GuLinux

My major concern right now is polar alignment. With some work, I can get it to align quite precisely, the polar scope is very nice, the knobs are a bit too wobbly, but in the end, it's doable; the problem is that whenever I touch my camera(s), the alignment goes off, sometimes by a lot. Last time I used it, my images had a huge drift, almost 2 degrees over 5/6 hours! I use it with a slighly high focal length (200mm), and I wish to go further in the future, around 300/350mm, but unless I solve the polar alignment issue, it's gonna be tough. I use the L bracket, so you can avoid a few problems (you don't need to mount the cameras after polar alignment), but when I point them it' still the same, I loose much of the polar alignment precision anyway. When using the L bracket you can still look through the polar scope, so I was thinking of a different polar alignment workflow: first a rough polar alignment, then pointing the cameras, then a precise polar alignment, but if you rotate the RA axis, you loose your reference to the exact position of Polaris, and you don't know where it should actually be. Has anyone found out how to improve polar alignment?

I found some unpacking/first light pictures, I forgot they were in my girlfriend's phone

Well, this is a first "preview": telescope close to my luggage and laptop backpack. As you can see, it's just slightly bigger then the latter (although much much heavier... almost breaking my hands... I need to add wheels ) I was expecting troubles at the security checks, but surprisingly they didn't even ask me for further inspection. Ready to go

Thanks for the tip. Fortunately I just found out what was wrong with my thumbscrews: when I first tried the collimation, I probably did tighten one of them too much. As result, the little nut that's between the mirror cell and the support go tighten too much as well, basically creating loads of friction. Just loosening it a bit had a massive improvement.

Will do Well, there are a few airline companies that allow "as much as you can lift" (easyjet) and up to 23 KG (BA). I'm much worried about airport security, though

After a long wait (ordered on May, received it on August) I finally received my new baby The scope is the Sumerian Optics Alkaid, 12 inches version (300mm). http://www.sumerianoptics.com/products-price/ It was ordered from Teleskop Express (DE) It's a bit expensive for a dobsonian telescope, but I was really looking into something very portable. The "fold into a hand-luggage compliant suitcase" feature is really amazing. Not many airline companies do actually allow so much weight (16 KG), but still you can find a few, and I'm gonna see what happens on my next trip in Italy in a couple of days. I haven't yet used it a lot, due to weather, moon, and laziness but these are my first impressions: Unboxing The scope was very well packaged, it was a mess to cleanup the house with all that foam peanuts This of course is all very nice for transport, what was less nice is that all this, and the protective cotton over the mirrors, did create a lot of dust and filaments all over the mirrors. Nothing serious, cleaned most of it with a little air pump, but they might think of a different protection layer for the mirrors. Assembling The first time you read through the provided manual, get it wrong on a few steps, but overall instructions are clear enough, and most of the pieces can be mounted in one way only, so it's quite straightforward. Mounting the suitcase back requires some attention too, but there are instructions for this as well, so it's easy. After doing it a couple of times, you can really assemble and disassemble the whole thing in a matter of 5/10 minutes. Collimation This is where I'm still having some problems. Some of them due to the scope it self, but some might also be because of my inexperience with it, and with the Cheshire tool (I was previously using laser collimators on smaller newtonians). The secondary collimation is quite straightforward. I'm still having some minor issues in aligning it to the focuser, but with more experience it should get better. The primary is what troubles me most. Both the secondary and the primary use a two screws system. The third one is fixed, and you should align it by moving the other two. This in theory should work, but it seems that the two screws don't have enough run to compensate for major misalignments. Also, the screws movement is quite irregular, and after a few tries, one of them became very very hard to move. I will try again using some grease, otherwise I might think of replacing them with some plain old allen keys. Movements and stability Movements seem to be quite smooth. The scope is also provided with a shock cord "counterweight" system for balancing heavier eyepieces. I don't have any (yet), but I'm planning to buy a 1KG ep with a big FOV, so I tested balancing with a 1KG counterweight attached to the focuser, and it seems to hold on quite well. I also bought a third shock cord in addition to the two provided, just in case I need more traction. Red dot finderscope Mixed feelings with this: it certainly looks nice, and it also has a green setting (for daily usage/bright objects I guess?). But to align it you need an allen key (included), which feels a bit uncomfortable, and the window doesn't seem clear enough, blocking too much light, so it's a bit difficult to point at faint objects/stars. The finderscope is also too close to the tube, so it's not very comfortable. I will have a few more runs, and then decide if I want to replace it with a different one (I have a Celestron Starpointer Pro, which I have used with quite some satisfaction). Light shroud There is a little shroud provided, but honestly I haven't even tried it, I really didn't like the idea of an open truss. Instead, I sewed a full length shroud using some lycra cloth. I added some magnets to the top and bottom of the telescope, in order to keep the shroud in place. First light I had a quite unlucky first light, actually. There was too much dew, and the moon rose slightly after 11 pm. I just made it to view a couple of objects (easly resolved polaris b, the ring nebula), but the eyepieces got quickly covered with dew. In a way that was also useful though, since I both tested that my light shroud protected quite well the primary mirror (no sign of dew in there), and the built in anti-dew of the secondary, that in 5 minutes cleared it out. Overall impressions I still have to familiarise with it, particularly with the collimation, but I am really satisfied with this setup. The portability side is quite amazing, I could put it in the back of a quite small car, with lots of room to spare! I'm looking forward to a few more detailed tests over the next few weeks, in a fairly darker spot. I'm a bit worried about the airplane trip, but we'll see about that...

Oh.. ok, yes.. that's it. I have to say, it doesn't exactly fit well, but hey, it could still come in handy!

Mmh, no, it doesn't seem to be an adapter... My illuminator already fits by itself. Beside, this round "thing" doesn't fit perfectly neither the polar scope, neither the illuminator...

I almost forgot to ask... When I ordered my Star Adventurer, I ordered the bundle package. There was this little thing included, which I am unable to identify: It looks the same size as the polar reticle light, I thought it must be some accessory for the polar finderscope, but I still cannot figure out its purpose.

That's a quite stunning image!

.

I just bought one from FLO... this little thing really intrigued me... My plan is to use it without a reflex, at least initially... ASi 178mm + canon lenses and RGB filters. Let's see how it goes...

Again, in theory, yes. In practice, even if you achieve perfect alignment (which it's not that easy, sometimes) this particular telescope is very hard to balance: unlike german equatorial mounts where you can release the friction in order to verify your tube balance, in here you can't. I draw an arrow on the tube pointing to the balance point of my setup, but it's a very approximate way to balancing. There are also other reasons why one would need to use an autoguider port. Maybe you have dust on your sensor, so you don't just want to keep your planet "in the field", but in the exact spot where you know it's perfectly clean. Or you're shooting at the moon, so in order to maximize your final stack field of view, you want to get the field pretty much identical in all the frames. Or you are doing a moon mosaic, so you might want to use the guider port to move your field of view. I've heard of very expert planetary imagers (for instance Christopher Go) suggesting FireCapture just because it can autoguide while shooting images. Having said that, I just want to know if anyone knows about the aux port being used for autoguiders. An autoguider port is not really that necessary (I might use also the nexstar serial connection to PC), but it might be a bit easier to setup, that's all.

Well I know about field rotation, that's why I was mostly asking for planetary imaging. It's not entirely true that you don't require guiding for that: the idea is usually to capture as much frames as possible, so it's not that unusual to do a 60/120 seconds capture, and trust me, sometimes, particularly if the mount is not exactly well balanced, or properly aligned, it can drift a lot, even in a few seconds

Hi, The Celestron Nexstar SLT 127 (Mak) has an "Aux" port, in which my autoguider cable fits perfectly. However, before trying it, I was wondering if anyone knows if this port can actually accept autoguider commands or not. I know autoguider is mostly useful for deep sky imaging, but it might be in handy also for planetary imaging, without using a guide scope. Thanks Marco

Well, Registax and AutoStakkert! both work quite good under wine... sure, a native application would be much better, but they do their job, and it's enough. And for both planetary and deep sky stacking, siril is quite good too... probably a bit more oriented to deep sky, I still have to test it for planetary stacking. Maybe it has a slightly steeper learning curve, but it's worth it. I think actually what's a bit lacking in the linux world is a good postprocessing application, many on windows use Photoshop, and gimp is out of business because it's not handling properly 16bit images. I know there's a beta, but... it's still a beta, afterall, and apparently there are no imminent plans on releasing a stable version for that. I tried Darktable for that... decent results, but it's a very confusing software.

I agree with all you said, but I also want to add that Linux > INDI. INDI forum is specific to that platform, while a general Linux area in a forum like this could actually cover much more stuff (I also made a few non-INDI astronomical applications for Linux... why not?)

What about having a separate subforum for linux? This would help separating different issues/questions/topics in different threads

I wouldn't really recommend mint, as it's still based on Ubuntu 14.04 (quite an old release). Directly using ubuntu would provide both more up to date packages, and a wider community for support. Also, if you're looking for a more "window-ish" look there's always the kde version (and you can install kde over the regular ubuntu by simply installing the "kubuntu-desktop" package), which imho never had the success it deserved. Personally I don't use ubuntu (nor mint) so I hope I'm not biased towards it, I just would like to suggest different alternatives, particularly for "newbies"