Galaxies near the Zenith

26 April 2020, 22:00 – 00:30

Conditions: Chilly, very light breeze. Patches of high cirrus and vapour trails lingering across parts of the sky (fortunately not the part I was looking at). Very heavy condensation by the end of the session.

Seeing: Good / average
Transparency: Very good (condensation aside)

Having imaged M101 and its companion galaxies the previous night (see below), I was keen to see how much of this view I could replicate visually in the XT10, especially with M101 nearly overhead after nightfall. I used Sky Atlas 2000 to get my bearings and left the PSA indoors for once (and with hindsight it was just as well I did, because the pages would have been a soggy mess by the end of the session).

The eyepiece of choice for such a large, low surface brightness galaxy was of course the Ethos 13mm (92x).

M101, Pinwheel Galaxy, Ursa Major
This was, without doubt, the best view I’ve ever had of this often frustrating galaxy. With averted vision the spiral pattern was vaguely discernible for the first time, even if it did look a bit like an untidy old spring (and it still didn’t come close to the best views of M51). The eastern spiral arm was particularly loose, though it’s easy to confuse this with the nearby curving line of field stars, which gave the galaxy the appearance of a ragged number 6.

I didn’t have to nudge the scope too far to find the first companion galaxy:

NGC 5474, galaxy, Ursa Major
Visible to the south-southeast of M101 as an amorphous round glow. Gradually brighter towards the core with averted vision, but the core itself appears offset from the centre in the direction of M101.

NGC 5473, galaxy, Ursa Major
Very small, round, condensed galaxy near a bright star, north and a little east of M101. Easy to overlook because of its diminutive size. Bright core.

NGC 5485, galaxy, Ursa Major
Same distance again, roughly east of NGC 5473, but larger and fainter. Brighter towards centre with averted vision. Apparently a background galaxy rather than a physical companion of M101.

NGC 5422, galaxy, Ursa Major
North-northwest of M101, opposite side to NGC 5474. Small needle-streak of light pointing back towards M101. Forms a near-rectangular trapezoid with three field stars of equal brightness. Bright core with averted vision. Most likely another background galaxy.

I’d spent over an hour studying this small patch of sky (and I was impressed by what I’d seen) so I took a break from the eyepiece to check the transparency. Looking directly towards the zenith, the faintest star I could see was 82 Ursae Majoris, which has a listed magnitude of 5.46. This is about as good as it gets for my observing location. Unfortunately the condensation was on its way to becoming about as bad as it gets for my location: the steel tube of the telescope already had a light coating of moisture, and beads of dew were forming on the Sky Atlas.

As I was pushing the scope towards the next target, I saw a bright meteor at 23:25: a late Lyrid burning a trail towards Polaris.

NGC 4236 (Caldwell 3), galaxy, Draco
Emboldened by my success with M101, I thought I’d have another attempt at NGC 4236. Tonight it was visible as a very large (even for the Ethos fov) and long streak of light, of extremely low surface brightness. It was only through tube-tapping that I was able to spot it; had I not known it was there I wouldn’t have seen it at all. After staring at it (and around it) for several minutes I could start to detect a very vague brightening towards the centre, but nothing more than that. Visually, the only thing interesting about this galaxy is its size, and - unless it it plays host to a supernova - I doubt I'll revisit it.

NGC 4128, galaxy, Draco
Small, faint streak of light near a gathering (not a cluster) of bright stars. Bright core with averted vision. Not far from NGC 4236.

NGC 5982 & 5985, galaxies, Draco
As per previous observation: short bright streak (5982) and a round faint glow (5985). No sign of 5981.

NGC 5963 & 5965, galaxies, Draco
Faint round galaxy (NGC 5963) with a field star just southeast of the core. The other galaxy (NGC 5965, in the same fov) is fainter, larger and more elongated. Apparently their proximity is just a chance alignment: NGC 5963 is 40 million light years away; NGC 5965 is 150 million light years away.

NGC 5907, “Splinter Galaxy”, Draco
Large, razor-thin, edge-on galaxy. Not bright (compared to say, 4565) but still an exquisite sight. Brighter towards the centre with averted vision. The eastern side of the galaxy seemed to have a sharper cut-off when I looked at it, even though photos show the dust lane to be on the western side (perhaps in this case it has a feathering effect).

NGC 5879, galaxy, Draco
Faint oval glow south of bright star. Bright core with averted vision.

NGC 5866 (M102), galaxy, Draco
As per previous observation of this object: small and relatively bright spindle galaxy.

With the eye-lens of the Ethos rapidly succumbing to the condensation, I swapped it out for the DeLite, but quick looks at M92 and M13 in Hercules confirmed I was fighting a losing battle, so I called it a night. The scope was dripping wet, the Sky Atlas was heavily beaded with dew and my notebook was almost too damp to write in. With hindsight, I’m glad I didn’t try any imaging tonight. That would not have ended well.

With a new lunar cycle already underway and bad weather forecast for most of the following week, that might be the end of my galaxy season for this year. If so, it’s been better than I could have hoped for, with lots of new observations added to the log, including several (NGC 4889, M83 etc.) I didn’t think were possible from my location. And I’ve probably still only seen a fraction of the spring galaxies that are available to my scope.

Nature note:
Two bats flying over the garden at dusk!