SkyWatcher 190MN...

[RobertM]

Well, this was a re-delivery as the first one was unusable due to shipping excesses.

This wasn't really a hard choice given that John's scope is so impressive, the reviews (biased a little me thinks) have been good.  I just hope the 6 week wait was worth it and it doesn't prove to be a dud.

It should have a nice flat field so will replace the C9.25 which I'll keep for planetary if it doesn't sell.

As for any new scope, the collimation is miles out ! Just wish I hadn't left the laser collimator on...

Robert

[mickw]

Congratulations on the new baby 

[JohnP]

So looking forward to seeing the results you get with this.... John

[RobertM]

Just a quick update...

Collimation:

When it first arrived the collimation was way out.  After adjusting that; something was still not quite right.  Looking down the focuser tube it was obvious that the focuser wasn't directly over the secondary; furtunately there is enough lateral adjustment so that was fixed in a couple of minutes.  I think it's still a little out but collimation looks quite good now.

First light report:

Managed to get out last night with it and had a quick view of Saturn and some starfields through light cloud.  Left the scope to cool down for an hour but that probably should have been longer considering it's a closed system.  Stars looked very good edge to edge with a TV 55mm Plossl (x18 and 2.8 degrees FOV) and had a quick look at Saturn with a Meade 4.7mm UWA. Saturn did seem to hold up quite well under that magnification considering the cloud and I did briefly try the 4.7 with a x5 powermate.  I know that was well OTT (x1000); unfortunately seeing was poor with thicker cloud coming over but through the gaps the image did look quite good.  I think it does have potential for planetary work even though it's f/5.3.  I'd need a night without cloud to see what it can really do.

One thing I did notice was that with the heavy TV Plossl (about 1lb) is that I had to use about 3.5-4" of extenders to reach focus and with the Meade UWA about 3".  That should means it has plenty of back focus for a long imaging train.  What was fairly noticable is that with all that weight and torsion, the focuser just isn't up to the job for imaging.  Being a simple cheapo (though it looks nice) Crayford focuser it just doesn't cut the mustard.  Having said that, it would be perfectly adequate for visual and planetary imaging and managed to hold that large eyepiece with the tension right up.

What's next:

1) Try a camera.
2) Try the converted 50mm finder/guide scope as the guider.
3) Check the tube rings don't flex with the rather small synta foot they have (maybe add more?).
4) Get a lighter losmandy dovetail plate (using a heavyweight side by side bar (3Kg) for now).
5) Upgrade the focuser ( Wyrock/Moonlight/Starlight ?) - need to check that there is no tube flex under weight.

In summary, bar the niggles, it's looking very encouraging.

Anyone any thought on a replacement focuser ?

Thanks
Robert

[RobertM]

First test image.  30 x 60s with the SXV-H9 and a Astronomik luminance filter SD-Mask stacked and DDP stretched only; focused once at the beginning of session:



Collimation is still a tad out.

[JohnP]

Robert for a 'quick' first light that looks really promising. Is that full frame? Star shape at edge looks excellent - no detectable sign of coma that I can see & resolution down to core... Wow..! You must be chuffed?

John

[Fay]

Looks even better this morning, Robert!

[Rocket Pooch]

Hmmmm food for thought?

Nice 1st light Rob...

[RobertM]

John, Yes thats a full frame; I'll try the AP 0.67 reducer and Canon 450 next.  Pixel scale is 1.3 arcsec/pixel which is quite nice.

Fay, yes the one I sent you was 20 frames stacked so this would be slightly better.

I does seem slightly out of focus top right so I'm not sure whether that's flexure in the focuser, alignment or (because I see a similar thing on the refractor) the ccd a few microns off being square.

I've uploaded the FITS file to the gallery if you want to take a look.

Robert

[Fay]

Out of focus.....your eyes are too good Robert! I would be happy with that