates far less movement than if allowed to sit freely and 'slide' as the mount turns. The layer of silicone is only 1mm or so, depending upon the mass of the mirror.

FWIW, it was the only best way we fount to tame a f3.9 to hold collimation both during and between sessions; the silicone can be allowed expand up and around the sides of the mirror, thus providing control for lateral movement too. Tested on mirrors up to 254mm.

No theory. Very much hands on only evidence. I'm sure there are better ways, but this modification takes only 15 minutes and just works. 

Our 130 is out on loan ATM but here is a 200pds mirror cell which had awful diffraction spikes and would not hold collimation.

 

Thanks for the info, very interesting. What sort of silicone sealant should I look for? Is it the stuff that seals around baths and sinks? 

[alacant]

2 hours ago, edarter said:

What sort of silicone sealant

Hi

Not the ones you find in long tubes to use with a pistol grip, rather the non acidic type which retain their fluidity and do not harden over time.

Not sure if this brand is available in UK but there's sure to be something similar. It's usually sold in toothpaste-type tubes, quite possibly advertised as able to be used on coloured material and/or neutral, A+, etc.

HTH

 

[g-rex]

Managed to save enough for a cooled camera. Bit of a jump from my self modded 450d! Still learning but it's looking promising.

 

Altair 269c Pro Tec

Eq5 using Onstep

1.5hrs of 3min subs

 

 

[RolandKol]

Hi guys,

any advise will do!

P.S.

Focuser circumcised (-1cm)... cannot try GPU CC.