TerryMcK

There were just facula visible today.

Yes it has shrunk. I imaged it for the first time on Sunday and looked for it yesterday and it was there but seemed to have split into two much small spots. I saw it(them) around 11AM and by 4PM couldn't see them.

I leave the rig going all night and get up early in the morning to put the lens cap on. I don't fancy clearing guano from the front element. My sequencing software takes care of meridian flips and I have decent cable management which, in my view, is a must to prevent snags. I have a pier extension so clouting the camera on the tripod is impossible.

Here is my cleaned up version. Scope WO ZS103 Camera ZWO ASI183MM Pro with Ha filter only - 7 x 360 second subs. Processed in PixInsight and PS M52 can be seen on the right hand side and some faint Ha from the Bubble Nebula can be seen creeping in at the bottom.

Frankly I was struggling to find it in my binocs but I was imaging the exact coordinates last night, Sunday 21st March 2021, as there was a brief spell of clear sky. This is a rough of one of the seven 6 minute subs I got.

OK I have found out what the issue was with my William Optics scope - after quite a bit of testing with the artificial star and different scenarios. It was not pinched optics, nor aperture vignetting in fact it was nothing to do with the front elements at all. It appears that the field flattener had a slight burr that had been raised on the clamping ring probably in the factory. This burr was what could be seen on larger stars. I took a small file to it to remove the burr and all is ok again. No lighthouse effect at all. The burr can be seen on the tightening slot (slightly out of focus but try getting an iphone to focus this close ) of the clamping ring. It could be felt quite prominently as a sharp raised point. The burr was the slight shark fin shaped lump in the corner of the slot in this close up shot. The miniature file smoothed it out, I blew the metal away carefully with a blower and then reassembled the flattener.

The ZWO ASI 2600MM is the way I would go

Here is mine processed in PixInsight Combined rgb with ChannelCombination in rgb mode Combined lum to rgb with ChannelCombination in HSI mode Ran Dynamic Background extraction Ran Photometric Colour Calibration Histogram transform after tweaking the STF slightly Ran Starnet on this image to remove stars Created a rangemask and applied it to destarred image Inverted the mask to project the galaxy core and then tweaked the saturation, luminescence slightly to bring out some colour Next stretched the Ha image and removed the stars Ran the script NBRGB combination to add the Ha to the red channel Denoised the NBRGB_Combination image Ran the DarkStructure Enhance script Ran a local histogram equalization twice on the image with slightly different parameters Used PixelMath to add the RGB StarMask back to the NBRGB Image Called it finished

Just ordered one. Thanks for the heads up Adam. It looks useful.

Very nice image

Looking good so far Michael. It is a difficult target as it is so faint.

I can concur the 120MM mini is fine on Pi.

I've been able to remove the dew shield. It was very easy in the end. Hold the aluminium ring where the clamping thumbscrew is and simply unscrew the shield and withdraw it off the main tube. Couldn't have been easier. Underneath the cell mounting is clearly evident and has a number of screws around the periphery arranged in two lines one per lens. I used a jewellers screwdriver to see if any were tight. Most of them were barely nipped up apart from one which was slightly tighter than the others so I have backed it off a hair. We are talking probably a 1/32 of a turn so nothing much. I have assembled it back together and will wait for a clearance in the cloud test. If it is something else then happy to listen. Here is a zoomed in view with PI STF - an hour at 60 second exposures. I have noticed this before and it seems to occur in the winter. It was about -2C last night but I had the dew heaters on around the cell area. If not the lens cell could it be at the other end where the field flattener is?

That was some other place Carole

It looks similar to this old thread hence my assumption that it may be pinched optics

I was out last night taking snaps of M45 and have just done some processing only to find what looks like pinched optics or maybe something else from the scope. The scope was out all day so had plenty of time to acclimatize. I have seen this intermittently before and now is the time to take action. Anybody know how to move the dew shield, not necessarily remove it or dismantle the entire scope, on a ZenithStar to gain access to the cell securing screws?

Not sure if you have one but a Bahtinov mask will get you in focus really easily. It takes all the guess work out of it.

There is something in there but I struggled to bring it out. I've removed the stars and denoised it. The dust bunnies can be partially removed in post as I have done here but you can lose data of course. I can see some glimmer of red in the image so I'm guessing that this camera hasn't been astro modded at all? Here I have run Gradient Exterminator and brought up the reds selectively I then used some masking to bring up the detail and added the stars back after doing a star reduction Quite rough processing on my side, a lot of dust moats and quite blurry. But it shows it can be done with a little work. The colour detail is quite sparse hence the fuzzyness however it has caught some of the shape of the Rosette. I used a combination of PixInsight, PhotoshopCC 2021 and Topaz Denoise AI BTW.. You are on the right tracks with going forward with the purchase of a light flats panel as that will minimize dust bunnies and vignetting.

Use MLT before stretching or as it is called histogram transformation. Use TGVDenoise after stretching.

Hi Craig. Try the new weighted batch preprocessing script in Script>Batch Processing>WeightedBatchPreProcessing If using CMOS add your lights, darks and flats - use your normal subs for CCD (I think that is just lights and flats?). Click on the control panel tab and experiment with clicking a few of the parameters. Set your output directory and click Run and you will get pretty good results. You can put all subs taken with all three filters in at once and they will be sorted into Ha, SII, OIII etc dependant upon the FITS header. There are 3 free tutorial videos from Warren Keller here if you want his explanation on how to tweak things. https://www.mastersofpixinsight.com/wbppv2

Very well done. It looks great.

Glad you got that sorted out. I have a box full of those flat cables and haven’t used them. I may put them in recyc.

Here is mine processed as HSO. All done in PixInsight

Here is my entry processed in PixInsight. I have mapped it as SHO and played around a little with that big star Navi to reduce its size as it dominates the picture. I am aware that green is the result of SHO initial processing but think that the ghosts look apt in a greenish glow. The ghosts appear to be back illuminated with the light from that star. But in actual fact it is much closer than the nebula.

I have been working on NGC6888 again based upon the data I collected back in August/September 2020 and processed in PixInsight in my Bortle 7/8 skies with no real darkness. Telescope: William Optics ZS103 with x0.8 flattener/reducer Camera: ZWO ASI183MM Mono 154 x Ha subs at 3 minute duration. Gain 111. Offset 8 90 x OIII subs at 3 minute duration. Gain 111. Offset 8 43 x SII subs at 3 minute duration. Gain 111. Offset 8 Processed as HOS with PixInsight and cropped. I tried HSO and SHO but liked the HOS much more.