TheSkySearchers

I caught a little light on M45 a couple of years back at the end of a long night of collecting M33 subs. It really didn't do justice to the nebulosity and I wanted to get out and give it a real run. Wednesday night (coldest of the season so far) was that chance.

It was an auspicious start as after I placed the tripod in its marks, installed all the gear and wired up, then went to drift align, I found I was within two arc-minutes of the pole. I took that as a good omen and moved along. It was the first time I haven't had to make any tweaks to the alignment when setting up.

Next was focusing. Because it was still too early for Aldebaran or Capella to be high enough in my sky. I slewed to Caph and started there. I haven't quite gotten the knack of using the Bahtinov mask tool in APT, so I have been using the FWHM/HFD measurement to fine tune the focus. That went OK and I was able to slew over to my target for framing.

One thing I have noticed in earlier images is that the coma correction hasn't been quite what I expected. After reading through Toms thread, I spent some time earlier this week validating that the back focus spacing was actually 55mm (44 for the Canon and 11 for the t-ring). I also decided to remove the stop-ring from the back of the CC to allow the front face of the t-ring to sit flush with the top of the focuser tube. As I tightened the locking nuts on the focuser I applied even pressure to the back of the camera to keep everything as flush as possible while securing the DSLR/CC into the drawtube. I like the results better than any I have seen thus far.

By 1915 I started collecting 180 second subs and ran until about 0100 Thursday morning when the clouds started to move in. During that time I got 84 subs and APT did an automatic meridian flip - I love the tool for that capability. I wound up tossing 6 subs because they were somewhat invaded by clouds and had a lighter background than the rest. I calibrated with 81 flats and 81 dark flats. I like this combination better than flats and a master bias, it seems to produce better results for me. I also passed on adding any darks as I had nothing nearly cold enough in the library and as the temps had dropped to 17F I didn't want to spend more time collecting them. Frost was forming on the OTA and camera and I didn't want to keep them out in the air either. I find that dithering between each image does a decent job of reducing noise when I get this many subs.

Data was calibrated and stacked with DSS and post-processed using StarTools 1.6.382. I tried first with 1.7.447 but I still don't have the hang of the new modules and terminology yet. I will go back and try again. The 1.7 version did keep more faint nebulosity, but felt a bit "unkempt" to me. I used a pretty standard process for me - Autodev, Bin, Crop, Wipe, Autodev w/ROI selected, Deconvolution, HDR, Sharpen, Color, and de-noise classic. Went over to PhotoShop, but just to save the upload jpg file - no adjustments done there.
Comments and suggestions are encouraged.

Bob

in my eyes, it's very pretty.
the nebulosity is superb.
thx.

Looks great! Well done!

Looks good to my eyes Bob.

That's a thing of beauty Bob! The nebulosity around Merope is really detailed.

Regards

Graeme

Outstanding image Bob!

The sparkle, nebulosity, color and dustiness are all there in fine form!

You really did a nice job on this version for sure. One of your best images! Definitely for the "Wall"!

Just to note, the Batinov Tool in APT in Live View worked very well for me. Early on, I found lots of jumpiness until I set the stack count to 10-15. You might have already tried that, but it really settled things down for me. Now with the ASI camera, I use 5 second exposures and it takes a bit longer, but works great.

Thanks for sharing your wonderful image!

Twinle, twinkel not-so-little stars. Beautiful.

BABO

Juno16 wrote: ↑Sat Nov 21, 2020 12:29 pm Outstanding image Bob!

The sparkle, nebulosity, color and dustiness are all there in fine form!

You really did a nice job on this version for sure. One of your best images! Definitely for the "Wall"!

Just to note, the Batinov Tool in APT in Live View worked very well for me. Early on, I found lots of jumpiness until I set the stack count to 10-15. You might have already tried that, but it really settled things down for me. Now with the ASI camera, I use 5 second exposures and it takes a bit longer, but works great.

Thanks for sharing your wonderful image!

Thanks, Jim. I am pretty pleased with this one. Thanks for the info on the baht mask tool. I rarely (if ever) use the "Live View" function in an effort to keep the sensor from heating up. Over a six hour period it probably doesn't make much difference. I take single images using the "Shoot" button and load the Baht tool to analyze the output. It tends to go to 0.00 offset very quickly no matter what the diffraction image looks like. A problem on my part, I'm sure. I just need to get used it it. It is the only feature that makes me want to go back to BYEOS sometimes.

Graeme1858 wrote: ↑Sat Nov 21, 2020 8:04 am That's a thing of beauty Bob! The nebulosity around Merope is really detailed.

Regards

Graeme

Thank you Graeme. I am really happy with the detail in this one. Not that I won't reprocess it a few times, who can resist tinkering!

Bob

Bob, that looks great. Love the C6N for imaging. 2 thumbs up.

I really like it Bob, and the twinkling nature of the stars really shows.

Hi Bob. A superb M45 (Pleiades or Seven Sisters). This is my favorite DSO and a sign of the upcoming winter in our skies. Excellent contrast and beautiful blue reflection nebulosity in your work. And as Graeme said, you did a great job with the Merope Nebula details too. Thanks for sharing your capture with us on here Bob, and the best of regards.

Very nice Bob, that coma corrector works really well! All stars are perfectly round. You captured some great nebulosity.

I just ordered a fancy Paracorr because of Tom's experiences, but yours seems to work great. Yours is an F/5 though while mine (once I receive it, I have to wonder if I ever will) will be F/4 like Tom's so maybe that's the difference.

Beautiful capture Bob!! Soooo much nebulosity! Just a GREAT JOB!!
Tom

SkyHiker wrote: ↑Sat Nov 21, 2020 4:25 pm Very nice Bob, that coma corrector works really well! All stars are perfectly round. You captured some great nebulosity.

I just ordered a fancy Paracorr because of Tom's experiences, but yours seems to work great. Yours is an F/5 though while mine (once I receive it, I have to wonder if I ever will) will be F/4 like Tom's so maybe that's the difference.

Not to worry, Henk. I'm sure the Paracorr will do a better job at f/4. Keep in mind that it took me two years with the mkiii to get this nice a result. Getting everything aligned without threads in the draw tube has been a challenge.

Bob

Very nice! I love the muted/subtle blues and the pinpoint stars. Excellent

Beautiful!

Sweet, Bob. Nice nebulosity. For some reason it reminds me of Christmas.

Very nice

Great image Bob. I particularly like how you have got the colours of the background stars so well defined.

I've given up with bahtinov tool in apt. I just "shoot" successive images under a magnifier tool and eyeball it. I guess if I pixel peep my focus may not be perfect but it's pretty close.

Most definitely a keeper, superb work. Well done Bob!