M13 & M92 – shake-down test for Esprit 120ED

[AKB]

I've been struggling for the last couple of years in my early attempts at imaging with things like an 8" F4 Netwtonian and a C9.25" Hyperstar giving me some inadequately good star shapes.  I love those tools for EEVA quick-looks, but they really don't stand up to close inspection.

I knew this already, because I had read the sage advice from SOMEONE WHO KNOWS BETTER...

On 10/09/2017 at 21:40, ollypenrice said:

A gentleman uses a refractor. A professional uses a reflector.

...but, somehow, although I think of myself as a gentleman, I had to learn the hard (and expensive) way.

However, I resolved that 2019 would be the year of the refractor (my first, aside from a guidescope!) and happily, in May, an Esprit 120ED came up here on the For Sale board.  I grabbed it eagerly from the previous owner's arms (in a car park near Rugby – thanks for meeting halfway) but it's taken this long to really get set up.  This was in part due to me having sent my mount back to Italy for an upgrade (it's now a dual-mount M-Uno.)

 

Having spent the last couple of nights getting everything set up, drift-aligned, etc... I've managed to grab a couple of short images to test it all out for real.  Seeing that stars had always been my nemesis, I've gone for a couple of globulars.  Not yet delved into detail with CCD Inspector, but at first glance it looks OK, although maybe a bit of sensor tilt?  Anyway, a vast improvement on what went before, IMHO.

Details:

• SkyWatcher Esprit 120ED on M-Uno mount
• ASI294MC OSC with Skywatcher flattener and IDAS-P2 filter
• Guided and dithered
• M13 - 15 x 60s
• M92 - 10 x 60s
• Bias only, no darks or flats
• Simply processed in PixInsight, just colour calibration and stretching

M13:

 

M92:

 

I know that this isn't real imaging yet, partly because the total exposures are shorter than many people's individual subs, but it is a start.

Comments and criticism, plus suggestions for improvement welcomed.

Tony

 

Edited September 21, 2019 by AKB
typo

[Knighty2112]

 Nice shots. Well done! Fail to see why this is not ‘real imaging’ though? Just as pleasing to look at and enjoy as something like the Veil etc. 

[teoria_del_big_bang]

If they are what you infer as test shots then wow there is some good stuff to come 🙂 

Like you say you have learned the hard way (expensive is probably normal so I wouldn't lose sleep over that) but it looks like in the end it will be worth it.

That looks a great imaging rig and the images above prove it. 

17 minutes ago, Knighty2112 said:

Nice shots. Well done! Fail to see why this is not ‘real imaging’ though? Just as pleasing to look at and enjoy as something like the Veil etc. 

And I agree 

Steve

[celestron8g8]

Very nice captures of two fine GC’s ! Those have been my favorite DSO. Thanks for sharing ! 

[Laurin Dave]

Very nice, I took his advice too and now have a 100 and a 150.   There's a bit of amp glow on the top right, classic 294, and easily removed by using matched darks to calibrate. What have you got on the other side?

Dave

[AKB]

5 minutes ago, Laurin Dave said:

I took his advice too and now have a 100 and a 150.

Nice!  A 150 is out ,based on my criterion of "never buy a telescope you cannot lift."

6 minutes ago, Laurin Dave said:

There's a bit of amp glow on the top right, classic 294, and easily removed by using matched darks to calibrate.

Yes indeed, classic.  It does so much look like light leakage, though, but I now know better.   Darks will have to wait a bit, but I've just done some flats this afternoon (sensor temperature 37.5C !)

8 minutes ago, Laurin Dave said:

What have you got on the other side?

Spent a while looking at the other side of the image from the amp glow, but now suppose that you mean the mount ?!

Actually, just now, it's the 60mm guide scope (not the best place for it) with a QHY8L just to look at the FOV.   A 100 would be nice, but maybe just too large for this setup, so I'm planning a 80, but trying to work out which camera will be best.  I'd like OSC on one side and Mono on the other (the 120) with the same FOV but that means a huge sensor if I'm to stick with my 294C.

[tomato]

 Very nice,  this is real imaging in my book.

I agree there may be a tiny bit of sensor tilt as the stars in the lower LH corner look slightly elongated compared to the other corners, but your colours are great, something I struggle with on CMOS mono cameras and filters.