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View Full Version here: : LMC under clear Bortle 4 skies


Plossl68
08-01-2024, 08:35 PM
I find this a beautiful target. Equipment for this one was:

Samyang 135mm prime lens at F8
SkyGuider pro with ASIAIR+ guiding
ZWO 2600MC
50 x 120 sec lights
25 x 120 sec darks
No filters
Bortle 4 skies
No flats nor bias frames
Stacked and processed in Affinity Photo.

Unfortunately the 200kb version has lost some of the sharpness. I swear the original is better ;)

Cheers,
Paul

AstroViking
09-01-2024, 09:58 AM
The LMC is an interesting target to image. Once you start looking closely into what's present, there is simply so much going on that you can lose yourself in it.

Dave882
09-01-2024, 12:01 PM
Great shot! I’d love to see the bigger version

John W
09-01-2024, 03:45 PM
Nice image Paul - well done. A good target.

Plossl68
09-01-2024, 10:23 PM
Thanks guys,

I was pretty happy with how that one turned out. @AstroViking, I’m completely with you on there’s so much in the LMC. Time to up the focal length now and dive into it piece by piece. Alas, I’m back home now under bortle 7 skies :(

foc
26-01-2024, 04:29 PM
Attractive result. Are good flats hard to get with that gear combination or you just felt they did not add much?

Saturnine
26-01-2024, 11:32 PM
The guiding, focus and the processing looks good, unfortunately the framing leaves a lot to be desired. Would have been a great image if the LMC was more centred in the frame .

OzEclipse
29-01-2024, 11:05 AM
That's a very nice shot but would you share your thinking about why you stopped the lens down to f8?

The Samyang 135mm f2 is very sharp at f2. Stopping down to f2.8 or f4 it quickly becomes quite superb to the corners even with a full frame sensor and certainly with an APSc sensor. I have only ever stopped it down to f 5.6 once when I deliberately wanted to extend the exposure time to 4 mins to test the tracking accuracy of a small SW Star Adventurer tracker.

The main problem with that lens using full frame is vignetting where flats would help. The cut is very hard on full frame and on APSc it is far less of a problem.

cheers

Joe

Plossl68
02-02-2024, 05:43 PM
Hi Joe,

I’m embarrassed to admit this but……

The last time I used the lens was on the beach. To protect it from any mist fogging it, I’d bought an inexpensive UV filter to screw on the front. Problem was that I forgot to remove the filter before packing it away. So, when I pulled it out in the dark at Daylesford 3 months later I didn’t even see the filter was still screwed on. I took some test shots and noticed some slight star shape issues. To try and improve things I stopped it down and ran my sequence. It was only when I was packing up the next morning that I saw the filter was still in place.

Lots of cursing, but I only have myself to blame.

Cheers,
Paul

Plossl68
02-02-2024, 10:43 PM
Hi Ross,

No, I just hadn’t taken the flats when I processed that run. I took them later that day but haven’t reprocessed yet. Will be doing though as I quite like that data.

Cheers,
Paul

OzEclipse
06-02-2024, 11:44 PM
Hi Paul,

Don't be embarrassed. We all have our moments. I certainly have.

Going back 45 years to 1979, a friend of mine was using a Unitron 60mm refractor with manual slow motion controls to hand guide a film SLR with 50mm lens. In freezing cold conditions at a winter astrocamp at Cottonvale, near Stanthorpe, he painstakingly turned that slow motion control following that star on the eyepiece crosshairs for 60 minutes. At the end of the exposure, he released the cable release but didn't hear the shutter close. When he checked, the shutter speed was set to 125th of a second.

Before I moved here, I used to observe and photograph from a friends property north of Yass, 1 hrs drive from my home in Canberra. On various occasions I drove out there and arrived to find:-
1. No power supply cable to connect power to the mount
2. No key to the roof boot where the mounts tripod was stowed
3. Had key to the roof boot where the mounts tripod was stowed but grit in the lock and couldn't open it. Didn't have any silcon lube spray.
4. Arrived to find I left battery on charger in Canberra. Property is remote and I didn't like running scope off the car battery. Compact hatch with small battery.
5. No eyepieces
6. No camera battery
and so on.

The really great thing about having backyard Bortle 1/2 is that I can't forget anything at home.

I didn't ask to embarrass you, I only asked you to see if you had a really bad version of the lens. If so, it would be the first I'd heard of. Every person I know who has bought one, has been stoked with the lens quality.

Cheers

Joe

Plossl68
08-02-2024, 10:31 PM
All good Joe,

I’m long enough in the tooth to be able to laugh at my mistakes, which is a useful trait with astrophotography as a hobby. Thanks for sharing your stories too.

I’m truly riddled with envy though at your Bortle 1 / 2 skies.

Re the lens, I’ve been very impressed with the quality. Dollar for dollar, it’s one of the best bits of kit I own.

Cheers,
Paul