My New Sellina Telescope
Amateur Astronomy has been a hobby for some time.I went through two large telescopes and learned to process and align the images. Eventually I got tired of working in the shed all night and found getting all the programs to work together difficult. I must also admit that my aging body did not like climbing a 12 ft ladder alone in the dark, so I sold all my equipment.
Recently I read great things about a new telescope that does everything but brush your teeth.The Sellena telescope is almost completely automatic and therefore perfect for old farts like me. It takes a photo of the night sky and calculates its precise location. It also begins tracking the stars. You select an object to image from the supplied list which contains objects visible from your location. The scope then starts imaging, making multiple images of 10 sec each. The scope is controlled by the Stellina app in your Iphone. The images appear on your Iphone over the wireless connection, and are automatically aligned and bad images are discarded. The scope calculates how many exposures are required and the images slowly improve while the tracking prevents movement of the stars. The program also improves the aligned stack by using software.
You can easily share the program with anyone and they can also see the improving image. The images can be saved as Jpeg, Tiff or Fit format in the app or in the Pictures folder. There are some simple editing commands but it is best to use one of the free editing programs.
The scope can sense rain and it closes itself down. Well, this year we moved from Los Angeles to Falmouth, MA, in Cape Cod. Unfortunately, The Cape has had very few clear skies this year. Last night was finally great so I imaged the Veil Nebula. I left it run overnight and it took 763 10 sec images and created a stack!
See the image below
Here are some technical data about the telescope:
"I received the Stellina. This scope is really amazing. I'm a scientist by education, not an engineer, so I have little love with plugging things together and tune them until they work as expected. I'm more interested in exploring the sky. I also like to digitally develop photographs. So, Stellina is just made for me.
I live in a Bortle 5 area. When the sky is clear, I just put Stellina on my balcony. In a few minutes it is ready to work. You can see the image forming on your tablet but I prefer to do other things (or even go to sleep). During the first couple of week, I was just amazed by the JPEG images produced by Stellina.
But then I wanted more. I wanted more control over the photographs. Thus I learned how I could develop the TIFF produced by Stellina. The scope does all the job of discarding bad frames and stacking the good ones, removing biases and so on. However, the 16-bit TIFF is useless before you have developped it. Already this was making me feel much more in control. I could also try to make mosaics of larger objects, although I still have a lot to learn on that subject...
Then, I wanted to stack more frames than can be acquired in a single night (in particular as those were getting shorter and shorter). Thus I taught myself how to use DeepSkyStacker to stack the FITS produced by Stellina. Here, you control even more details, although it takes now much more time. But for the paler nebulae, it is worth it as you get a much better image."
"That's about where I am. I'm still learning a lot. What is nice with Stellina is that the set-up process is so short that you don't even think twice whether you'll do it or not. Initially I took several objects per night but now I tend to take only one so that I can collect more frames. If that'0s not enough, I'll continue the next clear night to get more captures. Thus you can learn fast. If the photograph you took yesterday was not what you expected, just do it again with different settings and see how it changes. This is pure pleasure."
"Every update of the firmware brings new possibilities, my skills keep improving and the sky is so vast that I don't see myself getting bored of this scope for the foreseeable future.
"Basically, I almost always use Stellina from my balcony. I've only moved elsewhere when I needed an uncluttered western horizon for comets Atlas and NEOWISE. So, when I see that the forecast is good for the night, I put Stellina out as soon as the sun has set to let it cool down. About one hour later, when the sky is dark enough, I switch it on, connect my tablet to its WiFi and start the initialisation process. Stellina unfolds its arm, point at a "random" section of the sky (about 60° from the horizon and in the direction I have faced it to). It then goes through a process of recognizing the star field and, combined with the smartphone's GPS coordinates, it can orientate itself (plate solving). Then it sets its focus automatically. The entire operation takes a couple of minutes. Once done, Stellina is ready to function."
" Then I select which object I want to capture. It can be done from Stellina's extensive catalog where they are sorted by type of object and by constellation (the latter is greatly useful when you can only see a part of the sky from your position, as long as you know the constellations, of course). You tap the "capture" button and there it goes. After another couple of minutes, the first images begin to appear on your screen, and as the stacking progresses, the image gets better and better. At this point you can reframe (rotate and pan) the field of view to change the composition. Stellina recommands a time of exposition for each object but for nebulae and galaxies I tend to at least double that time to get the best possible image. Often I even leave Stellina working the whole night on the same object."
"Alternately, I can use Stellarium to find an object that is not in the catalog. I enter its coordinates in Stellina's application, and what type of object it is (nebula, cluster, galaxy or star/planet). And there it goes, as described above."
"Stellina produces three types of images :
JPEG for quick sharing. They don't need any post-treatment, although you can improve them by reducing the noise in an external application.
16-bits HDR TIFF. Those you'll have to develop yourself in some image processor (I use Affinity Photo), but the stacking has already been done by Stellina.
16-bits FITS (RAW images). Those have to be stacked by yourself (I use DeepSkyStacker), and then developped. This is the process that is the longest but it also provides the best quality and the most control.
As for problems, I've not met a lot. The most annoying one happens when the temperature changes a lot during the night as it alters focus. When the temperature has dropped by 3°C after the autofocus, Stellina will display a warning. You can then decide to continue the capture (with bloated stars) or restart (and then the stacking will start from the beginning). That's one of the main reasons why I use FITS, because you can refocus as often as you want and stack all the FITS by yourself later.
Another problem is that Stellina needs to see stars in order to do its autoguiding and field derotating. So, when you want to capture objects too close to the sun, in the dawn light, it used not to be able to do it. It was annoying to capture comets. The latest firmware version has however solved this problem.
Also, at the moment, if you don't use FITS, you will get images at half the nominal resolution. However, they say they are in the final stages of working on this and this Fall we should get JPG and TIFF in 6 MP as well. That's going to be a great improvement. Stellina is designed to capture large (about 1°) nebulae and galaxies. You can capture planets too but they are clearly not what Stellina is optimised for. You will still see Saturn's ring and Jupiter's bands (even the red spot, if you have a perfect sky). I've managed to "hack" the manual pointing system to see Saturn's and Jupiter's moons, which I have always loved to see. Vaonis says they are working on a solar mode, that should be available before the end of 2020. We'll see... Obviously we'll need to purchase a solar filter, I guess. At the moment, you can only use it during the night. Ah, the moon pictures are amazing, but once again, you can't zoom on particular craters. When we get the full resolution in a few months, the images are going to be even better, I suppose."
Phew... that's quite the wall of text. I hope this is going to help though. Stellina is really a lot of untarnished fun! That's about it. That's my first-hand experience. If you want more details, I'll be happy to tell more, if I can.
Here are some utube videos on using the scope.
https://www.cloudynights.com/topic/721381-stellina-for-anyone-wanting-to-share-experiences/
https://nightskypix....cking-software/
https://www.cloudynights.com/topic/721381-stellina-for-anyone-wanting-to-share-experiences/
https://nightskypix....cking-software/
