JCIdaho

Apologies for this @scotty38. Please see the below two images I originally meant to post.

One is a sub after calibration:

The other is the same sub, after calibration + registration.

I've never seen this kind of weird lattice pattern before.

As mentioned, this sub is the R. All the post registration subs have this problem. The other L/G/B subs are absolutely fine. The R flats look OK, so I'm just puzzled.

thanks.

Hi,

(edited, - please see my next comment in this thread for a more accurate description of my issue)

Please, any idea why this registration would result in the attached?

During calibration it checks out OK - also attached.

This is for all my R images - the L/G/B came out just fine, with the same bias frames etc.

Thanks!

I bought a counterweight for the AM5 and it has made a difference. I've been tracking tonight a between.4 to .6 arc secs. Much better than had before, around 1 arc sec.

On 15/01/2023 at 22:29, AstroGS said:

Hi Gordon,

It is the opposite I am afraid - I did widen the BB Planet's adaptor circumference by almost 1mm. I did not want to alter the PE200 as I will be using it with other tripods when I am in the field.

Excuse me - how did you widen the adaptor by 1mm? Filing?

Thank you both @Paul Puntin and @Starflyer, good know the iOptron Tri Pier received!

Hi All,

Looking at Trevor's latest video on YouTube, I'm quite taken with the Starfield Tri Pier. I've never considered a portable Tri Pier, but I'm considering now because a) I think I'd getting better guiding for my AM5 than the carbon fibre mount, b) thinking of getting a bigger refractor than my SM90, and the extra vertical clearance would help, c) more vertical clearance helps generally to access more sky, d) it just looks very cool, and I want one.

There doesn't seem to me, to be much in the way of reviews for Tri Piers, probably because despite my reasons above, they aren't killer reasons? Has anyone had recent experience with a portable model, like this Starfield one, or perhaps the iOptron portable Tri Pier?

I'm based in the UK, and so getting the Starfield one in Trevor's video could be tricky. I note that Altair Astro, that look a lot like the Starfield one, but they're out of stock.

Any thoughts / recommendations welcome!

Hi All,

Appreciate some help. I messed up the rotation of the image train between consecutive nights, by a whopping 90 degrees difference! You can see below that I have 5 different exposures here for L: 60, 30, 15, 8, 4 seconds.

On the first night I took the 15 seconds - the top right image - and you can see how registration has rotated it, but I've lost a substantial chunk in the process (the black areas).

 This is my first attempt at HDRComposition. If I blindly run HDRComposition against the five images, PI gives an error, which is fair enough: "Error: Inconsistent HDR composition detected (bad linear fit, channel 0)".

Any ideas here? For completeness sake, the 30 exposure was completed over both nights, and you can see an imperfect blending of the two framings, in the middle left image, happening during registration.

Is there a tool, to potentially stitch together two of the images, so I use the foreground of one, on top of the other, to allow HDRComposition to then work?

I'd appreciate any advice on a route to take!

Thanks.

Thank you all for the feedback. I'll have a continued play with it. I didn't apply PCC, and that has made a difference. Thanks!

Hi All,

This is my third go at M45. I'm going a bit blind looking at it! I'd really appreciate any feedback. My PixInsight process:

R G B -> DBE, BX, LinearFit, ChannelCombination, BackgroundNeutralisation, HistogramTransformation

L -> DBE, BX, HistogramTransformation

LRGBCombination

EZ Denoise

HistogramTransformation

RangeSelection Mask, then CurvesTransformation, increase saturation, make the background darker. More Curves work to try and make the blue pop out.

XISF is here if anyone fancies poking about: https://drive.google.com/drive/folders/1an-M2oCxnTdO1diHoSP71UT143wgRG7K?usp=share_link

thank you.

Managed to solve it - ABE wasn't my friend here. DBE was 🙂

Hi,

I look some data on M45 - there is some light pollution, which has caused some gradients and vignetting. It's a shame, as the image has the potential to look good I feel. I am new to LRGB processing, using an asi2600mm-pro camera. I'm using PixInsight.

I've tried running ABE (automatic background extractor) loads on the sub images, but when I combine RGB, I get the corners full of light, which makes creating a subsequent mask using RangeSelection difficult. Any tips would be appreciated. I can't seem to effectively kill these gradients! Is my data just too light polluted?

The stacked-data for the LRGB images are here: https://drive.google.com/drive/folders/1d_W0KYxmWyDV_ONhkSR8elmxMXph-Q2B?usp=sharing.

thanks.

On 28/11/2022 at 22:51, tooth_dr said:

Wee bit of haze creeping in

 

What camera / setup is that?

8 hours ago, Ratlet said:

The full moon always brings clear skies.

Is that a thing, or sods law?

@MartthebassThanks. Are you using the AsiAir? I've bought the pier, and the guiding still can go whacky when it gets near the meridian, using NINA and PHD2. Seems it's a known issue - near the meridian, the AM5 'stops' - https://bbs.astronomy-imaging-camera.com/d/12297-major-issues-with-meridian-flip-please-fix/37.

Using a StellaMira90, but with a chunky imaging train on the back.

I can't see any damage, and it subsequently worked OK. I've ordered the pier extension, I hope all will be well.

Anyone else having issues with the scope/camera hitting the tripod when focusing on something at/near the Zenith. I've just ordered the pier to help with this, but wondering if others have had issues?

Hi @Steve Ward,

I think it's safe to say, it's user error and clumsiness on my part. I turned a knob so hard it actually bent inside the thread, part frustration, and maybe it was also quite stiff. Probably not worth dwelling on. I also don't loosen the main bolt.. I will in future!

Thanks for the advice on seeking out a local engineer. Sadly I don't live near @Peter Drew!

Jon.

Hi All,

My A/Z threads have worn through on my CGEM II and I'd like to repair it, as per this thread on CN. I've contemplated doing this myself, but I'd rather find someone UK based able to do it, given there's plenty of scope for it to go wrong.

Any recommendations / advice where to look, to find someone?

Thanks!

Jon.

Hi All,

I took another picture on a recent moonless night, and there's NO gradient, so I can conclude the original gradient was directional light pollution, as suggested on this thread. Thanks! Any other feedback would be appreciated, but I'm happy with the result. As auggested, I also went down to 3 min subs and took 30.

SM90, asi2600mc-pro

Thanks all for the great feedback / answers.

@Laurieast it was around midnight 13/14th August 2022.

@Clarkey thanks. 5 mins subs has been my go-to 'safe zone', but I will heed your advice in future.

@Laurieast @Felias @Ratlet @Lee_P - thank, great to learn there's a bunch of options for dealing with gradients. I'll definitely have another go at it.

@The Lazy Astronomer @Clarkey @Laurieast - general consensus is the moon! Fair to say then, that directional light pollution is a common reason for gradients. Looking forward to trying again on a moonless evening.

Thanks @Laurieast and @Felias for processing the images I uploaded. It's amazing to see what dealing with the background does to the image.

Hi all,

I snapped this pic of M31, 10 x 5 min subs using an asi2600mc-pro on an SM90, with a flattener/reducer. I'm a relative beginner... one thing I'd love to know, is what's causing the light gradient here, i.e. the image is 10% brighter on the left than the right.

What typically causes this? Could it be the moon light creeping in (pretty much a full moon), or a tilt on my sensor, or something else? I was at a bortle 4 site, so I don't think there was much light pollution at play. This isn't the first time I've seen such a gradient, but then at other times I've had images with zero gradient like this, so it's bit of a puzzle, something that shows up for time to time. It could be also be my flats setup, for which I used an ipad + flashlight-app + white t-shirt + elastic band. It could also be something up with the camera (amp glow?).

Or am I just overthinking this, and that a full-moon is always going to give a proper challenge?

If I do a dynamic background extraction, I can make the above image significantly better:

Any thoughts welcome!

Thanks.

Hi SGL!

I took this pic of M86 and friends last night. This is just auto-stretched in PixInsight, no background extraction or playing with the levels.

Note that there's a light haze emanating from the left hand side leading to a clear overall horizontal gradient, and there's a hazy round donut in there which is harder to see, plus vignetting in the corners.

If I play with the histogram, dynamic background extraction, I can get this end result, although if you look hard for it, you can still find the donut.

I'm going a bit blind looking at these images now! Here's another one, but without using flats, just to see what the effect the flats have on vignetting:

Firstly, should I be concerned about this Vignetting? Is it something I can live with by improving on making better flats and processing to mitigate?

For making flats, I'm using a Galaxy Tablet with an app called LightBox, with a white t-shirt over the scope, and the AsiAir to capture. My exposure lengths are 1.4 seconds and I used 20 for the above images.

I suspect though, the flats aren't the issue, and the vignetting is being caused by my setup. I noticed that the vignetting largely appeared when I added the M42M-M42F-2L, that gave me the correct 55mm back-focus as needed, to proper flatten the images.

I'm using:

StellaMira 90mm ED Triplet f/6
StellaMira 2" 0.8x Reducer / Field Flattener
Optolong L-Pro Light Pollution Broadband Filter
ZWO ASI 2600MC-PRO (IMX571)

Any thoughts / advice appreciated!

Thanks for the advice.

@Cosmic Geoff - noted, I should refer to it as a C8, as without the supplied mount, it's not an 8SE!

@Same old newbie alert - my camera is a asi2600mc-pro. I'll look into a getting a reducer.

@catburglar thanks for explaining the concern with the mirror focus. It does seem a OAG would help here! I'll look into it

I'm broadly happy with my CGEM II, so it feels that with a reducer + OAG, this is something I need to try! Thanks.

Thank you for the feedback. Onwards and upwards!

@alacant @barbulo @Clarkey - adding 55mm of backfocus properly has solved my curvature issues! See my new image below.

@AstroNebulee - thanks for reassuring me on the flats!

When the clear skies return, I'm going for shorter (3 min) exposures and lots more integration time (only managed 90mins thus far). Thinking of getting a LP fitler, and a Bahtinov mask!

Jon.

Looks flatter:

And here on M44.

On forums there's lots about the Nexstar 8SE being a difficult choice for AP.

Is the concern over the 8SE mostly about the mount, or is there some concern about the OTA also? I've a CGEM II, so would the OTA put on this mount be a good setup?

Note, I've a Stellamira 90mm I'm happy with, but I'm looking ahead at another option for the smaller DSOs.

Thanks!