SW 150 ED Pro First Light

[Roy Foreman]

I've wanted a large ED refractor for some time, but just could not justify the expense and weight of something like an Esprit 150.  Ever since Skywatcher introduced the 150 ED Pro I thought this might be the scope for me and eventually ended up buying one.  I'm no refractor expert but I have to say I'm impressed with its performance.  FLO forgot to include clouds in the box, so it's arrival was followed by a few half decent clear evenings with the moon on display.  First night out I went on a colour hunt with 22mm and 5mm Nagler eyepieces.  I scoured the limb and terminator for any sign of CA but found none.  If there was any colour fringing I couldn't see it, so that's good enough for me.

A couple of nights later I tried some imaging, using a 2x Powermate, ASI 183MM and a #25 red filter just after sunset, and the results are shown below.

The first four shots were taken with the 150 ED and a TV 2" 2x Powermate  2400mm F/16

The final image was taken with my SW 180mm F/15 Mak at prime focus 2700mm for comparison. I think the Mak just edges ahead of the 150 ED.

Hope this is of interest and, of course, C and C's always welcome.

Thanks for looking.

 

 

 

[BRADLEY 1953]

Lovely crisp images Roy, you must be pleased with first light performance.

[Roy Foreman]

On 20/05/2022 at 22:53, BRADLEY 1953 said:

Lovely crisp images Roy, you must be pleased with first light performance.

Apologies for delay in response - I did post one but somehow it seems to have got lost !

Thanks for your comments, and yes I am very pleased with these first light images, especially as the seeing wasn't particularly brilliant.

The comparison with the 180 Mak image (last one) is interesting.  It seems the Mak picks up a little more detail, but the 150 ED has better contrast, which is what I would expect, although differences in seeing between taking each image could have an effect on the final results.

[CraigT82]

Nice scope and nice shots too, thanks for sharing. 

I put the images side by side to make a better comparison (top is frac, bottom is mak). The mak180 seems to be resolving a lot more fine details, more than I’d have expected from its 30mm advantage. Did you also use a red filter with the Mak too? 
 

How did the two scopes compare visually? I’d imagined them to be pretty close and then only if the mak is thermally managed.

Edited May 25, 2022 by CraigT82

[Alan White]

1 hour ago, Roy Foreman said:

Apologies for delay in response - I did post one but somehow it seems to have got lost !

Thanks for your comments, and yes I am very pleased with these first light images, especially as the seeing wasn't particularly brilliant.

The comparison with the 180 Mak image (last one) is interesting.  It seems the Mak picks up a little more detail, but the 150 ED has better contrast, which is what I would expect, although differences in seeing between taking each image could have an effect on the final results.

I was thinking the seeing was proabably differening between each scope and that could be the only difference.
 

[Roy Foreman]

Those side by side images really do show that the Mak is pulling in more detail.  However, it may have had an unfair advantage.  Knowing it needs a good cool down time, I set it on the mount a couple of hours before imaging, so it was the first scope to be used.  I started imaging around sunset which, at my location is when the seeing is usually at it's best.  By the time it was the turn of the refractor it was starting to get dark and the seeing had deteriorated a bit.  A red filter was used on both telescopes to counteract the blueness of the sky.  In addition, the Mak has electric focussing, which the frac does no yet have.

You would expect the frac to have a clear advantage with its 150mm clear unobstructed aperture and no mirrors, in spite of the Mak's 30mm (or 20mm as some say) additional aperture.  I now need to repeat the process to substantiate the results.  Nonetheless, a very encouraging first light.

Visually there didn't seem to be much in it, although the refractor's higher contrast gave the appearance of sharper views.

Thank you for taking the time to  composite the images, much appreciated.

[CraigT82]

That probably explains it then, I’ve often found that the seeing just as the sun is setting can be very good but then deteriorates quickly after sunset. I’d love to see what the big frac can do under good seeing, that scope is on my ‘must own someday’ list.

Cheers 

[Roy Foreman]

8 hours ago, CraigT82 said:

That probably explains it then, I’ve often found that the seeing just as the sun is setting can be very good but then deteriorates quickly after sunset. I’d love to see what the big frac can do under good seeing, that scope is on my ‘must own someday’ list.

Cheers 

I'll take and post some images when sky conditions permit.  I'm keen to see how it does on deep sky too, but that will have to wait for darker nights !

For what it's worth, the scope is lighter and more manageable than it looks, but the metal case it comes in is huge and weighs twice as much as the scope does !  Had to give the delivery man a helping hand to get the box up the 38 steps leading to my front door !!!

[nightfisher]

very nice, great images