tomato

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.

With those points driving your decision, I think a used KAF 8300 CCD is a sensible way to go. There is a Moravian G2-8300 currently on ABS UK.

Bravo for rising to the challenge of imaging a broadband target like M51 from a Bortle 8 location.👍

I did some tests last night with the RisingCam IMX571/Esprit 150 in poor conditions (some thin cloud, nearby 90% illuminated moon) and the subs look like this: Fair enough, you might say, the dust bunnies are visible due to the poor quality background. However, the QHY268c on the other Esprit 150 was downloading subs like this: An equally light polluted background but the dust bunnies are much less apparent. I'm trying to run these cameras as close as I can to have the same image capturing properties, with the RC at 100 Gain, 900 offset in High Gain mode, and the QHY at Gain 30, Offset 30 in DSO mode. I don't believe the QHY sensor window is free of dust particles so is it just that the RC is more sensitive compared to the QHY with these settings?

The RASA8 at F2 is super sensitive to focus and tilt. I agree the focus is off a bit but the bottom LH corner stars look a better shape than the others so that would indicate to me that the backfocus is not far off and there is some tilt on the sensor. Other RASA8 owners on SGL have made a simple jig to allow tilt adjustments off the scope, see attached thread. I have a QHY 268c which has a coarse tilt adjuster built in which allows me to make adjustments fairly easily when the camera is on the scope but either way you need to have some form of tilt adjustment with your ASI 1600. The Celestron RASA camera adapter has some squidgy material on the mating face which I wasn't keen on, as it introduces a variable into the imaging train at a critical point, but other RASA imagers use it OK. Don't be put off, the RASA is an amazing imaging scope.

@gorann has a point, sales of new CCD cameras must be dwindling, but on the other hand there are an awful lot of outstanding CCD images out there and I’ve made the point before that these cameras don’t suddenly stop being able to produce quality results just because CMOS has come along. So here is maybe another topic for discussion: are CMOS cameras a better choice for folks buying a dedicated Astro camera for the first time? Personally I find the processing stage the more challenging aspect of the process with either type of camera, and the approaches to capturing the data are different, but if you are on tight budget I would still seriously consider a used CCD.

I’m a bit late to the thread, but I think it’s a great image worthy of some more integration, but then galaxies and galaxy clusters are far and away my favourite imaging subjects.

I have used both the Atik and Moravian mono cameras, they are both solidly built and perform flawlessly. I'm sure the QSI would get the same assessment. The Atik might be available cheaper but you would need a separate filter wheel. Steer clear of the OSC versions, though I think they are quite thin on the ground.

I have just connected the camera through NINA, here are the details: If you have the camera with the integated filter wheel, you will need to connect to this separately on the FW screen.