iOptron 150mm Rumak - first light

[Mr Spock]

Well, almost first light. It was out a few nights ago but seeing was so mushy I didn't really get to see much.
A bit better tonight. The seeing was more stable but, marred by some thin high cloud no doubt illuminated by a combination of light pollution and the rising moon. Naked eye mag was limited to around 3.5 in the good parts.

Mars. Not a bad view, if a little lacking in contrast. Detail was visible at x144 (12.5mm Or) with a nice crisp edge to the disk. Moving up in mag to x257 (7mm Or) showed an increase in detail, with parts looking quite busy, but not as much contrast as x144; the detail was very delicate.

A couple of Pegasus doubles next.

Σ2986: A nice wide pair to start. No colour seen. At x257 the mag 6.61 primary showed a nice airy disk with minimal diffraction rings - a pleasing result.

Σ2983: A close by, similar pair, but much fainter. The secondary at mag 11.24 was difficult in the conditions, but just visible at x144 with averted vision.

After this my back started aching due to the finder. It was in almost impossible positions. Despite its fine quality, I'll be swapping it out for my RACI before the next session.

The only other minor complaint was the focuser was right up against the diagonal making focusing difficult. I might think about rotating the optical assemblies around in the tube by 120°; I believe they are held in by three screws.

 

[faulksy]

how did it compare to your 9.25 michael

[Mr Spock]

It's difficult to tell from one session, but the way stars look tells me it has a much higher strehl ratio. I also saw more detail on Mars despite it being half the size of my last view.

Size isn't everything 😜

[johninderby]

One good test I’ve found for how good the optics are when comparing scopes is what sort of magnification is usuable while maintaining a sharp clear image.

Edited December 31, 2020 by johninderby

[RobertI]

Looking forward to hearing more about your experiences with this scope, I really like the look of it. 

[Mr Spock]

18 hours ago, Mr Spock said:

I might think about rotating the optical assemblies around in the tube by 120°; I believe they are held in by three screws.

Four screws, but, I'm not touching it while it's under warranty. Instead I'm going to use a 1.25" diagonal. I only need the 2" when I use my 42mm LVW - how often will that be? The 1.25" leaves plenty of room for the focuser. I guess there's only so much space on the back of a 150mm...

The 1.25" diagonal I have is an old Helios. It will do for now; image quality is good though it is lacking modern coatings. I'll get a better one when some stock is available. Most likely another Revelation as they offer the best price v performance; I can't fault the 2" I have.

[Mr Spock]

Decided to spend a few extra quid on the diagonal and bought a matching iOptron. Like most things I'll have to wait for it coming.

The one I have is sharp optically but doesn't have modern coatings. It is noticeably darker than the Revelation 2".