Imaging with the 130pds

[Pitch Black Skies]

33 minutes ago, rotatux said:

BTW about an aperture mask, to avoid reducing the aperture I'm thinking about masking just the clips with half-circles of cardboard or hard paper, which would be sandwiched in the head of the clips. Would it have a chance to work ?

Hi mate,

That wouldn't work. The idea of the primary baffle is not really to mask the clips but rather the area between them, along with the clips.

Check out this post, it explains it well.

Now you could make your own primary baffle and fit it but for the sake of a few £, you can get a robust one specifically made for it. Truth be told, it only pushes the focal ratio from F5 to F5.3ish.

As alacant has mentioned, you could try the silicone method which might negate the need for a baffle altogether, depending on how the mirrors edge behaves.

[Robculm]

Hi All, Just a word of warning on the silicone method (albeit on my 200PDS not the 130). Do be sure to only use 'dabs'. I got a bit carried away & siliconed around the complete edge which resulted in significant primary astigmatism, which took quite some time to figure out & it wasn't much fun cutting the mirror out again! For now I've reverted to the clips. Given how thick these mirrors are, it's really surprising how much stress the clips introduce, you really have to tighten them the bare minimum, just enough to secure the mirror in place. I will be taking another shot at the silicone approach in future as it did for sure remove some of the 'artifacts', but for now I'd just be happy with some imaging of any sort if the weather ever improves! Cheers, Rob (from cloudy Devon)

[edarter]

Question on baffles and silicone to replace mirror clips. If I were to use silicone and remove the clips, does this mean I could print a much thinner baffle and therefore not reduce the light gathering capability so much?

[alacant]

3 hours ago, edarter said:

print a much thinner baffle

Hi

We find that nothing in the way of the mirror works best.

 

[Pitch Black Skies]

4 hours ago, edarter said:

Question on baffles and silicone to replace mirror clips. If I were to use silicone and remove the clips, does this mean I could print a much thinner baffle and therefore not reduce the light gathering capability so much?

The thickness of the baffle doesn't really matter, it's more about the size of it's inner diameter.

With the clips removed, you could manufacturer a baffle to just cover the bevel on the mirror edge but I'm not sure how you're going to fix it in place.

I wouldn't worry too much about the aperture being stopped down. A few of us here use the baffle specifically designed for the 130pds and see no significant difference in light gathering.

Alternatively, you could just decide to not use a baffle and go with the silicone method only. It will only become obvious that you aren't using the aperture mask if there is really bright stars in your pictures. You will see slight diffraction spikes and halo's but you will have to go looking for them, and even then, they will look okay.

[Gerr]

Can you not place an aperture type mask at the front end of the telescope? I'm wondering whether putting something like draft excluder foam around the inside edge of the front of the telescope would have a similar effect to the methods outlined above?? Or is this idea too simplistic / ineffective??

 

[rotatux]

On 25/12/2021 at 11:38, Pitch Black Skies said:

The idea of the primary baffle is not really to mask the clips but rather the area between them, along with the clips.

I already understand the enough repeated principle of the primary baffle, But that's not what I want, because I believe  (can't re-check at the moment) to have a quality-chamfered mirror variant described by alacant. My problem is now *only* the shadows from the clips -- as I already fixed the protruding focuser ; I find the remaining (uniform) diffraction from the bevel acceptable or even nice

I'm also not very comfortable with the silicon solution to remove the clips, as I typically transport the OTA upside down in a photo suitcase.

[Pitch Black Skies]

36 minutes ago, Gerr said:

Can you not place an aperture type mask at the front end of the telescope? I'm wondering whether putting something like draft excluder foam around the inside edge of the front of the telescope would have a similar effect to the methods outlined above?? Or is this idea too simplistic / ineffective??

 

Good question, it's worth trying mate.

[Pitch Black Skies]

@rotatux

"I already understand the enough repeated principle of the primary baffle."

Are you sure?

You intend to mask just the clips with half circles of cardboard...

That will still leave the bevelled edges exposed and then you would have 3 new shadows, of 3 semi circle cardboard masks...

Maybe I'm misunderstanding what it is you are trying to describe.

A quick sketch/diagram might help to explain what you want to do better.

I can't see how masking just the clips is going to help in anyway.

Edited December 31, 2021 by Pitch Black Skies

[edarter]

19 hours ago, alacant said:

Hi

We find that nothing in the way of the mirror works best.

 

So use silicone and no clips or baffle? I thought from earlier posts in this thread that this would result in diffraction all round the mirror, albeit even diffraction.

Just to clarify my previous question, when I said thinner baffle, I poorly worded that. I meant a larger diameter one that would only just protrude over the edge of the mirror.

[Pitch Black Skies]

8 minutes ago, edarter said:

Just to clarify my previous question, when I said thinner baffle, I poorly worded that. I meant a larger diameter one that would only just protrude over the edge of the mirror.

In that case, my answer is yes. A baffle that just covers the mirrors edge with the clips removed would be the ideal solution. That would completely prevent the mirror from being stopped down.

[alacant]

55 minutes ago, edarter said:

So use silicone and no clips or baffle?

Yes. Anything near the mirror causes light spread. No theory i'm afraid, just hands on, but our conclusion after correcting several pds'  is that it's best (and easier) to have nothing in the light path. 

Each sw is different though. Try it on yours, With and without, With and without... until you get fed up dismantling/collimating and re-aligning the thing, decide you can't see any difference anyway or drop the mirror cell in the dark, breaking the main mirror. Whichever comes first!

Cheers

Edited December 27, 2021 by alacant

[Susaron]

It is been ages since I posted something here. Just an urban picture from comet Leonard with M3. 15 x 10s s at ISO 12600 with the Nikon 5600 attached to the SW130PDS.

[Imd]

On 24/03/2014 at 00:24, Uranium235 said:

And another:

 

Excellent images,  what camera have you used for your imaging with the 130pds please?

[Mycro]

Hello Everyone. After playing for the first time in my apartment a few months ago with the scope (from the balcony in a bortle  location without proper collimation), I had the first proper attempt at taking some pictures. I Should have sticked to one target, but I was so excited that I dispersed myself. I Still have to learn how to process, to plan ahead my exposures and some tweaks to do in the scope. I am using the EQM-35 pro, guided with an xbox livecam and a 30mm guide scope (I have trouble finding stars, but I tried 300s exposures without any stretching on the stars). The Imaging Camera is a Canon 2000d unmoded with the Baader MPCC comma corrector.

M31 - 90 x 120s at ISO 1600

M42 - 30 x 30s at ISO 1600 + 30 x 60s at iso 1600

M45 - 20 x 180s at ISO 1600.

All Stacked in DSS and processed with GIMP.

For all of them I took 10 darks, 10 Flats and 10 Bias. I Havent tried diethering yet, since I believe I will have some things to solve regarding backlash with my mount.

I can tel right away that andromeda core was blown up, and i didn't process it right to make the transition more smoth. For M42, at least those stars could be improved. M45 was done in a hurry, and I think I pushed the contrast too hard. I wold apreciate any comment on where to improve so I can go in the right direction.

 

PS - The day before this pictures, I spent all day trying to distance properly the spider vanes, to collimate etc... and at night I could not achieve focus. I Thought I have messed something up. Tried to collimate at night again pushing the mirror fwd making things worst before I took everything back inside just to find out that... I left the eyepiece extender in the focuser and that was the reason I was not focusing. Stupid mistake but lesson learned. Glad It was nothing I messed up trying to olimate.

[Uranium235]

On 03/01/2022 at 08:21, Imd said:

Excellent images,  what camera have you used for your imaging with the 130pds please?

For that image (and most of my other stuff), the camera used was the Atik 383L+  

[Jim Smith]

...and finally a clear night.

I removed the primary clips entirely and fixed the mirror with silicone sealant. I recollimated.

So here is my modified "no triangular stars" 130pds in action. Nikon Z50, Baader mpcc III, extra 1mm spacer ring, shortened draw tube, no mirror clips, no mirror edge baffle.

One 30s exposure, ISO800, +3ev in Lightroom, uncropped...

 

 

[alacant]

4 hours ago, Jim Smith said:

shortened draw tube, no mirror clips, no mirror edge baffle

Well done. It really is the only way. And just look how clean those stars appear:) 

Congratulations.

You can now use the primary locking screws as they were intended to be used or -even better- fit six stronger springs; three to replace the existing weak springs and a further three, passive style, over the locking screws, leaving the latter loose. 

Cheers

 

Edited January 5, 2022 by alacant

[Pitch Black Skies]

1 hour ago, Jim Smith said:

...and finally a clear night.

I removed the primary clips entirely and fixed the mirror with silicone sealant. I recollimated.

So here is my modified "no triangular stars" 130pds in action. Nikon Z50, Baader mpcc III, extra 1mm spacer ring, shortened draw tube, no mirror clips, no mirror edge baffle.

One 30s exposure, ISO800, +3ev in Lightroom, uncropped...

 

 

Looks great Jim, well done mate.

[Pitch Black Skies]

M51 (Whirlpool Galaxy)

 

Its spiral arms were first discovered in 1845 by astronomer William Parsons, 3rd Earl of Rosse.

Lord Rosse used his Leviathan telescope which still resides today at Birr Castle, Co. Offaly, Republic of Ireland.

[Jim Smith]

Messier 78

Nikon Z50  55x30s  ISO800

[Bigyin13]

NGC 281 Pacman Nebula

Canon EOS 2000D

40 x 300s ISO 1600 L-eNhance

Hi guys, first time posting but I've been lurking this thread for months trying to scrape as much information as I can and piece everything together. I love the dedicated following this scope has.

It was only over the holiday period I got to use the scope in anger. Prior to that I've been using a lighter redcat/Star adventurer setup rather than battle taking the eq6r/130pds up and down a long flight of stairs with work the next morning. I'll work out something more permanent  outdoors in the better weather.

Anyhow so far I have a baader CC and taking on board the wealth of information regarding sagging with the standard configuration I have bought both the recommended compression ring as well as the lacerta thread adapter. I make use of a modified canon 2000d for imaging and use a zwo eaf for focus all controlled with a newly purchased asiair plus.

I also 3d printed a ring to hide the mirror clips as well as a cover plate for the scope base to prevent light seepage.

Is there any other improvements I have missed?

I see I still have some egg shape stars largely to the lower left corner.

Also please give me any and all feedback on my image both in imaging and post processing, I'm here to improve after all.

Edited January 7, 2022 by Bigyin13

[tony8690]

Hi All,

 

Haven't posted here for a couple years!

Recently moved to Northumberland (originally from Kent) am loving the dark sky’s !

My first night out in my garden for a loooong time and here is the result.

 

M42 - 10 x 240s at 1600 iso  - unguided - Manually stacked in photoshop and edited in Photoshop. no darks flats or bias taken.  

I work on a Macbook Pro, any good advice on post processing? 

IMO this has been the best photo of M42 i have ever taken and am really happy with it. 

 

[Spaced Out]

4 hours ago, tony8690 said:

Hi All,

 

Haven't posted here for a couple years!

Recently moved to Northumberland (originally from Kent) am loving the dark sky’s !

 

Northumberland rocks ! 👍 🙂

[barbulo]

Yesterday we had around 3 hours of clear skies. Instead of weeping for joy, I decided to get the equipment out and give a try: 

NGC281 (Pacman Nebula) with Canon 600D (mod), 68x120s usable lights @ISO800 + flats + dark-flats + bias. Stacked in DSS and post-processed with Siril and PS. 

Still some coma in both top corners. I'm starting thinking sensor tilt is the source. I'll give a try with another camera some day.

Autosave002.fts