MichaelBibby

I don't see how: its just a 1.25" filter threaded onto the end of the barrel of the camera. I suppose I could test it with and without...

No filter wheel, just a uv/ir cut filter threaded onto the front of the camera. No OAG. Just a 2" to 1.25" adapter. Yes, your right, it might still be there but just out of view. I guess what I really want to know, from people with more experience than me, is is this evidently and obviously an internal reflection from the inside of the OTA? I will eventually flock the entire OTA, but I'm not in any hurry (unless I know that it will resolve this issue).

I think I already know: what else could it be but the inside of the OTA? I have a theory as to why it wasn't there after the meridian flip: because the position of Alnitak flipped around, and the small amount of flocking I already did on the OTA, opposite the focuser, probably blocked the reflection from that angel. Thoughts?

I am using a Sky-Watcher 6" F5 Newtonian (not the PDS version) with a Uranus-C (IMX 585) and need some advice isolating the cause of an internal reflection in my optics train. Here is my first image of the Horsehead nebula, with Alnitak just out of the frame, and you can clearly see an internal reflection underneath the diffraction spike (ignore the tilt in my optics train, I'm working on it...). After this image was taken I flocked the inside of the tube opposite the focuser, the inside of my dew shield, the inside of the aluminum focus tube, and took a black sharpie to the side of the secondary mirror which was facing the focuser (using a flashlight I determined that these were all possible sources of internal reflection). I then re-imaged the Horsehead with Anlitak clearly in frame and got this image (obviously nothing I did helped because you can still see the internal reflection). The same night I caught that image I did a meridian flip and took this image immediately after (notice the absence of the internal reflection). I'm not sure what else to try. I think I know what most people will say (and its something I'd rather avoid!): completely flock the inside of the OTA, but the inside of the OTA has already been blackened by the manufacturer (not very well, but better than many other newts), and even the aluminum draw tube was also blackened before I flocked it. Why is the internal reflection not apparent after the meridian flip? Any help would be greatly appreciated.

I'm assuming the the diffraction spike that seems to be coming from the right hand side is an internal reflection in my optical train (probably the drawtube of my 6" F5 Newt) of the massive diffraction spike from Alnitak? This is about 100 minutes of 90's subs at a gain of 200 with darks and flats applied. EDIT: I've just flocked the draw tube, the inside of the OTA opposite the focuser, and the edge of the secondary mirror (which were all a source of reflection). Hopefully I'll get a chance to image the Horsehead again tonight, and let it run for at least a couple of hours.

Livestack of the Rosette nebula which I let run for an hour (90" subs at gain of 300, 6" F5 Newt) and which got photobombed by a recent Starlink launch. I think I got rid of most of the tilt in my optics train, so it should give people a bit of an idea of how the coma looks with this chip on an F5 Newt without a coma corrector (this image hasn't been cropped).

NGC300 also known as the Southern Pinwheel galaxy. I used poorly calibrated, barely adequate flats and darks, so its a pretty noisy image with a big stretch on it. Probably about 1 hours worth of data. Minimal post in Siril. Some very distant galaxies in the bottom left.

Yes, plywood is notorious for moisture damage, and its just generic plywood, not for external use. I gave it 3 coats of exterior varnish and intend on giving it a couple of coats of weather proof paint. Someone else suggested giving the ends a coat of epoxy to help better seal the wood, which is a good idea. I'll likely remake it in a year or two (in the shape of a TARDIS), so this is kind of temporary. But the basic idea works very well.

Just a quick update, I've replaced the makeshift coreflute shadecover with a plywood shadecover and installed the solar panel and fan, just in time for summer. When I had the coreflute cover the mount was getting pretty warm (it was semi-transparent and let a lot of light through to the inner plastic cover), whereas with the plywood cover the mount hardly gets warm even on very hot days (I really think it would get warmer if I left it in the house!). I make sure to wipe all the dew away after a viewing session before putting the covers back on and put a moisture absorber in the inner plastic cover to soak up any excess. All in all its working perfectly, I have absolutely no concerns about leaving the mount out all summer. The only thing remaining is the TARDIS makeover...

Seeing conditions were better tonight, this is about 35 minutes of 45 second exposures at gain of 181. Ridiculous....

Here's the Orion Nebula from livestacking session last night, 45" at a gain of 181, let it run for an hour. The only real limiting factor was the seeing conditions which haven't been very good here for about a month. And here is the region of the Carina nebula which contains the 'Cosmic Cliffs' also from last night (you can see a bit of camera tilt across the horizontal plane). 90" at a gain of 181, which I let run for about 30 minutes.

Everything is wrong with this image (bad polar alignment, bad guiding, terrible atmospheric conditions, moonlight, bad focus, over-exposed, etc.,) but the Carina nebula-- the location of Webb's famous 'Cosmic Cliffs' image-- is such a beautiful and forgiving target that it looks amazing anyway. Off the back of a livestacking EAA session, no post-processing (60" exposures at gain of 350, about 20 minutes of data).

Took another shot at the Orion Nebula as the moon was rising under not so great seeing conditions. 30 second exposures at a gain of 250 (think I'll try 45 seconds at 180 next time, so I can get even more dynamic range). Live stack, no post, 150p, guided. Such a beautiful thing... And for something different, this is a look at the Magnificent Seven in the Small Magellanic Cloud (probably a little out of focus, I was testing my guiding setup and was trying to beat the clouds, so I was in a bit of a hurry). The clouds held off long enough for me to refocus and get a quick stack of NGC1232.

Nice, the glories of heaven have been veiled by clouds at my location for weeks. Love F5 Newts, would never use higher focal ratio, also love the idea of F4 Newts with coma corrector reducers which bring it closer to F3. I've noticed the RASA's are very popular, along with Hyperstars, I think both are at about F2.2. Fashion seems to favour faster scopes right now, which also reducers the need for guiding and long exposures.

Yes, it doesn't seem to be the camera causing it, it's the first time I've seen it. I only stack in Sharpcap at the moment, which I imagine is pretty rudimentary. Thanks for your knowledge @vlaiv.

Helix Nebula. Livestack of 102 lights (no darks), at 65", gain 200, guided, 150/750. I didn't apply darks (hence the image isn't as clean as it otherwise would be) because the darks I captured last night introduce a weird colour cast into the image (also effected above image) and a checkboard (debayer pattern?), no idea why, maybe some light got in? New to all this, still so much to learn... Edit: here is a version I made with my darks (and before I took out the satellite trail). It has less sensor pattern noise, but you can see the matrix patterning that my darks introduced.

Up close and personal with the Sculpture Galaxy. Live stack of 54 lights (12 darks), at 65", gain 200, through a 150/750, guided shot in Bortal 3 sky. No post processing (except crop). I used the Smart Histogram in SharpCap to determine exposure times, gain, offset, etc., but I think I'll try 90" or 120" at this gain next time. I really need to learn how to use the Smart Histogram function better... And here with a bit of editing in Siril.

Yes, thats what I was basically testing with my current setup: what can be done achieved using a sensitive, low noise OSC and reasonably fast optics (F5) without guiding. I've been pretty happy with the results, but of course, I suffer from the same obsessive neurosis as pretty much everyone else here and so have quickly moved on to guiding. In the future, I would like to get a 8" Quattro with a focal reducer to image at about 3.5 or so and really pull the light in (not interested in the ultra fast RASA 8, I like my Newtonians! and I probably wont be able to afford a SCT with a hyperstar anytime soon).

As I understand it the lack of sensitivity is the main issue of using colour camera's, as compared to mono camera's, for guiding, but many OSC these days are very sensitive, so maybe that conventional wisdom no longer applies?

Can I use the Uranus-C as a guide camera with PHD2? Can anyone see any reasons why not? I just checked and the camera connects okay to PHD2, so I can't see any reason why not. I'm sure its sensitive enough too, and the small pixel size makes it ideal for that application (on a guidescope at focal length of 190mm, F4). If the weather wasn't so bad here I could try and see for myself but I am growing impatient of waiting to find out... Also, would there be any problems with using two Uranus-c on one computer: one for guiding with PHD2 and one for imaging with Sharpcap? Might this itself create a problem? Edit: there is no option for me to adjust the gain settings in the camera settings tab. I've downloaded the Ascom driver for my camera. Any ideas whats going on there? Is the camera not fully supported?

Yes, I know, I was just complaining about the inconvenience of having to order it from an international seller, but really I'm grateful that I such a thing is even possible! I placed an order, glade this solution exists, surprised it took me so long to discover and that its not more widely known.

I just wish there was someone selling them here in Australia...

Update: Its actually possible to get a dual-speed upgrade kit for the Skywatcher single speed Crayford focuser. It looks like its only available from one UK seller though: https://www.365astronomy.com/lacerta-dual-speed-1-10-microfocus-upgrade-kit-for-skywatcher-crayford-focusers?search=Lacerta Dual Speed 1%3A10 Microfocus Upgrade Kit Another option is to add a helical focuser. See here: https://www.cloudynights.com/topic/607401-35-alternative-to-a-2-speed-focuser/

Update: Just a quick update on what I ended up doing. I had to scrap my original plan of using a round bin because the scope would have hit the base plate, so I instead used a rectangular shaped bin so that it is large enough to cover the mount but doesn't protrude too much on the east and west side of the pier. This is pretty much water tight. I then made a shade cover out of coreflute with a pvc bend joint to allow some air circulation. So far its worked well: the mount stays nice and dry, and doesn't get hot. Don't know if I will really need to go to the extent of installing a solar powered fan to help circulate the air. The coreflute cover is a bit flimsy and so I'll probably end up rebuilding it properly out of plywood and fashion it in the shape of a TARDIS (I'm really wedded to that idea!). I'll add some 'tie down' of some sort to further secure the covers to the base plate for now, and upgrade it to a latch system later (and ideally make it lockable).

Yes, I'll explore these options. It will all depend on just how usable the single speed focuser ends up being for astro. There is a simple mod for this focuser on Youtbe where you 'square off' the part of the tube where the focuser adjustment makes contact, which should make the focusing action smoother and more precise. Haven't received the OTA yet, but I'm hoping its not as bad as I assumed...