GSO 12" - 305mm Dobsonian - Unpacking & First Light

[AstralFields]

I've had an 8" Sky-Watcher 200p for about 2 years. While it was the best beginner telescope I could've possibly pick, I started thinking about an upgrade sometime in the future but I decided to wait until I would complete the full Messier catalog. My thinking was along the lines that until I get the whole catalog completed, I wouldn't know if I still would want to stick with this hobby and invest more money into it. Also I just felt I should somehow 'deserve' a bigger telescope. Another reason was that the 8" is an f/6 telescope and while my budget eyepieces worked reasonably well there, I was afraid that in the brighter f/5 they would look pretty lousy, so there was not only the investment into a new telescope but into new eyepieces as well.  And yes , I was right about that part, the budget stuff is simply not suitable for telescopes under f/6. They should ideally be used at f/8.

At the same time I discovered a nice APM 30mm UFF clone from Aliexpress for about 180$, which is a great deal as well as a Panoptic 14mm clone for like 83$. I bought both of them and they are just amazing in the 12" f/5, which is great as these two focal lenghts are used in my observations for like 90% of the time, the rest is done with my SVBony Zoom 7-21mm which is a great performer in the new scope as well. So basically I will be selling most of my budget stuff along with the 8" during this year. 

On to the scope itself. It arrived in two big boxes, the guy in the van warned me that this is some heavy stuff. I've been worried about the weight of this thing from the moment I clicked the order button. The whole thing cost me 1020$ , although I could've saved 30$ had I used my local currency. Had no idea they accepted it in the neighboring country. Very good price anyway as locally they go for 1100 to 1200$.

Why did I choose the GSO and not my beloved Sky-Watcher? Well.. Sky-Watcher apparently is not that great after all. Sure the mirror is superb with Pyrex and all of that but the rest is nothing to write home about.

GSO Mirror is BK7 - so a bit worse on the thermal side of things but it comes with a fan at the bottom pre-installed.. so no biggie. Also I store it in my cellar which is not that bad temperature difference wise to the outside. And I also am more of a DSO than planetary guy.. so there is that.

Focuser - Hands down the GSO is two leagues better than Sky-Watcher. It also has dual speed.

The adapters of the GSO are a LOT better with compression rings allowing for a tighter more accurate fit. So good that my Cheshire and Laser collimator finally agree. I could not get them to agree in the Sky-Watcher due to lousy adapters.

GSO - A big downside is the absolute lack of backfocus... Most stuff focuses quite closer to the secondary mirror even when there is a lot of focus travel to use, never-mind there is also a 35mm extension for 2" which doesn't get any use. Raising the primary to the maximum the screws allow alleviated a bit the problem but it was so bad that I barely got focus after raising the primary in my 3x Barlow. Sky-Watcher is so much better here and it provides the possibility to focus and attach a DSLR. That is not possible with the GSO if I ever wanted to get one. The only way I got my security/astro 4K cam to focus was to put the whole thing into the 2" extender... well at least I got it to work.

Finder - the finder is a regular straight view 40mm finder. After unboxing it and checking it out I put it back in the box. I hate optical finders as I find a laser and RDF combo so much better and so much lighter. With a 19kg OTA, every gram I can save counts. 

Eyepieces - The GSO here wins hands down. Sky-Watcher cheaps you out with a 10mm and 25mm Plossl (a.k.a are you freaking kidding me??). GSO is extremely gracious that it gives you a 30mm SuperView Erfle which normally goes for like 70$ to 100$. Not a bad value at all. I will probably sell it as I have the far superior 30mm UFF now. It also gives you a 9mm Plossl which I will also sell as the eye relief on those things is abysmal.

The bearings Alt / Azimuth are also better, the GSO comes with a lazy susan type. Maybe the Sky-Watcher 300p also has it, not sure. But I can say that the motions of the 12" are a lot better than my 8", both Alt and Azimuth. Another big plus for the GSO.

Also the GSO is a lot cheaper than Sky-Watcher... so really, GSO all the way in my book.

Collimation was totally messed up from the factory, the secondary was like 15mm off vertically. I don't think they care at all. Doesn't matter, I am pretty good with collimation so I got it spot on.

Transporting the thing was not as bad as I had feared, especially after I installed some wheels and carrying straps. It basically made no noticeable difference to my observation preparation, drive and setup.. like maybe an extra 5 minutes out of the one hour it takes me to prepare, pack, drive and unpack at the destination. The weight is perfectly fine once you have a good way to strap that thing. I use two carrying straps and one extra to put over my shoulder. My son is 20kg and I carry him all the time.. so it is not the weight itself but more about figuring out a way to properly attach that weight and distribute to the body. The base is basically the same weight as the Sky-Watcher, so no difference there at all.

The first night observing was a real blast.

M51 - We all saw the dust lines pretty clearly that night as it was at 90 degrees up in the sky on a clear night

M104 - Looked amazing and showed clear structure.

Leo Triplet - Fit nicely in the 30mm UFF and they looked very clear, bright with easily recognizable structure.

The Ring Nebula was also amazing as was the Cat's Eye.

Checked also M13 and M92 and again, very very nice in the 14mm panoptic clone.

The Beehive Cluster in the sharp edge to edge 30mm UFF was out of this world, simply great to look at.

Going through the Virgo cluster with the 30mm UFF yielded a ton of NGC galaxies, easily visible with direct vision and actually confusing us from identifying the Messier galaxies we were looking for. A big step-up from the 8" where only the brightest galaxies are easily visible.

I also got to compare the Kellner 32mm eyepiece to the SuperView Erfle 30mm and the APM UFF 30mm clone. It really showed nicely why the first one costs 45$ , the second 100$ and the third 180$. I will be making a video focused on this and why there is such a difference. 

That is about all for now, I will be making a proper detailed review half a year down the road once I've gotten some field experience with the scope under various conditions and done some imaging.

 

[Mr Spock]

If it's anything like my 12" StellaLyra (GSO), the optics should be great.

I too use the 30mm UFF - one of the best eyepieces made. In comparison the Superview 30mm is pants.

I don't have any problems focusing. I only photograph the moon using a x4 Powermate though.

[AstralFields]

7 minutes ago, Mr Spock said:

If it's anything like my 12" StellaLyra (GSO), the optics should be great.

I too use the 30mm UFF - one of the best eyepieces made. In comparison the Superview 30mm is pants.

I don't have any problems focusing. I only photograph the moon using a x4 Powermate though.

Yeah , it is the same telescope. Using the 4x Powermate shifts your focus outwards. I managed to resolve the backfocus issues but it could've been done smarter like Sky-Watcher does it. They provide 50mm extensions and once removed, you get an extra 50mm backfocus.