wimvb

Well done, winners!

We're already there. I saw very thin clouds two nights ago. Unfortunately too thin to photograph.

Hear, hear! Adam is a first class educator, who not only explains the "how", but also the "why". Thanks for inviting him.

Only 11.35 hours according to the publication by Gabany and Martinez-Delgado. It's the dark site that is most important here.

Here's how far I could push the tidal stream. and my final image: https://www.astrobin.com/buqeoi/?nc=user

Wow! impressive guiding for this "budget" mount. I must tune mine and start using it more for widefield imaging.

Great image. Just curious: what guiding rms do you get with the eq3?

Very nice. The stellar stream only shows if your last name is Gabany. https://www.cosmotography.com/ I imaged this galaxy earlier this season, and after 10 hours I still had to use my imagination to see it in a superstretced luminance image. I never included it in the final version.

Captured just before summer recess. A few galaxies, some not so far away, others a bit further. In the "foreground" are six galaxies which are at distances varying from 39 Mly (ngc 3972) to 260 Mly (ngc 3921). ngc 3972 39 MLy ngc 3913 42 MLy ngc 3982 49 MLy ngc 3916 254 MLy ngc 3977 254 MLy ngc 3921 260 MLy The "faint fuzzies" in this image are galaxies with a redshift between 0.05 and 0.06, which puts them at distances between 660 and 790 Mly. LEDA 2490407 @ 660 MLy 2MASX J11542652+5517512 @ 776 MLy Then there are the really faint fuzzies with redshifts around 0.08 - 0.14 or higher, which means these galaxies are 1000 to 1800 Mly distant. 2MASS J11511344+5506592 1045 MLy LEDA 2494537 1606 MLy SDSS J115149.73+550258.6 1800 MLy And finally, there is galaxy cluster [SPD2011] 45352 with its brightest member SDSS J115352.61+551357.9 at a distance of 3040 MLy. Ngc 3921 (Arp224) is a galaxy with a violent past. During an interaction with another galaxy (probably absorbed by ngc 3921), a tidal tail was formed. Also interesting is the string of bright spots on the right hand side of this galaxy. According to Simbad, these are possible globular clusters, but in a Hubble image, they look more like distant galaxies. Capture details: Telescope & camera: Skywatcher MN190 on AZ-EQ6 with ZWO ASI294MM Integration time: L: 7 hrs RGB: 7 hrs (combined) Processed in PixInsight.

It's doable, but with your camera you have the risk of enhancing microlens diffractions. I think that they're just about visible around the brightest star in your image. Btw, this galaxy benefits from Ha: https://www.astrobin.com/full/th3p15/B/

Very nice. This galaxy is a lot weaker than it seems. Which gear did you use?

Yes, but (p/F)^2 is still the same for all three. Noah and Jemima adjusted the F ratio, each in their own way. The third person adjusted the second parameter: pixel size.

Jemima. She doesn't lose pixel scale or field of view. Noah does. But they both can get away with shorter exposure times because of the gain in F-ratio.

No not at all, those are the things we take off a telescope when we put a camera in place. Oh wait a minute, those are focuser caps. No, no, now I got it. It's those things you put in the holes in that plate under the mount. (Now you see why imagers want a pier.)

Use the same argument next time she wants to go on vacation, just when you want to catch that solar eclipse, comet, etc. 😉

What if you swap the eyepiece? Edit: unintended doubling of the magnification

If the camera is the same, it's only pixel size in micrometers that is the same, hence (p/F)^2. Pixel scale still changes with focal length. The interpretation of the formulas is that if you change aperture, you change the collecting opening of your system. Whereas, if you change the focal length, you change the sky area that is covered by each pixel. Shorter focal length means that each pixel collects light from a larger patch of sky. Larger aperture means that the photons coming from a patch of sky are collected by a larger funnel. Either way, you get more photons on each pixel. And also, either way, you decreased the F-number of your system.

The light gathering ability (efficiency) of an imaging system is proportional to (p/F)^2, where p is pixel size, and F is the F-number. This can be rearranged to (r*D)^2, where r is pixel scale (arcsecs / pixel) and D is aperture. When @gorann and I processed images from the Liverpool telescope, we didn't need lots of data because a slow system , F=10 was combined with large pixels (30 um). When Göran switched to a RASA, he used a more common pixel size with a fast system. Again, he didn't need much integration time. The optical resolution of the system is an entirely different matter.

Try more aggressive pixel rejection in dss; what you have is hot pixels and so called walking noise. For future images, increase the dither step in PHD, this will break up the pattern created by hot pixels. For a dslr ( and in my opinion also for cooled cmos), you need to dither at least 12-15 pixels in your imaging camera. Have you tried stacking the individual exposure times, ie a stack with only 180 s exposures, one with only 300s , and one with only 600 s? It may very well be that one of the three exposure times deteriorates the whole stack.

Use scnr green, then saturate away.

There's no need to. Great image

Yes, I agree. But there should be more colour in your image.

Thanks, Peter. This wasn’t an easy image. The galaxy is very faint, and needs a lot of data to lift it from the noise floor. I also have Ha, but so far I haven’t managed to incorporate it the way I would like it.

Holm 124 or Holmberg 124 or LGG 173 is a group of four interacting galaxies in the constellation Ursa Major. Both "Holm" and "Holmberg" are used as names for this group. The latter makes more sense to me, since there are several Holmberg objects, but I hadn't heard the name "Holm" before. Anyway, the largest galaxy in the group, ngc 2805 is at a distance of approximately 80 million light years, while the other members are somewhat closer; 72 - 75 Mly. Ngc 2805 was discovered by William Herschel in 1791. This is a barred spiral galaxy with a diameter of about 149 000 light years, almost 50% larger than the Milky Way. In this fov, it only covers 6.3 x 4.8 arcminutes. The edge on galaxy in this image is ngc 2820, approximately 74 million light years distant and 85 000 light years across. The tiny galaxy at its lower tip is IC 2458 or ngc 2820A, a lenticular dwarf galaxy, only 10 000 ly across. Finally in this group is ngc 2814, just to the right of ngc 2820. This barred spiral galaxy, also seen edge on, is approximately 25 000 ly across. Quite a bit further away are galaxy clusters [AM2011] 2 (near the lower right corner of the image, looking like a swarm of gnats) and SDSSCGB 30048 (just above the larger red star in the lower right corner). The former has about 50 members and is at a distance of 1.6 billion light years, while the latter is at a distance of 1.8 billion light years. Capture details: Telescope: MN190 on a AZ-EQ6 Camera: ASI294MM with Optolong LRGB filters Exposures: L 145 x 150 s; R 42 x 150 s, G 40 x 150 s, B 52 x 150 s Total integration time: 11.5 hours. Captured last February.

Port 3389 is the most common RDP port, so any intruder would try that first. You can have RDP through any port, but you have to specify it when connecting. For example, if you open port 54321 on your router for RDP, and your public IP address is 111.222.333.444, you connect with: 111.222.333.444:54321 Your router will route any incoming conection to your RDP assigned address: 192.168.1.999:3389 The advantage of also changing the port is that any intruder will need to know both your IP/domain name AND port to gain access.