tomato

Great M51 Wim, another fine result from your MN190/ASI 294 combination. My Astro darkness is dwindling fast but will keep going into June. I like your observation on the Ha channel, I think there is science to be found as well as beauty in the images we capture.

Great result on a galaxy that doesn’t seem to get much attention from imagers. I also suffer terribly from the “I must post this now syndrome”. l think I should automatically defer from posting my first ‘final’ image as invariably I will produce two or three more later on which I will deem to be better than the first one.

Given Orion Optic’s USP appears to be that they offer exquisitely engineered telescopes with outstanding optics, I do hope they read this thread and address your concerns. I bought a scope off them way back in 1990, I wasn’t impressed with the engineering. I don’t know if the optics were any good, because I could never collimate the darn thing properly.

It is a quite humbling notion that for some alien imager to capture our galaxy at the time you imaged theirs, if life and evolution follows a universal timeline, their species hasn’t actually evolved yet… Great image BTW.

You are quite right, l have noticed ghostly remnants of trails if I zoom in, but I’ve never changed the default settings. I do need to become more of a pixel peeper.🧐

Here is a 5 panel mosaic (well, 4.5 really, I needed an extra panel to fill in the top LH corner of my original plan) of Markarian's Chain and associated galaxies, centred on the 'Eyes', NGC 4438 and NGC 4435. The FOV is about 2.5 x 1.5 degrees, the PI annotated image lists a total of 302 galaxies. Captured with the Esprit 150/IMX571 OSC dual rig, 60 x 2 mins on each panel. Calibrated, stacked and mosaic assembled in APP (1st LNC, 3 iterations, MBB set at 10%), further processing in APP, PI and AP. This version is at the original sampling rate, 0.714 arcsec per pixel, no resampling.

Excuse my ignorance but can I infer from the above that the Mesu mk 1 has some technical advantage over the Mk 2? From what I have seen they perform the same. What do the extra encoders on the mk 1 allow you to do?

With a few clear and moonless nights recently, I have been attempting a mosaic of the Virgo galaxy cluster. With it only reaching an altitude of 50 degrees from my location I have to image either side of the meridian which means it is in the South west for the latter stages of the session and unfortunately only about 15 degrees above a tall LED streetlight. This means the rig is looking at this: However, the panel in question captured on the scope nearest the light came out like this, (Esprit 150/QHY268c/IR/UV cut filter, 15x 2 mins, default stretch in APP, no gradient removal applied): After APP Light Pollution removal: For sure, it would be better without the streetlight, but I am pleasantly surprised with what modern cameras can deliver under these conditions. Maybe my extended dewshields help? Oh, and 10 out of the 15 subs had very prominent satellite trails, but APP sorted those out as well.

Here’s a thread on this target w.r.t. minimum integration time needed to capture the squid. 72 mins with a RASA8/QHY268 OSC/IDAS NBZ dual band filter made it just visible.

Well they calibrated out ok, so that’s sorted.

It’s interesting that the RA is especially poor, since I’m assuming this doesn’t suffer from backlash as it either gets speeded up or slowed down to maintain tracking? Are your corrections all on the same side? I would agree that if all the parts are in good order, then you should be able to fettle it to achieve a performance much closer to your other EQ6, though if the previous owner has destroyed the ALT/AZ adjustments, I wonder what other abuse has it received? Good look with the second rebuild.

You won’t have the right imaging set up for it, but if I’m ever fortunate to have the opportunity I would want to image NGC 1365 in Fornax, for me the most photogenic galaxy in the heavens, North and South. Enjoy your stay under Southern skies.

Nice image, it does look like it might be a tough one to process.

If you have to come down on the size of your FOV, you can still image larger objects by doing a mosaic, ie taking a number of overlapping images and then combining them together, but it will take a lot longer to collect the data and there is more involved in the processing. However there are some really good software packages available these days for planning and processing mosaics. And there are cheaper alternatives to the ZWO or the QHY cameras that use the same APS-C sensor, see attached thread:

I've never suffered with walking noise on the 8300. I calibrate with darks, flats and bias frames using APP, this software creates a Bad Pixel Map from these. I have been running a dual rig for quite a while so dithering can be a challenge to implement.

I couldn’t get NINA to work with two HITEC Focusmasters connected via the Generic Hub option to a single working copy of NINA, but it did work using the two instances, and I got the synchronised dithering working also. However, for other reasons to do with dome control I now run a separate PC for each scope.

Like I said, it is a very unscientific comparison. As I recall conditions were better when the CCD image was taken and M33 was better positioned in the sky, and the data was certainly processed differently. The point I was trying to make is even if the market deems CCD cameras to now be near financially worthless, that doesn’t make them worthless as an Astro imaging camera.

There’s a chance the (I stress unscientific) comparison post will resurrect the mono+filters vs OSC debate, but if it does I think the mono camp will have the upper hand based on the images.

I agree the rule is applicable to current kit, I guess the argument is has CCD had it’s day for Astro imaging? I would argue no, but the market decides.

Just out of interest, here is a sort of (unscientific) side by side comparison of CCD vs CMOS, M33 taken with the same scope from the same location: Esprit 150/Moravian G2-8300 mono LRGB 160 mins Esprit 150/IMX 571 CMOS OSC 210 mins: I actually prefer the CCD image…

Really enjoyed watching, thanks for the heads up.👍

You can always bin the ASI 1600 mono if the arcsec per pixel number is a problem.

Another snippet about the dewshield which might be peculiar to me as I operate the RASA inside a dome, but on warm nights I have found that the warm air expelled by the camera gets recirculated inside the confines of the dewshield which results in a drop off in performance of the camera cooler. It’s not a big deal as with CMOS cameras as I don’t run them well below zero, and if you are outside it might not even show up as a problem. The RASA8 with the dual band filter or in broadband imaging is outstanding. I obtained a decent image of the Dark Shark Nebula in a few hours, that my dual Esprit 150 rig, using the same cameras, could not match.

Might be ok on top of a mountain, but down in the lowlands with plenty of ambient temperature variation, Peltier cooler every time. You can retro fit the coolers for a modest cost, but it will void your warranty and they won’t perform as well as a factory installed item. With the latest CMOS cameras, keeping the sensor temperature stable is more important than sub zero cooling, but you need a cooler to achieve that.

Agreed that’s a great price for a used 383, way below the 67% rule of thumb for good quality used Astro equipment. The ASI 1600 would give you the same FOV as the 383 but they might be holding their second hand price a bit more than the CCD cameras.