Starwiz

1 hour ago, malc-c said:

It look like the star just disappeared around frame 590.  Whilst the S/N and Starmass is up and down (possibly related to the guide rates being low) at that frame it dropped completely.  Could it be that after the 47 minute mark the star went out of the fields of view of the OAG or cloud cover ?

Yes, I definitely lost the star sometime during the night probably due to clouds coming over.  I still got 14 x 360s of OIII, so the session was worth it.

John

18 minutes ago, kens said:

I usually disbale Star Mass detection:

https://openphdguiding.org/man-dev/Advanced_settings.htm#Guiding_Tab

Or it could be a camera or USB problem? PHD2 has an option to save lost star images as well. It is normally enabled to some level so you may be able to view/post one or more of those.

Not related but your guide rate is very low at 0.1x sidereal. You should increase it to 0.5 to 0.9

Many thanks for the advice Ken, I'll try it out tonight if it stays clear.

John

35 minutes ago, malc-c said:

If you have the log file enabled and saved, maybe post that to help diagnose what the issue my be.

Thanks.

I think this the relevant log.  Star mass changed?
 

PHD2_GuideLog_2020-07-15_232352.txt

I started guiding last night and did a calibration first.  It seemed like every other frame, the PHD2 window flashed red like it had lost the guide star, but the guiding looked fine.   The guide star was also bright enough.  I'm using OAG.

The only time I've seen this before is when the guide star disappears due to clouds.

Any thoughts?

John

32 minutes ago, x6gas said:

That colour mapping does work well and the star colour looks good to me.

On my screen parts of the nebula look over-cooked (both in terms of saturation and brightness) but that's a matter of personal taste.

Yes, quite possibly.  I have two laptops and it looks different on each due to the screens.  It looks different again on my mobile phone, where the colour saturation always looks much higher.

John

Imaged from Mellieha, Malta during the last week.

I wasn't happy with the way the standard Hubble Palette turned out, so I swapped the mappings to:

SII = Red

Ha = Blue

OIII = Green

John

18 hours ago, Colossal Plossl said:

Hoping to see Saturn one clear night.....

Welcome.  You'll never forget the first time you see Saturn.  Enjoy.

John

19 hours ago, John said:

- Cartes-du-Ciel

- Stellarium

John,

I use CdC, but have never tried Stellarium.  Does either have advantages over the other?

Thanks

John (A.K.A. Starwiz)

Not quite sure what's going on here, but the unwanted artifacts at the bottom of the image don't show when I open it on my machine?

NGC 6960, 'The Witch's Broom'.

Imaged over several nights from Mellieha, Malta in SHO.

The stars were shot in RGB and were processed separately.

This was a difficult one to process because of the very bright 'witch' star.

61 x 360s Ha

41 x 360s OIII

56 x 360s SII

2 hours ago, John said:

I'm not going to turn into an imager any time soon

That's what you think.  😆  This is how it all starts, and before you know it....................

1 hour ago, Tommohawk said:

Looks pretty good to me!

Regarding correcting coma, are you using a coma corrector? In any event I think you might want to look at collimation - you seem to have quite a bit of coma bottom right and not much top left.

The bright star does look a bit green - easy fix though just select it and change hue/saturation. Hmmm.. just had a try at this and not so easy! Maybe careful use of clone stamp?

Thanks.

Hopefully I'll be getting a coma corrector in late December.  I've written to Santa already.  😀

I last collimated a couple of weeks ago, but will re-check.

Green hue on star - I've used a lot of clone stamping on the mono images to removed the star, so will take another look.

Thanks for your help.

John

So here's my attempt at controlling the 'witch' star.  I've still more work to do on correcting some of the coma and cropping out a few stacking artifacts.  I also want to alter the hue of the bright star as it's looking a little green.  Comments for improvements welcome as always.

John

47 minutes ago, alacant said:

Hi

Do you mean without a dedicated processing app? There's a tried and tested method from way back which consists of stretching your image with an inverted star mask layer over the top of a duplicated image. This guy explains it.

Not very elegant, but it maybe worth a try.

Cheers and HTH.

 

 

Thanks. 

I'm using Straton to remove the stars, but the brightness from the 'witch' star is such that much of the area surrounding it becomes brighter than the nebula when stretching.

John

8 hours ago, Aramcheck said:

I haven't tried this properly yet, but there's a free script for Pixinsight called GAME which is very good for creating masks. You can use it to mask star halos by creating a Gradient mask and a Brightness mask; and then subtracting the Brightness Mask from the Gradient mask to create the Star Halo mask.

Here's a very rough example, which should have had intermediate steps added to exclude the dimmer stars & probably should have been done whilst the image was still linear.

Cheers
Ivor

That's interesting, thanks.  I'm processing in PS, so there may be an equivalent way to do the same.

John

13 hours ago, happy-kat said:

What are you using to process your image?

Have other members mentioned what they did when processing this target?

I'm processing in PS.

I've had a good search in the NGC6960 posts, but haven't been able to find anything useful.

John

I guess that's a 'No' then.  🙂

This was my primary a couple of weeks ago just before I cleaned it for the first time in about 10 years.  The secondary was just as dusty, but I'd been taking great images without any noticeable effects.

John

1 minute ago, Tomatobro said:

Although I have not used it I think that dither is controlled by PHD and not the imaging laptop.

I think it works that APT sends a command to PHD2 to tell it to dither, so I think this would be a problem if both were running on different laptops.

APT needs to do this as PHD2 doesn't know when the imaging frame has been completed.

John

7 hours ago, Tomatobro said:

I run one laptop to manage the mount, navigation and guiding and another for the imaging camera. The mount control laptop is a used £70 win 7 version and works flawlessly, first time every time just like an Anvil. The imagining laptop is not quite as reliable but near enough.

I keep looking at ASIair pro to replace the mount laptop but still undecided.

I have seen that when both the imaging and guiding are on a single laptop when both download images together  then a conflict seems to occur and its PHD that looses its guiding camera but it usually re-establishes its camera connection after the camera timeout setting limit is reached.

 

I just thought.  If you're using one laptop to control guiding and another for imaging, how would dithering work?

John

6 hours ago, nigelg said:

Open Devise Manager and check all devises unchecking Power Management. I have had it closing down a device during a long exposure.

Thanks, I'll have a look.

John

4 hours ago, Aramcheck said:

If I could change one thing, it would be my location. I've not had any issues (yet) with USB reliability, but neighbours lights and general light pollution / sky brightness is something I'd love to be able to sort out.
Cheers
Ivor

That's under your control.  Move to mid Wales.  🤣

Cheers

John

1 hour ago, Tomatobro said:

I run one laptop to manage the mount, navigation and guiding and another for the imaging camera. The mount control laptop is a used £70 win 7 version and works flawlessly, first time every time just like an Anvil. The imagining laptop is not quite as reliable but near enough.

I keep looking at ASIair pro to replace the mount laptop but still undecided.

I have seen that when both the imaging and guiding are on a single laptop when both download images together  then a conflict seems to occur and its PHD that looses its guiding camera but it usually re-establishes its camera connection after the camera timeout setting limit is reached.

 

Thanks.  I have two laptops although one is quite old, but I'll give it a go.

Yes, I was seeing PHD2 losing the guiding camera, then reconnecting last night so it sounds like it could be the same problem you've seen.

John

If you could change one thing to remove some of the frustrations of deep sky imaging, what would it be and why would you choose to improve USB connections reliability? 

I began setting up my imaging run last night which took two hours because of connections reliability.  I finally got the imaging run going with 360s SII frames and waited to check the first frame came out OK.  The imaging camera, my ASI1600mm-Pro wouldn't download the first image.  I checked everything and in PHD2 I noticed that the guide star looked a lot smaller than when I set it running.

What had happened was, my guide camera had disconnected and PHD2 had grabbed the main imaging camera and started guiding from this.  Very weird.   After fixing the connection and updating the camera in PHD2,  I had to shut down APT and reconnect.  It ran fine until about 3 in the morning when I think a similar problem must have occurred as it was still trying to download an image when I went back out at 5 AM.

John

Does anyone know of any tutorials that deal with processing images that have a really bright star?

I've been searching the web but can't seem to find anything.

I'm processing some NB data for the witches broom NGC 6960, but the bright star is over-saturating.

Thanks

John