Friday, April 24, 2020

imaged with MRO (Stillwater Lake)

Popped into Facebook for a moment to check for vindaloo messages and saw "Mini-Ralph should be operating tonight!" All right! The wide-field, big Finest NGCs are all a little out-of-season. And then it hit me. Bright galaxy groups. I aimed at GSC 00861-1046 to collect photons for the Leo Triplet.

the Leo Triplet galaxy group in luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, GIMP. Slight curve in GIMP. North is up; east is left. There are slight registration problems in this image. Looks like the polar alignment is off a bit.

Messier 65 (M65) is south-west of centre, a compact edge-on spiral galaxy with an intense bright core. Finally Messier 66 (M66) is south of centre, a large barred spiral galaxy. I first viewed the Charles Messier objects on 8 May 2011.

NGC 3628 is to the north. Large but faint. Dark dust lane in the foreground. It was on 11 June 2011 that I first visually spotted the fainter edge-on galaxy. I imaged this galaxy, the Hamburger, on its own recently. Also a target on the RASC Finest list.

Together this group is known as Arp 317. It's fantastic seeing them all together in one field. That view is approximately 1¼ degrees square.

This is my first run with the Mini-Ralph Observatory (MRO) in Nova Scotia, currently located at the Abbey Ridge Observatory near Stillwater Lake.

The optical tube assembly is a Tele Vue Genesis 100mm. It's on a Celeston AVX German equatorial mount—atop a custom made wooden platform. The (CMOS) camera is the ZWO ASI 1600 MM monochrome mated with a EFW filter wheel with 8 positions. The whole rig is manually set up and polar aligned on clear nights.


Now for some deep stuff...

Tiny galaxy IC 2708 is visible to the south-west, near the bottom-right corner of the image.

The little sliver of IC 2763 shows to the south-east.

Left of centre, very close to a star, is the edge on distant galaxy IC 2745.

Quasar WEE 48 is north-west of NGC 3628 while WEE 55 is to the north-east. 48, aka Q1117+0139, is magnitude 19.9, has a redshift (z) of 2.06, and a light time of 8.9 Gyr. 55 or Q1118+0139 is mag 20.5, z 1.94, and light time 8.7 Gyr. WEE 55 is a maybe... star J112104.1+133822 at mag 16.8 is nearby... And WEE 48 is near J111944.6+133818 at mag 15.5. On second thought, I don't think I nabbed quasars. Looks like the mag limit in this image is around 16½.


Millie liked the image.


MRO's minion reported "I still have some work to do on image calibrations for CMOS cameras - a bit different than CCD but not a big issue so far."


In an effort to learn the limits of this new rig, I did a deep dive. Looks like I can tag stars around magnitude 17. And there's a very faint pair (mag 16) of equal stars with J111920.2+132330 between 3628 and 65, east of the bright star, with a black line between. SkyTools says the separation is 9.0 seconds of arc. So it looks like MRO will give splits of equal stars around 8".


Wikipedia link: Leo Triplet.

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