New 20" Dob, I'm now officially obsessed !

Hi All,
I've been debating in my mind over the past few years whether to go for a nice new mount for the 12" or get a massive Dobsonian. For a while it was looking like getting a new mount, but over the past few months I started leaning towards the Dob. Last week an opportunity came up where a 2 year old 20" F5 Obsession became available at the right price, so I went for it !! At this stage, I figured I'd get more enjoyment out of this rather then a new mount.



This scope is gi-normous!! As its an F5, the focuser is 8.5~ feet in the air at the zenith, I have a small step ladder for this. I had a laser collimator for the SCT which works perfectly on 20", just as well as it didn't work on the SCT well at all. It is very simple to collimate and takes about 5 minutes to do. The base is fairly hefty, but the support truss and focuser section are very light. I have to say that its magnificently well built and well thought out!.

I had it at the clubs observing session at Boher last night (Sat April 7th) and the views through it were absolutely stunning, we were there until 4.30 in the morning, there was quite alot of high altitude haze and occasional small clouds so the sky was more orange then normal last night at that site.
We could clearly see M51's spiral arms, clear as day!, M66 & 67 in Leo took on their familiar appearance. M13 was absolutely stunning!, I could pump up the magnification to 500X where it filled the field of view, and looked truly photographic!. M81 and M82 was amazingly bright, while searching for them I found 2 other galaxies by accident which I must look up, The owl nebula had its 2 "eyes". I only wish I could catch the Orion nebula, it was in the hazy blue sky at this stage. We looked at a few other globulars which were all easily visible and resolved right down to the core. The ring nebula, although low was also easily visible. The sombrero had its distinct shape with its central dark band, still visible through the high altitude haze which was heavy at that time.

The most surprising thing about this scope was the views of the planets, the view of Saturn was absolutely awesome at 500x, it looked like a stacked image right out of registax, you could drive a truck through the cassini division, the ring and globe were razor sharp and there were hints of the encke division. At 605X, the image started to look a small bit washed out but was still quite clear, the hardest thing was to actually keep up with Saturn and is rocketed across the field of view. It was easily the best image of the planet I have ever seen. I tested it on stars like the double-double in Lyra and Albireo in Cygnus, it split the double-double very nicely and the colours of Albireo were perfect. Venus was also excellent through it.

I have to say that Obsession make killer scopes, the movement of the mount is so smooth and clean. The optics are first class (Enhanced galaxy optics) and the primary mirror has a strehl value of 0.963 with an rms wave value of 0.031 (I think that reads as 1/32.5 wave accurate surface). The secondary looks so small in the unfocused star view. It held its collimation (using the laser) at all altitudes in the sky, in other words, the spider is well able to hold the secondary in place.

Needless to day, this is a scope for a dark site, my location in Limerick isn't ideal for it, but the way I see it is that I can use the 12" here and bring the Dob to remote sites, observing sessions and star parties. Having carried around both the 12"LX200 and now the Dob, I can say the Dob is easier to setup and requires less setup time. Needless to say, I hope its clear tonight so I can use it again where I can push it a little harder and get some more fainter fuzzies. Climbing a ladder to look through an eyepiece gives the phrase "reaching for the stars" a whole new meaning :lol:




Thanks to Mikkel Bo Rasmussesn (SAC) for the images.

WOAH! :shock: :shock: :shock: ! Congrats dave! How portable is it? So the horsehead visually eh!?! Ive seen about 4 of these on astrobuysell!
Many clear skies!
Matthew

As you can see from Mikkels first pic above I'm green with envy!!

Nah, seriously...
Thanks Dave for letting so many of us have the absolute pleasure
of looking through this unbelievable scope!
The views were just :shock:

Great time last night I must say...
Thanks also Con for the tips...It's like I have a new scope now!
I couldn't believe the accuracy of it on the high percision.

By the way Dave..
It looks like we can get the keys for the 'soon-to-be-sister-in-laws'
holiday home in Doonbeg for some weekend for another session!
The dark skies there will blow you away!


All hail 'Dobsonian' Dave!!!!

Wow, congrats Dave.

That is one beast of a scope. Heard so much about those Obsessions.

Trev

Holy shamoley,
Well done Dave, it is a great looking scope I'm not surprised you went for it how could you not she is a beauty, may the too of you have many sleepless nights together.

Welcome to the 'big boys' club, and congrats on a fantastic new scope - just wait until you can view the M33 face-on galaxy in Triangulum at low power from a dark site - it's just mind blowing - the whole galaxy just fits into a 1degree field and you can see more detail visually than in most photos!!! :shock:

Your main problem now will be trying to identify all those pesky little faint-fuzzies that litter the field of view where ever you point the scope! It's a tough life, but I'm sure you'll manage

Phil.