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I use Aladin nowadays. It doesn’t have any scope information or anything, but I just set the fov close to that of my scope and camera. Aladin allows me to explore what will else beside the main target will be in the image and explore the best framing. A 1000 mm fl telescope is a wide field instrument for these small galaxies, and rather than crop, I try to include some extra ”eye candy”. All images from the 2020/2021 season on my astrobin page were planned this way. https://aladin.u-strasbg.fr/AladinLite/

@AstroMuni, probably posted in the wrong section. This is the galaxy competition thread. You probably want to post this in the imaging section. cheers,

Orientation of the guidecam is unimportant. That’s why you do a calibration. But there is an easy way to align your guidecam. Turn tracking of and take an exposure of at least ten seconds with the guide cam. You should see star trails, mainly in the RA direction. If they are very short, repeat with double the exposure time. Turn your guide camera so that the trails line up with one edge of the sensor. If dec drift caused guiding to fail, phd would show the message ”star lost”. And you would see a drop in star mass. This is not the case. Poor polar alignment is in my opinion NOT the cause of RA wandering off that quickly. Next time out, do a polar alignment. Then point near the meridian, about 40 degrees up and do a phd calibration. After that, run guiding assistant for at least 10 minutes, preferrably longer. Use the suggested settings, and check polar alignment error. Then start guiding while you sit by the mount. (Let phd choose a star, as long as it is not too close to the edge of the frame) Make sure cables are tidied up or hang free. And of course, make sure the mount is balanced, perhaps slightly heavier on the east side. Watch the guide graph and take note when RA starts to wander off. Good luck

I would probably run the polar alignment procedure twice. That should get it close enough.

PEC helps unguided tracking in RA. With good correction and a high end mount, you may very well be able to do 5 minutes unguided exposures. But with long exposures, you also need good polar adjustments, or you’ll get DEC drift. You should definitely try this: record the periodic error and load it into your mount or its control software. Then with sidereal + pec tracking, use the phd guiding assistant to show residual periodic error plus polar alignment error. Let that determine your longest exposure time.

? Binning has the effect of doubling the pixel scale (”/pixel), not dividing by 2.

That step in DEC is interesting. Something caused a sudden jump, even in RA. But guiding recovered. There is a smaller step earlier in the sequence. Even here, guiding took care of it. But it makes me wonder; how is the guidescope attached?

It’s a star adventurer, so no dec motor. This is ok in the settings. According to the log, there are sections where guiding is fine during at least 1.5 worm cycles. If the mount gets stuck, it must be in the main RA wheel. When this issue is resolved, there is still room for improvement, because the guiding shows a period of about 17 s, which is in the gear near the stepper motor. If the ASIAIR guider outputs a guidelog, the OP should try this guider and compare with phd. The only conclusion I can draw so far is to check the mechanics: balance, clutch, cables, free movement. For the latter, with no load, release the clutch and spin the RA. It should move easily and not get stuck anywhere.

I'm confused here. This image is not from your phd log file, because the equipment is a G11 mount connected with ASCOM, whereas in your original post you wrote that you use a star adventurer. And the guide log that you provided is for a star adventurer (ST4 port and only RA calibration). Anyhow, when the guiding suddenly starts to wander off, it is usually a mechanical failure or cable snag.

My thought also. You wouldn’t want much heat coming from the camera, because that would create problems of its own. I don’t think it matters much where you have the cables crossing the light path. The distance from the back of the camera to the corrector plate can’t be more than about 15 - 20 cm. On the other hand, there is more diffraction from the full loop in Göran’s setup as compared to a half loop, since it is every edge that contributes to diffraction. Whether this will be noticable in the images is another matter.

How long does it take to download an image from the dslr to the RPi? You may have to add a delay in the focus routine to allow for the download time. Just an idea.

You wrote that it happened shortly after sunset. At your altitude it probably didn’t last long as the sun moved further ”down” and couldn’t illuminate the clouds any longer. To see nlc during most of the night, you need to be further north.

Most likely what you guessed already: featureless noctilucent clouds, at lower than normal height.

in short, indi is an alternative to ascom, a system of drivers and software for hardware control (mount, focuser, camera, guiding, observatory automation, input from weather station, etc). It runs mainly on linux, as opposed to ascom which runs on windows. Indi connects also to a user interface or stellarium program. Many users let a stellarium program called kstars connect to indi. These programs that are the user interface to the hardware are called clients. Even PixInsight has some basic functionality to be used as a client. Ekos is the plugin to kstars that does the actual hardware controll. https://indilib.org/ One of many videos on youtube: finally:

Clear give aways: INDI with Kstars/ekos For robotic imaging, to quote George Clooney: ”what else?” 😋😋

From a dark site, you need longer exposures to clear the read noise floor. Unless you use a cmos at high gain (low dynamic range), the exposure time will be too long for guideless imaging. At low gain, expect even L to need at least 1-2 minutes exposure time. With an osc, the exposure times quoted by Olly and Göran are what you would expect. Next thing Olly will drop down on us, is that he will do the processing entirely in PixInsight. 😋

It does. A mountain surrounded by dark clouds.

Very nice. Isn't this also known as the propeller nebula?

Excellent image of this little gem. I found that it benefits from adding Ha. https://www.astrobin.com/full/th3p15/B/

Let us know how it is when you get it back. Good luck!

That's a nice start. Since you are targeting stars, you probably don't need to worry too much about exposure time. Keep the time short enough so you don't blow out the core of the stars. I would keep the camera gain constant, but maybe increase the exposure time for B (or just take double as many exposures). This will make calibration easier. As far as I know, the ASI178MM has amp glow, and in order to calibrate this out, you need to match the dark frames to the light frames in exposure time, gain, and (if possible) temperature. Having fewer settings to worry about makes this process easier. Good luck.

Very nice catch. To improve this image, you should really take more exposures. The cluster is bright enough, so you probably don't need to use longer exposures, but do take more of them. Dark frames don't always help if you have a dslr, only experimentation will tell. But flat frames are a must, especially if you want to try larger targets. There are quite a few targets that fit your setup very nicely: the Andromeda galaxy (M31), the Pleiades (M45), the Beehive cluster (M44), the Orion nebula (M42), the Leo triplet of galaxies (M65, M66), etc. The simplest way is to check with a field of view calculator, such as this one https://astronomy.tools/calculators/field_of_view/

Another way to see how aperture, focal length and field of view are related is to compare to a zoom lens. When you zoom in, the lens diameter stays the same, but the focal length and the view change. So does the F-number.

In a standard newtonian, there's only one distance to take care of, and that's from the primary mirror to the focal point. If you move the primary up the tube, you also move the focus outward, and vice versa. Basically, you can move the primary, the secondary, and the focuser up or down the tube in unison, without changing anything. In a Mak-Newt on the other hand, you have the critical distance from the fixed corrector plate to the primary. And just because the corrector plate is fixed, everything else is fixed as well. The only freedom you have, is tilting the optical components (secondary, primary and focuser), but you should not move things up or down the tube, because then you change the distance to the corrector plate. Btw, I always have this site up as a good MN190 reference. https://www.iceinspace.com.au/forum/showthread.php?t=140193 Rereading your thread, I see that I linked to this site before. I still have it open in a tab in my web browser. 😁

At unity gain (100 setting), the camera has a substantial decrease in read noise, and a corresponding increase in dynamic range. That's why it makes sense to start with this gain. For nb imaging you may want to use a higher gain setting in order to keep the exposure time down.