150 mm f/5 Achromat just arrived.

[John Baars]

This evening my 150mm Skytraveller arrived. I spent the evening re-arranging accessoires. And I made a finder on it.
The evening was not clear, I had trouble finding the Summer triangle in the misty skies. Nevertheless it showed various DSO's.
I like him already..

I'll make a report in the morning.

[Don Quixote]

I am excited about this John.
As you know I have very recently acquired a 152 f6.5.

I am eager to follow you here with your workings of this telescope. I know we have different focal ratios and this is interesting to me.
Your scope is a Fraunhofer design as I understand it. Are all of these Chinese150 achros of that design?

Sorry for asking so many questions.
I will probably be asking a lot more...

Last question for today...are you going to use a mirror or prism diagonal ?

I am looking for to more from you on this, John.
Clear skies to you.

[Bigzmey]

Congrats on the big gun and welcome to the 6" refractor club John! I have Celestron brother of your SW and it delivers fantastic views of clusters and nebulae.

[helicon]

Great new scope John and welcome to the six inch refractor club indeed!

[bladekeeper]

Nice! Congrats on the cannon, John!

[Thefatkitty]

Good for you, John, look forward to your report!

All the best,

[John Baars]

As promised, my report of the first light.

At arrival in the original box the 6 inch was in a perfect condition. No scratschmarks, no stains, no dust inside. The first owner used it as a photographic instrument and had mounted a far better focusser than the original. I had seen his pictures with this instrument and knew nothing could be wrong optically either.It seemed a bit lighter than my fully equipped 4.7 inch. Soon I found out that was not the case once fully equipped.

It came with two Vixen dovetails, one of which was used as a handlebar and photographic platform. The gap between handlebar and tube was rather narrow so I enlarged it by adding some extra nuts. Since the new TS-focusser had no finder-shoe-holder, I used the handlebar to act like a good base for that. Drilling and tapping an already home-made existing hole took care of that.

Time for mounting. Balancing showed me that I had to move one counterweight a bit outside. I had to shove the tube down in the cradle and mount the middle of the dovetail a bit off the middle. While looking at the zenit I want to sit down on a small stool, still I have to bend a lot, but luckily I won't have to sit on the floor. The picture above shows the balanced telescope.

I aligned the finder on some trees far away, it was not really dark yet and in the meantime found out I could not reach sharp focus. Since It had been designed for use with a 2" mirror, focus was far more further away than I could reach with the 1.25" Zeiss prism. Yes, Mark, I put in the prism from the start. A comparison of its behavior with a mirror will follow in near future:-)) Luckily I still had a 2" extension tube from previous experiments. It fitted of course and focussing problems were over.


Time to check if the telescope sits on the mount the same way as my 120mm refractor does. It does. Vega was still in the memory and after entering it showed up in the 30mm Eudiascopic eyepiece. I checked collimation with my Pentax XO 2.58, at 300X and found out it was all right. The startest on Altair did not reveal major problems. I was a bit surprised about the small Airydisc, until I remembered that an F5 system produces smaller Airydiscs then a F7.5 Nice promise for double stars. A bit of coma in the order of 1/10 wave, but nothing to be alarmed, quite normal for its budget range. Spherical aberration seems to be in the order of 1/5 to 1/6 wave. According to the program Aberrator it should even be better. I did not check on axial astigmatisme, but as I did not detect it in the first place, it should be low-leveled. This refractor meets the 0.8 Strehl limit effortlessly.

Since it was a very misty night, the Summer-triangle was the only naked eye-object, I wondered how much this telescope should reveal on some DSO's I had in mind. I put in a UHC filter and went for M27. I was not surprised to see it quite clearly and I could detect its form. M57 was even more clear and sharply defined. I nodded, this is how I wanted it to be. M71 ( without the UHC) was visible, but without the well known little stars. M15 showed individual stars in its periphery. I wondered how M13 would look like. Surprisingly well, as if I looked down a ( dark) sugarpot.

The one issue almost every review keeps dragging on about, the CA ( as if there is nothing else to remark about this telescope), is no issue for me. Surely I saw a blue halo around Wega an Altair, but I think it was a moderate one. I was not impressed. Maybe due to the use of a prism instead of a mirror, but I am gonna find out. Saturn was all right. Jupiter showed some cloudbelts and zones, the GRS ( ever so clear) and was certainly not what I am used to in my 120mm Apo. Well, it is not made for Jupiter, that's for sure. But it shows me 99% of all other objects with a big smile.

I could have been going on like that for several hours, despite the very bad circumstances. But the weather worsened , I saw lightning on the horizon and heard rumbling. So I called it the day and went in. Satisfied. Can't wait for a real transparent night.

[Bigzmey]

Nice first light John! I have noticed in the photo that the focuser is not the stock one, even better deal! I have replaced the focuser on mine to. I also added second dovetail bar to use it as a handle and raised it up with longer bolts to have enough grip room.

As you already discovered 120mm APO will do circles around 150ST achro on planets, Moon and doubles. But that is not what 150ST made for. 150ST is a beast on DSOs!

One thing I never warm up to was the dew shield made out of steel tube. It was unnecessary heavy, and I swear worked more as a dew attractor. I replaced it with the extra long dew shield I made form black 3mm crafting foam. It protects better from stray light and dew and makes balancing easier.

[John Baars]

Thanks to you all for your kind remarks!

[Lady Fraktor]

A lovely looking new refractor John, they do produce some nice views but my first thought is always "where is the rest of the tube"?
I hope you get a lot of use from it!

[Ylem]

Wow! That's a big boy!!

ST80 on steroids!!

:Angry Orc: